#
#  Copyright 2025 The InfiniFlow Authors. All Rights Reserved.
#
#  Licensed under the Apache License, Version 2.0 (the "License");
#  you may not use this file except in compliance with the License.
#  You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
#  Unless required by applicable law or agreed to in writing, software
#  distributed under the License is distributed on an "AS IS" BASIS,
#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#  See the License for the specific language governing permissions and
#  limitations under the License.
#
import asyncio
import json
import logging
import os
import random
import re
import time
from abc import ABC
from copy import deepcopy
from urllib.parse import urljoin

import json_repair
from json.decoder import JSONDecodeError
import litellm
import openai
from openai import AsyncOpenAI, OpenAI
from enum import StrEnum

from common.misc_utils import thread_pool_exec
from common.llm_request_context import current_llm_user
from common.token_utils import num_tokens_from_string, total_token_count_from_response, usage_from_response
from rag.llm import FACTORY_DEFAULT_BASE_URL, LITELLM_PROVIDER_PREFIX, SupportedLiteLLMProvider
from rag.llm.key_utils import _normalize_replicate_key
from rag.llm.tool_decorator import FunctionToolSession, is_tool
from rag.nlp import is_chinese, is_english
from rag.utils.url_utils import ensure_v1


class LLMErrorCode(StrEnum):
    ERROR_RATE_LIMIT = "RATE_LIMIT_EXCEEDED"
    ERROR_AUTHENTICATION = "AUTH_ERROR"
    ERROR_INVALID_REQUEST = "INVALID_REQUEST"
    ERROR_SERVER = "SERVER_ERROR"
    ERROR_TIMEOUT = "TIMEOUT"
    ERROR_CONNECTION = "CONNECTION_ERROR"
    ERROR_MODEL = "MODEL_ERROR"
    ERROR_MAX_ROUNDS = "ERROR_MAX_ROUNDS"
    ERROR_CONTENT_FILTER = "CONTENT_FILTERED"
    ERROR_QUOTA = "QUOTA_EXCEEDED"
    ERROR_MAX_RETRIES = "MAX_RETRIES_EXCEEDED"
    ERROR_GENERIC = "GENERIC_ERROR"


class ReActMode(StrEnum):
    FUNCTION_CALL = "function_call"
    REACT = "react"


ERROR_PREFIX = "**ERROR**"
LENGTH_NOTIFICATION_CN = "······\n由于大模型的上下文窗口大小限制，回答已经被大模型截断。"
LENGTH_NOTIFICATION_EN = "...\nThe answer is truncated by your chosen LLM due to its limitation on context length."

# Generation parameters that are safe to forward to the underlying completion
# call. `gen_conf` originates from a chat assistant's `llm_setting`, which can
# also carry RAGFlow-internal metadata (e.g. `model_type`). Anything outside
# this set is dropped so providers don't reject the request with errors like
# "Extra inputs are not permitted" / "Unknown parameter: 'model_type'" (#15427).
ALLOWED_GEN_CONF_KEYS = frozenset(
    {
        "temperature",
        "max_completion_tokens",
        "top_p",
        "stream",
        "stream_options",
        "stop",
        "n",
        "presence_penalty",
        "frequency_penalty",
        "functions",
        "function_call",
        "logit_bias",
        "user",
        "response_format",
        "seed",
        "tools",
        "tool_choice",
        "logprobs",
        "top_logprobs",
        "extra_headers",
    }
)

# LiteLLM additionally understands reasoning-control parameters that the
# model-family policies may inject into `gen_conf` (e.g. `thinking` for
# Anthropic / Kimi reasoning models, `enable_thinking` for Qwen models,
# `reasoning_effort` for OpenAI o-series).
LITELLM_ALLOWED_GEN_CONF_KEYS = ALLOWED_GEN_CONF_KEYS | frozenset(
    {
        "thinking",
        "enable_thinking",
        "reasoning_effort",
        "extra_body",
    }
)


def _apply_model_family_policies(
    model_name: str,
    *,
    backend: str,
    provider: SupportedLiteLLMProvider | str | None = None,
    gen_conf: dict | None = None,
    request_kwargs: dict | None = None,
):
    model_name_lower = (model_name or "").lower()
    sanitized_gen_conf = deepcopy(gen_conf) if gen_conf else {}
    sanitized_kwargs = dict(request_kwargs) if request_kwargs else {}

    def _thinking_type():
        val = sanitized_gen_conf.get("thinking")
        if isinstance(val, dict):
            val = val.get("type")

        enable_thinking = sanitized_gen_conf.get("enable_thinking")

        if isinstance(val, str) and val in {"enabled", "disabled"}:
            return val
        if isinstance(enable_thinking, bool):
            return "enabled" if enable_thinking else "disabled"
        return None

    def _pop_thinking_controls():
        sanitized_gen_conf.pop("thinking", None)
        sanitized_gen_conf.pop("enable_thinking", None)

    def _merge_extra_body(target: dict, extra: dict) -> None:
        body = target.get("extra_body")
        if not isinstance(body, dict):
            body = {}
        body.update(extra)
        target["extra_body"] = body

    thinking_type = _thinking_type()

    # Qwen3 keeps RAGFlow's system default of disabling thinking unless explicitly overridden.
    if "qwen3" in model_name_lower:
        _pop_thinking_controls()
        enable_thinking = thinking_type == "enabled" if thinking_type else False
        if backend == "litellm" and provider in {
            SupportedLiteLLMProvider.Tongyi_Qianwen,
            SupportedLiteLLMProvider.Dashscope,
        }:
            sanitized_gen_conf["enable_thinking"] = enable_thinking
        else:
            _merge_extra_body(sanitized_kwargs, {"enable_thinking": enable_thinking})

    if backend == "base":
        return sanitized_gen_conf, sanitized_kwargs

    if backend == "litellm":
        if provider in {SupportedLiteLLMProvider.OpenAI, SupportedLiteLLMProvider.Azure_OpenAI} and "gpt-5" in model_name_lower:
            for key in ("temperature", "top_p", "logprobs", "top_logprobs"):
                sanitized_gen_conf.pop(key, None)
                sanitized_kwargs.pop(key, None)
        elif provider == SupportedLiteLLMProvider.Anthropic and model_name_lower in {"claude-opus-4-7", "claude-opus-4-8"}:
            for key in ("temperature", "top_p", "top_k"):
                sanitized_gen_conf.pop(key, None)
                sanitized_kwargs.pop(key, None)

        if provider == SupportedLiteLLMProvider.HunYuan:
            for key in ("presence_penalty", "frequency_penalty"):
                sanitized_gen_conf.pop(key, None)
        elif provider == SupportedLiteLLMProvider.Moonshot:
            if thinking_type:
                _pop_thinking_controls()
                sanitized_gen_conf["thinking"] = {"type": thinking_type}

            if thinking_type or "kimi-k2.5" in model_name_lower or "kimi-k2.6" in model_name_lower:
                sanitized_gen_conf.pop("temperature", None)
                sanitized_gen_conf["top_p"] = 0.95
                sanitized_gen_conf["n"] = 1
                sanitized_gen_conf["presence_penalty"] = 0.0
                sanitized_gen_conf["frequency_penalty"] = 0.0
        elif provider == SupportedLiteLLMProvider.ZHIPU_AI and "glm" in model_name_lower and thinking_type:
            _pop_thinking_controls()
            sanitized_gen_conf["thinking"] = {"type": thinking_type}

        return sanitized_gen_conf, sanitized_kwargs

    return sanitized_gen_conf, sanitized_kwargs


def _move_litellm_provider_body_fields(provider: SupportedLiteLLMProvider | str | None, completion_args: dict) -> dict:
    provider_body_fields = {
        SupportedLiteLLMProvider.Tongyi_Qianwen: {"enable_thinking"},
        SupportedLiteLLMProvider.Dashscope: {"enable_thinking"},
        SupportedLiteLLMProvider.Moonshot: {"thinking"},
        SupportedLiteLLMProvider.ZHIPU_AI: {"thinking"},
    }.get(provider, set())

    body = completion_args.get("extra_body")
    if not isinstance(body, dict):
        body = {}
    moved = False
    for key in provider_body_fields:
        if key in completion_args:
            body[key] = completion_args.pop(key)
            moved = True
    if moved or body:
        completion_args["extra_body"] = body
    return completion_args


class Base(ABC):
    def __init__(self, key, model_name, base_url, **kwargs):
        timeout = int(os.environ.get("LLM_TIMEOUT_SECONDS", 600))
        self.base_url = ensure_v1(base_url)
        self.client = OpenAI(api_key=key, base_url=self.base_url, timeout=timeout)
        self.async_client = AsyncOpenAI(api_key=key, base_url=self.base_url, timeout=timeout)
        self.model_name = model_name
        # Configure retry parameters
        self.max_retries = kwargs.get("max_retries", int(os.environ.get("LLM_MAX_RETRIES", 5)))
        self.base_delay = kwargs.get("retry_interval", float(os.environ.get("LLM_BASE_DELAY", 2.0)))
        self.max_rounds = kwargs.get("max_rounds", 5)
        self.is_tools = False
        self.tools = []
        self.toolcall_sessions = {}
        # Token usage split (prompt/completion/total) of the most recent chat call.
        # Consumed by LLMBundle for accurate Langfuse reporting and run aggregation.
        self.last_usage = {"prompt_tokens": 0, "completion_tokens": 0, "total_tokens": 0}

    def _get_delay(self):
        return self.base_delay * random.uniform(10, 150)

    def _classify_error(self, error):
        error_str = str(error).lower()

        keywords_mapping = [
            (["quota", "capacity", "credit", "billing", "balance", "欠费"], LLMErrorCode.ERROR_QUOTA),
            (["rate limit", "429", "tpm limit", "too many requests", "requests per minute"], LLMErrorCode.ERROR_RATE_LIMIT),
            (["auth", "key", "apikey", "401", "forbidden", "permission"], LLMErrorCode.ERROR_AUTHENTICATION),
            (["invalid", "bad request", "400", "format", "malformed", "parameter"], LLMErrorCode.ERROR_INVALID_REQUEST),
            (["server", "503", "502", "504", "500", "unavailable"], LLMErrorCode.ERROR_SERVER),
            (["timeout", "timed out"], LLMErrorCode.ERROR_TIMEOUT),
            (["connect", "network", "unreachable", "dns"], LLMErrorCode.ERROR_CONNECTION),
            (["filter", "content", "policy", "blocked", "safety", "inappropriate"], LLMErrorCode.ERROR_CONTENT_FILTER),
            (["model", "not found", "does not exist", "not available"], LLMErrorCode.ERROR_MODEL),
            (["max rounds"], LLMErrorCode.ERROR_MODEL),
        ]
        for words, code in keywords_mapping:
            if re.search("({})".format("|".join(words)), error_str):
                return code

        return LLMErrorCode.ERROR_GENERIC

    def _clean_conf(self, gen_conf):
        if "max_tokens" in gen_conf:
            del gen_conf["max_tokens"]

        gen_conf = {k: v for k, v in gen_conf.items() if k in ALLOWED_GEN_CONF_KEYS}
        return gen_conf

    async def _async_chat_streamly(self, history, gen_conf, **kwargs):
        logging.info("[HISTORY STREAMLY]" + json.dumps(history, ensure_ascii=False, indent=4))
        reasoning_start = False

        gen_conf, extra_request_kwargs = _apply_model_family_policies(
            self.model_name,
            backend="base",
            gen_conf=gen_conf,
            request_kwargs={},
        )
        request_kwargs = {"model": self.model_name, "messages": history, "stream": True, **gen_conf}
        stop = kwargs.get("stop")
        if stop:
            request_kwargs["stop"] = stop
        request_kwargs.update(extra_request_kwargs)

        response = await self.async_client.chat.completions.create(**request_kwargs)
        async for resp in response:
            if not resp.choices:
                continue
            if not resp.choices[0].delta.content:
                resp.choices[0].delta.content = ""
            _reasoning = getattr(resp.choices[0].delta, "reasoning_content", None) or getattr(resp.choices[0].delta, "reasoning", None)
            if kwargs.get("with_reasoning", True) and _reasoning:
                ans = ""
                if not reasoning_start:
                    reasoning_start = True
                    ans = "<think>"
                ans += _reasoning + "</think>"
            else:
                reasoning_start = False
                ans = resp.choices[0].delta.content
            tol = total_token_count_from_response(resp)
            if not tol:
                tol = num_tokens_from_string(resp.choices[0].delta.content)

            finish_reason = resp.choices[0].finish_reason if hasattr(resp.choices[0], "finish_reason") else ""
            if finish_reason == "length":
                if is_chinese(ans):
                    ans += LENGTH_NOTIFICATION_CN
                else:
                    ans += LENGTH_NOTIFICATION_EN
            yield ans, tol

    async def async_chat_streamly(self, system, history, gen_conf: dict | None = None, **kwargs):
        gen_conf = dict(gen_conf or {})
        if system and history and history[0].get("role") != "system":
            history.insert(0, {"role": "system", "content": system})
        gen_conf = self._clean_conf(gen_conf)
        ans = ""
        total_tokens = 0
        # Reset so a stale split from a previous call can't leak into this one.
        self.last_usage = {"prompt_tokens": 0, "completion_tokens": 0, "total_tokens": 0}

        for attempt in range(self.max_retries + 1):
            try:
                async for delta_ans, tol in self._async_chat_streamly(history, gen_conf, **kwargs):
                    ans = delta_ans
                    total_tokens += tol
                    yield ans

                yield total_tokens
                return
            except Exception as e:
                e = await self._exceptions_async(e, attempt)
                if e:
                    yield e
                    yield total_tokens
                    return

    def _length_stop(self, ans):
        if is_chinese([ans]):
            return ans + LENGTH_NOTIFICATION_CN
        return ans + LENGTH_NOTIFICATION_EN

    @property
    def _retryable_errors(self) -> set[str]:
        return {
            LLMErrorCode.ERROR_RATE_LIMIT,
            LLMErrorCode.ERROR_SERVER,
        }

    def _should_retry(self, error_code: str) -> bool:
        return error_code in self._retryable_errors

    def _exceptions(self, e, attempt) -> str | None:
        logging.exception("OpenAI chat_with_tools")
        # Classify the error
        error_code = self._classify_error(e)
        if attempt == self.max_retries:
            error_code = LLMErrorCode.ERROR_MAX_RETRIES

        if self._should_retry(error_code):
            delay = self._get_delay()
            logging.warning(f"Error: {error_code}. Retrying in {delay:.2f} seconds... (Attempt {attempt + 1}/{self.max_retries})")
            time.sleep(delay)
            return None

        msg = f"{ERROR_PREFIX}: {error_code} - {str(e)}"
        logging.error(f"sync base giving up: {msg}")
        return msg

    async def _exceptions_async(self, e, attempt):
        logging.exception("OpenAI async completion")
        error_code = self._classify_error(e)
        if attempt == self.max_retries:
            error_code = LLMErrorCode.ERROR_MAX_RETRIES

        if self._should_retry(error_code):
            delay = self._get_delay()
            logging.warning(f"Error: {error_code}. Retrying in {delay:.2f} seconds... (Attempt {attempt + 1}/{self.max_retries})")
            await asyncio.sleep(delay)
            return None

        msg = f"{ERROR_PREFIX}: {error_code} - {str(e)}"
        logging.error(f"async base giving up: {msg}")
        return msg

    def _verbose_tool_use(self, name, args, res):
        return "<tool_call>" + json.dumps({"name": name, "args": args, "result": res}, ensure_ascii=False, indent=2) + "</tool_call>"

    def _append_history(self, hist, tool_call, tool_res):
        hist.append(
            {
                "role": "assistant",
                "tool_calls": [
                    {
                        "index": getattr(tool_call, "index", None),
                        "id": tool_call.id,
                        "function": {
                            "name": tool_call.function.name,
                            "arguments": tool_call.function.arguments,
                        },
                        "type": "function",
                    },
                ],
            }
        )
        try:
            if isinstance(tool_res, dict):
                tool_res = json.dumps(tool_res, ensure_ascii=False)
        finally:
            hist.append({"role": "tool", "tool_call_id": tool_call.id, "content": str(tool_res)})
        return hist

    def _append_history_batch(self, hist, results):
        """
        Append a batch of tool calls to history following the OpenAI protocol:
        one assistant message containing all tool_calls, followed by one tool message per call.
        results: list of (tool_call, name, args, result, error)
        """
        hist.append(
            {
                "role": "assistant",
                "tool_calls": [
                    {
                        "index": getattr(tc, "index", None),
                        "id": tc.id,
                        "function": {"name": tc.function.name, "arguments": tc.function.arguments},
                        "type": "function",
                    }
                    for tc, _, _, _, _ in results
                ],
            }
        )
        for tc, _, _, result, err in results:
            if err:
                content = str(err)
            elif isinstance(result, dict):
                content = json.dumps(result, ensure_ascii=False)
            else:
                content = str(result)
            hist.append({"role": "tool", "tool_call_id": tc.id, "content": content})
        return hist

    def bind_tools(self, toolcall_session=None, tools=None):
        """Register tools the LLM can call.

        Two calling styles are accepted:

        * Legacy: ``bind_tools(toolcall_session, tools_schemas)`` where
          ``toolcall_session`` implements :class:`ToolCallSession` and
          ``tools_schemas`` is a pre-built list of OpenAI function-schema
          dicts (used by the agent/dialog layer).
        * Decorator: ``bind_tools(tools=[fn1, fn2, ...])`` where each ``fn``
          is decorated with :func:`rag.llm.tool_decorator.tool`. The session
          and schemas are derived from the callables automatically.
        """
        if tools is None and isinstance(toolcall_session, list):
            tools, toolcall_session = toolcall_session, None

        if tools and toolcall_session is None and all(is_tool(t) for t in tools):
            session = FunctionToolSession(tools)
            self.is_tools = True
            self.toolcall_session = session
            self.tools = session.schemas
            return

        if not (toolcall_session and tools):
            return
        self.is_tools = True
        self.toolcall_session = toolcall_session
        self.tools = tools

    async def async_chat_with_tools(self, system: str, history: list, gen_conf: dict | None = None):
        gen_conf = dict(gen_conf or {})
        gen_conf = self._clean_conf(gen_conf)
        gen_conf, extra_request_kwargs = _apply_model_family_policies(
            self.model_name,
            backend="base",
            gen_conf=gen_conf,
            request_kwargs={},
        )
        if system and history and history[0].get("role") != "system":
            history.insert(0, {"role": "system", "content": system})

        ans = ""
        tk_count = 0
        # Aggregate prompt/completion/total across all tool-calling rounds.
        agg_usage = {"prompt_tokens": 0, "completion_tokens": 0, "total_tokens": 0}

        def _add_round_usage(resp):
            nonlocal tk_count
            u = usage_from_response(resp)
            agg_usage["prompt_tokens"] += u["prompt_tokens"]
            agg_usage["completion_tokens"] += u["completion_tokens"]
            agg_usage["total_tokens"] += u["total_tokens"] or total_token_count_from_response(resp)
            tk_count = agg_usage["total_tokens"]
            self.last_usage = dict(agg_usage)

        hist = deepcopy(history)
        for attempt in range(self.max_retries + 1):
            history = deepcopy(hist)
            try:
                for _ in range(self.max_rounds + 1):
                    logging.info(f"{self.tools=}")
                    response = await self.async_client.chat.completions.create(model=self.model_name, messages=history, tools=self.tools, tool_choice="auto", **gen_conf, **extra_request_kwargs)
                    _add_round_usage(response)
                    if not response.choices or not response.choices[0].message:
                        raise Exception(f"500 response structure error. Response: {response}")

                    if not hasattr(response.choices[0].message, "tool_calls") or not response.choices[0].message.tool_calls:
                        _reasoning = getattr(response.choices[0].message, "reasoning_content", None) or getattr(response.choices[0].message, "reasoning", None)
                        if _reasoning:
                            ans += "<think>" + _reasoning + "</think>"

                        ans += response.choices[0].message.content
                        if response.choices[0].finish_reason == "length":
                            ans = self._length_stop(ans)

                        return ans, tk_count

                    async def _exec_tool(tc):
                        name = tc.function.name
                        try:
                            args = json_repair.loads(tc.function.arguments)
                            if not isinstance(args, dict):
                                raise TypeError(f"Tool arguments for {name} must be a JSON object, got {type(args).__name__}")
                            if hasattr(self.toolcall_session, "tool_call_async"):
                                result = await self.toolcall_session.tool_call_async(name, args)
                            else:
                                result = await thread_pool_exec(self.toolcall_session.tool_call, name, args)
                            return tc, name, args, result, None
                        except Exception as e:
                            logging.exception(f"Tool call failed: {tc}")
                            return tc, name, {}, None, e

                    logging.info(f"Response tool_calls={response.choices[0].message.tool_calls}")
                    results = await asyncio.gather(*[_exec_tool(tc) for tc in response.choices[0].message.tool_calls])
                    history = self._append_history_batch(history, results)
                    for tc, name, args, result, err in results:
                        ans += self._verbose_tool_use(name, args, err if err else result)

                logging.warning(f"Exceed max rounds: {self.max_rounds}")
                history.append({"role": "user", "content": f"Exceed max rounds: {self.max_rounds}"})
                response, token_count = await self._async_chat(history, gen_conf)
                ans += response
                # _async_chat set self.last_usage to its own call; fold it into the aggregate.
                _fb = getattr(self, "last_usage", None) or {}
                agg_usage["prompt_tokens"] += int(_fb.get("prompt_tokens", 0) or 0)
                agg_usage["completion_tokens"] += int(_fb.get("completion_tokens", 0) or 0)
                agg_usage["total_tokens"] += int(_fb.get("total_tokens", 0) or token_count)
                tk_count = agg_usage["total_tokens"]
                self.last_usage = dict(agg_usage)
                return ans, tk_count
            except Exception as e:
                e = await self._exceptions_async(e, attempt)
                if e:
                    return e, tk_count

        assert False, "Shouldn't be here."

    async def async_chat_streamly_with_tools(self, system: str, history: list, gen_conf: dict | None = None):
        gen_conf = dict(gen_conf or {})
        gen_conf = self._clean_conf(gen_conf)
        gen_conf, extra_request_kwargs = _apply_model_family_policies(
            self.model_name,
            backend="base",
            gen_conf=gen_conf,
            request_kwargs={},
        )
        tools = self.tools
        if system and history and history[0].get("role") != "system":
            history.insert(0, {"role": "system", "content": system})

        total_tokens = 0
        # Aggregate prompt/completion/total across all tool-calling rounds. The split is
        # captured opportunistically when the provider reports usage on a chunk; otherwise
        # only the (estimated) total accumulates.
        agg_usage = {"prompt_tokens": 0, "completion_tokens": 0, "total_tokens": 0}
        hist = deepcopy(history)

        def _commit_round(round_usage, round_estimate):
            nonlocal total_tokens
            if round_usage and round_usage["total_tokens"]:
                agg_usage["prompt_tokens"] += round_usage["prompt_tokens"]
                agg_usage["completion_tokens"] += round_usage["completion_tokens"]
                agg_usage["total_tokens"] += round_usage["total_tokens"]
            else:
                agg_usage["total_tokens"] += round_estimate
            total_tokens = agg_usage["total_tokens"]
            self.last_usage = dict(agg_usage)

        for attempt in range(self.max_retries + 1):
            history = deepcopy(hist)
            try:
                for _round in range(self.max_rounds + 1):
                    reasoning_start = False
                    logging.info(f"[ToolLoop] round={_round} model={self.model_name} tools={[t['function']['name'] for t in tools]}")

                    response = await self.async_client.chat.completions.create(
                        model=self.model_name, messages=history, stream=True, tools=tools, tool_choice="auto", **gen_conf, **extra_request_kwargs
                    )

                    final_tool_calls = {}
                    answer = ""
                    round_estimate = 0
                    round_usage = None

                    async for resp in response:
                        _u = usage_from_response(resp)
                        if _u["total_tokens"]:
                            round_usage = _u

                        if not hasattr(resp, "choices") or not resp.choices:
                            continue

                        delta = resp.choices[0].delta

                        if hasattr(delta, "tool_calls") and delta.tool_calls:
                            for tool_call in delta.tool_calls:
                                index = tool_call.index
                                if index not in final_tool_calls:
                                    if not tool_call.function.arguments:
                                        tool_call.function.arguments = ""
                                    final_tool_calls[index] = tool_call
                                else:
                                    final_tool_calls[index].function.arguments += tool_call.function.arguments or ""
                            continue

                        if not hasattr(delta, "content") or delta.content is None:
                            delta.content = ""

                        _reasoning = getattr(delta, "reasoning_content", None) or getattr(delta, "reasoning", None)
                        if _reasoning:
                            ans = ""
                            if not reasoning_start:
                                reasoning_start = True
                                ans = "<think>"
                            ans += _reasoning + "</think>"
                            yield ans
                        else:
                            reasoning_start = False
                            answer += delta.content
                            yield delta.content

                        if not _u["total_tokens"]:
                            round_estimate += num_tokens_from_string(delta.content)

                        finish_reason = getattr(resp.choices[0], "finish_reason", "")
                        if finish_reason == "length":
                            yield self._length_stop("")

                    # Commit this round's tokens (each round is a separate provider
                    # request — accumulate, never overwrite).
                    _commit_round(round_usage, round_estimate)

                    if answer and not final_tool_calls:
                        logging.info(f"[ToolLoop] round={_round} completed with text response, exiting")
                        yield total_tokens
                        return

                    async def _exec_tool(tc):
                        name = tc.function.name
                        try:
                            args = json_repair.loads(tc.function.arguments)
                            if not isinstance(args, dict):
                                raise TypeError(f"Tool arguments for {name} must be a JSON object, got {type(args).__name__}")
                            if hasattr(self.toolcall_session, "tool_call_async"):
                                result = await self.toolcall_session.tool_call_async(name, args)
                            else:
                                result = await thread_pool_exec(self.toolcall_session.tool_call, name, args)
                            return tc, name, args, result, None
                        except Exception as e:
                            logging.exception(f"Tool call failed: {tc}")
                            return tc, name, {}, None, e

                    tcs = list(final_tool_calls.values())
                    logging.info(f"[ToolLoop] round={_round} executing {len(tcs)} tool(s): {[tc.function.name for tc in tcs]}")
                    for tc in tcs:
                        try:
                            args = json_repair.loads(tc.function.arguments)
                        except Exception:
                            args = {}
                        yield self._verbose_tool_use(tc.function.name, args, "Begin to call...")
                    results = await asyncio.gather(*[_exec_tool(tc) for tc in tcs])
                    history = self._append_history_batch(history, results)
                    for tc, name, args, result, err in results:
                        yield self._verbose_tool_use(name, args, err if err else result)

                logging.warning(f"Exceed max rounds: {self.max_rounds}")
                history.append({"role": "user", "content": f"Exceed max rounds: {self.max_rounds}"})

                response = await self.async_client.chat.completions.create(
                    model=self.model_name,
                    messages=history,
                    stream=True,
                    tools=tools,
                    tool_choice="auto",
                    **gen_conf,
                    **extra_request_kwargs,
                )

                fb_estimate = 0
                fb_usage = None
                async for resp in response:
                    _u = usage_from_response(resp)
                    if _u["total_tokens"]:
                        fb_usage = _u
                    if not hasattr(resp, "choices") or not resp.choices:
                        continue
                    delta = resp.choices[0].delta
                    if not hasattr(delta, "content") or delta.content is None:
                        continue
                    if not _u["total_tokens"]:
                        fb_estimate += num_tokens_from_string(delta.content)
                    yield delta.content

                _commit_round(fb_usage, fb_estimate)
                yield total_tokens
                return

            except Exception as e:
                e = await self._exceptions_async(e, attempt)
                if e:
                    logging.error(f"async_chat_streamly failed: {e}")
                    yield e
                    yield total_tokens
                    return

        assert False, "Shouldn't be here."

    async def _async_chat(self, history, gen_conf, **kwargs):
        logging.info("[HISTORY]" + json.dumps(history, ensure_ascii=False, indent=2))
        if self.model_name.lower().find("qwq") >= 0:
            logging.info(f"[INFO] {self.model_name} detected as reasoning model, using async_chat_streamly")

            final_ans = ""
            tol_token = 0
            async for delta, tol in self._async_chat_streamly(history, gen_conf, with_reasoning=False, **kwargs):
                if delta.startswith("<think>") or delta.endswith("</think>"):
                    continue
                final_ans += delta
                tol_token = tol

            if len(final_ans.strip()) == 0:
                final_ans = "**ERROR**: Empty response from reasoning model"

            return final_ans.strip(), tol_token

        gen_conf, kwargs = _apply_model_family_policies(
            self.model_name,
            backend="base",
            gen_conf=gen_conf,
            request_kwargs=kwargs,
        )

        response = await self.async_client.chat.completions.create(model=self.model_name, messages=history, **gen_conf, **kwargs)

        # Capture prompt/completion split for accurate Langfuse + run aggregation.
        self.last_usage = usage_from_response(response)
        if not response.choices or not response.choices[0].message or not response.choices[0].message.content:
            return "", 0
        ans = response.choices[0].message.content.strip()
        if response.choices[0].finish_reason == "length":
            ans = self._length_stop(ans)
        return ans, total_token_count_from_response(response)

    async def async_chat(self, system, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        if system and history and history[0].get("role") != "system":
            history.insert(0, {"role": "system", "content": system})
        gen_conf = self._clean_conf(gen_conf)

        for attempt in range(self.max_retries + 1):
            try:
                return await self._async_chat(history, gen_conf, **kwargs)
            except Exception as e:
                e = await self._exceptions_async(e, attempt)
                if e:
                    return e, 0
        assert False, "Shouldn't be here."


class XinferenceChat(Base):
    _FACTORY_NAME = "Xinference"

    def __init__(self, key=None, model_name="", base_url="", **kwargs):
        if not base_url:
            raise ValueError("Local llm url cannot be None")
        super().__init__(key, model_name, base_url, **kwargs)


class HuggingFaceChat(Base):
    _FACTORY_NAME = "HuggingFace"

    def __init__(self, key=None, model_name="", base_url="", **kwargs):
        if not base_url:
            raise ValueError("Local llm url cannot be None")
        super().__init__(key, model_name.split("___")[0], base_url, **kwargs)


class ModelScopeChat(Base):
    _FACTORY_NAME = "ModelScope"

    def __init__(self, key=None, model_name="", base_url="", **kwargs):
        if not base_url:
            raise ValueError("Local llm url cannot be None")
        super().__init__(key, model_name.split("___")[0], base_url, **kwargs)


class BaiChuanChat(Base):
    _FACTORY_NAME = "BaiChuan"

    def __init__(self, key, model_name="Baichuan3-Turbo", base_url="https://api.baichuan-ai.com/v1", **kwargs):
        if not base_url:
            base_url = "https://api.baichuan-ai.com/v1"
        super().__init__(key, model_name, base_url, **kwargs)

    @staticmethod
    def _format_params(params):
        return {
            "temperature": params.get("temperature", 0.3),
            "top_p": params.get("top_p", 0.85),
        }

    def _clean_conf(self, gen_conf):
        return {
            "temperature": gen_conf.get("temperature", 0.3),
            "top_p": gen_conf.get("top_p", 0.85),
        }

    def _chat(self, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        response = self.client.chat.completions.create(
            model=self.model_name,
            messages=history,
            extra_body={"tools": [{"type": "web_search", "web_search": {"enable": True, "search_mode": "performance_first"}}]},
            **gen_conf,
        )
        if not response.choices:
            raise ValueError("LLM returned empty response")  # pact: guard empty choices list
        ans = response.choices[0].message.content.strip()
        if response.choices[0].finish_reason == "length":
            if is_chinese([ans]):
                ans += LENGTH_NOTIFICATION_CN
            else:
                ans += LENGTH_NOTIFICATION_EN
        return ans, total_token_count_from_response(response)

    def chat_streamly(self, system, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        if system and history and history[0].get("role") != "system":
            history.insert(0, {"role": "system", "content": system})
        if "max_tokens" in gen_conf:
            del gen_conf["max_tokens"]
        ans = ""
        total_tokens = 0
        try:
            response = self.client.chat.completions.create(
                model=self.model_name,
                messages=history,
                extra_body={"tools": [{"type": "web_search", "web_search": {"enable": True, "search_mode": "performance_first"}}]},
                stream=True,
                **self._format_params(gen_conf),
            )
            for resp in response:
                if not resp.choices:
                    continue
                if not resp.choices[0].delta.content:
                    resp.choices[0].delta.content = ""
                ans = resp.choices[0].delta.content
                tol = total_token_count_from_response(resp)
                if not tol:
                    total_tokens += num_tokens_from_string(resp.choices[0].delta.content)
                else:
                    total_tokens = tol
                if resp.choices[0].finish_reason == "length":
                    if is_chinese([ans]):
                        ans += LENGTH_NOTIFICATION_CN
                    else:
                        ans += LENGTH_NOTIFICATION_EN
                yield ans

        except Exception as e:
            yield ans + "\n**ERROR**: " + str(e)

        yield total_tokens


class LocalAIChat(Base):
    _FACTORY_NAME = "LocalAI"

    def __init__(self, key, model_name, base_url=None, **kwargs):
        super().__init__(key, model_name, base_url=base_url, **kwargs)

        if not base_url:
            raise ValueError("Local llm url cannot be None")
        self.client = OpenAI(api_key="empty", base_url=self.base_url)
        self.model_name = model_name.split("___")[0]


class LocalLLM(Base):
    def __init__(self, key, model_name, base_url=None, **kwargs):
        super().__init__(key, model_name, base_url=base_url, **kwargs)
        from jina import Client

        self.client = Client(port=12345, protocol="grpc", asyncio=True)

    def _prepare_prompt(self, system, history, gen_conf):
        from rag.svr.jina_server import Prompt

        if system and history and history[0].get("role") != "system":
            history.insert(0, {"role": "system", "content": system})
        return Prompt(message=history, gen_conf=gen_conf)

    def _stream_response(self, endpoint, prompt):
        from rag.svr.jina_server import Generation

        answer = ""
        loop = asyncio.new_event_loop()
        try:
            res = self.client.stream_doc(on=endpoint, inputs=prompt, return_type=Generation)
            try:
                while True:
                    answer = loop.run_until_complete(res.__anext__()).text
                    yield answer
            except StopAsyncIteration:
                pass
        except Exception as e:
            yield answer + "\n**ERROR**: " + str(e)
        finally:
            loop.close()
        yield num_tokens_from_string(answer)

    def chat(self, system, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        if "max_tokens" in gen_conf:
            del gen_conf["max_tokens"]
        prompt = self._prepare_prompt(system, history, gen_conf)
        chat_gen = self._stream_response("/chat", prompt)
        ans = next(chat_gen)
        total_tokens = next(chat_gen)
        return ans, total_tokens

    def chat_streamly(self, system, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        if "max_tokens" in gen_conf:
            del gen_conf["max_tokens"]
        prompt = self._prepare_prompt(system, history, gen_conf)
        return self._stream_response("/stream", prompt)


class VolcEngineChat(Base):
    _FACTORY_NAME = "VolcEngine"

    def __init__(self, key, model_name, base_url="https://ark.cn-beijing.volces.com/api/v3", **kwargs):
        """
        Since do not want to modify the original database fields, and the VolcEngine authentication method is quite special,
        Assemble ark_api_key, ep_id into api_key, store it as a dictionary type, and parse it for use
        model_name is for display only
        """
        base_url = base_url if base_url else "https://ark.cn-beijing.volces.com/api/v3"
        try:
            ark_api_key = json.loads(key).get("ark_api_key", "")
            model_name = json.loads(key).get("ep_id", "") + json.loads(key).get("endpoint_id", "")
            super().__init__(ark_api_key, model_name, base_url, **kwargs)
        except JSONDecodeError:
            super().__init__(key, model_name, base_url, **kwargs)


class MistralChat(Base):
    _FACTORY_NAME = "Mistral"

    def __init__(self, key, model_name, base_url=None, **kwargs):
        super().__init__(key, model_name, base_url=base_url, **kwargs)

        from mistralai.client import MistralClient

        self.client = MistralClient(api_key=key)
        self.model_name = model_name

    def _clean_conf(self, gen_conf):
        for k in list(gen_conf.keys()):
            if k not in ["temperature", "top_p", "max_tokens"]:
                del gen_conf[k]
        return gen_conf

    def _chat(self, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        gen_conf = self._clean_conf(gen_conf)
        response = self.client.chat(model=self.model_name, messages=history, **gen_conf)
        if not response.choices:
            raise ValueError("LLM returned empty response")  # pact: guard empty choices list
        ans = response.choices[0].message.content
        if response.choices[0].finish_reason == "length":
            if is_chinese(ans):
                ans += LENGTH_NOTIFICATION_CN
            else:
                ans += LENGTH_NOTIFICATION_EN
        return ans, total_token_count_from_response(response)

    def chat_streamly(self, system, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        if system and history and history[0].get("role") != "system":
            history.insert(0, {"role": "system", "content": system})
        gen_conf = self._clean_conf(gen_conf)
        ans = ""
        total_tokens = 0
        try:
            response = self.client.chat_stream(model=self.model_name, messages=history, **gen_conf, **kwargs)
            for resp in response:
                if not resp.choices or not resp.choices[0].delta.content:
                    continue
                ans = resp.choices[0].delta.content
                total_tokens += 1
                if resp.choices[0].finish_reason == "length":
                    if is_chinese(ans):
                        ans += LENGTH_NOTIFICATION_CN
                    else:
                        ans += LENGTH_NOTIFICATION_EN
                yield ans

        except openai.APIError as e:
            yield ans + "\n**ERROR**: " + str(e)

        yield total_tokens


class LmStudioChat(Base):
    _FACTORY_NAME = "LM-Studio"

    def __init__(self, key, model_name, base_url, **kwargs):
        if not base_url:
            raise ValueError("Local llm url cannot be None")
        super().__init__(key, model_name, base_url, **kwargs)
        self.client = OpenAI(api_key="lm-studio", base_url=self.base_url)
        self.model_name = model_name


class OpenAI_APIChat(Base):
    _FACTORY_NAME = ["VLLM", "OpenAI-API-Compatible"]

    def __init__(self, key, model_name, base_url, **kwargs):
        if not base_url:
            raise ValueError("url cannot be None")
        model_name = model_name.split("___")[0]
        super().__init__(key, model_name, base_url, **kwargs)


class Xiaomi(Base):
    _FACTORY_NAME = "Xiaomi"

    def __init__(self, key, model_name, base_url, **kwargs):
        if not base_url:
            base_url = "https://api.xiaomimimo.com/v1"
        super().__init__(key, model_name, base_url, **kwargs)


class LeptonAIChat(Base):
    _FACTORY_NAME = "LeptonAI"

    def __init__(self, key, model_name, base_url=None, **kwargs):
        if not base_url:
            base_url = urljoin("https://" + model_name + ".lepton.run", "api/v1")
        super().__init__(key, model_name, base_url, **kwargs)


class ReplicateChat(Base):
    _FACTORY_NAME = "Replicate"

    def __init__(self, key, model_name, base_url=None, **kwargs):
        super().__init__(key, model_name, base_url=base_url, **kwargs)

        from replicate.client import Client

        self.model_name = model_name
        self.client = Client(api_token=_normalize_replicate_key(key))

    def _chat(self, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        system = history[0]["content"] if history and history[0]["role"] == "system" else ""
        prompt = "\n".join([item["role"] + ":" + item["content"] for item in history[-5:] if item["role"] != "system"])
        response = self.client.run(
            self.model_name,
            input={"system_prompt": system, "prompt": prompt, **gen_conf},
        )
        ans = "".join(response)
        return ans, num_tokens_from_string(ans)

    def chat_streamly(self, system, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        if "max_tokens" in gen_conf:
            del gen_conf["max_tokens"]
        prompt = "\n".join([item["role"] + ":" + item["content"] for item in history[-5:]])
        ans = ""
        try:
            response = self.client.run(
                self.model_name,
                input={"system_prompt": system, "prompt": prompt, **gen_conf},
            )
            for resp in response:
                ans = resp
                yield ans

        except Exception as e:
            yield ans + "\n**ERROR**: " + str(e)

        yield num_tokens_from_string(ans)

    async def async_chat_streamly(self, system, history, gen_conf: dict | None = None, **kwargs):
        gen_conf = dict(gen_conf or {})
        if "max_tokens" in gen_conf:
            del gen_conf["max_tokens"]

        def _do_chat():
            msgs = list(history or [])
            if system and msgs and msgs[0].get("role") != "system":
                msgs.insert(0, {"role": "system", "content": system})
            elif system and not msgs:
                msgs = [{"role": "system", "content": system}]

            system_msg = msgs[0]["content"] if msgs and msgs[0].get("role") == "system" else ""
            prompt = "\n".join([item["role"] + ":" + item["content"] for item in msgs[-5:] if item.get("role") != "system"])
            try:
                response = self.client.run(
                    self.model_name,
                    input={"system_prompt": system_msg, "prompt": prompt, **gen_conf},
                )
                chunks = []
                for resp in response:
                    chunks.append(resp if isinstance(resp, str) else str(resp))
                answer = "".join(chunks)
                return chunks or ([answer] if answer else []), num_tokens_from_string(answer), None
            except Exception as e:
                return [], 0, e

        chunks, total_tokens, error = await asyncio.to_thread(_do_chat)
        if error:
            yield f"**ERROR**: {error}"
        else:
            for chunk in chunks:
                yield chunk
        yield total_tokens


class SparkChat(Base):
    _FACTORY_NAME = "XunFei Spark"

    def __init__(self, key, model_name, base_url="https://spark-api-open.xf-yun.com/v1", **kwargs):
        if not base_url:
            base_url = "https://spark-api-open.xf-yun.com/v1"
        model2version = {
            "Spark-Max": "generalv3.5",
            "Spark-Max-32K": "max-32k",
            "Spark-Lite": "lite",
            "Spark-Pro": "generalv3",
            "Spark-Pro-128K": "pro-128k",
            "Spark-4.0-Ultra": "4.0Ultra",
        }
        version2model = {v: k for k, v in model2version.items()}
        assert model_name in model2version or model_name in version2model, f"The given model name is not supported yet. Support: {list(model2version.keys())}"
        if model_name in model2version:
            model_version = model2version[model_name]
        else:
            model_version = model_name
        super().__init__(key, model_version, base_url, **kwargs)


class BaiduYiyanChat(Base):
    _FACTORY_NAME = "BaiduYiyan"

    def __init__(self, key, model_name, base_url=None, **kwargs):
        super().__init__(key, model_name, base_url=base_url, **kwargs)

        import qianfan

        key = json.loads(key)
        ak = key.get("yiyan_ak", "")
        sk = key.get("yiyan_sk", "")
        self.client = qianfan.ChatCompletion(ak=ak, sk=sk)
        self.model_name = model_name.lower()

    def _clean_conf(self, gen_conf):
        gen_conf["penalty_score"] = ((gen_conf.get("presence_penalty", 0) + gen_conf.get("frequency_penalty", 0)) / 2) + 1
        if "max_tokens" in gen_conf:
            del gen_conf["max_tokens"]
        return gen_conf

    def _chat(self, history, gen_conf):
        system = history[0]["content"] if history and history[0]["role"] == "system" else ""
        response = self.client.do(model=self.model_name, messages=[h for h in history if h["role"] != "system"], system=system, **gen_conf).body
        ans = response["result"]
        return ans, total_token_count_from_response(response)

    def chat_streamly(self, system, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        gen_conf["penalty_score"] = ((gen_conf.get("presence_penalty", 0) + gen_conf.get("frequency_penalty", 0)) / 2) + 1
        if "max_tokens" in gen_conf:
            del gen_conf["max_tokens"]
        ans = ""
        total_tokens = 0

        try:
            response = self.client.do(model=self.model_name, messages=history, system=system, stream=True, **gen_conf)
            for resp in response:
                resp = resp.body
                ans = resp["result"]
                total_tokens = total_token_count_from_response(resp)

                yield ans

        except Exception as e:
            return ans + "\n**ERROR**: " + str(e), 0

        yield total_tokens

    async def async_chat_streamly(self, system, history, gen_conf: dict | None = None, **kwargs):
        gen_conf = dict(gen_conf or {})
        gen_conf["penalty_score"] = ((gen_conf.get("presence_penalty", 0) + gen_conf.get("frequency_penalty", 0)) / 2) + 1
        if "max_tokens" in gen_conf:
            del gen_conf["max_tokens"]

        def _do_chat():
            system_msg = history[0]["content"] if history and history[0].get("role") == "system" else ""
            msgs = [h for h in history if h.get("role") != "system"]
            try:
                response = self.client.do(model=self.model_name, messages=msgs, system=system_msg, stream=True, **gen_conf)
                result_text = ""
                total_tokens = 0
                for resp in response:
                    resp = resp.body
                    result_text = resp["result"]
                    total_tokens = total_token_count_from_response(resp)
                return result_text, total_tokens, None
            except Exception as e:
                return "", 0, e

        result_text, total_tokens, error = await asyncio.to_thread(_do_chat)
        if error:
            yield f"**ERROR**: {error}"
        else:
            yield result_text
        yield total_tokens


class GoogleChat(Base):
    _FACTORY_NAME = "Google Cloud"

    @staticmethod
    def _vertex_http_options(region: str):
        region_norm = (region or "").strip().lower()
        multipoint_hosts = {
            "eu": "https://aiplatform.eu.rep.googleapis.com/",
            "us": "https://aiplatform.us.rep.googleapis.com/",
        }
        base_url = multipoint_hosts.get(region_norm)
        if base_url:
            from google.genai.types import HttpOptions

            # Gemini 3.x multi-region endpoints require *.rep hostnames
            # instead of region-aiplatform host synthesis.
            return HttpOptions(base_url=base_url, api_version="v1")
        return None

    def __init__(self, key, model_name, base_url=None, **kwargs):
        super().__init__(key, model_name, base_url=base_url, **kwargs)

        import base64

        from google.oauth2 import service_account

        key = json.loads(key)
        access_token = json.loads(base64.b64decode(key.get("google_service_account_key", "")))
        project_id = key.get("google_project_id", "")
        region = key.get("google_region", "")

        scopes = ["https://www.googleapis.com/auth/cloud-platform"]
        self.model_name = model_name

        if "claude" in self.model_name:
            from anthropic import AnthropicVertex
            from google.auth.transport.requests import Request

            if access_token:
                credits = service_account.Credentials.from_service_account_info(access_token, scopes=scopes)
                request = Request()
                credits.refresh(request)
                token = credits.token
                self.client = AnthropicVertex(region=region, project_id=project_id, access_token=token)
            else:
                self.client = AnthropicVertex(region=region, project_id=project_id)
        else:
            from google import genai

            client_kwargs = {
                "vertexai": True,
                "project": project_id,
                "location": region,
            }
            http_options = self._vertex_http_options(region)
            if http_options is not None:
                client_kwargs["http_options"] = http_options

            if access_token:
                credits = service_account.Credentials.from_service_account_info(access_token, scopes=scopes)
                client_kwargs["credentials"] = credits
                self.client = genai.Client(**client_kwargs)
            else:
                self.client = genai.Client(**client_kwargs)

    def _clean_conf(self, gen_conf):
        if "claude" in self.model_name:
            if "max_tokens" in gen_conf:
                del gen_conf["max_tokens"]
        else:
            if "max_tokens" in gen_conf:
                gen_conf["max_output_tokens"] = gen_conf["max_tokens"]
                del gen_conf["max_tokens"]
            for k in list(gen_conf.keys()):
                if k not in ["temperature", "top_p", "max_output_tokens"]:
                    del gen_conf[k]
        return gen_conf

    def _chat(self, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        system = history[0]["content"] if history and history[0]["role"] == "system" else ""

        if "claude" in self.model_name:
            gen_conf = self._clean_conf(gen_conf)
            response = self.client.messages.create(
                model=self.model_name,
                messages=[h for h in history if h["role"] != "system"],
                system=system,
                stream=False,
                **gen_conf,
            ).json()
            ans = response["content"][0]["text"]
            if response["stop_reason"] == "max_tokens":
                ans += "...\nFor the content length reason, it stopped, continue?" if is_english([ans]) else "······\n由于长度的原因，回答被截断了，要继续吗？"
            return (
                ans,
                response["usage"]["input_tokens"] + response["usage"]["output_tokens"],
            )

        # Gemini models with google-genai SDK
        # Set default thinking_budget=0 if not specified
        if "thinking_budget" not in gen_conf:
            gen_conf["thinking_budget"] = 0

        thinking_budget = gen_conf.pop("thinking_budget", 0)
        gen_conf = self._clean_conf(gen_conf)

        # Build GenerateContentConfig
        try:
            from google.genai.types import Content, GenerateContentConfig, Part, ThinkingConfig
        except ImportError as e:
            logging.error(f"[GoogleChat] Failed to import google-genai: {e}. Please install: pip install google-genai>=1.41.0")
            raise

        config_dict = {}
        if system:
            config_dict["system_instruction"] = system
        if "temperature" in gen_conf:
            config_dict["temperature"] = gen_conf["temperature"]
        if "top_p" in gen_conf:
            config_dict["top_p"] = gen_conf["top_p"]
        if "max_output_tokens" in gen_conf:
            config_dict["max_output_tokens"] = gen_conf["max_output_tokens"]

        # Add ThinkingConfig
        config_dict["thinking_config"] = ThinkingConfig(thinking_budget=thinking_budget)

        config = GenerateContentConfig(**config_dict)

        # Convert history to google-genai Content format
        contents = []
        for item in history:
            if item["role"] == "system":
                continue
            # google-genai uses 'model' instead of 'assistant'
            role = "model" if item["role"] == "assistant" else item["role"]
            content = Content(
                role=role,
                parts=[Part(text=item["content"])],
            )
            contents.append(content)

        response = self.client.models.generate_content(
            model=self.model_name,
            contents=contents,
            config=config,
        )

        ans = response.text
        # Get token count from response
        try:
            total_tokens = response.usage_metadata.total_token_count
        except Exception:
            total_tokens = 0

        return ans, total_tokens

    def chat_streamly(self, system, history, gen_conf=None, **kwargs):
        gen_conf = dict(gen_conf or {})
        if "claude" in self.model_name:
            if "max_tokens" in gen_conf:
                del gen_conf["max_tokens"]
            ans = ""
            total_tokens = 0
            try:
                response = self.client.messages.create(
                    model=self.model_name,
                    messages=history,
                    system=system,
                    stream=True,
                    **gen_conf,
                )
                for res in response.iter_lines():
                    res = res.decode("utf-8")
                    if "content_block_delta" in res and "data" in res:
                        text = json.loads(res[6:])["delta"]["text"]
                        ans = text
                        total_tokens += num_tokens_from_string(text)
            except Exception as e:
                yield ans + "\n**ERROR**: " + str(e)

            yield total_tokens
        else:
            # Gemini models with google-genai SDK
            ans = ""
            total_tokens = 0

            # Set default thinking_budget=0 if not specified
            if "thinking_budget" not in gen_conf:
                gen_conf["thinking_budget"] = 0

            thinking_budget = gen_conf.pop("thinking_budget", 0)
            gen_conf = self._clean_conf(gen_conf)

            # Build GenerateContentConfig
            try:
                from google.genai.types import Content, GenerateContentConfig, Part, ThinkingConfig
            except ImportError as e:
                logging.error(f"[GoogleChat] Failed to import google-genai: {e}. Please install: pip install google-genai>=1.41.0")
                raise

            config_dict = {}
            if system:
                config_dict["system_instruction"] = system
            if "temperature" in gen_conf:
                config_dict["temperature"] = gen_conf["temperature"]
            if "top_p" in gen_conf:
                config_dict["top_p"] = gen_conf["top_p"]
            if "max_output_tokens" in gen_conf:
                config_dict["max_output_tokens"] = gen_conf["max_output_tokens"]

            # Add ThinkingConfig
            config_dict["thinking_config"] = ThinkingConfig(thinking_budget=thinking_budget)

            config = GenerateContentConfig(**config_dict)

            # Convert history to google-genai Content format
            contents = []
            for item in history:
                # google-genai uses 'model' instead of 'assistant'
                role = "model" if item["role"] == "assistant" else item["role"]
                content = Content(
                    role=role,
                    parts=[Part(text=item["content"])],
                )
                contents.append(content)

            try:
                for chunk in self.client.models.generate_content_stream(
                    model=self.model_name,
                    contents=contents,
                    config=config,
                ):
                    text = chunk.text
                    ans = text
                    total_tokens += num_tokens_from_string(text)
                    yield ans

            except Exception as e:
                yield ans + "\n**ERROR**: " + str(e)

            yield total_tokens


class TokenPonyChat(Base):
    _FACTORY_NAME = "TokenPony"

    def __init__(self, key, model_name, base_url="https://ragflow.vip-api.tokenpony.cn/v1", **kwargs):
        if not base_url:
            base_url = "https://ragflow.vip-api.tokenpony.cn/v1"
        super().__init__(key, model_name, base_url, **kwargs)


class N1nChat(Base):
    _FACTORY_NAME = "n1n"

    def __init__(self, key, model_name, base_url="https://api.n1n.ai/v1", **kwargs):
        if not base_url:
            base_url = "https://api.n1n.ai/v1"
        super().__init__(key, model_name, base_url, **kwargs)


class AvianChat(Base):
    _FACTORY_NAME = "Avian"

    def __init__(self, key, model_name, base_url="https://api.avian.io/v1", **kwargs):
        if not base_url:
            base_url = "https://api.avian.io/v1"
        super().__init__(key, model_name, base_url, **kwargs)


class AstraflowChat(Base):
    _FACTORY_NAME = "Astraflow"

    def __init__(self, key, model_name, base_url="https://api-us-ca.umodelverse.ai/v1", **kwargs):
        if not base_url:
            base_url = "https://api-us-ca.umodelverse.ai/v1"
        super().__init__(key, model_name, base_url, **kwargs)


class AstraflowCNChat(Base):
    _FACTORY_NAME = "Astraflow-CN"

    def __init__(self, key, model_name, base_url="https://api.modelverse.cn/v1", **kwargs):
        if not base_url:
            base_url = "https://api.modelverse.cn/v1"
        super().__init__(key, model_name, base_url, **kwargs)


class FuturMixChat(Base):
    _FACTORY_NAME = "FuturMix"

    def __init__(self, key, model_name, base_url="https://futurmix.ai/v1", **kwargs):
        if not base_url:
            base_url = "https://futurmix.ai/v1"
        super().__init__(key, model_name, base_url, **kwargs)
        logging.info("[FuturMix] Chat initialized with model %s", model_name)


class LiteLLMBase(ABC):
    _FACTORY_NAME = [
        "Tongyi-Qianwen",
        "Bedrock",
        "Moonshot",
        "xAI",
        "DeepInfra",
        "Groq",
        "Cohere",
        "Gemini",
        "DeepSeek",
        "NVIDIA",
        "TogetherAI",
        "Anthropic",
        "Ollama",
        "LongCat",
        "CometAPI",
        "SILICONFLOW",
        "OpenRouter",
        "StepFun",
        "PPIO",
        "PerfXCloud",
        "Upstage",
        "NovitaAI",
        "01.AI",
        "GiteeAI",
        "302.AI",
        "Jiekou.AI",
        "ZHIPU-AI",
        "MiniMax",
        "DeerAPI",
        "GPUStack",
        "OpenAI",
        "Azure-OpenAI",
        "Tencent Hunyuan",
    ]

    def __init__(self, key, model_name, base_url=None, **kwargs):
        self.timeout = int(os.environ.get("LLM_TIMEOUT_SECONDS", 600))
        self.provider = kwargs.get("provider", "")
        self.prefix = LITELLM_PROVIDER_PREFIX.get(self.provider, "")
        self.model_name = f"{self.prefix}{model_name}"
        self.api_key = key
        self.base_url = (base_url or FACTORY_DEFAULT_BASE_URL.get(self.provider, "")).rstrip("/")
        # Configure retry parameters
        self.max_retries = kwargs.get("max_retries", int(os.environ.get("LLM_MAX_RETRIES", 5)))
        self.base_delay = kwargs.get("retry_interval", float(os.environ.get("LLM_BASE_DELAY", 2.0)))
        self.max_rounds = kwargs.get("max_rounds", 5)
        self.is_tools = False
        self.tools = []
        self.toolcall_sessions = {}
        # Token usage split (prompt/completion/total) of the most recent chat call.
        # Consumed by LLMBundle for accurate Langfuse reporting and run aggregation.
        self.last_usage = {"prompt_tokens": 0, "completion_tokens": 0, "total_tokens": 0}

        # Factory specific fields
        if self.provider == SupportedLiteLLMProvider.OpenRouter:
            try:
                self.api_key = json.loads(key).get("api_key", "")
                self.provider_order = json.loads(key).get("provider_order", "")
            except JSONDecodeError:
                self.api_key = key
                self.provider_order = ""
        elif self.provider == SupportedLiteLLMProvider.Azure_OpenAI:
            self.api_key = json.loads(key).get("api_key", "")
            self.api_version = json.loads(key).get("api_version", "2024-02-01")
        elif self.provider == SupportedLiteLLMProvider.MiniMax:
            # MiniMax requires GroupId as a query parameter for API authentication
            try:
                key_obj = json.loads(key) if isinstance(key, str) else key
                self.api_key = key_obj.get("api_key", key) if isinstance(key_obj, dict) else key
                self.group_id = key_obj.get("group_id", "") if isinstance(key_obj, dict) else ""
            except (json.JSONDecodeError, TypeError):
                self.api_key = key
                self.group_id = ""
        else:
            self.group_id = ""

    def _get_delay(self):
        return self.base_delay * random.uniform(10, 150)

    def _classify_error(self, error):
        error_str = str(error).lower()

        keywords_mapping = [
            (["quota", "capacity", "credit", "billing", "balance", "欠费"], LLMErrorCode.ERROR_QUOTA),
            (["rate limit", "429", "tpm limit", "too many requests", "requests per minute"], LLMErrorCode.ERROR_RATE_LIMIT),
            (["auth", "key", "apikey", "401", "forbidden", "permission"], LLMErrorCode.ERROR_AUTHENTICATION),
            (["invalid", "bad request", "400", "format", "malformed", "parameter"], LLMErrorCode.ERROR_INVALID_REQUEST),
            (["server", "503", "502", "504", "500", "unavailable"], LLMErrorCode.ERROR_SERVER),
            (["timeout", "timed out"], LLMErrorCode.ERROR_TIMEOUT),
            (["connect", "network", "unreachable", "dns"], LLMErrorCode.ERROR_CONNECTION),
            (["filter", "content", "policy", "blocked", "safety", "inappropriate"], LLMErrorCode.ERROR_CONTENT_FILTER),
            (["model", "not found", "does not exist", "not available"], LLMErrorCode.ERROR_MODEL),
            (["max rounds"], LLMErrorCode.ERROR_MODEL),
        ]
        for words, code in keywords_mapping:
            if re.search("({})".format("|".join(words)), error_str):
                return code

        return LLMErrorCode.ERROR_GENERIC

    def _clean_conf(self, gen_conf):
        gen_conf, _ = _apply_model_family_policies(
            self.model_name,
            backend="litellm",
            provider=self.provider,
            gen_conf=gen_conf,
        )

        gen_conf.pop("max_tokens", None)
        gen_conf = {k: v for k, v in gen_conf.items() if k in LITELLM_ALLOWED_GEN_CONF_KEYS}
        return gen_conf

    def _need_reasoning_content_back(self) -> bool:
        return self.provider == SupportedLiteLLMProvider.DeepSeek

    async def async_chat(self, system, history, gen_conf, **kwargs):
        hist = list(history) if history else []
        if system:
            if not hist or hist[0].get("role") != "system":
                hist.insert(0, {"role": "system", "content": system})

        logging.info("[HISTORY]" + json.dumps(hist, ensure_ascii=False, indent=2))
        gen_conf = self._clean_conf(gen_conf)
        _, kwargs = _apply_model_family_policies(
            self.model_name,
            backend="litellm",
            provider=self.provider,
            request_kwargs=kwargs,
        )

        completion_args = self._construct_completion_args(history=hist, stream=False, tools=False, **{**gen_conf, **kwargs})

        for attempt in range(self.max_retries + 1):
            try:
                response = await litellm.acompletion(
                    **completion_args,
                    drop_params=True,
                    timeout=self.timeout,
                )

                # Capture the prompt/completion split for accurate per-call usage
                # reporting (Langfuse + agent run aggregation).
                self.last_usage = usage_from_response(response)
                if not response.choices or not response.choices[0].message or not response.choices[0].message.content:
                    return "", 0
                ans = response.choices[0].message.content.strip()
                if response.choices[0].finish_reason == "length":
                    ans = self._length_stop(ans)

                return ans, total_token_count_from_response(response)
            except Exception as e:
                e = await self._exceptions_async(e, attempt)
                if e:
                    return e, 0

        assert False, "Shouldn't be here."

    async def async_chat_streamly(self, system, history, gen_conf, **kwargs):
        if system and history and history[0].get("role") != "system":
            history.insert(0, {"role": "system", "content": system})
        logging.info("[HISTORY STREAMLY]" + json.dumps(history, ensure_ascii=False, indent=4))
        gen_conf = self._clean_conf(gen_conf)
        reasoning_start = False
        total_tokens = 0
        # Reset so a stale split from a previous call can't leak into this one.
        self.last_usage = {"prompt_tokens": 0, "completion_tokens": 0, "total_tokens": 0}

        completion_args = self._construct_completion_args(history=history, stream=True, tools=False, **gen_conf)
        stop = kwargs.get("stop")
        if stop:
            completion_args["stop"] = stop
        # Ask the provider to include authoritative usage in the final streaming chunk.
        # drop_params=True ensures this is silently ignored by providers that don't support it.
        completion_args.setdefault("stream_options", {})["include_usage"] = True

        for attempt in range(self.max_retries + 1):
            try:
                stream = await litellm.acompletion(
                    **completion_args,
                    drop_params=True,
                    timeout=self.timeout,
                )

                async for resp in stream:
                    # Authoritative usage may arrive on a usage-only final chunk that
                    # carries no choices (OpenAI/OpenRouter with include_usage). Read it
                    # before the choices guard so the prompt/completion split is captured.
                    _usage = usage_from_response(resp)
                    if _usage["total_tokens"]:
                        total_tokens = _usage["total_tokens"]
                        self.last_usage = _usage

                    if not hasattr(resp, "choices") or not resp.choices:
                        continue

                    delta = resp.choices[0].delta
                    if not hasattr(delta, "content") or delta.content is None:
                        delta.content = ""

                    _reasoning = getattr(delta, "reasoning_content", None) or getattr(delta, "reasoning", None)
                    if kwargs.get("with_reasoning", True) and _reasoning:
                        ans = ""
                        if not reasoning_start:
                            reasoning_start = True
                            ans = "<think>"
                        ans += _reasoning + "</think>"
                    else:
                        reasoning_start = False
                        ans = delta.content

                    if not _usage["total_tokens"]:
                        # No authoritative usage yet: keep a running estimate as fallback.
                        total_tokens += num_tokens_from_string(delta.content)

                    finish_reason = resp.choices[0].finish_reason if hasattr(resp.choices[0], "finish_reason") else ""
                    if finish_reason == "length":
                        if is_chinese(ans):
                            ans += LENGTH_NOTIFICATION_CN
                        else:
                            ans += LENGTH_NOTIFICATION_EN

                    yield ans
                yield total_tokens
                return
            except Exception as e:
                e = await self._exceptions_async(e, attempt)
                if e:
                    yield e
                    yield total_tokens
                    return

    def _length_stop(self, ans):
        if is_chinese([ans]):
            return ans + LENGTH_NOTIFICATION_CN
        return ans + LENGTH_NOTIFICATION_EN

    @property
    def _retryable_errors(self) -> set[str]:
        return {
            LLMErrorCode.ERROR_RATE_LIMIT,
            LLMErrorCode.ERROR_SERVER,
        }

    def _should_retry(self, error_code: str) -> bool:
        return error_code in self._retryable_errors

    async def _exceptions_async(self, e, attempt):
        logging.exception("LiteLLMBase async completion")
        error_code = self._classify_error(e)
        if attempt == self.max_retries:
            error_code = LLMErrorCode.ERROR_MAX_RETRIES

        if self._should_retry(error_code):
            delay = self._get_delay()
            logging.warning(f"Error: {error_code}. Retrying in {delay:.2f} seconds... (Attempt {attempt + 1}/{self.max_retries})")
            await asyncio.sleep(delay)
            return None
        msg = f"{ERROR_PREFIX}: {error_code} - {str(e)}"
        logging.error(f"async_chat_streamly giving up: {msg}")
        return msg

    def _verbose_tool_use(self, name, args, res):
        return (
            "<tool_call>"
            + json.dumps(
                {"name": name, "args": args, "result": str(res) if isinstance(res, Exception) else res},
                ensure_ascii=False,
                indent=2,
            )
            + "</tool_call>"
        )

    def _append_history(self, hist, tool_call, tool_res, reasoning_content=None):
        assistant_msg = {
            "role": "assistant",
            "tool_calls": [
                {
                    "index": getattr(tool_call, "index", None),
                    "id": tool_call.id,
                    "function": {
                        "name": tool_call.function.name,
                        "arguments": tool_call.function.arguments,
                    },
                    "type": "function",
                },
            ],
        }
        if reasoning_content:
            assistant_msg["reasoning_content"] = reasoning_content
        hist.append(assistant_msg)
        try:
            if isinstance(tool_res, dict):
                tool_res = json.dumps(tool_res, ensure_ascii=False)
        finally:
            hist.append({"role": "tool", "tool_call_id": tool_call.id, "content": str(tool_res)})
        return hist

    def _append_history_batch(self, hist, results, reasoning_content=None):
        """
        Append a batch of tool calls to history following the OpenAI protocol:
        one assistant message containing all tool_calls, followed by one tool message per call.
        results: list of (tool_call, name, args, result, error)
        """
        assistant_msg = {
            "role": "assistant",
            "tool_calls": [
                {
                    "index": getattr(tc, "index", None),
                    "id": tc.id,
                    "function": {"name": tc.function.name, "arguments": tc.function.arguments},
                    "type": "function",
                }
                for tc, _, _, _, _ in results
            ],
        }
        if reasoning_content:
            assistant_msg["reasoning_content"] = reasoning_content
        hist.append(assistant_msg)
        for tc, _, _, result, err in results:
            if err:
                content = str(err)
            elif isinstance(result, dict):
                content = json.dumps(result, ensure_ascii=False)
            else:
                content = str(result)
            hist.append({"role": "tool", "tool_call_id": tc.id, "content": content})
        return hist

    def bind_tools(self, toolcall_session=None, tools=None):
        """Register tools the LLM can call.

        Two calling styles are accepted:

        * Legacy: ``bind_tools(toolcall_session, tools_schemas)`` where
          ``toolcall_session`` implements :class:`ToolCallSession` and
          ``tools_schemas`` is a pre-built list of OpenAI function-schema
          dicts (used by the agent/dialog layer).
        * Decorator: ``bind_tools(tools=[fn1, fn2, ...])`` where each ``fn``
          is decorated with :func:`rag.llm.tool_decorator.tool`. The session
          and schemas are derived from the callables automatically.
        """
        if tools is None and isinstance(toolcall_session, list):
            tools, toolcall_session = toolcall_session, None

        if tools and toolcall_session is None and all(is_tool(t) for t in tools):
            session = FunctionToolSession(tools)
            self.is_tools = True
            self.toolcall_session = session
            self.tools = session.schemas
            return

        if not (toolcall_session and tools):
            return
        self.is_tools = True
        self.toolcall_session = toolcall_session
        self.tools = tools

    async def async_chat_with_tools(self, system: str, history: list, gen_conf: dict | None = None):
        gen_conf = dict(gen_conf or {})
        gen_conf = self._clean_conf(gen_conf)
        if system and history and history[0].get("role") != "system":
            history.insert(0, {"role": "system", "content": system})

        ans = ""
        tk_count = 0
        # Aggregate prompt/completion/total across every tool-calling round so the
        # whole multi-round exchange is reported once with a correct split.
        agg_usage = {"prompt_tokens": 0, "completion_tokens": 0, "total_tokens": 0}

        def _add_usage(resp):
            nonlocal tk_count
            u = usage_from_response(resp)
            agg_usage["prompt_tokens"] += u["prompt_tokens"]
            agg_usage["completion_tokens"] += u["completion_tokens"]
            agg_usage["total_tokens"] += u["total_tokens"] or total_token_count_from_response(resp)
            tk_count = agg_usage["total_tokens"]
            self.last_usage = dict(agg_usage)

        hist = deepcopy(history)
        for attempt in range(self.max_retries + 1):
            history = deepcopy(hist)
            try:
                for _ in range(self.max_rounds + 1):
                    logging.info(f"{self.tools=}")

                    completion_args = self._construct_completion_args(history=history, stream=False, tools=True, **gen_conf)
                    response = await litellm.acompletion(
                        **completion_args,
                        drop_params=True,
                        timeout=self.timeout,
                    )

                    _add_usage(response)

                    if not hasattr(response, "choices") or not response.choices or not response.choices[0].message:
                        raise Exception(f"500 response structure error. Response: {response}")

                    message = response.choices[0].message
                    reasoning_content = None
                    if self._need_reasoning_content_back():
                        reasoning_content = getattr(message, "reasoning_content", None) or getattr(message, "reasoning", None)

                    if not hasattr(message, "tool_calls") or not message.tool_calls:
                        if reasoning_content:
                            ans += f"<think>{reasoning_content}</think>"
                        ans += message.content or ""
                        if response.choices[0].finish_reason == "length":
                            ans = self._length_stop(ans)
                        return ans, tk_count

                    async def _exec_tool(tc):
                        name = tc.function.name
                        try:
                            args = json_repair.loads(tc.function.arguments)
                            if not isinstance(args, dict):
                                raise TypeError(f"Tool arguments for {name} must be a JSON object, got {type(args).__name__}")
                            if hasattr(self.toolcall_session, "tool_call_async"):
                                result = await self.toolcall_session.tool_call_async(name, args)
                            else:
                                result = await thread_pool_exec(self.toolcall_session.tool_call, name, args)
                            return tc, name, args, result, None
                        except Exception as e:
                            logging.exception(f"Tool call failed: {tc}")
                            return tc, name, {}, None, e

                    logging.info(f"Response tool_calls={message.tool_calls}")
                    results = await asyncio.gather(*[_exec_tool(tc) for tc in message.tool_calls])
                    history = self._append_history_batch(
                        history,
                        results,
                        reasoning_content=reasoning_content if self._need_reasoning_content_back() else None,
                    )
                    for tc, name, args, result, err in results:
                        ans += self._verbose_tool_use(name, args, err if err else result)

                logging.warning(f"Exceed max rounds: {self.max_rounds}")
                history.append({"role": "user", "content": f"Exceed max rounds: {self.max_rounds}"})

                response, token_count = await self.async_chat("", history, gen_conf)
                ans += response
                # self.async_chat set self.last_usage to its own call; fold it into the aggregate.
                _fb = getattr(self, "last_usage", None) or {}
                agg_usage["prompt_tokens"] += int(_fb.get("prompt_tokens", 0) or 0)
                agg_usage["completion_tokens"] += int(_fb.get("completion_tokens", 0) or 0)
                agg_usage["total_tokens"] += int(_fb.get("total_tokens", 0) or token_count)
                tk_count = agg_usage["total_tokens"]
                self.last_usage = dict(agg_usage)
                return ans, tk_count

            except Exception as e:
                e = await self._exceptions_async(e, attempt)
                if e:
                    return e, tk_count

        assert False, "Shouldn't be here."

    async def async_chat_streamly_with_tools(self, system: str, history: list, gen_conf: dict | None = None):
        gen_conf = dict(gen_conf or {})
        gen_conf = self._clean_conf(gen_conf)
        tools = self.tools
        if system and history and history[0].get("role") != "system":
            history.insert(0, {"role": "system", "content": system})

        total_tokens = 0
        # Aggregate usage across every tool-calling round (each round is a separate
        # provider request). Committing per round avoids the previous bug where a later
        # round's total overwrote earlier rounds.
        agg_usage = {"prompt_tokens": 0, "completion_tokens": 0, "total_tokens": 0}
        hist = deepcopy(history)

        def _commit_round(round_usage, round_estimate):
            nonlocal total_tokens
            if round_usage and round_usage["total_tokens"]:
                agg_usage["prompt_tokens"] += round_usage["prompt_tokens"]
                agg_usage["completion_tokens"] += round_usage["completion_tokens"]
                agg_usage["total_tokens"] += round_usage["total_tokens"]
            else:
                agg_usage["total_tokens"] += round_estimate
            total_tokens = agg_usage["total_tokens"]
            self.last_usage = dict(agg_usage)

        for attempt in range(self.max_retries + 1):
            history = deepcopy(hist)
            try:
                for _round in range(self.max_rounds + 1):
                    reasoning_start = False
                    reasoning_content = ""
                    logging.info(f"[ToolLoop] round={_round} model={self.model_name} tools={[t['function']['name'] for t in tools]}")

                    completion_args = self._construct_completion_args(history=history, stream=True, tools=True, **gen_conf)
                    # Request authoritative usage on the final streaming chunk.
                    completion_args.setdefault("stream_options", {})["include_usage"] = True
                    response = await litellm.acompletion(
                        **completion_args,
                        drop_params=True,
                        timeout=self.timeout,
                    )

                    final_tool_calls = {}
                    answer = ""
                    round_usage = None
                    round_estimate = 0

                    async for resp in response:
                        # Usage-only final chunk may carry no choices — read it first.
                        _u = usage_from_response(resp)
                        if _u["total_tokens"]:
                            round_usage = _u

                        if not hasattr(resp, "choices") or not resp.choices:
                            continue

                        delta = resp.choices[0].delta

                        if hasattr(delta, "tool_calls") and delta.tool_calls:
                            for tool_call in delta.tool_calls:
                                index = tool_call.index
                                if index not in final_tool_calls:
                                    if not tool_call.function.arguments:
                                        tool_call.function.arguments = ""
                                    final_tool_calls[index] = tool_call
                                else:
                                    final_tool_calls[index].function.arguments += tool_call.function.arguments or ""
                            continue

                        if not hasattr(delta, "content") or delta.content is None:
                            delta.content = ""

                        _reasoning = getattr(delta, "reasoning_content", None) or getattr(delta, "reasoning", None)
                        if _reasoning:
                            if self._need_reasoning_content_back():
                                reasoning_content += _reasoning
                            ans = ""
                            if not reasoning_start:
                                reasoning_start = True
                                ans = "<think>"
                            ans += _reasoning + "</think>"
                            yield ans
                        else:
                            reasoning_start = False
                            answer += delta.content
                            yield delta.content

                        if not _u["total_tokens"]:
                            round_estimate += num_tokens_from_string(delta.content)

                        finish_reason = getattr(resp.choices[0], "finish_reason", "")
                        if finish_reason == "length":
                            yield self._length_stop("")

                    # Commit this round's tokens to the running aggregate.
                    _commit_round(round_usage, round_estimate)

                    if answer and not final_tool_calls:
                        logging.info(f"[ToolLoop] round={_round} completed with text response, exiting")
                        yield total_tokens
                        return

                    async def _exec_tool(tc):
                        name = tc.function.name
                        try:
                            args = json_repair.loads(tc.function.arguments)
                            if not isinstance(args, dict):
                                raise TypeError(f"Tool arguments for {name} must be a JSON object, got {type(args).__name__}")
                            if hasattr(self.toolcall_session, "tool_call_async"):
                                result = await self.toolcall_session.tool_call_async(name, args)
                            else:
                                result = await thread_pool_exec(self.toolcall_session.tool_call, name, args)
                            return tc, name, args, result, None
                        except Exception as e:
                            logging.exception(f"Tool call failed: {tc}")
                            return tc, name, {}, None, e

                    tcs = list(final_tool_calls.values())
                    logging.info(f"[ToolLoop] round={_round} executing {len(tcs)} tool(s): {[tc.function.name for tc in tcs]}")
                    for tc in tcs:
                        try:
                            args = json_repair.loads(tc.function.arguments)
                        except Exception:
                            args = {}
                        yield self._verbose_tool_use(tc.function.name, args, "Begin to call...")
                    results = await asyncio.gather(*[_exec_tool(tc) for tc in tcs])
                    history = self._append_history_batch(
                        history,
                        results,
                        reasoning_content=reasoning_content if self._need_reasoning_content_back() else None,
                    )
                    for tc, name, args, result, err in results:
                        yield self._verbose_tool_use(name, args, err if err else result)

                logging.warning(f"Exceed max rounds: {self.max_rounds}")
                history.append({"role": "user", "content": f"Exceed max rounds: {self.max_rounds}"})

                completion_args = self._construct_completion_args(history=history, stream=True, tools=True, **gen_conf)
                completion_args.setdefault("stream_options", {})["include_usage"] = True
                response = await litellm.acompletion(
                    **completion_args,
                    drop_params=True,
                    timeout=self.timeout,
                )

                fb_usage = None
                fb_estimate = 0
                async for resp in response:
                    _u = usage_from_response(resp)
                    if _u["total_tokens"]:
                        fb_usage = _u
                    if not hasattr(resp, "choices") or not resp.choices:
                        continue
                    delta = resp.choices[0].delta
                    if not hasattr(delta, "content") or delta.content is None:
                        continue
                    if not _u["total_tokens"]:
                        fb_estimate += num_tokens_from_string(delta.content)
                    yield delta.content

                _commit_round(fb_usage, fb_estimate)
                yield total_tokens
                return

            except Exception as e:
                e = await self._exceptions_async(e, attempt)
                if e:
                    yield e
                    yield total_tokens
                    return

        assert False, "Shouldn't be here."

    def _construct_completion_args(self, history, stream: bool, tools: bool, **kwargs):
        completion_args = {
            "model": self.model_name,
            "messages": history,
            "api_key": self.api_key,
            "num_retries": self.max_retries,
            **kwargs,
        }
        # Forward the originating session/user as the OpenAI-standard `user` field so
        # providers (OpenAI, OpenRouter, ...) receive it in the request body and
        # upstream activity can be correlated back to the session. An explicit
        # caller-supplied `user` (including an empty string to suppress it) wins, so
        # check key presence rather than truthiness.
        if "user" not in completion_args:
            request_user = current_llm_user()
            if request_user:
                completion_args["user"] = request_user
        if stream:
            completion_args.update(
                {
                    "stream": stream,
                }
            )
        if tools and self.tools:
            completion_args.update(
                {
                    "tools": self.tools,
                    "tool_choice": "auto",
                }
            )
        if self.provider in FACTORY_DEFAULT_BASE_URL:
            completion_args.update({"api_base": self.base_url})
        elif self.provider == SupportedLiteLLMProvider.Bedrock:
            import boto3

            completion_args.pop("api_key", None)
            completion_args.pop("api_base", None)

            bedrock_key = json.loads(self.api_key)
            mode = bedrock_key.get("auth_mode")
            if not mode:
                logging.error("Bedrock auth_mode is not provided in the key")
                raise ValueError("Bedrock auth_mode must be provided in the key")

            bedrock_region = bedrock_key.get("bedrock_region")

            if mode == "access_key_secret":
                completion_args.update({"aws_region_name": bedrock_region})
                completion_args.update({"aws_access_key_id": bedrock_key.get("bedrock_ak")})
                completion_args.update({"aws_secret_access_key": bedrock_key.get("bedrock_sk")})
            elif mode == "iam_role":
                aws_role_arn = bedrock_key.get("aws_role_arn")
                sts_client = boto3.client("sts", region_name=bedrock_region)
                resp = sts_client.assume_role(RoleArn=aws_role_arn, RoleSessionName="BedrockSession")
                creds = resp["Credentials"]
                completion_args.update({"aws_region_name": bedrock_region})
                completion_args.update({"aws_access_key_id": creds["AccessKeyId"]})
                completion_args.update({"aws_secret_access_key": creds["SecretAccessKey"]})
                completion_args.update({"aws_session_token": creds["SessionToken"]})
            else:  # assume_role - use default credential chain (IRSA, instance profile, etc.)
                completion_args.update({"aws_region_name": bedrock_region})

        elif self.provider == SupportedLiteLLMProvider.OpenRouter:
            if self.provider_order:

                def _to_order_list(x):
                    if x is None:
                        return []
                    if isinstance(x, str):
                        return [s.strip() for s in x.split(",") if s.strip()]
                    if isinstance(x, (list, tuple)):
                        return [str(s).strip() for s in x if str(s).strip()]
                    return []

                extra_body = {}
                provider_cfg = {}
                provider_order = _to_order_list(self.provider_order)
                provider_cfg["order"] = provider_order
                provider_cfg["allow_fallbacks"] = False
                extra_body["provider"] = provider_cfg
                completion_args.update({"extra_body": extra_body})
        elif self.provider == SupportedLiteLLMProvider.GPUStack:
            completion_args.update(
                {
                    "api_base": urljoin(self.base_url, "v1"),
                }
            )
        elif self.provider == SupportedLiteLLMProvider.Azure_OpenAI:
            completion_args.pop("api_key", None)
            completion_args.pop("api_base", None)
            completion_args.update(
                {
                    "api_key": self.api_key,
                    "api_base": self.base_url,
                    "api_version": self.api_version,
                }
            )

        # Ollama deployments commonly sit behind a reverse proxy that enforces
        # Bearer auth. Ensure the Authorization header is set when an API key
        # is provided, while respecting any user-supplied headers. #11350
        extra_headers = deepcopy(completion_args.get("extra_headers") or {})
        if self.provider == SupportedLiteLLMProvider.Ollama and self.api_key and "Authorization" not in extra_headers:
            extra_headers["Authorization"] = f"Bearer {self.api_key}"
        # MiniMax requires GroupId as a query parameter for API authentication
        if self.provider == SupportedLiteLLMProvider.MiniMax and hasattr(self, "group_id") and self.group_id:
            api_base = completion_args.get("api_base", self.base_url)
            separator = "&" if "?" in api_base else "?"
            completion_args["api_base"] = f"{api_base}{separator}GroupId={self.group_id}"
        _move_litellm_provider_body_fields(self.provider, completion_args)
        if extra_headers:
            completion_args["extra_headers"] = extra_headers
        return completion_args


class RAGconChat(Base):
    """
    RAGcon Chat Provider - routes through LiteLLM proxy

    All model types are handled through a unified LiteLLM endpoint.
    Default Base URL: https://connect.ragcon.com/v1
    """

    _FACTORY_NAME = "RAGcon"

    def __init__(self, key, model_name, base_url=None, **kwargs):
        if not base_url:
            base_url = "https://connect.ragcon.com/v1"

        super().__init__(key, model_name, base_url, **kwargs)


class NewAPIChat(Base):
    _FACTORY_NAME = "New API"

    def __init__(self, key, model_name, base_url, **kwargs):
        if not base_url:
            raise ValueError("url cannot be None")
        model_name = model_name.split("___")[0]
        super().__init__(key, model_name, base_url, **kwargs)
