import uuid
from collections.abc import Generator, Mapping
from typing import Any, Union

from configs import dify_config
from core.app.apps.advanced_chat.app_generator import AdvancedChatAppGenerator
from core.app.apps.agent_chat.app_generator import AgentChatAppGenerator
from core.app.apps.chat.app_generator import ChatAppGenerator
from core.app.apps.completion.app_generator import CompletionAppGenerator
from core.app.apps.workflow.app_generator import WorkflowAppGenerator
from core.app.entities.app_invoke_entities import InvokeFrom
from core.app.features.rate_limiting import RateLimit
from enums.quota_type import QuotaType, unlimited
from extensions.otel import AppGenerateHandler, trace_span
from models.model import Account, App, AppMode, EndUser
from models.workflow import Workflow
from services.errors.app import InvokeRateLimitError, QuotaExceededError, WorkflowIdFormatError, WorkflowNotFoundError
from services.workflow_service import WorkflowService


class AppGenerateService:
    @classmethod
    @trace_span(AppGenerateHandler)
    def generate(
        cls,
        app_model: App,
        user: Union[Account, EndUser],
        args: Mapping[str, Any],
        invoke_from: InvokeFrom,
        streaming: bool = True,
        root_node_id: str | None = None,
    ):
        """
        App Content Generate
        :param app_model: app model
        :param user: user
        :param args: args
        :param invoke_from: invoke from
        :param streaming: streaming
        :return:
        """
        quota_charge = unlimited()
        if dify_config.BILLING_ENABLED:
            try:
                quota_charge = QuotaType.WORKFLOW.consume(app_model.tenant_id)
            except QuotaExceededError:
                raise InvokeRateLimitError(f"Workflow execution quota limit reached for tenant {app_model.tenant_id}")

        # app level rate limiter
        max_active_request = cls._get_max_active_requests(app_model)
        rate_limit = RateLimit(app_model.id, max_active_request)
        request_id = RateLimit.gen_request_key()
        try:
            request_id = rate_limit.enter(request_id)
            if app_model.mode == AppMode.COMPLETION:
                return rate_limit.generate(
                    CompletionAppGenerator.convert_to_event_stream(
                        CompletionAppGenerator().generate(
                            app_model=app_model, user=user, args=args, invoke_from=invoke_from, streaming=streaming
                        ),
                    ),
                    request_id=request_id,
                )
            elif app_model.mode == AppMode.AGENT_CHAT or app_model.is_agent:
                return rate_limit.generate(
                    AgentChatAppGenerator.convert_to_event_stream(
                        AgentChatAppGenerator().generate(
                            app_model=app_model, user=user, args=args, invoke_from=invoke_from, streaming=streaming
                        ),
                    ),
                    request_id,
                )
            elif app_model.mode == AppMode.CHAT:
                return rate_limit.generate(
                    ChatAppGenerator.convert_to_event_stream(
                        ChatAppGenerator().generate(
                            app_model=app_model, user=user, args=args, invoke_from=invoke_from, streaming=streaming
                        ),
                    ),
                    request_id=request_id,
                )
            elif app_model.mode == AppMode.ADVANCED_CHAT:
                workflow_id = args.get("workflow_id")
                workflow = cls._get_workflow(app_model, invoke_from, workflow_id)
                return rate_limit.generate(
                    AdvancedChatAppGenerator.convert_to_event_stream(
                        AdvancedChatAppGenerator().generate(
                            app_model=app_model,
                            workflow=workflow,
                            user=user,
                            args=args,
                            invoke_from=invoke_from,
                            streaming=streaming,
                        ),
                    ),
                    request_id=request_id,
                )
            elif app_model.mode == AppMode.WORKFLOW:
                workflow_id = args.get("workflow_id")
                workflow = cls._get_workflow(app_model, invoke_from, workflow_id)
                return rate_limit.generate(
                    WorkflowAppGenerator.convert_to_event_stream(
                        WorkflowAppGenerator().generate(
                            app_model=app_model,
                            workflow=workflow,
                            user=user,
                            args=args,
                            invoke_from=invoke_from,
                            streaming=streaming,
                            root_node_id=root_node_id,
                            call_depth=0,
                        ),
                    ),
                    request_id,
                )
            else:
                raise ValueError(f"Invalid app mode {app_model.mode}")
        except Exception:
            quota_charge.refund()
            rate_limit.exit(request_id)
            raise
        finally:
            if not streaming:
                rate_limit.exit(request_id)

    @staticmethod
    def _get_max_active_requests(app: App) -> int:
        """
        Get the maximum number of active requests allowed for an app.

        Returns the smaller value between app's custom limit and global config limit.
        A value of 0 means infinite (no limit).

        Args:
            app: The App model instance

        Returns:
            The maximum number of active requests allowed
        """
        app_limit = app.max_active_requests or dify_config.APP_DEFAULT_ACTIVE_REQUESTS
        config_limit = dify_config.APP_MAX_ACTIVE_REQUESTS

        # Filter out infinite (0) values and return the minimum, or 0 if both are infinite
        limits = [limit for limit in [app_limit, config_limit] if limit > 0]
        return min(limits) if limits else 0

    @classmethod
    def generate_single_iteration(cls, app_model: App, user: Account, node_id: str, args: Any, streaming: bool = True):
        if app_model.mode == AppMode.ADVANCED_CHAT:
            workflow = cls._get_workflow(app_model, InvokeFrom.DEBUGGER)
            return AdvancedChatAppGenerator.convert_to_event_stream(
                AdvancedChatAppGenerator().single_iteration_generate(
                    app_model=app_model, workflow=workflow, node_id=node_id, user=user, args=args, streaming=streaming
                )
            )
        elif app_model.mode == AppMode.WORKFLOW:
            workflow = cls._get_workflow(app_model, InvokeFrom.DEBUGGER)
            return AdvancedChatAppGenerator.convert_to_event_stream(
                WorkflowAppGenerator().single_iteration_generate(
                    app_model=app_model, workflow=workflow, node_id=node_id, user=user, args=args, streaming=streaming
                )
            )
        else:
            raise ValueError(f"Invalid app mode {app_model.mode}")

    @classmethod
    def generate_single_loop(cls, app_model: App, user: Account, node_id: str, args: Any, streaming: bool = True):
        if app_model.mode == AppMode.ADVANCED_CHAT:
            workflow = cls._get_workflow(app_model, InvokeFrom.DEBUGGER)
            return AdvancedChatAppGenerator.convert_to_event_stream(
                AdvancedChatAppGenerator().single_loop_generate(
                    app_model=app_model, workflow=workflow, node_id=node_id, user=user, args=args, streaming=streaming
                )
            )
        elif app_model.mode == AppMode.WORKFLOW:
            workflow = cls._get_workflow(app_model, InvokeFrom.DEBUGGER)
            return AdvancedChatAppGenerator.convert_to_event_stream(
                WorkflowAppGenerator().single_loop_generate(
                    app_model=app_model, workflow=workflow, node_id=node_id, user=user, args=args, streaming=streaming
                )
            )
        else:
            raise ValueError(f"Invalid app mode {app_model.mode}")

    @classmethod
    def generate_more_like_this(
        cls,
        app_model: App,
        user: Union[Account, EndUser],
        message_id: str,
        invoke_from: InvokeFrom,
        streaming: bool = True,
    ) -> Union[Mapping, Generator]:
        """
        Generate more like this
        :param app_model: app model
        :param user: user
        :param message_id: message id
        :param invoke_from: invoke from
        :param streaming: streaming
        :return:
        """
        return CompletionAppGenerator().generate_more_like_this(
            app_model=app_model, message_id=message_id, user=user, invoke_from=invoke_from, stream=streaming
        )

    @classmethod
    def _get_workflow(cls, app_model: App, invoke_from: InvokeFrom, workflow_id: str | None = None) -> Workflow:
        """
        Get workflow
        :param app_model: app model
        :param invoke_from: invoke from
        :param workflow_id: optional workflow id to specify a specific version
        :return:
        """
        workflow_service = WorkflowService()

        # If workflow_id is specified, get the specific workflow version
        if workflow_id:
            try:
                _ = uuid.UUID(workflow_id)
            except ValueError:
                raise WorkflowIdFormatError(f"Invalid workflow_id format: '{workflow_id}'. ")
            workflow = workflow_service.get_published_workflow_by_id(app_model=app_model, workflow_id=workflow_id)
            if not workflow:
                raise WorkflowNotFoundError(f"Workflow not found with id: {workflow_id}")
            return workflow

        if invoke_from == InvokeFrom.DEBUGGER:
            # fetch draft workflow by app_model
            workflow = workflow_service.get_draft_workflow(app_model=app_model)

            if not workflow:
                raise ValueError("Workflow not initialized")
        else:
            # fetch published workflow by app_model
            workflow = workflow_service.get_published_workflow(app_model=app_model)

            if not workflow:
                raise ValueError("Workflow not published")

        return workflow
