import copy
import logging
import time
from collections.abc import Callable
from collections.abc import Iterator
from typing import Any

import requests
from pydantic import BaseModel
from requests.exceptions import HTTPError
from typing_extensions import override

from common.data_source.config import ZENDESK_CONNECTOR_SKIP_ARTICLE_LABELS, DocumentSource
from common.data_source.exceptions import ConnectorValidationError, CredentialExpiredError, InsufficientPermissionsError
from common.data_source.html_utils import parse_html_page_basic
from common.data_source.interfaces import CheckpointOutput, CheckpointOutputWrapper, CheckpointedConnector, IndexingHeartbeatInterface, SlimConnectorWithPermSync
from common.data_source.models import BasicExpertInfo, ConnectorCheckpoint, ConnectorFailure, Document, DocumentFailure, GenerateSlimDocumentOutput, SecondsSinceUnixEpoch, SlimDocument
from common.data_source.utils import retry_builder, time_str_to_utc, rate_limit_builder

MAX_PAGE_SIZE = 30  # Zendesk API maximum
MAX_AUTHOR_MAP_SIZE = 50_000  # Reset author map cache if it gets too large
_SLIM_BATCH_SIZE = 1000


class ZendeskCredentialsNotSetUpError(PermissionError):
    def __init__(self) -> None:
        super().__init__("Zendesk Credentials are not set up, was load_credentials called?")


class ZendeskClient:
    def __init__(
        self,
        subdomain: str,
        email: str,
        token: str,
        calls_per_minute: int | None = None,
    ):
        self.base_url = f"https://{subdomain}.zendesk.com/api/v2"
        self.auth = (f"{email}/token", token)
        self.make_request = request_with_rate_limit(self, calls_per_minute)


def request_with_rate_limit(client: ZendeskClient, max_calls_per_minute: int | None = None) -> Callable[[str, dict[str, Any]], dict[str, Any]]:
    @retry_builder()
    @(rate_limit_builder(max_calls=max_calls_per_minute, period=60) if max_calls_per_minute else lambda x: x)
    def make_request(endpoint: str, params: dict[str, Any]) -> dict[str, Any]:
        response = requests.get(f"{client.base_url}/{endpoint}", auth=client.auth, params=params)

        if response.status_code == 429:
            retry_after = response.headers.get("Retry-After")
            if retry_after is not None:
                # Sleep for the duration indicated by the Retry-After header
                time.sleep(int(retry_after))

        elif response.status_code == 403 and response.json().get("error") == "SupportProductInactive":
            return response.json()

        response.raise_for_status()
        return response.json()

    return make_request


class ZendeskPageResponse(BaseModel):
    data: list[dict[str, Any]]
    meta: dict[str, Any]
    has_more: bool


def _get_content_tag_mapping(client: ZendeskClient) -> dict[str, str]:
    content_tags: dict[str, str] = {}
    params = {"page[size]": MAX_PAGE_SIZE}

    try:
        while True:
            data = client.make_request("guide/content_tags", params)

            for tag in data.get("records", []):
                content_tags[tag["id"]] = tag["name"]

            # Check if there are more pages
            if data.get("meta", {}).get("has_more", False):
                params["page[after]"] = data["meta"]["after_cursor"]
            else:
                break

        return content_tags
    except Exception as e:
        raise Exception(f"Error fetching content tags: {str(e)}")


def _get_articles(client: ZendeskClient, start_time: int | None = None, page_size: int = MAX_PAGE_SIZE) -> Iterator[dict[str, Any]]:
    params = {"page[size]": page_size, "sort_by": "updated_at", "sort_order": "asc"}
    if start_time is not None:
        params["start_time"] = start_time

    while True:
        data = client.make_request("help_center/articles", params)
        for article in data["articles"]:
            yield article

        if not data.get("meta", {}).get("has_more"):
            break
        params["page[after]"] = data["meta"]["after_cursor"]


def _get_article_page(
    client: ZendeskClient,
    start_time: int | None = None,
    after_cursor: str | None = None,
    page_size: int = MAX_PAGE_SIZE,
) -> ZendeskPageResponse:
    params = {"page[size]": page_size, "sort_by": "updated_at", "sort_order": "asc"}
    if start_time is not None:
        params["start_time"] = start_time
    if after_cursor is not None:
        params["page[after]"] = after_cursor

    data = client.make_request("help_center/articles", params)
    return ZendeskPageResponse(
        data=data["articles"],
        meta=data["meta"],
        has_more=bool(data["meta"].get("has_more", False)),
    )


def _get_tickets(client: ZendeskClient, start_time: int | None = None) -> Iterator[dict[str, Any]]:
    params = {"start_time": start_time or 0}

    while True:
        data = client.make_request("incremental/tickets.json", params)
        for ticket in data["tickets"]:
            yield ticket

        if not data.get("end_of_stream", False):
            params["start_time"] = data["end_time"]
        else:
            break


# TODO: maybe these don't need to be their own functions?
def _get_tickets_page(client: ZendeskClient, start_time: int | None = None) -> ZendeskPageResponse:
    params = {"start_time": start_time or 0}

    # NOTE: for some reason zendesk doesn't seem to be respecting the start_time param
    # in my local testing with very few tickets. We'll look into it if this becomes an
    # issue in larger deployments
    data = client.make_request("incremental/tickets.json", params)
    if data.get("error") == "SupportProductInactive":
        raise ValueError("Zendesk Support Product is not active for this account, No tickets to index")
    return ZendeskPageResponse(
        data=data["tickets"],
        meta={"end_time": data["end_time"]},
        has_more=not bool(data.get("end_of_stream", False)),
    )


def _fetch_author(client: ZendeskClient, author_id: str | int) -> BasicExpertInfo | None:
    # Skip fetching if author_id is invalid
    # cast to str to avoid issues with zendesk changing their types
    if not author_id or str(author_id) == "-1":
        return None

    try:
        author_data = client.make_request(f"users/{author_id}", {})
        user = author_data.get("user")
        return BasicExpertInfo(display_name=user.get("name"), email=user.get("email")) if user and user.get("name") and user.get("email") else None
    except requests.exceptions.HTTPError:
        # Handle any API errors gracefully
        return None


def _article_to_document(
    article: dict[str, Any],
    content_tags: dict[str, str],
    author_map: dict[str, BasicExpertInfo],
    client: ZendeskClient,
) -> tuple[dict[str, BasicExpertInfo] | None, Document]:
    author_id = article.get("author_id")
    if not author_id:
        author = None
    else:
        author = author_map.get(author_id) if author_id in author_map else _fetch_author(client, author_id)

    new_author_mapping = {author_id: author} if author_id and author else None

    updated_at = article.get("updated_at")
    update_time = time_str_to_utc(updated_at) if updated_at else None

    text = parse_html_page_basic(article.get("body") or "")
    blob = text.encode("utf-8", errors="replace")
    # Build metadata
    metadata: dict[str, str | list[str]] = {
        "labels": [str(label) for label in article.get("label_names", []) if label],
        "content_tags": [content_tags[tag_id] for tag_id in article.get("content_tag_ids", []) if tag_id in content_tags],
    }

    # Remove empty values
    metadata = {k: v for k, v in metadata.items() if v}

    return new_author_mapping, Document(
        id=f"article:{article['id']}",
        source=DocumentSource.ZENDESK,
        semantic_identifier=article["title"],
        extension=".txt",
        blob=blob,
        size_bytes=len(blob),
        doc_updated_at=update_time,
        primary_owners=[author] if author else None,
        metadata=metadata,
    )


def _is_indexable_article(article: dict[str, Any]) -> bool:
    body = article.get("body")
    return bool(body) and not article.get("draft") and not any(label in ZENDESK_CONNECTOR_SKIP_ARTICLE_LABELS for label in article.get("label_names") or [])


def _get_comment_text(
    comment: dict[str, Any],
    author_map: dict[str, BasicExpertInfo],
    client: ZendeskClient,
) -> tuple[dict[str, BasicExpertInfo] | None, str]:
    author_id = comment.get("author_id")
    if not author_id:
        author = None
    else:
        author = author_map.get(author_id) if author_id in author_map else _fetch_author(client, author_id)

    new_author_mapping = {author_id: author} if author_id and author else None

    comment_text = f"Comment{' by ' + author.display_name if author and author.display_name else ''}"
    comment_text += f"{' at ' + comment['created_at'] if comment.get('created_at') else ''}:\n{comment['body']}"

    return new_author_mapping, comment_text


def _ticket_to_document(
    ticket: dict[str, Any],
    author_map: dict[str, BasicExpertInfo],
    client: ZendeskClient,
) -> tuple[dict[str, BasicExpertInfo] | None, Document]:
    submitter_id = ticket.get("submitter")
    if not submitter_id:
        submitter = None
    else:
        submitter = author_map.get(submitter_id) if submitter_id in author_map else _fetch_author(client, submitter_id)

    new_author_mapping = {submitter_id: submitter} if submitter_id and submitter else None

    updated_at = ticket.get("updated_at")
    update_time = time_str_to_utc(updated_at) if updated_at else None

    metadata: dict[str, str | list[str]] = {}
    if status := ticket.get("status"):
        metadata["status"] = status
    if priority := ticket.get("priority"):
        metadata["priority"] = priority
    if tags := ticket.get("tags"):
        metadata["tags"] = tags
    if ticket_type := ticket.get("type"):
        metadata["ticket_type"] = ticket_type

    # Fetch comments for the ticket
    comments_data = client.make_request(f"tickets/{ticket.get('id')}/comments", {})
    comments = comments_data.get("comments", [])

    comment_texts = []
    for comment in comments:
        new_author_mapping, comment_text = _get_comment_text(comment, author_map, client)
        if new_author_mapping:
            author_map.update(new_author_mapping)
        comment_texts.append(comment_text)

    comments_text = "\n\n".join(comment_texts)

    subject = ticket.get("subject")
    full_text = f"Ticket Subject:\n{subject}\n\nComments:\n{comments_text}"

    blob = full_text.encode("utf-8", errors="replace")
    return new_author_mapping, Document(
        id=f"zendesk_ticket_{ticket['id']}",
        blob=blob,
        extension=".txt",
        size_bytes=len(blob),
        source=DocumentSource.ZENDESK,
        semantic_identifier=f"Ticket #{ticket['id']}: {subject or 'No Subject'}",
        doc_updated_at=update_time,
        primary_owners=[submitter] if submitter else None,
        metadata=metadata,
    )


def _is_indexable_ticket(ticket: dict[str, Any]) -> bool:
    return ticket.get("status") != "deleted"


class ZendeskConnectorCheckpoint(ConnectorCheckpoint):
    # We use cursor-based paginated retrieval for articles
    after_cursor_articles: str | None

    # We use timestamp-based paginated retrieval for tickets
    next_start_time_tickets: int | None

    cached_author_map: dict[str, BasicExpertInfo] | None
    cached_content_tags: dict[str, str] | None


class ZendeskConnector(SlimConnectorWithPermSync, CheckpointedConnector[ZendeskConnectorCheckpoint]):
    def __init__(
        self,
        content_type: str = "articles",
        calls_per_minute: int | None = None,
    ) -> None:
        self.content_type = content_type
        self.subdomain = ""
        # Fetch all tags ahead of time
        self.content_tags: dict[str, str] = {}
        self.calls_per_minute = calls_per_minute

    def load_credentials(self, credentials: dict[str, Any]) -> dict[str, Any] | None:
        # Subdomain is actually the whole URL
        subdomain = credentials["zendesk_subdomain"].replace("https://", "").split(".zendesk.com")[0]
        self.subdomain = subdomain

        self.client = ZendeskClient(
            subdomain,
            credentials["zendesk_email"],
            credentials["zendesk_token"],
            calls_per_minute=self.calls_per_minute,
        )
        return None

    @override
    def load_from_checkpoint(
        self,
        start: SecondsSinceUnixEpoch,
        end: SecondsSinceUnixEpoch,
        checkpoint: ZendeskConnectorCheckpoint,
    ) -> CheckpointOutput[ZendeskConnectorCheckpoint]:
        if self.client is None:
            raise ZendeskCredentialsNotSetUpError()
        if checkpoint.cached_content_tags is None:
            checkpoint.cached_content_tags = _get_content_tag_mapping(self.client)
            return checkpoint  # save the content tags to the checkpoint
        self.content_tags = checkpoint.cached_content_tags

        if self.content_type == "articles":
            checkpoint = yield from self._retrieve_articles(start, end, checkpoint)
            return checkpoint
        elif self.content_type == "tickets":
            checkpoint = yield from self._retrieve_tickets(start, end, checkpoint)
            return checkpoint
        else:
            raise ValueError(f"Unsupported content_type: {self.content_type}")

    def _retrieve_articles(
        self,
        start: SecondsSinceUnixEpoch | None,
        end: SecondsSinceUnixEpoch | None,
        checkpoint: ZendeskConnectorCheckpoint,
    ) -> CheckpointOutput[ZendeskConnectorCheckpoint]:
        checkpoint = copy.deepcopy(checkpoint)
        # This one is built on the fly as there may be more many more authors than tags
        author_map: dict[str, BasicExpertInfo] = checkpoint.cached_author_map or {}
        after_cursor = checkpoint.after_cursor_articles
        doc_batch: list[Document] = []

        response = _get_article_page(
            self.client,
            start_time=int(start) if start else None,
            after_cursor=after_cursor,
        )
        articles = response.data
        has_more = response.has_more
        after_cursor = response.meta.get("after_cursor")
        for article in articles:
            if not _is_indexable_article(article):
                continue

            try:
                new_author_map, document = _article_to_document(article, self.content_tags, author_map, self.client)
            except Exception as e:
                logging.error(f"Error processing article {article['id']}: {e}")
                yield ConnectorFailure(
                    failed_document=DocumentFailure(
                        document_id=f"{article.get('id')}",
                        document_link=article.get("html_url", ""),
                    ),
                    failure_message=str(e),
                    exception=e,
                )
                continue

            if new_author_map:
                author_map.update(new_author_map)
            updated_at = document.doc_updated_at
            updated_ts = updated_at.timestamp() if updated_at else None
            if updated_ts is not None:
                if start is not None and updated_ts <= start:
                    continue
                if end is not None and updated_ts > end:
                    continue

            doc_batch.append(document)

        if not has_more:
            yield from doc_batch
            checkpoint.has_more = False
            return checkpoint

        # Sometimes no documents are retrieved, but the cursor
        # is still updated so the connector makes progress.
        yield from doc_batch
        checkpoint.after_cursor_articles = after_cursor

        last_doc_updated_at = doc_batch[-1].doc_updated_at if doc_batch else None
        checkpoint.has_more = bool(end is None or last_doc_updated_at is None or last_doc_updated_at.timestamp() <= end)
        checkpoint.cached_author_map = author_map if len(author_map) <= MAX_AUTHOR_MAP_SIZE else None
        return checkpoint

    def _retrieve_tickets(
        self,
        start: SecondsSinceUnixEpoch | None,
        end: SecondsSinceUnixEpoch | None,
        checkpoint: ZendeskConnectorCheckpoint,
    ) -> CheckpointOutput[ZendeskConnectorCheckpoint]:
        checkpoint = copy.deepcopy(checkpoint)
        if self.client is None:
            raise ZendeskCredentialsNotSetUpError()

        author_map: dict[str, BasicExpertInfo] = checkpoint.cached_author_map or {}

        doc_batch: list[Document] = []
        next_start_time = int(checkpoint.next_start_time_tickets or start or 0)
        ticket_response = _get_tickets_page(self.client, start_time=next_start_time)

        tickets = ticket_response.data
        has_more = ticket_response.has_more
        next_start_time = ticket_response.meta["end_time"]
        for ticket in tickets:
            if not _is_indexable_ticket(ticket):
                continue

            try:
                new_author_map, document = _ticket_to_document(
                    ticket=ticket,
                    author_map=author_map,
                    client=self.client,
                )
            except Exception as e:
                logging.error(f"Error processing ticket {ticket['id']}: {e}")
                yield ConnectorFailure(
                    failed_document=DocumentFailure(
                        document_id=f"{ticket.get('id')}",
                        document_link=ticket.get("url", ""),
                    ),
                    failure_message=str(e),
                    exception=e,
                )
                continue

            if new_author_map:
                author_map.update(new_author_map)

            updated_at = document.doc_updated_at
            updated_ts = updated_at.timestamp() if updated_at else None

            if updated_ts is not None:
                if start is not None and updated_ts <= start:
                    continue
                if end is not None and updated_ts > end:
                    continue

            doc_batch.append(document)

        if not has_more:
            yield from doc_batch
            checkpoint.has_more = False
            return checkpoint

        yield from doc_batch
        checkpoint.next_start_time_tickets = next_start_time
        last_doc_updated_at = doc_batch[-1].doc_updated_at if doc_batch else None
        checkpoint.has_more = bool(end is None or last_doc_updated_at is None or last_doc_updated_at.timestamp() <= end)
        checkpoint.cached_author_map = author_map if len(author_map) <= MAX_AUTHOR_MAP_SIZE else None
        return checkpoint

    def retrieve_all_slim_docs_perm_sync(
        self,
        callback: IndexingHeartbeatInterface | None = None,
    ) -> GenerateSlimDocumentOutput:
        slim_doc_batch: list[SlimDocument] = []
        if self.content_type == "articles":
            articles = _get_articles(self.client)
            for article in articles:
                if not _is_indexable_article(article):
                    continue
                slim_doc_batch.append(
                    SlimDocument(
                        id=f"article:{article['id']}",
                    )
                )
                if len(slim_doc_batch) >= _SLIM_BATCH_SIZE:
                    yield slim_doc_batch
                    slim_doc_batch = []
        elif self.content_type == "tickets":
            tickets = _get_tickets(self.client)
            for ticket in tickets:
                if not _is_indexable_ticket(ticket):
                    continue
                slim_doc_batch.append(
                    SlimDocument(
                        id=f"zendesk_ticket_{ticket['id']}",
                    )
                )
                if len(slim_doc_batch) >= _SLIM_BATCH_SIZE:
                    yield slim_doc_batch
                    slim_doc_batch = []
        else:
            raise ValueError(f"Unsupported content_type: {self.content_type}")
        if slim_doc_batch:
            yield slim_doc_batch

    @override
    def validate_connector_settings(self) -> None:
        if self.client is None:
            raise ZendeskCredentialsNotSetUpError()

        try:
            _get_article_page(self.client, start_time=0)
        except HTTPError as e:
            # Check for HTTP status codes
            if e.response.status_code == 401:
                raise CredentialExpiredError("Your Zendesk credentials appear to be invalid or expired (HTTP 401).") from e
            elif e.response.status_code == 403:
                raise InsufficientPermissionsError("Your Zendesk token does not have sufficient permissions (HTTP 403).") from e
            elif e.response.status_code == 404:
                raise ConnectorValidationError("Zendesk resource not found (HTTP 404).") from e
            else:
                raise ConnectorValidationError(f"Unexpected Zendesk error (status={e.response.status_code}): {e}") from e

    @override
    def validate_checkpoint_json(self, checkpoint_json: str) -> ZendeskConnectorCheckpoint:
        return ZendeskConnectorCheckpoint.model_validate_json(checkpoint_json)

    @override
    def build_dummy_checkpoint(self) -> ZendeskConnectorCheckpoint:
        return ZendeskConnectorCheckpoint(
            after_cursor_articles=None,
            next_start_time_tickets=None,
            cached_author_map=None,
            cached_content_tags=None,
            has_more=True,
        )


if __name__ == "__main__":
    import os

    connector = ZendeskConnector(content_type="articles")
    connector.load_credentials(
        {
            "zendesk_subdomain": os.environ["ZENDESK_SUBDOMAIN"],
            "zendesk_email": os.environ["ZENDESK_EMAIL"],
            "zendesk_token": os.environ["ZENDESK_TOKEN"],
        }
    )

    current = time.time()
    one_day_ago = current - 24 * 60 * 60  # 1 day

    checkpoint = connector.build_dummy_checkpoint()

    while checkpoint.has_more:
        gen = connector.load_from_checkpoint(one_day_ago, current, checkpoint)

        wrapper = CheckpointOutputWrapper()
        any_doc = False

        for document, failure, next_checkpoint in wrapper(gen):
            if document:
                print("got document:", document.id)
                any_doc = True

        checkpoint = next_checkpoint
        if any_doc:
            break
