import logging
from datetime import datetime

from sqlalchemy import delete
from sqlalchemy.ext.asyncio import AsyncSession

from app.db import Chunk, Document
from app.services.llm_service import get_user_long_context_llm
from app.utils.document_converters import (
    create_document_chunks,
    embed_text,
    generate_content_hash,
    generate_document_summary,
)

logger = logging.getLogger(__name__)


class NotionKBSyncService:
    def __init__(self, db_session: AsyncSession):
        self.db_session = db_session

    async def sync_after_update(
        self,
        document_id: int,
        appended_content: str,
        user_id: str,
        search_space_id: int,
        appended_block_ids: list[str] | None = None,
    ) -> dict:
        from app.tasks.connector_indexers.base import (
            get_current_timestamp,
            safe_set_chunks,
        )

        try:
            logger.debug(f"Starting KB sync for document {document_id}")
            document = await self.db_session.get(Document, document_id)

            if not document:
                logger.warning(f"Document {document_id} not found in KB")
                return {"status": "not_indexed"}

            page_id = document.document_metadata.get("page_id")
            if not page_id:
                logger.error(f"Document {document_id} missing page_id in metadata")
                return {"status": "error", "message": "Missing page_id in metadata"}

            logger.debug(
                f"Document found: id={document_id}, page_id={page_id}, connector_id={document.connector_id}"
            )

            from app.connectors.notion_history import NotionHistoryConnector

            notion_connector = NotionHistoryConnector(
                session=self.db_session, connector_id=document.connector_id
            )

            logger.debug(f"Fetching page content from Notion for page {page_id}")
            blocks, _ = await notion_connector.get_page_content(
                page_id, page_title=None
            )

            from app.utils.notion_utils import extract_all_block_ids, process_blocks

            fetched_content = process_blocks(blocks)
            logger.debug(f"Fetched content length: {len(fetched_content)} chars")

            if not fetched_content or not fetched_content.strip():
                logger.warning(
                    f"Fetched empty content for page {page_id} - document will have minimal searchable text"
                )

            content_verified = False
            if appended_block_ids:
                fetched_block_ids = set(extract_all_block_ids(blocks))
                found_blocks = [
                    bid for bid in appended_block_ids if bid in fetched_block_ids
                ]

                logger.debug(
                    f"Block verification: {len(found_blocks)}/{len(appended_block_ids)} blocks found"
                )
                logger.debug(
                    f"Appended IDs (first 3): {appended_block_ids[:3]}, Fetched IDs count: {len(fetched_block_ids)}"
                )

                if len(found_blocks) >= len(appended_block_ids) * 0.8:  # 80% threshold
                    logger.info(
                        f"Content verified fresh: found {len(found_blocks)}/{len(appended_block_ids)} appended blocks"
                    )
                    full_content = fetched_content
                    content_verified = True
                else:
                    logger.warning(
                        "No appended blocks found in fetched content - appending manually"
                    )
                    full_content = fetched_content + "\n\n" + appended_content
                    content_verified = False
            else:
                logger.warning("No block IDs provided - using fetched content as-is")
                full_content = fetched_content
                content_verified = False

            logger.debug(
                f"Final content length: {len(full_content)} chars, verified={content_verified}"
            )

            logger.debug("Generating summary and embeddings")
            user_llm = await get_user_long_context_llm(
                self.db_session,
                user_id,
                search_space_id,
                disable_streaming=True,  # disable streaming to avoid leaking into the chat
            )

            if user_llm:
                document_metadata_for_summary = {
                    "page_title": document.document_metadata.get("page_title"),
                    "page_id": document.document_metadata.get("page_id"),
                    "document_type": "Notion Page",
                    "connector_type": "Notion",
                }
                summary_content, summary_embedding = await generate_document_summary(
                    full_content, user_llm, document_metadata_for_summary
                )
                logger.debug(f"Generated summary length: {len(summary_content)} chars")
            else:
                logger.warning("No LLM configured - using fallback summary")
                summary_content = f"Notion Page: {document.document_metadata.get('page_title')}\n\n{full_content}"
                summary_embedding = embed_text(summary_content)

            logger.debug(f"Deleting old chunks for document {document_id}")
            await self.db_session.execute(
                delete(Chunk).where(Chunk.document_id == document.id)
            )

            logger.debug("Creating new chunks")
            chunks = await create_document_chunks(full_content)
            logger.debug(f"Created {len(chunks)} chunks")

            logger.debug("Updating document fields")
            document.content = summary_content
            document.content_hash = generate_content_hash(full_content, search_space_id)
            document.embedding = summary_embedding
            document.document_metadata = {
                **document.document_metadata,
                "indexed_at": datetime.now().strftime("%Y-%m-%d %H:%M:%S"),
            }
            safe_set_chunks(document, chunks)
            document.updated_at = get_current_timestamp()

            logger.debug("Committing changes to database")
            await self.db_session.commit()

            logger.info(
                f"Successfully synced KB for document {document_id}: "
                f"summary={len(summary_content)} chars, chunks={len(chunks)}, "
                f"content_verified={content_verified}"
            )
            return {"status": "success"}

        except Exception as e:
            logger.error(
                f"Failed to sync KB for document {document_id}: {e}", exc_info=True
            )
            await self.db_session.rollback()
            return {"status": "error", "message": str(e)}