import logging
from fastapi import APIRouter, Depends, HTTPException, BackgroundTasks
from sqlalchemy.orm import Session
from typing import List
from datetime import datetime

from api.auth import get_current_user
from models import db_models
from models.schemas import MindMapGenerateRequest, MindMapResponse
from core.database import get_db, SessionLocal
from api.websocket_routes import manager
from services.mindmap_service import mindmap_service

router = APIRouter(prefix="/api/mindmaps", tags=["mindmaps"])
logger = logging.getLogger(__name__)

async def run_mindmap_generation(mindmap_id: int, request: MindMapGenerateRequest, user_id: int):
    """Background task for mind map generation"""
    db = SessionLocal()
    connection_id = f"user_{user_id}"
    try:
        db_mindmap = db.query(db_models.MindMap).filter(db_models.MindMap.id == mindmap_id).first()
        if not db_mindmap: return

        # Call AI service
        mermaid_code = await mindmap_service.generate_mindmap(
            file_key=request.file_key,
            text_input=request.text_input
        )

        if not mermaid_code:
            raise Exception("AI failed to generate mind map code")

        db_mindmap.mermaid_code = mermaid_code
        db_mindmap.status = "completed"
        db.commit()

        # Notify via WebSocket
        await manager.send_result(connection_id, {
            "type": "mindmap",
            "id": db_mindmap.id,
            "status": "completed",
            "title": db_mindmap.title
        })

    except Exception as e:
        logger.error(f"Background mindmap generation failed: {e}")
        db_mindmap = db.query(db_models.MindMap).filter(db_models.MindMap.id == mindmap_id).first()
        if db_mindmap:
            db_mindmap.status = "failed"
            db_mindmap.error_message = str(e)
            db.commit()
        await manager.send_error(connection_id, f"Mind map generation failed: {str(e)}")
    finally:
        db.close()

@router.post("/generate", response_model=MindMapResponse)
async def generate_mindmap(
    request: MindMapGenerateRequest,
    background_tasks: BackgroundTasks,
    current_user: db_models.User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """
    Initiates mind map generation in the background.
    """
    source_id = None
    if request.file_key:
        source = db.query(db_models.Source).filter(
            db_models.Source.s3_key == request.file_key,
            db_models.Source.user_id == current_user.id
        ).first()
        if not source:
            raise HTTPException(status_code=403, detail="Not authorized to access this file")
        source_id = source.id

    # Create initial processing record
    file_base = request.file_key.split('/')[-1].rsplit('.', 1)[0] if request.file_key else None
    print(f'file_base: {file_base}')
    
    # Priority: 1. File-based name, 2. User Title (if not default 'string'), 3. Default timestamp
    if file_base:
        title = f"Mind Map-{file_base}"
    elif request.title and request.title != "string":
        title = request.title
    else:
        title = f"Mind Map {datetime.utcnow().strftime('%Y-%m-%d %H:%M')}"
    db_mindmap = db_models.MindMap(
        title=title,
        user_id=current_user.id,
        source_id=source_id,
        status="processing"
    )
    db.add(db_mindmap)
    db.commit()
    db.refresh(db_mindmap)

    # Offload to background task
    background_tasks.add_task(run_mindmap_generation, db_mindmap.id, request, current_user.id)

    # return processing state
    resp = MindMapResponse.model_validate(db_mindmap)
    resp.message = "Mind map generation started"
    return resp

@router.get("/list", response_model=List[MindMapResponse])
async def list_mindmaps(
    current_user: db_models.User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """
    Lists all mind maps for the current user.
    """
    try:
        mindmaps = db.query(db_models.MindMap).filter(
            db_models.MindMap.user_id == current_user.id
        ).order_by(db_models.MindMap.created_at.desc()).all()
        
        return [MindMapResponse.model_validate(m) for m in mindmaps]
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))

@router.delete("/{mindmap_id}")
async def delete_mindmap(
    mindmap_id: int,
    current_user: db_models.User = Depends(get_current_user),
    db: Session = Depends(get_db)
):
    """
    Deletes a specific mind map.
    """
    mindmap = db.query(db_models.MindMap).filter(
        db_models.MindMap.id == mindmap_id,
        db_models.MindMap.user_id == current_user.id
    ).first()
    
    if not mindmap:
        raise HTTPException(status_code=404, detail="Mind map not found")
    
    db.delete(mindmap)
    db.commit()
    return {"message": "Mind map deleted successfully"}