from typing import Optional, List
from datetime import datetime, timedelta, UTC

from PIL.ImageChops import offset
from bson import ObjectId
from motor.motor_asyncio import AsyncIOMotorClient

from api.models.GenerationRequest import GenerationResponse
from models.Generation import Generation, GenerationStatus


class GenerationRepo:
    def __init__(self, client: AsyncIOMotorClient, db_name="bot_db"):
        self.collection = client[db_name]["generations"]

    async def create_generation(self, generation: Generation) -> str:
        res = await self.collection.insert_one(generation.model_dump())
        return str(res.inserted_id)

    async def get_generation(self, generation_id: str) -> Optional[Generation]:
        res = await self.collection.find_one({"_id": ObjectId(generation_id)})
        if res is None:
            return None
        else:
            res["id"] = str(res.pop("_id"))
            return Generation(**res)

    async def get_generations(self, character_id: Optional[str] = None, status: Optional[GenerationStatus] = None,
                              limit: int = 10, offset: int = 0, created_by: Optional[str] = None, project_id: Optional[str] = None, idea_id: Optional[str] = None) -> List[Generation]:
        
        filter = {"is_deleted": False}
        if character_id is not None:
            filter["linked_character_id"] = character_id
        if status is not None:
            filter["status"] = status
        if created_by is not None:
            filter["created_by"] = created_by
            # If filtering by created_by user (e.g. "My Generations"), we typically imply personal scope if project_id is None.
            # But if project_id is passed, we filter by that.
            if project_id is None:
                filter["project_id"] = None
        if project_id is not None:
            filter["project_id"] = project_id
        if idea_id is not None:
            filter["idea_id"] = idea_id

        # If fetching for an idea, sort by created_at ascending (cronological)
        # Otherwise typically descending (newest first)
        sort_order = 1 if idea_id else -1

        res = await self.collection.find(filter).sort("created_at", sort_order).skip(
            offset).limit(limit).to_list(None)
        generations: List[Generation] = []
        for generation in res:
            generation["id"] = str(generation.pop("_id"))
            generations.append(Generation(**generation))
        return generations

    async def count_generations(self, character_id: Optional[str] = None, status: Optional[GenerationStatus] = None, 
                                album_id: Optional[str] = None, created_by: Optional[str] = None, project_id: Optional[str] = None, idea_id: Optional[str] = None) -> int:
        args = {}
        if character_id is not None:
            args["linked_character_id"] = character_id
        if status is not None:
            args["status"] = status
        if created_by is not None:
            args["created_by"] = created_by
        if project_id is not None:
            args["project_id"] = project_id
        if idea_id is not None:
            args["idea_id"] = idea_id
        return await self.collection.count_documents(args)

    async def get_generations_by_ids(self, generation_ids: List[str]) -> List[Generation]:
        object_ids = [ObjectId(gen_id) for gen_id in generation_ids if ObjectId.is_valid(gen_id)]
        res = await self.collection.find({"_id": {"$in": object_ids}}).to_list(None)
        generations: List[Generation] = []
        
        # Maintain order of generation_ids
        gen_map = {str(doc["_id"]): doc for doc in res}
        
        for gen_id in generation_ids:
            doc = gen_map.get(gen_id)
            if doc:
                doc["id"] = str(doc.pop("_id"))
                generations.append(Generation(**doc))
                
        return generations

    async def update_generation(self, generation: Generation, ):
        res = await self.collection.update_one({"_id": ObjectId(generation.id)}, {"$set": generation.model_dump()})

    async def get_generations_by_group(self, group_id: str) -> List[Generation]:
        res = await self.collection.find({"generation_group_id": group_id, "is_deleted": False}).sort("created_at", 1).to_list(None)
        generations: List[Generation] = []
        for generation in res:
            generation["id"] = str(generation.pop("_id"))
            generations.append(Generation(**generation))
        return generations

    async def cancel_stale_generations(self, timeout_minutes: int = 60) -> int:
        cutoff_time = datetime.now(UTC) - timedelta(minutes=timeout_minutes)
        res = await self.collection.update_many(
            {
                "status": GenerationStatus.RUNNING,
                "created_at": {"$lt": cutoff_time}
            },
            {
                "$set": {
                    "status": GenerationStatus.FAILED,
                    "failed_reason": "Timeout: Execution time limit exceeded",
                    "updated_at": datetime.now(UTC)
                }
            }
        )
        return res.modified_count