import uuid
from datetime import UTC, datetime
from typing import Any

from motor.motor_asyncio import AsyncIOMotorDatabase
from pymongo import ReturnDocument

COLLECTION = "templates"


async def ensure_template_indexes(db: AsyncIOMotorDatabase) -> None:
    await db[COLLECTION].create_index([("owner_id", 1), ("updated_at", -1)])
    await db[COLLECTION].create_index([("owner_id", 1), ("category", 1)])


def _serialize(template: dict[str, Any]) -> dict[str, Any]:
    return {
        "id": template["_id"],
        "owner_id": template["owner_id"],
        "name": template["name"],
        "description": template.get("description", ""),
        "category": template.get("category", "General"),
        "emoji": template.get("emoji", "📄"),
        "content": template.get("content", {}),
        "created_at": template["created_at"],
        "updated_at": template["updated_at"],
        "members": template.get("members", []),
    }


async def list_templates(db: AsyncIOMotorDatabase, owner_id: int) -> list[dict[str, Any]]:
    cursor = db[COLLECTION].find(
        {"$or": [{"owner_id": owner_id}, {"members.user_id": owner_id}]}
    ).sort([("category", 1), ("updated_at", -1)])
    return [_serialize(template) async for template in cursor]


async def create_template(
    db: AsyncIOMotorDatabase,
    owner_id: int,
    data: dict[str, Any],
) -> dict[str, Any]:
    now = datetime.now(UTC)
    template = {
        "_id": str(uuid.uuid4()),
        "owner_id": owner_id,
        **data,
        "created_at": now,
        "updated_at": now,
        "members": [],
    }
    await db[COLLECTION].insert_one(template)
    return _serialize(template)


async def delete_template(db: AsyncIOMotorDatabase, template_id: str, owner_id: int) -> bool:
    result = await db[COLLECTION].delete_one({"_id": template_id, "owner_id": owner_id})
    return result.deleted_count == 1


async def share_template(
    db: AsyncIOMotorDatabase,
    template_id: str,
    owner_id: int,
    member: dict[str, Any],
) -> dict[str, Any] | None:
    template = await db[COLLECTION].find_one({"_id": template_id, "owner_id": owner_id})
    if template is None:
        return None
    members = [item for item in template.get("members", []) if item.get("user_id") != member["user_id"]]
    members.append(member)
    result = await db[COLLECTION].find_one_and_update(
        {"_id": template_id, "owner_id": owner_id},
        {"$set": {"members": members, "updated_at": datetime.now(UTC)}},
        return_document=ReturnDocument.AFTER,
    )
    return _serialize(result) if result else None