from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy.future import select
from sqlalchemy import delete, update
from app.models.user_images import UserImage
from app.schemas.user_image import UserImageCreate, UserImageUpdate
from typing import List, Optional

async def get_user_image(db: AsyncSession, image_id: int):
    """获取单个用户形象"""
    result = await db.execute(select(UserImage).filter(UserImage.id == image_id))
    return result.scalars().first()

async def get_user_images_by_user(db: AsyncSession, user_id: int, skip: int = 0, limit: int = 100):
    """获取用户的所有形象图片"""
    result = await db.execute(
        select(UserImage)
        .filter(UserImage.user_id == user_id)
        .order_by(UserImage.create_time.desc())
        .offset(skip)
        .limit(limit)
    )
    return result.scalars().all()

async def create_user_image(db: AsyncSession, image: UserImageCreate):
    """创建用户形象
    
    image: 包含user_id的UserImageCreate对象
    """
    # 如果设置为默认形象，先重置用户的所有形象为非默认
    if image.is_default and image.user_id:
        await reset_default_images(db, image.user_id)
        
    db_image = UserImage(
        user_id=image.user_id,
        image_url=image.image_url,
        is_default=image.is_default
    )
    db.add(db_image)
    await db.commit()
    await db.refresh(db_image)
    return db_image

async def update_user_image(db: AsyncSession, image_id: int, image: UserImageUpdate):
    """更新用户形象"""
    db_image = await get_user_image(db, image_id)
    if not db_image:
        return None
    
    # 处理默认形象逻辑
    if image.is_default is not None and image.is_default and not db_image.is_default:
        # 如果设置为默认且之前不是默认，重置其他形象
        await reset_default_images(db, db_image.user_id)
        db_image.is_default = True
    elif image.is_default is not None:
        db_image.is_default = image.is_default
        
    # 更新图片URL
    if image.image_url:
        db_image.image_url = image.image_url
        
    await db.commit()
    await db.refresh(db_image)
    return db_image

async def delete_user_image(db: AsyncSession, image_id: int):
    """删除用户形象"""
    db_image = await get_user_image(db, image_id)
    if db_image:
        await db.delete(db_image)
        await db.commit()
    return db_image

async def delete_user_images(db: AsyncSession, user_id: int):
    """删除用户所有形象图片"""
    stmt = delete(UserImage).where(UserImage.user_id == user_id)
    await db.execute(stmt)
    await db.commit()
    return True

async def reset_default_images(db: AsyncSession, user_id: int):
    """重置用户所有形象为非默认"""
    stmt = update(UserImage).where(
        UserImage.user_id == user_id,
        UserImage.is_default == True
    ).values(is_default=False)
    await db.execute(stmt)
    
async def get_default_image(db: AsyncSession, user_id: int):
    """获取用户的默认形象"""
    result = await db.execute(
        select(UserImage)
        .filter(UserImage.user_id == user_id, UserImage.is_default == True)
    )
    return result.scalars().first()