from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.ext.asyncio import AsyncSession

from app.api.deps import get_current_user
from app.database import get_db
from app.models.user import User
from app.schemas.auth import (
    AccessTokenResponse,
    ChangePasswordRequest,
    ForgotPasswordRequest,
    RefreshTokenRequest,
    ResetPasswordRequest,
    TokenResponse,
    UpdateProfileRequest,
    UserLogin,
    UserRegister,
    UserResponse,
    VerifyEmailRequest,
)
from app.services.auth import (
    authenticate_user,
    change_password as change_password_service,
    create_access_token,
    create_refresh_token,
    register_user,
    reset_password as reset_password_service,
    send_reset_link,
    send_verification_code,
    update_profile as update_profile_service,
    verify_email as verify_email_service,
    verify_refresh_token,
)
from app.services.cache import get_cache_service, TTL_USER_PROFILE

router = APIRouter()


@router.post("/register", response_model=UserResponse, status_code=status.HTTP_201_CREATED)
async def register(user_data: UserRegister, db: AsyncSession = Depends(get_db)):
    try:
        user = await register_user(db, user_data)
    except ValueError:
        # 不泄露具体原因，防止用户枚举
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="注册失败，请检查输入信息是否已被使用")
    return user


@router.post("/login", response_model=TokenResponse)
async def login(user_data: UserLogin, db: AsyncSession = Depends(get_db)):
    user = await authenticate_user(db, user_data.email, user_data.password)
    if not user:
        # 统一错误消息，防止用户枚举（不区分“用户不存在” vs “密码错误”）
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="邮箱或密码错误",
            headers={"WWW-Authenticate": "Bearer"},
        )

    access_token = create_access_token(data={"sub": str(user.id)})
    refresh_token = create_refresh_token(data={"sub": str(user.id)})
    return {
        "access_token": access_token,
        "token_type": "bearer",
        "refresh_token": refresh_token,
        "user": user,
    }


@router.post("/refresh", response_model=AccessTokenResponse)
async def refresh_token(req: RefreshTokenRequest):
    """
    刷新接口：使用 refresh_token 获取新的 access_token + refresh_token（滑动过期）
    """
    try:
        payload = verify_refresh_token(req.refresh_token)
    except ValueError:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="刷新令牌无效或已过期",
            headers={"WWW-Authenticate": "Bearer"},
        )

    user_id = payload.get("sub")
    if not user_id:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="刷新令牌无效或已过期",
            headers={"WWW-Authenticate": "Bearer"},
        )

    new_access_token = create_access_token(data={"sub": user_id})
    new_refresh_token = create_refresh_token(data={"sub": user_id})  # 滑动过期
    return {
        "access_token": new_access_token,
        "token_type": "bearer",
        "refresh_token": new_refresh_token,
    }


@router.get("/me", response_model=UserResponse)
async def read_current_user(
    current_user: User = Depends(get_current_user),
):
    cache = get_cache_service()
    cache_key = f"user:profile:{current_user.id}"
    cached = await cache.get_json(cache_key)
    if cached is not None:
        return cached

    user_data = UserResponse.model_validate(current_user).model_dump(mode="json")
    await cache.set_json(cache_key, user_data, expire=TTL_USER_PROFILE)
    return current_user


@router.post("/forgot-password")
async def forgot_password(req: ForgotPasswordRequest, db: AsyncSession = Depends(get_db)):
    await send_reset_link(db, req.email)
    return {"message": "如果该邮箱已注册，重置链接已发送"}


@router.post("/reset-password")
async def reset_password(req: ResetPasswordRequest, db: AsyncSession = Depends(get_db)):
    success = await reset_password_service(db, req.token, req.new_password)
    if not success:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="无效的令牌或令牌已过期")
    return {"message": "密码重置成功"}


@router.post("/verify-email")
async def verify_email(req: VerifyEmailRequest, db: AsyncSession = Depends(get_db)):
    success = await verify_email_service(db, req.email, req.code)
    if not success:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="验证码无效或已过期")
    return {"message": "邮箱验证成功"}


@router.post("/resend-verification")
async def resend_verification(req: ForgotPasswordRequest, db: AsyncSession = Depends(get_db)):
    await send_verification_code(db, req.email)
    return {"message": "验证码已重新发送"}


@router.put("/change-password")
async def change_password(
    req: ChangePasswordRequest,
    user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    success = await change_password_service(db, user.id, req.old_password, req.new_password)
    if not success:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="旧密码错误")
    return {"message": "密码修改成功"}


@router.put("/profile", response_model=UserResponse)
async def update_profile(
    req: UpdateProfileRequest,
    user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    updated_user = await update_profile_service(db, user.id, req)
    if not updated_user:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="用户不存在")

    # 失效用户配置缓存
    cache = get_cache_service()
    await cache.delete(f"user:profile:{user.id}")

    return updated_user