from fastapi import APIRouter, Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from sqlalchemy.orm import Session
from typing import List

from app.models.database import get_db
from app.schemas.user import UserCreate, UserUpdate, UserResponse, UserListResponse, Token, LoginRequest
from app.services.user import UserService

# 创建路由器
router = APIRouter(prefix="/users", tags=["users"])

# OAuth2密码Bearer
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/users/login")


async def get_current_active_user(db: Session = Depends(get_db), token: str = Depends(oauth2_scheme)):
    """获取当前活跃用户"""
    user = UserService.get_current_user(db, token)
    if not user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Could not validate credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )
    if user.status != "active":
        raise HTTPException(status_code=400, detail="Inactive user")
    return user


from app.schemas.user import LoginRequest

@router.post("/login", response_model=Token)
async def login(login_request: LoginRequest, db: Session = Depends(get_db)):
    """用户登录"""
    user = UserService.authenticate_user(db, login_request.username, login_request.password)
    if not user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect username or password",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
    # 创建访问令牌
    access_token = UserService.create_access_token(
        data={"sub": user.username, "user_id": user.id}
    )
    
    return {"access_token": access_token, "token_type": "bearer"}


@router.post("/register", response_model=UserResponse)
async def register(user: UserCreate, db: Session = Depends(get_db)):
    """用户注册"""
    # 检查用户名是否已存在
    if UserService.get_user_by_username(db, user.username):
        raise HTTPException(status_code=400, detail="Username already registered")
    
    # 检查邮箱是否已存在
    if UserService.get_user_by_email(db, user.email):
        raise HTTPException(status_code=400, detail="Email already registered")
    
    # 创建用户
    db_user = UserService.create_user(db, user)
    
    return db_user


@router.get("/me", response_model=UserResponse)
async def read_users_me(current_user: UserResponse = Depends(get_current_active_user)):
    """获取当前用户信息"""
    return current_user


@router.get("/", response_model=UserListResponse)
async def get_users(
    skip: int = 0,
    limit: int = 100,
    current_user: UserResponse = Depends(get_current_active_user),
    db: Session = Depends(get_db)
):
    """获取用户列表"""
    # 只有管理员可以查看用户列表
    if current_user.role != "admin":
        raise HTTPException(status_code=403, detail="Not enough permissions")
    
    users = UserService.get_users(db, skip=skip, limit=limit)
    return {"users": users, "total": len(users)}


@router.get("/{user_id}", response_model=UserResponse)
async def get_user(
    user_id: str,
    current_user: UserResponse = Depends(get_current_active_user),
    db: Session = Depends(get_db)
):
    """获取用户信息"""
    # 只有管理员或用户本人可以查看用户信息
    if current_user.role != "admin" and current_user.id != user_id:
        raise HTTPException(status_code=403, detail="Not enough permissions")
    
    user = UserService.get_user_by_id(db, user_id)
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    
    return user


@router.put("/{user_id}", response_model=UserResponse)
async def update_user(
    user_id: str,
    user_update: UserUpdate,
    current_user: UserResponse = Depends(get_current_active_user),
    db: Session = Depends(get_db)
):
    """更新用户信息"""
    # 只有管理员或用户本人可以更新用户信息
    if current_user.role != "admin" and current_user.id != user_id:
        raise HTTPException(status_code=403, detail="Not enough permissions")
    
    # 非管理员只能更新自己的信息，不能更新角色
    if current_user.role != "admin" and "role" in user_update.dict():
        raise HTTPException(status_code=403, detail="Cannot update role")
    
    user = UserService.update_user(db, user_id, user_update)
    if not user:
        raise HTTPException(status_code=404, detail="User not found")
    
    return user