from fastapi import APIRouter, Depends, HTTPException, status
from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
from sqlalchemy.orm import Session
from datetime import timedelta
from pydantic import BaseModel, EmailStr
from app.db.database import get_db
from app.db.models import User
from app.core.security import verify_password, get_password_hash, create_access_token, decode_token
from app.core.config import settings
import logging

logger = logging.getLogger(__name__)

router = APIRouter()
security = HTTPBearer()

# Pydantic models
class UserRegistration(BaseModel):
    username: str
    email: EmailStr
    password: str
    fullName: str = None

class UserLogin(BaseModel):
    username: str
    password: str

class UserResponse(BaseModel):
    id: int
    username: str
    email: str
    fullName: str = None
    createdAt: str

    class Config:
        from_attributes = True

class TokenResponse(BaseModel):
    access_token: str
    token_type: str = "bearer"
    user: UserResponse

# Dependency to get current user
async def get_current_user(
    credentials: HTTPAuthorizationCredentials = Depends(security),
    db: Session = Depends(get_db)
) -> User:
    """Get current authenticated user"""
    token = credentials.credentials
    username = decode_token(token)
    
    if username is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid authentication credentials",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
    user = db.query(User).filter(User.username == username).first()
    if user is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="User not found",
            headers={"WWW-Authenticate": "Bearer"},
        )
    
    return user

@router.post("/register", response_model=TokenResponse)
async def register_user(user_data: UserRegistration, db: Session = Depends(get_db)):
    """Register a new user"""
    try:
        # Check if username already exists
        existing_user = db.query(User).filter(User.username == user_data.username).first()
        if existing_user:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Username already registered"
            )
        
        # Check if email already exists
        existing_email = db.query(User).filter(User.email == user_data.email).first()
        if existing_email:
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail="Email already registered"
            )
        
        # Create new user
        hashed_password = get_password_hash(user_data.password)
        new_user = User(
            username=user_data.username,
            email=user_data.email,
            hashed_password=hashed_password,
            full_name=user_data.fullName
        )
        
        db.add(new_user)
        db.commit()
        db.refresh(new_user)
        
        # Create access token
        access_token = create_access_token(
            subject=new_user.username,
            expires_delta=timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
        )
        
        logger.info(f"New user registered: {new_user.username}")
        
        return TokenResponse(
            access_token=access_token,
            user=UserResponse(
                id=new_user.id,
                username=new_user.username,
                email=new_user.email,
                fullName=new_user.full_name,
                createdAt=new_user.created_at.isoformat()
            )
        )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Registration error: {e}")
        db.rollback()
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="Registration failed"
        )

@router.post("/login", response_model=TokenResponse)
async def login_user(login_data: UserLogin, db: Session = Depends(get_db)):
    """Authenticate user and return token"""
    try:
        # Find user
        user = db.query(User).filter(User.username == login_data.username).first()
        if not user:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail="Invalid username or password"
            )
        
        # Verify password
        if not verify_password(login_data.password, user.hashed_password):
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail="Invalid username or password"
            )
        
        # Update last login
        from datetime import datetime
        user.last_login = datetime.utcnow()
        db.commit()
        
        # Create access token
        access_token = create_access_token(
            subject=user.username,
            expires_delta=timedelta(minutes=settings.ACCESS_TOKEN_EXPIRE_MINUTES)
        )
        
        logger.info(f"User logged in: {user.username}")
        
        return TokenResponse(
            access_token=access_token,
            user=UserResponse(
                id=user.id,
                username=user.username,
                email=user.email,
                fullName=user.full_name,
                createdAt=user.created_at.isoformat()
            )
        )
        
    except HTTPException:
        raise
    except Exception as e:
        logger.error(f"Login error: {e}")
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail="Login failed"
        )

@router.post("/logout")
async def logout_user(current_user: User = Depends(get_current_user)):
    """Logout user (client-side token removal)"""
    logger.info(f"User logged out: {current_user.username}")
    return {"message": "Successfully logged out"}

@router.get("/me", response_model=UserResponse)
async def get_current_user_info(current_user: User = Depends(get_current_user)):
    """Get current user information"""
    return UserResponse(
        id=current_user.id,
        username=current_user.username,
        email=current_user.email,
        fullName=current_user.full_name,
        createdAt=current_user.created_at.isoformat()
    )