"""Authentication router endpoints."""
from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from typing import Optional

from datetime import datetime

from app.core.database import get_db
from app.core.security import (
    verify_password,
    hash_password,
    create_access_token,
    create_refresh_token,
    decode_token,
)
from app.models.models import User
from app.schemas.schemas import (
    LoginRequest,
    LoginResponse,
    RefreshTokenRequest,
    TokenResponse,
    UserCreate,
    UserResponse,
)

router = APIRouter()


@router.post("/login", response_model=LoginResponse)
async def login(request: LoginRequest, db: AsyncSession = Depends(get_db)):
    """Authenticate user and return JWT tokens."""
    # Find user by username
    stmt = select(User).where(User.username == request.username)
    result = await db.execute(stmt)
    user = result.scalar_one_or_none()
    
    if not user or not verify_password(request.password, user.password_hash):
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid username or password",
        )
    
    if not user.is_active:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Account is disabled",
        )
    
    if user.is_banned and user.ban_ends and user.ban_ends > __import__("datetime").datetime.now():
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Account is banned",
        )
    
    # Update last login
    user.last_login = __import__("datetime").datetime.now()
    await db.flush()
    
    # Generate tokens
    access_token = create_access_token(str(user.id), user.privlevel or "User")
    refresh_token = create_refresh_token(str(user.id), user.privlevel or "User")
    
    return LoginResponse(
        access_token=access_token,
        refresh_token=refresh_token,
        user=UserResponse.model_validate(user).model_dump(),
    )


@router.post("/refresh", response_model=TokenResponse)
async def refresh_token(request: RefreshTokenRequest, db: AsyncSession = Depends(get_db)):
    """Refresh access token using refresh token."""
    payload = decode_token(request.refresh_token)
    
    if not payload or payload.get("type") != "refresh":
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid refresh token",
        )
    
    # Verify user still exists and is active
    user_id = payload["sub"]
    stmt = select(User).where(User.id == int(user_id))
    result = await db.execute(stmt)
    user = result.scalar_one_or_none()
    
    if not user or not user.is_active:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="User account is invalid",
        )
    
    # Generate new access token
    access_token = create_access_token(str(user.id), user.privlevel or "User")
    
    return TokenResponse(access_token=access_token)


@router.post("/register", response_model=UserResponse)
async def register(request: UserCreate, db: AsyncSession = Depends(get_db)):
    """Register a new user account."""
    # Check if username exists
    stmt = select(User).where(User.username == request.username)
    result = await db.execute(stmt)
    if result.scalar_one_or_none():
        raise HTTPException(
            status_code=status.HTTP_409_CONFLICT,
            detail="Username already exists",
        )
    
    # Check if email exists (if provided)
    if request.email:
        stmt = select(User).where(User.email == request.email)
        result = await db.execute(stmt)
        if result.scalar_one_or_none():
            raise HTTPException(
                status_code=status.HTTP_409_CONFLICT,
                detail="Email already registered",
            )
    
    # Create new user
    new_user = User(
        username=request.username,
        password_hash=hash_password(request.password),
        salt="random_salt",  # In production, generate random salt
        email=request.email,
        country=request.country,
        real_name=request.real_name,
    )
    db.add(new_user)
    await db.flush()
    
    return UserResponse.model_validate(new_user)


@router.get("/me", response_model=UserResponse)
async def get_current_user(
    token: str,
    db: AsyncSession = Depends(get_db),
):
    """Get current authenticated user."""
    payload = decode_token(token)
    
    if not payload or payload.get("type") != "access":
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid token",
        )
    
    user_id = payload["sub"]
    stmt = select(User).where(User.id == int(user_id))
    result = await db.execute(stmt)
    user = result.scalar_one_or_none()
    
    if not user:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="User not found",
        )
    
    return UserResponse.model_validate(user)