"""
Authentication API Endpoints - Login, Token Management, Telegram Binding
"""
from fastapi import APIRouter, Depends, HTTPException, Request
from pydantic import BaseModel, EmailStr
from typing import Optional
from sqlalchemy.orm import Session
from app.db.database import get_db
from app.services.auth_service import AuthService
from app.security.jwt_manager import jwt_manager
import logging


logger = logging.getLogger(__name__)
router = APIRouter(prefix="/api/v1/auth", tags=["authentication"])


# Request/Response Models
class LoginRequest(BaseModel):
    email: EmailStr
    password: str


class LoginResponse(BaseModel):
    access_token: str
    refresh_token: str
    user_id: int
    expires_in: int  # seconds


class TelegramBindingStartRequest(BaseModel):
    chat_id: int


class TelegramBindingStartResponse(BaseModel):
    code: str
    expires_in: int  # seconds


class TelegramBindingConfirmRequest(BaseModel):
    code: str
    chat_id: int
    username: Optional[str] = None
    first_name: Optional[str] = None
    last_name: Optional[str] = None


class TelegramBindingConfirmResponse(BaseModel):
    success: bool
    user_id: int
    jwt_token: str
    expires_at: str


class TokenRefreshRequest(BaseModel):
    refresh_token: str


class TokenRefreshResponse(BaseModel):
    access_token: str
    expires_in: int


@router.post(
    "/login",
    response_model=LoginResponse,
    summary="User login with email & password",
)
async def login(
    request: LoginRequest,
    db: Session = Depends(get_db),
) -> LoginResponse:
    """
    Authenticate user and create session.
    
    **Returns:**
    - access_token: Short-lived JWT (15 min)
    - refresh_token: Long-lived refresh token (30 days)
    
    **Usage:**
    ```
    Authorization: Bearer <access_token>
    X-Device-Id: device_uuid  # For tracking
    ```
    """
    
    # TODO: Verify email + password
    # For MVP: Assume credentials are valid
    
    from app.db.models import User
    
    user = db.query(User).filter(User.email == request.email).first()
    if not user:
        raise HTTPException(status_code=401, detail="Invalid credentials")
    
    service = AuthService(db)
    access_token, refresh_token = await service.create_session(
        user_id=user.id,
        device_id=request.__dict__.get("device_id"),
    )
    
    return LoginResponse(
        access_token=access_token,
        refresh_token=refresh_token,
        user_id=user.id,
        expires_in=15 * 60,  # 15 minutes
    )


@router.post(
    "/refresh",
    response_model=TokenRefreshResponse,
    summary="Refresh access token",
)
async def refresh_token(
    request: TokenRefreshRequest,
    db: Session = Depends(get_db),
) -> TokenRefreshResponse:
    """
    Issue new access token using refresh token.
    
    **Flow:**
    1. Access token expires
    2. Send refresh_token to this endpoint
    3. Receive new access_token (without creating new session)
    """
    
    try:
        token_payload = jwt_manager.verify_token(request.refresh_token)
        if token_payload.type != "refresh":
            raise ValueError("Not a refresh token")
        
        service = AuthService(db)
        new_access_token = await service.refresh_access_token(
            refresh_token=request.refresh_token,
            user_id=token_payload.sub,
        )
        
        return TokenRefreshResponse(
            access_token=new_access_token,
            expires_in=15 * 60,
        )
    
    except ValueError as e:
        raise HTTPException(status_code=401, detail=str(e))


@router.post(
    "/telegram/start",
    response_model=TelegramBindingStartResponse,
    summary="Start Telegram binding flow",
)
async def telegram_binding_start(
    request: TelegramBindingStartRequest,
    db: Session = Depends(get_db),
):
    """
    Generate binding code for Telegram user.
    
    **Bot Flow:**
    1. User sends /start
    2. Bot calls this endpoint: POST /auth/telegram/start
    3. Bot receives code and generates link
    4. Bot sends message with link to user
    5. User clicks link (goes to confirm endpoint)
    """
    
    service = AuthService(db)
    code = await service.create_telegram_binding_code(chat_id=request.chat_id)
    
    return TelegramBindingStartResponse(
        code=code,
        expires_in=600,  # 10 minutes
    )


@router.post(
    "/telegram/confirm",
    response_model=TelegramBindingConfirmResponse,
    summary="Confirm Telegram binding",
)
async def telegram_binding_confirm(
    request: TelegramBindingConfirmRequest,
    current_request: Request,
    db: Session = Depends(get_db),
):
    """
    Confirm Telegram binding and issue JWT.
    
    **Flow:**
    1. User logs in or creates account
    2. User clicks binding link with code
    3. Frontend calls this endpoint with code + user context
    4. Backend creates TelegramIdentity record
    5. Backend returns JWT for bot to use
    
    **Bot Usage:**
    ```python
    # Bot stores JWT for user
    redis.setex(f"chat_id:{chat_id}:jwt", 86400*30, jwt_token)
    
    # Bot makes API calls
    api_request.headers['Authorization'] = f'Bearer {jwt_token}'
    ```
    """
    
    # Get authenticated user from JWT
    user_id = getattr(current_request.state, "user_id", None)
    if not user_id:
        raise HTTPException(status_code=401, detail="User must be authenticated")
    
    service = AuthService(db)
    result = await service.confirm_telegram_binding(
        user_id=user_id,
        chat_id=request.chat_id,
        code=request.code,
        username=request.username,
        first_name=request.first_name,
        last_name=request.last_name,
    )
    
    if not result.get("success"):
        raise HTTPException(status_code=400, detail="Binding failed")
    
    return TelegramBindingConfirmResponse(**result)


@router.post(
    "/telegram/store-token",
    response_model=dict,
    summary="Store JWT token for Telegram user (called after binding confirmation)",
)
async def telegram_store_token(
    chat_id: int,
    jwt_token: str,
    db: Session = Depends(get_db),
):
    """
    Store JWT token in Redis after successful binding confirmation.
    
    **Flow:**
    1. User confirms binding via /telegram/confirm
    2. Frontend receives jwt_token
    3. Frontend calls this endpoint to cache token in bot's Redis
    4. Bot can now use token for API calls
    
    **Usage:**
    ```
    POST /auth/telegram/store-token?chat_id=12345&jwt_token=eyJ...
    ```
    """
    
    import redis
    
    # Get Redis client from settings
    from app.core.config import settings
    redis_client = redis.from_url(settings.redis_url)
    
    # Validate JWT token structure
    try:
        jwt_manager.verify_token(jwt_token)
    except ValueError as e:
        raise HTTPException(status_code=400, detail=f"Invalid token: {e}")
    
    # Store JWT in Redis with 30-day TTL
    cache_key = f"chat_id:{chat_id}:jwt"
    redis_client.setex(cache_key, 86400 * 30, jwt_token)
    
    logger.info(f"JWT token stored for chat_id={chat_id}")
    
    return {
        "success": True,
        "message": "Token stored successfully",
        "chat_id": chat_id,
    }


@router.post(
    "/telegram/authenticate",
    response_model=dict,
    summary="Authenticate by Telegram chat_id",
)
async def telegram_authenticate(
    chat_id: int,
    db: Session = Depends(get_db),
):
    """
    Get JWT token for Telegram user (bot authentication).
    
    **Usage in Bot:**
    ```python
    # Get token for authenticated user
    response = api.post("/auth/telegram/authenticate?chat_id=12345")
    jwt_token = response["jwt_token"]
    ```
    """
    
    service = AuthService(db)
    result = await service.authenticate_telegram_user(chat_id=chat_id)
    
    if not result:
        raise HTTPException(status_code=404, detail="Telegram identity not found")
    
    return result


@router.post(
    "/telegram/register",
    response_model=dict,
    summary="Create new user with Telegram binding",
)
async def telegram_register(
    chat_id: int,
    username: Optional[str] = None,
    first_name: Optional[str] = None,
    last_name: Optional[str] = None,
    db: Session = Depends(get_db),
):
    """
    Quick registration for new Telegram user.
    
    **Flow:**
    1. Bot calls this endpoint on /start
    2. Creates new User with telegram_id
    3. Returns JWT for immediate API access
    4. User can update email/password later
    
    **Usage in Bot:**
    ```python
    result = api.post(
        "/auth/telegram/register",
        params={
            "chat_id": 12345,
            "username": "john_doe",
            "first_name": "John",
            "last_name": "Doe",
        }
    )
    jwt_token = result["jwt_token"]
    ```
    """
    
    from app.db.models.user import User
    
    # Check if user already exists
    existing = db.query(User).filter_by(telegram_id=chat_id).first()
    if existing:
        service = AuthService(db)
        result = await service.authenticate_telegram_user(chat_id=chat_id)
        return {
            **result,
            "created": False,
            "message": "User already exists",
        }
    
    # Create new user
    new_user = User(
        telegram_id=chat_id,
        username=username,
        first_name=first_name,
        last_name=last_name,
        is_active=True,
    )
    
    try:
        db.add(new_user)
        db.commit()
        db.refresh(new_user)
    except Exception as e:
        db.rollback()
        logger.error(f"Failed to create user: {e}")
        raise HTTPException(status_code=400, detail="Failed to create user")
    
    # Create JWT
    service = AuthService(db)
    result = await service.authenticate_telegram_user(chat_id=chat_id)
    
    if result:
        result["created"] = True
        result["message"] = f"User created successfully (user_id={new_user.id})"
    
    logger.info(f"New Telegram user registered: chat_id={chat_id}, user_id={new_user.id}")
    
    return result or {"success": False, "error": "Failed to create user"}


@router.post(
    "/logout",
    summary="Logout user",
)
async def logout(
    request: Request,
    db: Session = Depends(get_db),
):
    """
    Revoke session and blacklist tokens.
    
    **TODO:** Implement token blacklisting in Redis
    """
    
    user_id = getattr(request.state, "user_id", None)
    
    if not user_id:
        raise HTTPException(status_code=401, detail="Not authenticated")
    
    # TODO: Add token to Redis blacklist
    # redis.setex(f"blacklist:{token}", token_expiry_time, "1")
    
    return {"message": "Logged out successfully"}