pounce/backend/app/api/oauth.py

"""
OAuth authentication endpoints.

Supports:
- Google OAuth 2.0
- GitHub OAuth
"""
import os
import secrets
import logging
from datetime import datetime, timedelta
from typing import Optional
from urllib.parse import urlencode

import httpx
from fastapi import APIRouter, HTTPException, status, Query
from fastapi.responses import RedirectResponse
from pydantic import BaseModel
from sqlalchemy import select

from app.api.deps import Database
from app.config import get_settings
from app.models.user import User
from app.services.auth import AuthService

logger = logging.getLogger(__name__)
router = APIRouter()
settings = get_settings()


# ============== Config ==============

GOOGLE_CLIENT_ID = os.getenv("GOOGLE_CLIENT_ID", "")
GOOGLE_CLIENT_SECRET = os.getenv("GOOGLE_CLIENT_SECRET", "")
GOOGLE_REDIRECT_URI = os.getenv("GOOGLE_REDIRECT_URI", "http://localhost:8000/api/v1/oauth/google/callback")

GITHUB_CLIENT_ID = os.getenv("GITHUB_CLIENT_ID", "")
GITHUB_CLIENT_SECRET = os.getenv("GITHUB_CLIENT_SECRET", "")
GITHUB_REDIRECT_URI = os.getenv("GITHUB_REDIRECT_URI", "http://localhost:8000/api/v1/oauth/github/callback")

FRONTEND_URL = os.getenv("SITE_URL", "http://localhost:3000")


# ============== Schemas ==============

class OAuthProviderInfo(BaseModel):
    """OAuth provider availability."""
    google_enabled: bool
    github_enabled: bool


class OAuthToken(BaseModel):
    """OAuth response with JWT token."""
    access_token: str
    token_type: str = "bearer"
    expires_in: int
    is_new_user: bool = False


# ============== Helper Functions ==============

async def get_or_create_oauth_user(
    db: Database,
    email: str,
    name: Optional[str],
    provider: str,
    oauth_id: str,
    avatar: Optional[str] = None,
) -> tuple[User, bool]:
    """Get existing user or create new one from OAuth."""
    is_new = False
    
    # First, check if user with this OAuth ID exists
    result = await db.execute(
        select(User).where(
            User.oauth_provider == provider,
            User.oauth_id == oauth_id,
        )
    )
    user = result.scalar_one_or_none()
    
    if user:
        return user, False
    
    # Check if user with this email exists (link accounts)
    result = await db.execute(
        select(User).where(User.email == email.lower())
    )
    user = result.scalar_one_or_none()
    
    if user:
        # Link OAuth to existing account
        user.oauth_provider = provider
        user.oauth_id = oauth_id
        if avatar:
            user.oauth_avatar = avatar
        user.is_verified = True  # OAuth emails are verified
        await db.commit()
        return user, False
    
    # Create new user
    user = User(
        email=email.lower(),
        hashed_password=secrets.token_urlsafe(32),  # Random password (won't be used)
        name=name,
        oauth_provider=provider,
        oauth_id=oauth_id,
        oauth_avatar=avatar,
        is_verified=True,  # OAuth emails are pre-verified
        is_active=True,
    )
    
    # Auto-admin for specific email
    ADMIN_EMAILS = ["guggeryves@hotmail.com"]
    if user.email.lower() in [e.lower() for e in ADMIN_EMAILS]:
        user.is_admin = True
    
    db.add(user)
    await db.commit()
    await db.refresh(user)
    
    return user, True


def create_jwt_for_user(user: User) -> tuple[str, int]:
    """Create JWT token for user."""
    expires_minutes = settings.access_token_expire_minutes
    access_token = AuthService.create_access_token(
        data={"sub": str(user.id), "email": user.email},
        expires_delta=timedelta(minutes=expires_minutes),
    )
    return access_token, expires_minutes * 60


# ============== Endpoints ==============

@router.get("/providers", response_model=OAuthProviderInfo)
async def get_oauth_providers():
    """Get available OAuth providers."""
    return OAuthProviderInfo(
        google_enabled=bool(GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET),
        github_enabled=bool(GITHUB_CLIENT_ID and GITHUB_CLIENT_SECRET),
    )


# ============== Google OAuth ==============

@router.get("/google/login")
async def google_login(redirect: Optional[str] = Query(None)):
    """Redirect to Google OAuth."""
    if not GOOGLE_CLIENT_ID:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="Google OAuth not configured",
        )
    
    # Store redirect URL in state
    state = secrets.token_urlsafe(16)
    if redirect:
        state = f"{state}:{redirect}"
    
    params = {
        "client_id": GOOGLE_CLIENT_ID,
        "redirect_uri": GOOGLE_REDIRECT_URI,
        "response_type": "code",
        "scope": "openid email profile",
        "state": state,
        "access_type": "offline",
        "prompt": "select_account",
    }
    
    url = f"https://accounts.google.com/o/oauth2/v2/auth?{urlencode(params)}"
    return RedirectResponse(url=url)


@router.get("/google/callback")
async def google_callback(
    code: str = Query(...),
    state: str = Query(""),
    db: Database = None,
):
    """Handle Google OAuth callback."""
    if not GOOGLE_CLIENT_ID or not GOOGLE_CLIENT_SECRET:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="Google OAuth not configured",
        )
    
    # Parse redirect from state
    redirect_path = "/dashboard"
    if ":" in state:
        _, redirect_path = state.split(":", 1)
    
    try:
        # Exchange code for tokens
        async with httpx.AsyncClient() as client:
            token_response = await client.post(
                "https://oauth2.googleapis.com/token",
                data={
                    "client_id": GOOGLE_CLIENT_ID,
                    "client_secret": GOOGLE_CLIENT_SECRET,
                    "code": code,
                    "redirect_uri": GOOGLE_REDIRECT_URI,
                    "grant_type": "authorization_code",
                },
            )
            
            if token_response.status_code != 200:
                logger.error(f"Google token error: {token_response.text}")
                return RedirectResponse(
                    url=f"{FRONTEND_URL}/login?error=oauth_failed"
                )
            
            tokens = token_response.json()
            access_token = tokens.get("access_token")
            
            # Get user info
            user_response = await client.get(
                "https://www.googleapis.com/oauth2/v2/userinfo",
                headers={"Authorization": f"Bearer {access_token}"},
            )
            
            if user_response.status_code != 200:
                logger.error(f"Google user info error: {user_response.text}")
                return RedirectResponse(
                    url=f"{FRONTEND_URL}/login?error=oauth_failed"
                )
            
            user_info = user_response.json()
        
        # Get or create user
        user, is_new = await get_or_create_oauth_user(
            db=db,
            email=user_info.get("email"),
            name=user_info.get("name"),
            provider="google",
            oauth_id=user_info.get("id"),
            avatar=user_info.get("picture"),
        )
        
        # Create JWT
        jwt_token, _ = create_jwt_for_user(user)
        
        # Redirect to frontend with token
        redirect_url = f"{FRONTEND_URL}/oauth/callback?token={jwt_token}&redirect={redirect_path}"
        if is_new:
            redirect_url += "&new=true"
        
        return RedirectResponse(url=redirect_url)
        
    except Exception as e:
        logger.exception(f"Google OAuth error: {e}")
        return RedirectResponse(
            url=f"{FRONTEND_URL}/login?error=oauth_failed"
        )


# ============== GitHub OAuth ==============

@router.get("/github/login")
async def github_login(redirect: Optional[str] = Query(None)):
    """Redirect to GitHub OAuth."""
    if not GITHUB_CLIENT_ID:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="GitHub OAuth not configured",
        )
    
    # Store redirect URL in state
    state = secrets.token_urlsafe(16)
    if redirect:
        state = f"{state}:{redirect}"
    
    params = {
        "client_id": GITHUB_CLIENT_ID,
        "redirect_uri": GITHUB_REDIRECT_URI,
        "scope": "user:email",
        "state": state,
    }
    
    url = f"https://github.com/login/oauth/authorize?{urlencode(params)}"
    return RedirectResponse(url=url)


@router.get("/github/callback")
async def github_callback(
    code: str = Query(...),
    state: str = Query(""),
    db: Database = None,
):
    """Handle GitHub OAuth callback."""
    if not GITHUB_CLIENT_ID or not GITHUB_CLIENT_SECRET:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="GitHub OAuth not configured",
        )
    
    # Parse redirect from state
    redirect_path = "/dashboard"
    if ":" in state:
        _, redirect_path = state.split(":", 1)
    
    try:
        async with httpx.AsyncClient() as client:
            # Exchange code for token
            token_response = await client.post(
                "https://github.com/login/oauth/access_token",
                data={
                    "client_id": GITHUB_CLIENT_ID,
                    "client_secret": GITHUB_CLIENT_SECRET,
                    "code": code,
                    "redirect_uri": GITHUB_REDIRECT_URI,
                },
                headers={"Accept": "application/json"},
            )
            
            if token_response.status_code != 200:
                logger.error(f"GitHub token error: {token_response.text}")
                return RedirectResponse(
                    url=f"{FRONTEND_URL}/login?error=oauth_failed"
                )
            
            tokens = token_response.json()
            access_token = tokens.get("access_token")
            
            if not access_token:
                logger.error(f"GitHub no access token: {tokens}")
                return RedirectResponse(
                    url=f"{FRONTEND_URL}/login?error=oauth_failed"
                )
            
            # Get user info
            user_response = await client.get(
                "https://api.github.com/user",
                headers={
                    "Authorization": f"Bearer {access_token}",
                    "Accept": "application/json",
                },
            )
            
            if user_response.status_code != 200:
                logger.error(f"GitHub user info error: {user_response.text}")
                return RedirectResponse(
                    url=f"{FRONTEND_URL}/login?error=oauth_failed"
                )
            
            user_info = user_response.json()
            
            # Get primary email (might need separate call)
            email = user_info.get("email")
            if not email:
                emails_response = await client.get(
                    "https://api.github.com/user/emails",
                    headers={
                        "Authorization": f"Bearer {access_token}",
                        "Accept": "application/json",
                    },
                )
                if emails_response.status_code == 200:
                    emails = emails_response.json()
                    for e in emails:
                        if e.get("primary"):
                            email = e.get("email")
                            break
                    if not email and emails:
                        email = emails[0].get("email")
            
            if not email:
                return RedirectResponse(
                    url=f"{FRONTEND_URL}/login?error=no_email"
                )
        
        # Get or create user
        user, is_new = await get_or_create_oauth_user(
            db=db,
            email=email,
            name=user_info.get("name") or user_info.get("login"),
            provider="github",
            oauth_id=str(user_info.get("id")),
            avatar=user_info.get("avatar_url"),
        )
        
        # Create JWT
        jwt_token, _ = create_jwt_for_user(user)
        
        # Redirect to frontend with token
        redirect_url = f"{FRONTEND_URL}/oauth/callback?token={jwt_token}&redirect={redirect_path}"
        if is_new:
            redirect_url += "&new=true"
        
        return RedirectResponse(url=redirect_url)
        
    except Exception as e:
        logger.exception(f"GitHub OAuth error: {e}")
        return RedirectResponse(
            url=f"{FRONTEND_URL}/login?error=oauth_failed"
        )