import os
import datetime
import requests
from app import router
from fastapi import FastAPI, Depends, HTTPException, status, Request, APIRouter
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
import firebase_admin
from firebase_admin import credentials, auth
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from app.models.api.user import UserCreate, UserSignIn, PasswordReset, TokenVerify, UserResponse, EmailVerifyRequest
from app.models.database.DBUser import DBUser
from app.core.database.session_manager import get_db_session as get_db


router = APIRouter(prefix="/FirebaseAuth", tags=["Firebase Auth"])

# Initialize OAuth2 scheme
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="/FirebaseAuth/token")

async def verify_firebase_token(token: str = Depends(oauth2_scheme)) -> dict:
    """Verify Firebase token and return user info"""
    try:
        # Verify the token
        decoded_token = auth.verify_id_token(token)
        user_id = decoded_token["uid"]
        
        # Get user from Firebase
        firebase_user = auth.get_user(user_id)
        
        return {
            "firebase_uid": user_id,
            "email": firebase_user.email,
            "email_verified": firebase_user.email_verified,
            "display_name": firebase_user.display_name
        }
    except Exception as e:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid authentication token",
            headers={"WWW-Authenticate": "Bearer"},
        )

# Initialize Firebase Admin SDK with better error handling
try:
    current_dir = os.path.dirname(os.path.abspath(__file__))
    # Try multiple possible paths for the service account file
    service_account_paths = [
        "/opt/MailPilot/MailPilot_ai_agents/app/serviceAccountKey/mailpoilt-firebase-adminsdk-fbsvc-26bb455f79.json",
        os.path.join(current_dir, "../serviceAccountKey/mailpoilt-firebase-adminsdk-fbsvc-26bb455f79.json"),
        os.path.join(current_dir, "../../serviceAccountKey/mailpoilt-firebase-adminsdk-fbsvc-26bb455f79.json")
    ]
    
    cred = None
    for path in service_account_paths:
        if os.path.exists(path):
            cred = credentials.Certificate(path)
            break
    
    if cred is None:
        raise FileNotFoundError("Firebase service account key not found")
        
    if not firebase_admin._apps:
        firebase_admin.initialize_app(cred)
        
except Exception as e:
    print(f"Firebase initialization error: {str(e)}")
    # Continue without crashing, but auth functions will fail

@router.post("/signup", response_model=dict)
async def create_user(user_data: UserCreate, db: AsyncSession = Depends(get_db)):
    """Create a new user with email and password and store in database"""
    try:
        # Check if user already exists
        try:
            existing_user = auth.get_user_by_email(user_data.email)
            raise HTTPException(
                status_code=status.HTTP_400_BAD_REQUEST,
                detail=f"User with email {user_data.email} already exists"
            )
        except auth.UserNotFoundError:
            # This is what we want - user doesn't exist yet
            pass
            
        # Create Firebase user
        firebase_user = auth.create_user(
            email=user_data.email,
            password=user_data.password,
            display_name=user_data.display_name,
            email_verified=False  # Explicitly set to false
        )
        
        # Generate email verification link
        action_code_settings = auth.ActionCodeSettings(
            url=f"https://mailpoilt.web.app/verify-email?email={user_data.email}",
            handle_code_in_app=True
        )
        verification_link = auth.generate_email_verification_link(
            user_data.email, 
            action_code_settings
        )
        
        # Firebase will handle sending the verification email automatically
        
        current_time = datetime.datetime.utcnow()
        
        db_user = DBUser(
            firebase_uid=firebase_user.uid,
            email=user_data.email,
            display_name=user_data.display_name,
            is_active=True,
            created_at=current_time,
            last_login=current_time,
            provider="email"
        )
        
        db.add(db_user)
        await db.commit()
        await db.refresh(db_user)
        
        return {
            "message": "User created successfully. Please check your email to verify your account.",
            "verification_link": verification_link,  # In production, you might not return this
            "user": {
                "firebase_uid": db_user.firebase_uid,
                "email": db_user.email,
                "display_name": db_user.display_name,
                "is_active": db_user.is_active,
                "created_at": db_user.created_at.isoformat() if db_user.created_at else None,
                "last_login": db_user.last_login.isoformat() if db_user.last_login else None,
                "provider": db_user.provider,
                "email_verified": firebase_user.email_verified
            }
        }
    except Exception as e:
        await db.rollback()
        try:
            if 'firebase_user' in locals():
                auth.delete_user(firebase_user.uid)
        except:
            pass
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Error creating user: {str(e)}"
        )

@router.post("/signin", response_model=dict)
async def signin_user(user_data: UserSignIn, db: AsyncSession = Depends(get_db)):
    """Sign in user and return token"""
    try:
        # Get Firebase API key from environment variable
        api_key = os.getenv("FIREBASE_API_KEY")
        if not api_key:
            raise ValueError("FIREBASE_API_KEY environment variable is not set")
            
        # Call Firebase Auth REST API to sign in with email/password
        response = requests.post(
            f"https://identitytoolkit.googleapis.com/v1/accounts:signInWithPassword?key={api_key}",
            json={
                "email": user_data.email,
                "password": user_data.password,
                "returnSecureToken": True
            }
        )
        
        if response.status_code != 200:
            error_data = response.json()
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail=f"Authentication failed: {error_data.get('error', {}).get('message', 'Invalid credentials')}"
            )
            
        auth_data = response.json()
        id_token = auth_data["idToken"]
        
        # Verify the ID token
        decoded_token = auth.verify_id_token(id_token)
        user_id = decoded_token["uid"]
        
        # Get user from Firebase
        firebase_user = auth.get_user(user_id)
        
        # Update last login in database
        result = await db.execute(
            select(DBUser).filter(DBUser.firebase_uid == user_id)
        )
        db_user = result.scalar_one_or_none()
        
        if db_user:
            db_user.last_login = datetime.datetime.utcnow()
            await db.commit()
        
        return {
            "access_token": id_token,
            "token_type": "bearer",
            "user": {
                "firebase_uid": firebase_user.uid,
                "email": firebase_user.email,
                "email_verified": firebase_user.email_verified,
                "display_name": firebase_user.display_name
            }
        }
    except Exception as e:
        if isinstance(e, HTTPException):
            raise e
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail=f"Authentication failed: {str(e)}"
        )

# Example of a protected endpoint
@router.get("/me", response_model=dict)
async def get_current_user(
    current_user: dict = Depends(verify_firebase_token),
    db: AsyncSession = Depends(get_db)
):
    """Get current user information"""
    try:
        result = await db.execute(
            select(DBUser).filter(DBUser.firebase_uid == current_user["firebase_uid"])
        )
        db_user = result.scalar_one_or_none()
        
        if not db_user:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="User not found in database"
            )
            
        return {
            "message": "User authenticated",
            "user": {
                "firebase_uid": db_user.firebase_uid,
                "email": db_user.email,
                "display_name": db_user.display_name,
                "is_active": db_user.is_active,
                "email_verified": current_user["email_verified"]
            }
        }
    except Exception as e:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=str(e)
        )

@router.post("/resend-verification", status_code=status.HTTP_200_OK)
async def resend_verification_email(
    email_data: EmailVerifyRequest = None,
    current_user: dict = Depends(verify_firebase_token)
):
    """
    Resend verification email to a user
    
    If user is logged in, uses their email.
    Otherwise, uses the email provided in the request body.
    """
    try:
        # If email is provided in request body, use that
        # Otherwise use logged in user's email
        email = email_data.email if email_data and email_data.email else current_user["email"]
        
        # Check if user exists
        try:
            firebase_user = auth.get_user_by_email(email)
        except auth.UserNotFoundError:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"No user found with email: {email}"
            )
            
        # Check if email is already verified
        if firebase_user.email_verified:
            return {"message": "Email is already verified"}
            
        # Generate a new verification link
        action_code_settings = auth.ActionCodeSettings(
            url=f"https://mailpoilt.web.app/verify-email?email={email}",
            handle_code_in_app=True
        )
        verification_link = auth.generate_email_verification_link(
            email, 
            action_code_settings
        )
        
        return {
            "message": "Verification email sent successfully",
            "verification_link": verification_link
        }
    except Exception as e:
        if isinstance(e, HTTPException):
            raise e
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Failed to resend verification email: {str(e)}"
        )

@router.post("/check-email-verified")
async def check_email_verified(email_data: EmailVerifyRequest):
    """Check if a user's email is verified"""
    try:
        # Check if user exists
        try:
            firebase_user = auth.get_user_by_email(email_data.email)
        except auth.UserNotFoundError:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail=f"No user found with email: {email_data.email}"
            )
            
        return {
            "email": email_data.email,
            "email_verified": firebase_user.email_verified
        }
    except Exception as e:
        if isinstance(e, HTTPException):
            raise e
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Failed to check email verification status: {str(e)}"
        )

@router.post("/verify-token", response_model=UserResponse)
async def verify_token(token_data: TokenVerify, db: AsyncSession = Depends(get_db)):
    """Verify a Firebase ID token or UID and return user data"""
    try:
        # First try to verify as an ID token
        try:
            decoded_token = auth.verify_id_token(token_data.token)
            user_id = decoded_token["uid"]
        except:
            # If that fails, treat it as a UID
            user_id = token_data.token

        try:
            firebase_user = auth.get_user(user_id)
        except auth.UserNotFoundError:
            raise HTTPException(
                status_code=status.HTTP_404_NOT_FOUND,
                detail="User not found"
            )
        
        result = await db.execute(select(DBUser).filter(DBUser.firebase_uid == user_id))
        db_user = result.scalar_one_or_none()
        
        if not db_user:
            # Create DB user if it doesn't exist
            db_user = DBUser(
                firebase_uid=user_id,
                email=firebase_user.email,
                display_name=firebase_user.display_name or firebase_user.email.split('@')[0],
                is_active=True,
                created_at=datetime.datetime.utcnow(),
                last_login=datetime.datetime.utcnow(),
                provider="firebase"
            )
            db.add(db_user)
            await db.commit()
            await db.refresh(db_user)
        else:
            # Update last_login time
            db_user.last_login = datetime.datetime.utcnow()
            await db.commit()
            await db.refresh(db_user)

        return UserResponse(
            firebase_uid=db_user.firebase_uid,
            email=db_user.email,
            display_name=db_user.display_name,
            is_active=db_user.is_active,
            created_at=db_user.created_at,
            last_login=db_user.last_login,
            provider=db_user.provider,
            email_verified=firebase_user.email_verified
        )
    except Exception as e:
        if isinstance(e, HTTPException):
            raise e
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail=f"Token verification failed: {str(e)}"
        )

@router.post("/token")
async def get_token(form_data: OAuth2PasswordRequestForm = Depends(), db: AsyncSession = Depends(get_db)):
    """Get access token using OAuth2 form"""
    try:
        # Get Firebase API key from environment variable
        api_key = os.getenv("FIREBASE_API_KEY")
        if not api_key:
            raise ValueError("FIREBASE_API_KEY environment variable is not set")
            
        # Call Firebase Auth REST API to sign in with email/password
        response = requests.post(
            f"https://identitytoolkit.googleapis.com/v1/accounts:signInWithPassword?key={api_key}",
            json={
                "email": form_data.username,  # Username field contains email
                "password": form_data.password,
                "returnSecureToken": True
            }
        )
        
        if response.status_code != 200:
            error_data = response.json()
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail=f"Authentication failed: {error_data.get('error', {}).get('message', 'Invalid credentials')}"
            )
            
        auth_data = response.json()
        id_token = auth_data["idToken"]
        
        # Verify the ID token
        decoded_token = auth.verify_id_token(id_token)
        user_id = decoded_token["uid"]
        
        # Update last login in database
        result = await db.execute(
            select(DBUser).filter(DBUser.firebase_uid == user_id)
        )
        db_user = result.scalar_one_or_none()
        
        if db_user:
            db_user.last_login = datetime.datetime.utcnow()
            await db.commit()
        
        return {
            "access_token": id_token,
            "token_type": "bearer"
        }
    except Exception as e:
        if isinstance(e, HTTPException):
            raise e
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail=f"Authentication failed: {str(e)}"
        )

# Function to verify token
async def verify_token(token: str = Depends(oauth2_scheme)):
    try:
        # Verify the token
        decoded_token = auth.verify_id_token(token)
        return decoded_token
    except:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid token"
        )

# Example protected route
@router.get("/protected")
async def protected_route(token: dict = Depends(verify_token)):
    return {"message": "You have access!", "token_info": token}