from fastapi import FastAPI, Depends, HTTPException, Request, Form, status, Header
from fastapi.responses import RedirectResponse, HTMLResponse
from fastapi.responses import JSONResponse
from fastapi.templating import Jinja2Templates
from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
from pydantic import BaseModel
from sqlalchemy.orm import Session
from database import get_db, get_user_by_email
from models import User
from passlib.context import CryptContext
from datetime import datetime, timedelta
import jwt
from emailx import send_verification_email, generate_verification_token

from fastapi.staticfiles import StaticFiles

from typing import Optional
import httpx
import os
from starlette.middleware.sessions import SessionMiddleware
from authlib.integrations.starlette_client import OAuth



# Environment variables
GOOGLE_CLIENT_ID = os.getenv('GOOGLE_CLIENT_ID')
GOOGLE_CLIENT_SECRET = os.getenv('GOOGLE_CLIENT_SECRET')
SECRET_KEY = os.getenv('SecretKey', 'default_secret')
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30

# FastAPI and OAuth setup
app = FastAPI()
app.add_middleware(SessionMiddleware, secret_key=SECRET_KEY)
oauth = OAuth()

# Password context
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

# OAuth2 scheme
oauth2_scheme = OAuth2PasswordBearer(tokenUrl="token")

class TokenData(BaseModel):
    token: str

class UserCreate(BaseModel):
    username: str
    email: str
    password: str
 #   confirm_password: str
# OAuth Configuration
oauth.register(
    name='google',
    client_id=os.environ['GOOGLE_CLIENT_ID'],
    client_secret=os.environ['GOOGLE_CLIENT_SECRET'],
    access_token_url='https://accounts.google.com/o/oauth2/token',
    authorize_url='https://accounts.google.com/o/oauth2/auth',
    authorize_params=None,
    api_base_url='https://www.googleapis.com/oauth2/v1/',
    client_kwargs={'scope': 'openid email profile'}
)

# Static and template configurations
app.mount("/static", StaticFiles(directory="static"), name="static")
templates = Jinja2Templates(directory="templates")

# OAuth routes
@app.get("/login/oauth")
async def login_oauth(request: Request):
    redirect_uri = request.url_for('auth_callback')
    return await oauth.google.authorize_redirect(request, redirect_uri)
    
@app.get("/auth/callback")
async def auth_callback(request: Request, db: Session = Depends(get_db)):
    token = await oauth.google.authorize_access_token(request)
    user_info = await oauth.google.parse_id_token(request, token)
    request.session["user_info"] = user_info

    db_user = db.query(User).filter(User.email == user_info['email']).first()
    if not db_user:
        db_user = User(email=user_info['email'], username=user_info['name'], is_verified=True)
        db.add(db_user)
        db.commit()
        db.refresh(db_user)

    access_token = create_access_token(data={"sub": db_user.email}, expires_delta=timedelta(minutes=30))
    response = RedirectResponse(url="/protected")
    response.set_cookie(key="access_token", value=f"Bearer {access_token}", httponly=True)
    return response
    
@app.post("/login")
async def login(form_data: OAuth2PasswordRequestForm = Depends(), db: Session = Depends(get_db), recaptcha_token: str = Form(...)):
    # Perform reCAPTCHA verification first
    
    recaptcha_secret = '6LeSJgwpAAAAAJrLrvlQYhRsOjf2wKXee_Jc4Z-k'  # Replace with your reCAPTCHA secret key
    recaptcha_url = 'https://www.google.com/recaptcha/api/siteverify'
    recaptcha_data = {
        'secret': recaptcha_secret,
        'response': recaptcha_token
    }
    
    async with httpx.AsyncClient() as client:
        recaptcha_response = await client.post(recaptcha_url, data=recaptcha_data)
    
    recaptcha_result = recaptcha_response.json()
    print(recaptcha_result)  # or use proper logging
    if not recaptcha_result.get('success', False):
        raise HTTPException(status_code=400, detail="reCAPTCHA validation failed.")
    if not form_data.username or not form_data.password:
        raise HTTPException(status_code=400, detail="Invalid email or password")
        
    user = authenticate_user(db, email=form_data.username, password=form_data.password)
    if not user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect email or password",
            headers={"WWW-Authenticate": "Bearer"},
        )
    access_token = create_access_token(data={"sub": user.email})
    return JSONResponse(content={"access_token": access_token, "token_type": "bearer"})
    
@app.get("/login", response_class=HTMLResponse)
async def login(request: Request, db: Session = Depends(get_db)):
    access_token = request.cookies.get("access_token")

    if access_token:
        try:
            user_email = verify_token(access_token.split("Bearer ")[1])
            if user_email:
                # Retrieve the user from the database
                db_user = db.query(User).filter(User.email == user_email).first()
                if not db_user:
                    raise HTTPException(status_code=HTTP_401_UNAUTHORIZED, detail="User not found")

                # Check if user is verified
                if not db_user.is_verified:
                    raise HTTPException(status_code=HTTP_401_UNAUTHORIZED, detail="User is not verified")

                # Create a new access token for the user
                new_access_token = create_access_token(
                    data={"sub": db_user.email},
                    expires_delta=timedelta(minutes=auth_views.ACCESS_TOKEN_EXPIRE_MINUTES)
                )

                # Redirect the user to the protected route
                url = app.url_path_for("get_protected")
                response = RedirectResponse(url)
                response.set_cookie(key="access_token", value=f"Bearer {new_access_token}", httponly=True)
                return response
        except ExpiredSignatureError:
            # Token has expired. You could redirect to the login page or inform the user
            raise HTTPException(status_code=HTTP_401_UNAUTHORIZED, detail="Token expired")
        except InvalidTokenError:
            # Token is invalid, inform the user or redirect
            raise HTTPException(status_code=HTTP_400_BAD_REQUEST, detail="Invalid token")
        except Exception as e:
            # General exception, log this exception for debugging
            # Respond with a generic error message
            raise HTTPException(status_code=HTTP_400_BAD_REQUEST, detail="An error occurred")

    # If not authenticated, show the login page with Google OAuth option
    google_oauth_url = request.url_for("login_oauth")  # URL to initiate Google OAuth
    return templates.TemplateResponse("login.html", {"request": request, "google_oauth_url": google_oauth_url})

@app.get("/register/google")
async def register_google(request: Request):
    # Redirect to Google OAuth
    redirect_uri = request.url_for('auth_callback')
    return await oauth.google.authorize_redirect(request, redirect_uri)

@app.get("/auth/callback")
async def auth_callback(request: Request, db: Session = Depends(get_db)):
    # Handle the Google OAuth callback and user registration
    token = await oauth.google.authorize_access_token(request)
    user_info = await oauth.google.parse_id_token(request, token)
    
    # Check if user already exists
    existing_user = db.query(User).filter(User.email == user_info['email']).first()
    if existing_user:
        # User already exists, handle accordingly (e.g., log in the user)
        # ...
        pass
    else:
        # Register new user
        new_user = User(
            email=user_info['email'],
            username=user_info.get('name'),
            is_verified=True  # Assuming Google users are verified by default
        )
        db.add(new_user)
        db.commit()
        db.refresh(new_user)
        # Store user info in session or create a token as needed
        request.session["user_info"] = {"username": new_user.username, "email": new_user.email}
        # ...

    # Redirect to a success or dashboard page
    return RedirectResponse(url="/registration_successful")

@app.post("/registration_successful", response_class=HTMLResponse)
async def registration_successful(request: Request, db: Session = Depends(get_db)):
    # Assuming the OAuth process has been completed and user info is stored in the session or a similar mechanism
    user_info = request.session.get("user_info")  # Replace with your method of retrieving user info

    if not user_info:
        raise HTTPException(status_code=401, detail="User not authenticated")

    email = user_info["email"]
    db_user = db.query(User).filter(User.email == email).first()
    if not db_user:
        raise HTTPException(status_code=404, detail="User not found")

    # Create an access token for the user
    access_token = create_access_token(
        data={"sub": db_user.email},
        expires_delta=timedelta(minutes=auth_views.ACCESS_TOKEN_EXPIRE_MINUTES)
    )

    # Redirect the user to the protected route
    response = RedirectResponse(url="/login")
    response.set_cookie(key="access_token", value=f"Bearer {access_token}", httponly=True)
    return response
    
async def verify_recaptcha(recaptcha_token: str) -> bool:
    recaptcha_secret = '6LeSJgwpAAAAAJrLrvlQYhRsOjf2wKXee_Jc4Z-k'  # Replace with your reCAPTCHA secret key
    recaptcha_url = 'https://www.google.com/recaptcha/api/siteverify'
    recaptcha_data = {
        'secret': recaptcha_secret,
        'response': recaptcha_token
    }

    async with httpx.AsyncClient() as client:
        recaptcha_response = await client.post(recaptcha_url, data=recaptcha_data)

    recaptcha_result = recaptcha_response.json()
    print(recaptcha_result)  # or use proper logging

    return recaptcha_result.get('success', False)

@app.get("/verify", response_class=HTMLResponse)
async def verify_email(token: str, db: Session = Depends(get_db)):
    user = get_user_by_verification_token(db, token)
    if not user:
        raise HTTPException(status_code=400, detail="Invalid verification token")

    if user.is_verified:
        raise HTTPException(status_code=400, detail="Email already verified")

    user.is_verified = True
    user.email_verification_token = None  # Clear the verification token
    db.commit()

    # Create access token for the user after successful verification
    access_token = create_access_token(data={"sub": user.email}, expires_delta=timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES))

    # Redirect to the protected route and set the token in a secure, HTTP-only cookie
    response = RedirectResponse(url="/protected")
    response.set_cookie(key="access_token", value=f"Bearer {access_token}", httponly=True, secure=True, samesite='Lax')
    return response

def is_username_available(db: Session, username: str) -> bool:
    return db.query(User).filter(User.username == username).first() is None
    
@app.get("/register", response_class=HTMLResponse)
async def register_get(request: Request):
    return templates.TemplateResponse("register.html", {"request": request, "google_oauth_url": request.url_for("login_oauth")})

@app.post("/register")
async def register_post(
    request: Request,
    username: str = Form(...),
    email: str = Form(...),
    password: str = Form(...),
    confirm_password: str = Form(...),
    recaptcha_token: str = Form(...),
    db: Session = Depends(get_db)
):
    if not await verify_recaptcha(recaptcha_token):
        return templates.TemplateResponse("register.html", {"request": request, "error_message": "reCAPTCHA validation failed."})

    if password != confirm_password:
        return templates.TemplateResponse("register.html", {"request": request, "error_message": "Passwords do not match."})

    user_data = UserCreate(username=username, email=email, password=password)
    if not is_username_available(db, user_data.username):
        raise HTTPException(status_code=400, detail="Username already taken")
    try:
        registered_user = register_user(user_data, db)

        # Create an access token
        access_token = create_access_token(data={"sub": registered_user.email}, 
        expires_delta=timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES))

        # Redirect to the protected route
        url = app.url_path_for("get_protected")
        #response = RedirectResponse(url, status_code=status.HTTP_303_SEE_OTHER)
       # response.set_cookie(key="access_token", value=f"Bearer {access_token}", httponly=True)
        #response.set_cookie(key="access_token", value=f"Bearer {access_token}", httponly=True, secure=True, samesite='Lax')
        #return response
          # Return the access token and redirection URL in the response
        return JSONResponse(content={
        "access_token": access_token,
        "redirect_url": url
    })

    except HTTPException as e:
        return templates.TemplateResponse("register.html", {"request": request, "error_message": e.detail})
    
@app.get("/", response_class=HTMLResponse)
async def landing(request: Request):
    return templates.TemplateResponse("landing.html", {"request": request})

def verify_password(plain_password, hashed_password):
    return pwd_context.verify(plain_password, hashed_password)

def get_password_hash(password):
    return pwd_context.hash(password)

def authenticate_user(db: Session, email: str, password: str):
    user = db.query(User).filter(User.email == username).first()
    if not user or not verify_password(password, user.hashed_password):
        return False
    return user

    
def create_access_token(data: dict, expires_delta: timedelta = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)):
    to_encode = data.copy()
    expire = datetime.utcnow() + expires_delta
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt

def verify_token(token: str = Depends(oauth2_scheme)):
    if token.startswith("Bearer "):
        token = token.split(" ")[1]  # Strip the 'Bearer ' prefix if it exists

    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        user_email = payload.get("sub")
        if user_email is None:
            raise HTTPException(status_code=401, detail="Invalid authentication credentials")
        return user_email
    except jwt.ExpiredSignatureError:
        raise HTTPException(status_code=401, detail="Token has expired")
    except jwt.PyJWTError as e:
        # Log the error for debugging
        print(f"JWT decoding error: {e}")
        raise HTTPException(status_code=401, detail="Could not validate credentials")
        
def validate_token(token: str):
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid token")
        return TokenData(username=username)
    except JWTError:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid token")

@app.get("/token/validate")
async def token_validate(token: str = Depends(oauth2_scheme)):
    return validate_token(token)

@app.post("/login")
async def login(form_data: OAuth2PasswordRequestForm = Depends(), db: Session = Depends(get_db)):
    return await login_for_access_token(form_data.username, form_data.password, db)

async def login_for_access_token(username: str, password: str, db: Session):
    user = authenticate_user(db,form_data.username, form_data.password)
    if not user:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Incorrect username or password",
            headers={"WWW-Authenticate": "Bearer"},
        )
    access_token = create_access_token(data={"sub": user.email})
    return {"access_token": access_token, "token_type": "bearer"}

def authenticate_user(db: Session, username: str, password: str):
    user = get_user_by_email(db, username)
    if not user or not pwd_context.verify(password, user.hashed_password):
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Incorrect email or password")
    return user

def register_user(user_data: UserCreate, db: Session):
    if get_user_by_email(db, user_data.email):
        raise HTTPException(status_code=400, detail="Email already registered")

    hashed_password = pwd_context.hash(user_data.password)
    verification_token = generate_verification_token(user_data.email)
    reset_link = f"http://gregniuki-loginauth.hf.space/verify?token={verification_token}"
    send_verification_email(user_data.email, reset_link)

    new_user = User(
        email=user_data.email,
        username=user_data.username,
        hashed_password=hashed_password,
        email_verification_token=verification_token
    )
    db.add(new_user)
    db.commit()
    db.refresh(new_user)
    return new_user

@app.get("/protected", response_class=HTMLResponse)
async def get_protected(
    request: Request,
    db: Session = Depends(get_db),
    authorization: Optional[str] = Header(None)  # token from Authorization header
):
    # Try to get the token from the Authorization header
    if authorization:
        scheme, _, token = authorization.partition(' ')
        if scheme.lower() != 'bearer':
            raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid authentication scheme")
    else:
        # Fall back to the cookie
        token = request.cookies.get("access_token")

    if not token:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Not authenticated")

    # Verify the token and get user
    try:
        user_email = verify_token(token)  # Implement your token verification logic
        db_user = get_user_by_email(db, user_email)
        if db_user is None or not db_user.is_verified:
            raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="User not found or not verified in the database")

        # Render a template response
        return templates.TemplateResponse("protected.html", {"request": request, "user": db_user.username})
    except Exception as e:  # Replace with specific exceptions as per your verification logic
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail=str(e))
    
def verify_email(verification_token: str, db: Session = Depends(get_db)):
    # Verify the email using the token
    user = get_user_by_verification_token(db, verification_token)
    
    if not user:
        raise HTTPException(status_code=400, detail="Invalid verification token")

    if user.is_verified:
        raise HTTPException(status_code=400, detail="Email already verified")

    # Mark the email as verified
    user.is_verified = True
    user.email_verification_token = None  # Optionally clear the verification token
    db.commit()
    return {"message": "Email verification successful"}
    
def get_user_by_verification_token(db: Session, verification_token: str):
    return db.query(User).filter(User.email_verification_token == verification_token).first()

def reset_password(user: User, db: Session):
    verification_token = generate_verification_token(user.email)
    reset_link = f"http://gregniuki-loginauth.hf.space/reset-password?token={verification_token}"
    send_verification_email(user.email, reset_link)

    user.email_verification_token = verification_token
    db.commit()

def get_current_user(token: str = Depends(verify_token)):
    return token