import os
from datetime import datetime, timedelta, timezone

import jwt
from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
from passlib.context import CryptContext
from dotenv import load_dotenv
from pathlib import Path

from database import get_user_by_email, get_user_by_id

load_dotenv(dotenv_path=Path(__file__).resolve().parent / ".env")

SECRET_KEY = os.getenv("SECRET_KEY", "change-me-in-production-use-env")
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 15

pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
security = HTTPBearer(auto_error=False)


def hash_password(password: str) -> str:
    return pwd_context.hash(password)


def verify_password(plain: str, hashed: str) -> bool:
    return pwd_context.verify(plain, hashed)


def create_access_token(data: dict) -> str:
    to_encode = data.copy()
    expire = datetime.now(timezone.utc) + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode["exp"] = expire
    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)


def decode_token(token: str) -> dict | None:
    try:
        return jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
    except jwt.PyJWTError:
        return None


async def get_current_user(
    credentials: HTTPAuthorizationCredentials | None = Depends(security),
) -> dict:
    if credentials is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Not authenticated",
            headers={"WWW-Authenticate": "Bearer"},
        )
    payload = decode_token(credentials.credentials)
    if payload is None:
        raise HTTPException(
            status_code=status.HTTP_401_UNAUTHORIZED,
            detail="Invalid or expired token",
            headers={"WWW-Authenticate": "Bearer"},
        )
    user_id = payload.get("sub")
    if not user_id:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="Invalid token")
    user = get_user_by_id(int(user_id))
    if user is None:
        raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED, detail="User not found")
    return user


async def get_optional_user(
    credentials: HTTPAuthorizationCredentials | None = Depends(security),
) -> dict | None:
    if credentials is None:
        return None
    payload = decode_token(credentials.credentials)
    if payload is None:
        return None
    user_id = payload.get("sub")
    if not user_id:
        return None
    return get_user_by_id(int(user_id))