from jose import JWTError, jwt
from datetime import datetime, timedelta
from . import schemas, database, models
from fastapi import Depends, status, HTTPException, Security
from fastapi.security import OAuth2PasswordBearer, APIKeyHeader
from sqlalchemy.orm import Session
from .config import settings

oauth2_scheme = OAuth2PasswordBearer(tokenUrl='login')
header_scheme = APIKeyHeader(name="X-API-KEY")

SECRET_KEY = settings.secret_key2
ALGORITHM = settings.algorithm
ACCESS_TOKEN_EXPIRE_MINUTES = settings.access_token_expire_minutes
REFRESH_TOKEN_EXPIRE_DAYS = settings.refresh_token_expire_days
X_API_KEY = settings.x_api_key

def verify_api_key(api_key_header: str = Security(header_scheme)):
    if api_key_header == X_API_KEY:
        return {"status": "OK"}
    raise HTTPException(status_code=status.HTTP_401_UNAUTHORIZED)

def create_access_token(data: dict):
    to_encode = data.copy()

    expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update(
        {"type": "access"})
    to_encode.update(
        {"exp": expire})  

    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)

    return encoded_jwt

def create_refresh_token(data: dict):
    to_encode = data.copy()

    expire = datetime.utcnow() + timedelta(days=REFRESH_TOKEN_EXPIRE_DAYS)
    to_encode.update(
        {"type": "refresh"})
    to_encode.update(
        {"exp": expire})        

    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)

    return encoded_jwt

def decode_and_verify_token(token: str, expected_type: str):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="Could not validate credentials",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        token_type: str = payload.get("type")
        if token_type != expected_type:
            raise HTTPException(
                status_code=status.HTTP_401_UNAUTHORIZED,
                detail=f"Invalid token type: expected {expected_type}, got {token_type}")
    except JWTError:
        raise credentials_exception

    return payload


def verify_access_token(access_token: str = Depends(oauth2_scheme)):
    payload = decode_and_verify_token(access_token, expected_type="access")
    
    user_id: str = payload.get("UserID")
    email: str = payload.get("Email")
    
    token_data = schemas.TokenData(UserID=user_id, Email=email)
    
    return token_data

def verify_refresh_token(refresh_token: str):
    payload = decode_and_verify_token(refresh_token, expected_type="refresh")
    
    user_id: str = payload.get("UserID")

    return user_id


def get_current_user(token_data: schemas.TokenData = Depends(verify_access_token), db: Session = Depends(database.get_db)):
    user = db.query(models.Users).filter(models.Users.UserID == token_data.UserID).first()
    if user is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="User not found")
    return user