import os
import jwt
from datetime import datetime, timedelta, timezone
from fastapi import Request, HTTPException, Security, Depends
from fastapi.security.api_key import APIKeyHeader
from app.models import get_agent_by_key, update_key_last_used

JWT_SECRET = os.environ.get("JWT_SECRET", "secret")
JWT_EXPIRE_HOURS = int(os.environ.get("JWT_EXPIRE_HOURS", "12"))

API_KEY_NAME = "X-API-Key"
api_key_header = APIKeyHeader(name=API_KEY_NAME, auto_error=False)

def create_jwt_token(data: dict) -> str:
    to_encode = data.copy()
    expire = datetime.now(timezone.utc) + timedelta(hours=JWT_EXPIRE_HOURS)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, JWT_SECRET, algorithm="HS256")
    return encoded_jwt

def verify_jwt_token(request: Request) -> dict:
    token = request.cookies.get("access_token")
    if not token:
        raise HTTPException(status_code=401, detail="Not authenticated")
    try:
        payload = jwt.decode(token, JWT_SECRET, algorithms=["HS256"])
        return payload
    except jwt.ExpiredSignatureError:
        raise HTTPException(status_code=401, detail="Token expired")
    except jwt.InvalidTokenError:
        raise HTTPException(status_code=401, detail="Invalid token")

async def get_current_agent(api_key: str = Security(api_key_header)) -> str:
    if not api_key:
        raise HTTPException(status_code=401, detail="API Key header missing")
    
    agent_name = await get_agent_by_key(api_key)
    if not agent_name:
        raise HTTPException(status_code=401, detail="Invalid API Key")
    
    await update_key_last_used(api_key)
    return agent_name