from fastapi import FastAPI, Request, Response
import httpx
import os

app = FastAPI()

BACKEND_URL = os.environ.get("BACKEND_URL")
AUTH_HEADER = os.environ.get("AUTH_HEADER")

async def is_session_valid(session_token: str) -> bool:
    async with httpx.AsyncClient() as client:
        resp = await client.get(
            f"{BACKEND_URL}/user/session",
            params={"token": session_token},
            headers={"Authorization": AUTH_HEADER}
        )
        if resp.status_code != 200:
            return False
        result = resp.json()
        return result.get("valid", False)

@app.api_route("/{full_path:path}", methods=["GET", "POST", "PUT", "DELETE", "PATCH", "OPTIONS"])
async def proxy(full_path: str, request: Request):
    url = f"{BACKEND_URL}/{full_path}"

    # Recebe o token de sessão no header 'token_session'
    session_token = request.headers.get("token_session")

    # Rotas públicas não exigem validação
    public_routes = ["user/login", "user/register", "user/session", "session/create", "session/end", "users/by_email"]
    if full_path not in public_routes:
        if not session_token or not await is_session_valid(session_token):
            return Response(content="Não autorizado", status_code=401)

    # Copia headers originais e sobrescreve Authorization com AUTH_HEADER
    headers = dict(request.headers)
    headers["Authorization"] = AUTH_HEADER

    # Remove headers que podem causar conflito
    for h in ["host", "content-length", "accept-encoding", "connection"]:
        headers.pop(h, None)
    # Remove o token_session do header antes de encaminhar ao backend
    headers.pop("token_session", None)

    body = await request.body()

    async with httpx.AsyncClient() as client:
        resp = await client.request(
            method=request.method,
            url=url,
            headers=headers,
            content=body if request.method != "GET" else None,
            params=dict(request.query_params)
        )

    return Response(
        content=resp.content,
        status_code=resp.status_code,
        headers={k: v for k, v in resp.headers.items() if k.lower() not in ["content-encoding", "transfer-encoding", "connection"]}
    )

# Para rodar:
# uvicorn proxy:app --reload --port 8000