import asyncio
import hashlib
import hmac
import logging

from fastapi import APIRouter, HTTPException, Request

from config import settings

logger = logging.getLogger("admin.deploy")

router = APIRouter(prefix="/api/admin", tags=["admin"])


@router.post("/deploy")
async def deploy(request: Request):
    """Gitea webhook endpoint — pulls latest code and rebuilds Docker containers.

    Gitea webhook configuration:
      URL:          https://<your-domain>/api/admin/deploy
      Secret token: value of DEPLOY_SECRET env var
      Content-Type: application/json
      Trigger:      Push events only (branch: main)

    Add to VPS .env:
      DEPLOY_SECRET=<random-strong-token>
      DEPLOY_PROJECT_PATH=/home/bellsystems/bellsystems-cp
    """
    if not settings.deploy_secret:
        raise HTTPException(status_code=503, detail="Deploy secret not configured on server")

    # Gitea sends the HMAC-SHA256 of the request body in X-Gitea-Signature
    sig_header = request.headers.get("X-Gitea-Signature", "")
    body = await request.body()
    expected_sig = hmac.new(
        key=settings.deploy_secret.encode(),
        msg=body,
        digestmod=hashlib.sha256,
    ).hexdigest()
    if not hmac.compare_digest(sig_header, expected_sig):
        raise HTTPException(status_code=403, detail="Invalid webhook signature")

    logger.info("Auto-deploy triggered via Gitea webhook")

    # Trigger the host-side systemd service which runs as the bellsystems user.
    # This avoids running git/docker as root inside the container.
    await asyncio.create_subprocess_shell(
        "systemctl start bellsystems-deploy",
        stdout=asyncio.subprocess.DEVNULL,
        stderr=asyncio.subprocess.DEVNULL,
    )

    logger.info("Auto-deploy triggered via systemd")
    return {"ok": True, "message": "Deploy started"}