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")

    project_path = settings.deploy_project_path
    cmd = (
        f"git config --global --add safe.directory {project_path} && "
        f"cd {project_path} && "
        f"git fetch origin main && "
        f"git reset --hard origin/main && "
        f"docker-compose up -d --build"
    )
    try:
        proc = await asyncio.create_subprocess_shell(
            cmd,
            stdout=asyncio.subprocess.PIPE,
            stderr=asyncio.subprocess.STDOUT,
        )
        stdout, _ = await asyncio.wait_for(proc.communicate(), timeout=300)
        output = stdout.decode(errors="replace") if stdout else ""

        if proc.returncode != 0:
            logger.error(f"Deploy failed (exit {proc.returncode}):\n{output}")
            raise HTTPException(status_code=500, detail=f"Deploy script failed:\n{output[-500:]}")

        logger.info(f"Deploy succeeded:\n{output[-300:]}")
        return {"ok": True, "output": output[-1000:]}

    except asyncio.TimeoutError:
        raise HTTPException(status_code=504, detail="Deploy timed out after 300 seconds")