name: Build & Deploy (Nix)

on:
  push:
    branches: [main]
  workflow_dispatch:

concurrency:
  group: deploy
  cancel-in-progress: false

permissions:
  contents: read
  id-token: write

env:
  VPS_HOST: ${{ secrets.VPS_HOST }}
  VPS_USER: ${{ secrets.VPS_USER }}

jobs:
  syntax-check:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v7

      - name: Python syntax check
        run: |
          python3 -m py_compile run_server.py auto_merge_bot.py callback_server.py setup_app.py setup_all.py generate_manifest.py generate_manifest_domain.py start_server.py

  build-and-deploy:
    needs: syntax-check
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v7
        with:
          fetch-depth: 0
          submodules: false

      - name: Install Nix
        uses: DeterminateSystems/nix-installer-action@v22
        with:
          determinate: false
          extra-conf: |
            sandbox = false
            accept-flake-config = true

      - name: Cache Nix
        uses: DeterminateSystems/magic-nix-cache-action@v14
        with:
          use-flakehub: false

      - name: Build pr-agent-server
        id: build
        run: |
          nix build .#default --impure --option sandbox false --print-build-logs
          STORE_PATH=$(readlink result)
          echo "store-path=$STORE_PATH" >> "$GITHUB_OUTPUT"
          echo "Build OK: $STORE_PATH"

      - name: Setup SSH key
        env:
          SSH_KEY: ${{ secrets.SSH_PRIVATE_KEY }}
        run: |
          mkdir -p ~/.ssh
          echo "$SSH_KEY" > ~/.ssh/id_ed25519
          chmod 600 ~/.ssh/id_ed25519
          sed -i 's/\r$//' ~/.ssh/id_ed25519
          ssh-keygen -y -f ~/.ssh/id_ed25519 >/dev/null 2>&1 || { echo "SSH key invalid"; exit 1; }
          ssh-keyscan -H "$VPS_HOST" >> ~/.ssh/known_hosts 2>/dev/null

      - name: Deploy pr-agent-server to VPS
        run: |
          STORE_PATH="${{ steps.build.outputs.store-path }}"
          echo "=== Copying pr-agent-server: $STORE_PATH ==="
          nix copy --to "ssh://$VPS_USER@$VPS_HOST" "$STORE_PATH"

          echo "=== Updating profile ==="
          ssh "$VPS_USER@$VPS_HOST" "sudo /nix/var/nix/profiles/default/bin/nix-env --profile /nix/var/nix/profiles/pr-agent-server --set '$STORE_PATH'"

          echo "=== Restarting service ==="
          ssh "$VPS_USER@$VPS_HOST" "sudo systemctl daemon-reload && sudo systemctl restart pr-agent-server && sleep 3 && sudo systemctl is-active pr-agent-server"
          echo "✅ pr-agent-server deployed"