name: Build & Deploy (Nix)

on:
  push:
    branches:
      - main

jobs:
  build-and-deploy:
    runs-on: ubuntu-latest

    strategy:
      fail-fast: false
      max-parallel: 1
      matrix:
        service: [backend, discord-gateway, proxy]

    steps:
      - name: Check out repository
        run: |
          git clone https://git.imrnes.team/MythEclipse/GMW.git .
          git checkout ${{ github.sha }}

      - name: Install Nix & Build ${{ matrix.service }}
        run: |
          set -eu

          # Install Nix (container-safe: --init none, root-only mode)
          curl -fsSL https://install.determinate.systems/nix \
            | sh -s -- install linux --no-confirm --init none 2>&1

          # Enable flakes
          mkdir -p /etc/nix
          echo "experimental-features = nix-command flakes" >> /etc/nix/nix.conf

          . /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh

          # Build
          nix build .#${{ matrix.service }} --impure --option sandbox false 2>&1

          echo "$(readlink result)" > /tmp/gmw-store-path-${{ matrix.service }}

      - name: Copy binary to target VPS & deploy ${{ matrix.service }}
        env:
          VPS_HOST: ${{ secrets.VPS_HOST }}
          VPS_USER: ${{ secrets.VPS_USER }}
          VPS_SSH_KEY_VALUE: ${{ secrets.VPS_SSH_KEY_VALUE }}
        run: |
          set -eu

          . /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh

          SERVICE="${{ matrix.service }}"
          STORE_PATH=$(cat "/tmp/gmw-store-path-$SERVICE")
          echo "=== $SERVICE — Store path: $STORE_PATH"

          key_file=$(mktemp /tmp/deploy-key.XXXXXX)
          printf '%s\n' "$VPS_SSH_KEY_VALUE" > "$key_file"
          chmod 600 "$key_file"

          # Copy binary closure to target VPS via Nix SSH store
          export NIX_SSHOPTS="-i $key_file -o StrictHostKeyChecking=no"
          nix copy --to "ssh://${VPS_USER}@${VPS_HOST}" "$STORE_PATH" 2>&1

          # Deploy: update profile + restart service
          NIX_BIN="/nix/var/nix/profiles/default/bin"
          PROFILE="/nix/var/nix/profiles/gmw-$SERVICE"
          UNIT="gmw-$SERVICE"

          ssh -i "$key_file" -o StrictHostKeyChecking=no \
            "${VPS_USER}@${VPS_HOST}" "
            # Remove stale profile dir if it exists as regular directory
            if [ -d $PROFILE ] && [ ! -L $PROFILE ]; then
              rm -rf $PROFILE
            fi

            export PATH=\$PATH:$NIX_BIN
            nix-env --profile $PROFILE --set $STORE_PATH

            if systemctl is-enabled --quiet $UNIT 2>/dev/null; then
              systemctl daemon-reload
              systemctl restart $UNIT
              sleep 3
              systemctl status $UNIT --no-pager 2>&1 | head -12
            else
              echo \"Unit $UNIT not yet created — run setup first\"
            fi
          " 2>&1