# Nix container build workflow
# Triggers on tags matching: <container>-nix-v<version>
# Builds from containers/<container>/default.nix using nix build
# Pushes to Zot registry via skopeo
#
# Examples:
#   nettest-nix-v1.0.0  -> builds containers/nettest/default.nix
#   myapp-nix-v2.1.0    -> builds containers/myapp/default.nix
name: Build Container (Nix)

on:
  push:
    tags:
      - '*-nix-v[0-9]*'

jobs:
  build:
    runs-on: nix-container-builder
    steps:
      - name: Parse tag
        id: parse
        run: |
          TAG="${GITHUB_REF_NAME}"
          echo "Tag: $TAG"

          # Extract container name (everything before -nix-v)
          # e.g., "nettest-nix-v1.0.0" -> "nettest"
          CONTAINER="${TAG%-nix-v[0-9]*}"
          VERSION="${TAG#"${CONTAINER}"-nix-}"

          echo "container=$CONTAINER" >> "$GITHUB_OUTPUT"
          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
          echo "Container: $CONTAINER"
          echo "Version: $VERSION"

      - name: Checkout
        uses: actions/checkout@v4

      - name: Check if nix container exists
        id: check
        run: |
          CONTAINER="${{ steps.parse.outputs.container }}"
          CONTEXT="containers/$CONTAINER"

          if [ -f "$CONTEXT/default.nix" ]; then
            echo "Found $CONTEXT/default.nix"
            echo "exists=true" >> "$GITHUB_OUTPUT"
          else
            echo "No default.nix found at $CONTEXT/default.nix"
            echo "exists=false" >> "$GITHUB_OUTPUT"
          fi

      - name: Skip if container not found
        if: steps.check.outputs.exists != 'true'
        run: |
          echo "========================================"
          echo "Nix container not found: ${{ steps.parse.outputs.container }}"
          echo "========================================"
          echo ""
          echo "Tag '${{ github.ref_name }}' does not match any nix container in containers/"
          echo ""
          echo "Available nix containers:"
          for nix in containers/*/default.nix; do
            [ -f "$nix" ] && echo "  - $(basename "$(dirname "$nix")")"
          done
          echo ""
          echo "Skipping build."

      - name: Build with nix
        if: steps.check.outputs.exists == 'true'
        id: build
        run: |
          CONTAINER="${{ steps.parse.outputs.container }}"
          echo "Building containers/$CONTAINER/default.nix"
          nix build -f "containers/$CONTAINER/default.nix" -o result
          echo "Build complete: $(readlink result)"

      - name: Push to registry
        if: steps.check.outputs.exists == 'true'
        run: |
          CONTAINER="${{ steps.parse.outputs.container }}"
          VERSION="${{ steps.parse.outputs.version }}"
          IMAGE="registry.ops.eblu.me/blumeops/$CONTAINER:$VERSION"

          echo "Pushing to $IMAGE"
          skopeo copy \
            "docker-archive:result" \
            "docker://$IMAGE"
          echo "Push complete: $IMAGE"