name: Build Images

# Only images whose files changed get built. A release is cut by pushing a tag
# named <image>/vX.Y.Z, which publishes that one image.
on:
  push:
    branches: [main]
    tags: ["*/v*"]
  pull_request:
    branches: [main]
  workflow_dispatch:
    inputs:
      image:
        description: Image to build, or "all"
        default: all
        required: true

concurrency:
  group: build-${{ github.ref }}
  cancel-in-progress: true

env:
  REGISTRY: gitea.libretechconsulting.com
  NAMESPACE: rmcguire
  DOCKER_USER: rmcguire

jobs:
  select:
    name: Select images
    runs-on: ubuntu-latest
    outputs:
      images: ${{ steps.select.outputs.images }}
      any: ${{ steps.select.outputs.any }}
    steps:
      - name: Check out repository
        uses: actions/checkout@v7
        with:
          fetch-depth: 0 # need history to diff against the base commit

      - name: Work out which images changed
        id: select
        run: ./hack/select-images.sh >> "$GITHUB_OUTPUT"
        env:
          DISPATCH_IMAGE: ${{ github.event.inputs.image }}
          BASE_SHA: ${{ github.event.pull_request.base.sha || github.event.before }}

  # One job that loops, rather than a matrix job per image: Gitea resolves a matrix
  # when it parses the workflow, before `needs` outputs exist, so a dynamic matrix
  # produces a single job named after the raw expression. Looping keeps the job name
  # readable and gives one collapsible log section per image.
  build:
    name: Build changed images
    needs: select
    if: needs.select.outputs.any == 'true'
    runs-on: ubuntu-latest
    steps:
      - name: Check out repository
        uses: actions/checkout@v7

      # Never on a pull request, which is exactly when nothing gets published.
      - name: Log in to the Gitea container registry
        if: github.event_name != 'pull_request'
        uses: docker/login-action@v4
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ env.DOCKER_USER }}
          password: ${{ secrets.API_TOKEN }}

      - name: Build, smoke-test and publish
        run: ./hack/build-images.sh ${{ needs.select.outputs.images }}
        env:
          PR_NUMBER: ${{ github.event.pull_request.number }}