name: build-ublue
on:
  pull_request:
    branches:
      - main
    paths-ignore:
      - '**.md'
      - '**.txt'
  schedule:
    - cron: '20 20 * * *'  # 8:20pm everyday
  push:
    branches:
      - main
    paths-ignore:
      - '**.md'
      - '**.txt'
env:
    IMAGE_BASE_NAME: base
    IMAGE_REGISTRY: ghcr.io/${{ github.repository_owner }}

jobs:
  push-ghcr:
    name: Build and push image
    runs-on: ubuntu-22.04
    permissions:
      contents: read
      packages: write
      id-token: write
    strategy:
      fail-fast: false
      matrix:
        image_name: [base]
        major_version: [37]
        include:
          - major_version: 37
            is_latest_version: true
            is_stable_version: true
    steps: 
      # Checkout push-to-registry action GitHub repository
      - name: Checkout Push to Registry action
        uses: actions/checkout@v3

      - name: Matrix Variables
        run: |
          echo "IMAGE_NAME=${{ format('{1}', matrix.image_name, env.IMAGE_BASE_NAME) }}" >> $GITHUB_ENV

      - name: Generate tags
        id: generate-tags
        shell: bash
        run: |
          # Generate a timestamp for creating an image version history
          TIMESTAMP="$(date +%Y%m%d)"
          MAJOR_VERSION="${{ matrix.major_version }}"
          COMMIT_TAGS=()
          BUILD_TAGS=()
          # Have tags for tracking builds during pull request
          SHA_SHORT="$(git rev-parse --short HEAD)"
          COMMIT_TAGS+=("pr-${{ github.event.number }}-${MAJOR_VERSION}")
          COMMIT_TAGS+=("${SHA_SHORT}-${MAJOR_VERSION}")
          if [[ "${{ matrix.is_latest_version }}" == "true" ]] && \
             [[ "${{ matrix.is_stable_version }}" == "true" ]]; then
              COMMIT_TAGS+=("pr-${{ github.event.number }}")
              COMMIT_TAGS+=("${SHA_SHORT}")
          fi

          BUILD_TAGS=("${MAJOR_VERSION}" "${MAJOR_VERSION}-${TIMESTAMP}")

          if [[ "${{ matrix.is_latest_version }}" == "true" ]] && \
             [[ "${{ matrix.is_stable_version }}" == "true" ]]; then
              BUILD_TAGS+=("${TIMESTAMP}")
              BUILD_TAGS+=("latest")
          fi

          if [[ "${{ github.event_name }}" == "pull_request" ]]; then
              echo "Generated the following commit tags: "
              for TAG in "${COMMIT_TAGS[@]}"; do
                  echo "${TAG}"
              done
              alias_tags=("${COMMIT_TAGS[@]}")
          else
              alias_tags=("${BUILD_TAGS[@]}")
          fi
          echo "Generated the following build tags: "
          for TAG in "${BUILD_TAGS[@]}"; do
              echo "${TAG}"
          done
          echo "alias_tags=${alias_tags[*]}" >> $GITHUB_OUTPUT

      # Build metadata
      - name: Image Metadata
        uses: docker/metadata-action@v4
        id: meta
        with:
          images: |
            $IMAGE_NAME
          labels: |
            org.opencontainers.image.title=$IMAGE_NAME
            org.opencontainers.image.description=A base $IMAGE_NAME image with batteries included
            io.artifacthub.package.readme-url=https://raw.githubusercontent.com/ublue-os/base/base/README.md
            io.artifacthub.package.logo-url=https://avatars.githubusercontent.com/u/120078124?s=200&v=4

      # Build image using Buildah action
      - name: Build Image
        id: build_image
        uses: redhat-actions/buildah-build@v2
        with:
          containerfiles: |
            ./Containerfile
          image: ${{ env.IMAGE_NAME }}
          tags: |
            ${{ steps.generate-tags.outputs.alias_tags }}
          build-args: |
            IMAGE_NAME=${{ matrix.image_name }}
            FEDORA_MAJOR_VERSION=${{ matrix.major_version }}
          labels: ${{ steps.meta.outputs.labels }}
          oci: false

      # Workaround bug where capital letters in your GitHub username make it impossible to push to GHCR.
      # https://github.com/macbre/push-to-ghcr/issues/12
      - name: Lowercase Registry
        id: registry_case
        uses: ASzc/change-string-case-action@v5
        with:
          string: ${{ env.IMAGE_REGISTRY }}

      # Push the image to GHCR (Image Registry)
      - name: Push To GHCR
        uses: redhat-actions/push-to-registry@v2
        id: push
        env:
          REGISTRY_USER: ${{ github.actor }}
          REGISTRY_PASSWORD: ${{ github.token }}
        with:
          image: ${{ steps.build_image.outputs.image }}
          tags: ${{ steps.build_image.outputs.tags }}
          registry: ${{ steps.registry_case.outputs.lowercase }}
          username: ${{ env.REGISTRY_USER }}
          password: ${{ env.REGISTRY_PASSWORD }}
          extra-args: |
            --disable-content-trust

      # Sign container
      - uses: sigstore/cosign-installer@main

      # Only needed when running `cosign sign` using a key
      - name: Write signing key to disk
        run: |
          echo "${{ env.COSIGN_PRIVATE_KEY }}" > cosign.key
          # DEBUG: get character count of key
          wc -c cosign.key
        env:
          COSIGN_PRIVATE_KEY: ${{ secrets.SIGNING_SECRET }}

      - name: Login to GitHub Container Registry
        uses: docker/login-action@v2
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # Sign container
      - uses: sigstore/cosign-installer@v3.0.1
        if: github.event_name != 'pull_request'

      - name: Sign container image
        run: |
          echo "${{ env.COSIGN_PRIVATE_KEY }}" > cosign.key
          wc -c cosign.key
          cosign sign -y --key cosign.key ${{ steps.registry_case.outputs.lowercase }}/${{ env.IMAGE_NAME }}@${TAGS}
        env:
          TAGS: ${{ steps.push.outputs.digest }}
          COSIGN_EXPERIMENTAL: false
          COSIGN_PRIVATE_KEY: ${{ secrets.SIGNING_SECRET }}

      - name: Echo outputs
        run: |
          echo "${{ toJSON(steps.push.outputs) }}"

      - name: Upload Container Export
        run: |
          mkdir -p output
          podman save -o output/image.tar ${{ steps.build_image.outputs.image }}
          echo "${{ steps.build_image.outputs.image }}" >> output/image
          echo "${{ steps.build_image.outputs.tags }}" >> output/tags
      
      - name: Publish Artifact
        uses: actions/upload-artifact@v2
        if: github.event_name == 'pull_request'
        with:
          name: output
          path: output