name: Build and push multi-arch container image

on:
  workflow_call:
    inputs:
      registry:
        required: true
        type: string
      registry_user:
        required: true
        type: string
      image_name:
        required: true
        type: string
      reproduce:
        required: true
        type: boolean
      sign:
        required: true
        type: boolean
      key_name:
        required: false
        type: string
        default: "dangerzone-tests"
      key_cache:
        required: false
        type: string
        default: "v1-keypair-${{ github.ref_name }}" # unique for the branch / PR
    secrets:
      registry_token:
        required: true

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Install dev. dependencies
        run: |-
          sudo apt-get update
          sudo apt-get install -y git python3-poetry --no-install-recommends
          poetry install --only package

      - name: Verify that the Dockerfile matches the commited template and params
        run: |-
          cp Dockerfile Dockerfile.orig
          make Dockerfile
          diff Dockerfile.orig Dockerfile

  prepare:
    runs-on: ubuntu-latest
    outputs:
      debian_archive_date: ${{ steps.params.outputs.debian_archive_date }}
      source_date_epoch: ${{ steps.params.outputs.source_date_epoch }}
      image: ${{ steps.params.outputs.full_image_name }}
      tag: ${{ steps.params.outputs.tag }}
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Compute image parameters
        id: params
        run: |
          source Dockerfile.env
          DEBIAN_ARCHIVE_DATE=$(date -u +'%Y%m%d')
          SOURCE_DATE_EPOCH=$(date -u -d ${DEBIAN_ARCHIVE_DATE} +"%s")
          TAG=${DEBIAN_ARCHIVE_DATE}-$(git describe --long --first-parent | tail -c +2)
          FULL_IMAGE_NAME=${{ inputs.registry }}/${{ inputs.image_name }}:${TAG}

          echo "debian_archive_date=${DEBIAN_ARCHIVE_DATE}" >> $GITHUB_OUTPUT
          echo "source_date_epoch=${SOURCE_DATE_EPOCH}" >> $GITHUB_OUTPUT
          echo "tag=${TAG}" >> $GITHUB_OUTPUT
          echo "full_image_name=${FULL_IMAGE_NAME}" >> $GITHUB_OUTPUT
          echo "buildkit_image=${BUILDKIT_IMAGE}" >> $GITHUB_OUTPUT

  build:
    name: Build ${{ matrix.platform.name }} image
    runs-on: ${{ matrix.platform.runs-on }}
    needs:
      - prepare
    outputs:
      debian_archive_date: ${{ needs.prepare.outputs.debian_archive_date }}
      source_date_epoch: ${{ needs.prepare.outputs.source_date_epoch }}
      image: ${{ needs.prepare.outputs.image }}
      tag: ${{ needs.prepare.outputs.tag }}
    strategy:
      fail-fast: false
      matrix:
        platform:
          - runs-on: "ubuntu-24.04"
            name: "linux/amd64"
          - runs-on: "ubuntu-24.04-arm"
            name: "linux/arm64"
    steps:
      - uses: actions/checkout@v4

      - name: Prepare
        run: |
          platform=${{ matrix.platform.name }}
          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV

      - name: Login to GHCR
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ inputs.registry_user }}
          password: ${{ secrets.registry_token }}

      # Instructions for reproducibly building a container image are taken from:
      # https://github.com/freedomofpress/repro-build?tab=readme-ov-file#build-and-push-a-container-image-on-github-actions
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
        with:
          driver-opts: image=${{ needs.prepare.outputs.buildkit_image }}

      - name: Build and push by digest
        id: build
        uses: docker/build-push-action@v6
        with:
          context: ./dangerzone/
          file: Dockerfile
          build-args: |
            DEBIAN_ARCHIVE_DATE=${{ needs.prepare.outputs.debian_archive_date }}
            SOURCE_DATE_EPOCH=${{ needs.prepare.outputs.source_date_epoch }}
          provenance: false
          outputs: type=image,"name=${{ inputs.registry }}/${{ inputs.image_name }}",push-by-digest=true,push=true,rewrite-timestamp=true,name-canonical=true
          cache-from: type=gha
          cache-to: type=gha,mode=max

      - name: Export digest
        run: |
          mkdir -p ${{ runner.temp }}/digests
          digest="${{ steps.build.outputs.digest }}"
          touch "${{ runner.temp }}/digests/${digest#sha256:}"
          echo "Image digest is: ${digest}"

      - name: Upload digest
        uses: actions/upload-artifact@v4
        with:
          name: digests-${{ env.PLATFORM_PAIR }}
          path: ${{ runner.temp }}/digests/*
          if-no-files-found: error
          retention-days: 1

  merge:
    runs-on: ubuntu-latest
    needs:
      - build
    outputs:
      debian_archive_date: ${{ needs.build.outputs.debian_archive_date }}
      source_date_epoch: ${{ needs.build.outputs.source_date_epoch }}
      image: ${{ needs.build.outputs.image }}
      tag: ${{ needs.build.outputs.tag }}
      digest_root: ${{ steps.image.outputs.digest_root }}
      digest_amd64: ${{ steps.image.outputs.digest_amd64 }}
      digest_arm64: ${{ steps.image.outputs.digest_arm64 }}
    steps:
      - uses: actions/checkout@v4

      - name: Download digests
        uses: actions/download-artifact@v4
        with:
          path: ${{ runner.temp }}/digests
          pattern: digests-*
          merge-multiple: true

      - name: Login to GHCR
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ inputs.registry_user }}
          password: ${{ secrets.registry_token }}

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
        with:
          driver-opts: image=${{ env.BUILDKIT_IMAGE }}

      - name: Create manifest list and push
        working-directory: ${{ runner.temp }}/digests
        run: |
          DIGESTS=$(printf '${{ needs.build.outputs.image }}@sha256:%s ' *)
          docker buildx imagetools create -t ${{ needs.build.outputs.image }} ${DIGESTS}

      - name: Inspect image
        id: image
        run: |
          # Inspect the image
          docker buildx imagetools inspect ${{ needs.build.outputs.image }}
          docker buildx imagetools inspect ${{ needs.build.outputs.image }} --format "{{json .Manifest}}" > manifest

          # Calculate and print the digests
          digest_root=$(jq -r .digest manifest)
          digest_amd64=$(jq -r '.manifests[] | select(.platform.architecture=="amd64") | .digest' manifest)
          digest_arm64=$(jq -r '.manifests[] | select(.platform.architecture=="arm64") | .digest' manifest)

          echo "The image digests are:"
          echo "  Root: $digest_root"
          echo "  linux/amd64: $digest_amd64"
          echo "  linux/arm64: $digest_arm64"

          # NOTE: Set the digests as an output because the `env` context is not
          # available to the inputs of a reusable workflow call.
          echo "digest_root=$digest_root" >> "$GITHUB_OUTPUT"
          echo "digest_amd64=$digest_amd64" >> "$GITHUB_OUTPUT"
          echo "digest_arm64=$digest_arm64" >> "$GITHUB_OUTPUT"

  # This step calls the container workflow to generate provenance and push it to
  # the container registry.
  provenance:
    needs:
      - merge
    strategy:
      matrix:
        manifest_type:
          - root
          - amd64
          - arm64
    permissions:
      actions: read # for detecting the Github Actions environment.
      id-token: write # for creating OIDC tokens for signing.
      packages: write # for uploading attestations.
    uses: slsa-framework/slsa-github-generator/.github/workflows/generator_container_slsa3.yml@v2.1.0
    with:
      digest: ${{ needs.merge.outputs[format('digest_{0}', matrix.manifest_type)] }}
      image: ${{ needs.merge.outputs.image }}
      registry-username: ${{ inputs.registry_user }}
    secrets:
      registry-password: ${{ secrets.registry_token }}

  # This step ensures that the image is reproducible
  check-reproducibility:
    if: ${{ inputs.reproduce }}
    needs:
      - merge
    runs-on: ${{ matrix.platform.runs-on }}
    strategy:
      fail-fast: false
      matrix:
        platform:
          - runs-on: "ubuntu-24.04"
            name: "amd64"
          - runs-on: "ubuntu-24.04-arm"
            name: "arm64"
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Reproduce the same container image
        run: |
          ./dev_scripts/reproduce-image.py \
            --runtime \
            docker \
            --debian-archive-date \
            ${{ needs.merge.outputs.debian_archive_date }} \
            --platform \
            linux/${{ matrix.platform.name }} \
            ${{ needs.merge.outputs[format('digest_{0}', matrix.platform.name)] }}

  sign:
    if: ${{ inputs.sign }}
    runs-on: "ubuntu-latest"
    env:
      COSIGN_PASSWORD: "password"
      COSIGN_YES: true
    needs:
      - merge
    # outputs: add signature location ?
    steps:
      - name: Install Cosign
        uses: sigstore/cosign-installer@d7d6bc7722e3daa8354c50bcb52f4837da5e9b6a
        with:
          cosign-release: 'v2.5.0'
      - name: Check install
        run: cosign version
      - name: Generate keypair
        run: |-
          cosign generate-key-pair --output-key-prefix="${{ inputs.key_name }}"
      - name: Cache keypair
        uses: actions/cache@v4
        with:
          path: "${{ inputs.key_name }}.*"
          key: ${{ inputs.key_cache }}
          enableCrossOsArchive: true

      - name: Login to GHCR
        uses: docker/login-action@v3
        with:
          registry: ghcr.io
          username: ${{ inputs.registry_user }}
          password: ${{ secrets.registry_token }}

      - name: Sign container
        run: |-
          export IMAGE_URI="${{ inputs.registry }}/${{ inputs.image_name }}:${{ needs.merge.outputs.tag }}@${{ needs.merge.outputs.digest_root }}"
          cosign sign -d --yes --key=${{ inputs.key_name }}.key "$IMAGE_URI"
        shell: bash