name: docker-reproducible

on:
  push:
    branches:
      - unstable
      - stable
    tags:
      - v*
  workflow_dispatch: # allows manual triggering for testing purposes and skips publishing an image

env:
  DOCKER_REPRODUCIBLE_IMAGE_NAME: >-
    ${{ github.repository_owner }}/lighthouse-reproducible
  DOCKER_PASSWORD: ${{ secrets.DH_KEY }}
  DOCKER_USERNAME: ${{ secrets.DH_ORG }}

jobs:
  extract-version:
    name: extract version
    runs-on: ubuntu-22.04
    steps:
      - name: Extract version
        run: |
          if [[ "${{ github.ref }}" == refs/tags/* ]]; then
            # It's a tag (e.g., v1.2.3)
            VERSION="${GITHUB_REF#refs/tags/}"
          elif [[ "${{ github.ref }}" == refs/heads/stable ]]; then
            # stable branch -> latest
            VERSION="latest"
          elif [[ "${{ github.ref }}" == refs/heads/unstable ]]; then
            # unstable branch -> latest-unstable
            VERSION="latest-unstable"
          else
            # For manual triggers from other branches and will not publish any image
            VERSION="test-build"
          fi
          echo "VERSION=$VERSION" >> $GITHUB_OUTPUT
        id: extract_version
    outputs:
      VERSION: ${{ steps.extract_version.outputs.VERSION }}

  verify-and-build:
    name: verify reproducibility and build
    needs: extract-version
    strategy:
      matrix:
        arch: [amd64, arm64]
        include:
          - arch: amd64
            rust_target: x86_64-unknown-linux-gnu
            rust_image: >-
              rust:1.88-bullseye@sha256:8e3c421122bf4cd3b2a866af41a4dd52d87ad9e315fd2cb5100e87a7187a9816
            platform: linux/amd64
            runner: ubuntu-22.04
          - arch: arm64
            rust_target: aarch64-unknown-linux-gnu
            rust_image: >-
              rust:1.88-bullseye@sha256:8b22455a7ce2adb1355067638284ee99d21cc516fab63a96c4514beaf370aa94
            platform: linux/arm64
            runner: ubuntu-22.04-arm
    runs-on: ${{ matrix.runner }}
    steps:
      - uses: actions/checkout@v4

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3
        with:
          driver: docker

      - name: Verify reproducible builds (${{ matrix.arch }})
        run: |
          # Build first image
          docker build -f Dockerfile.reproducible \
            --platform ${{ matrix.platform }} \
            --build-arg RUST_TARGET="${{ matrix.rust_target }}" \
            --build-arg RUST_IMAGE="${{ matrix.rust_image }}" \
            -t lighthouse-verify-1-${{ matrix.arch }} .

          # Extract binary from first build
          docker create --name extract-1-${{ matrix.arch }} lighthouse-verify-1-${{ matrix.arch }}
          docker cp extract-1-${{ matrix.arch }}:/lighthouse ./lighthouse-1-${{ matrix.arch }}
          docker rm extract-1-${{ matrix.arch }}

          # Clean state for second build
          docker buildx prune -f
          docker system prune -f

          # Build second image
          docker build -f Dockerfile.reproducible \
            --platform ${{ matrix.platform }} \
            --build-arg RUST_TARGET="${{ matrix.rust_target }}" \
            --build-arg RUST_IMAGE="${{ matrix.rust_image }}" \
            -t lighthouse-verify-2-${{ matrix.arch }} .

          # Extract binary from second build
          docker create --name extract-2-${{ matrix.arch }} lighthouse-verify-2-${{ matrix.arch }}
          docker cp extract-2-${{ matrix.arch }}:/lighthouse ./lighthouse-2-${{ matrix.arch }}
          docker rm extract-2-${{ matrix.arch }}

          # Compare binaries
          echo "=== Comparing binaries ==="
          echo "Build 1 SHA256: $(sha256sum lighthouse-1-${{ matrix.arch }})"
          echo "Build 2 SHA256: $(sha256sum lighthouse-2-${{ matrix.arch }})"

          if cmp lighthouse-1-${{ matrix.arch }} lighthouse-2-${{ matrix.arch }}; then
            echo "Reproducible build verified for ${{ matrix.arch }}"
          else
            echo "Reproducible build FAILED for ${{ matrix.arch }}"
            echo "BLOCKING RELEASE: Builds are not reproducible!"
            echo "First 10 differences:"
            cmp -l lighthouse-1-${{ matrix.arch }} lighthouse-2-${{ matrix.arch }} | head -10
            exit 1
          fi

          # Clean up verification artifacts but keep one image for publishing
          rm -f lighthouse-*-${{ matrix.arch }}
          docker rmi lighthouse-verify-1-${{ matrix.arch }} || true

          # Re-tag the second image for publishing (we verified it's identical to first)
          VERSION=${{ needs.extract-version.outputs.VERSION }}
          FINAL_TAG="${{ env.DOCKER_REPRODUCIBLE_IMAGE_NAME }}:${VERSION}-${{ matrix.arch }}"
          docker tag lighthouse-verify-2-${{ matrix.arch }} "$FINAL_TAG"

      - name: Log in to Docker Hub
        if: ${{ github.event_name != 'workflow_dispatch' }}
        uses: docker/login-action@v3
        with:
          username: ${{ env.DOCKER_USERNAME }}
          password: ${{ env.DOCKER_PASSWORD }}

      - name: Push verified image (${{ matrix.arch }})
        if: ${{ github.event_name != 'workflow_dispatch' }}
        run: |
          VERSION=${{ needs.extract-version.outputs.VERSION }}
          IMAGE_TAG="${{ env.DOCKER_REPRODUCIBLE_IMAGE_NAME }}:${VERSION}-${{ matrix.arch }}"
          docker push "$IMAGE_TAG"

      - name: Clean up local images
        run: |
          docker rmi lighthouse-verify-2-${{ matrix.arch }} || true
          VERSION=${{ needs.extract-version.outputs.VERSION }}
          docker rmi "${{ env.DOCKER_REPRODUCIBLE_IMAGE_NAME }}:${VERSION}-${{ matrix.arch }}" || true

      - name: Upload verification artifacts (on failure)
        if: failure()
        uses: actions/upload-artifact@v4
        with:
          name: verification-failure-${{ matrix.arch }}
          path: |
            lighthouse-*-${{ matrix.arch }}

  create-manifest:
    name: create multi-arch manifest
    runs-on: ubuntu-22.04
    needs: [extract-version, verify-and-build]
    if: ${{ github.event_name != 'workflow_dispatch' }}
    steps:
      - name: Log in to Docker Hub
        uses: docker/login-action@v3
        with:
          username: ${{ env.DOCKER_USERNAME }}
          password: ${{ env.DOCKER_PASSWORD }}

      - name: Create and push multi-arch manifest
        run: |
          IMAGE_NAME=${{ env.DOCKER_REPRODUCIBLE_IMAGE_NAME }}
          VERSION=${{ needs.extract-version.outputs.VERSION }}

          # Create manifest for the version tag
          docker manifest create \
            ${IMAGE_NAME}:${VERSION} \
            ${IMAGE_NAME}:${VERSION}-amd64 \
            ${IMAGE_NAME}:${VERSION}-arm64

          docker manifest push ${IMAGE_NAME}:${VERSION}