name: prepare-docker-build
description: |
  Prepare the Docker build environment for Continuwuity builds.
  Sets up Rust toolchain, Docker Buildx, caching, and extracts metadata for Docker builds.

inputs:
  platform:
    description: Target platform (e.g. linux/amd64, linux/arm64)
    required: true
  slug:
    description: Platform slug for artifact naming (e.g. linux-amd64, linux-arm64)
    required: true
  target_cpu:
    description: Target CPU architecture (e.g. haswell, empty for base)
    required: false
    default: ""
  profile:
    description: Cargo build profile (release or release-max-perf)
    required: true
  images:
    description: Container registry images (newline-separated)
    required: true
  registry_user:
    description: Registry username for authentication
    required: false
  registry_password:
    description: Registry password for authentication
    required: false

outputs:
  cpu_suffix:
    description: CPU suffix for artifact naming
    value: ${{ steps.cpu-suffix.outputs.suffix }}
  metadata_labels:
    description: Docker labels for the image
    value: ${{ steps.meta.outputs.labels }}
  metadata_annotations:
    description: Docker annotations for the image
    value: ${{ steps.meta.outputs.annotations }}

runs:
  using: composite
  steps:
    - name: Set CPU suffix variable
      id: cpu-suffix
      shell: bash
      run: |
        if [[ -n "${{ inputs.target_cpu }}" ]]; then
          echo "suffix=-${{ inputs.target_cpu }}" >> $GITHUB_OUTPUT
          echo "CPU_SUFFIX=-${{ inputs.target_cpu }}" >> $GITHUB_ENV
        else
          echo "suffix=" >> $GITHUB_OUTPUT
          echo "CPU_SUFFIX=" >> $GITHUB_ENV
        fi

    - name: Echo matrix configuration
      shell: bash
      run: |
        echo "Platform: ${{ inputs.platform }}"
        echo "Slug: ${{ inputs.slug }}"
        echo "Target CPU: ${{ inputs.target_cpu }}"
        echo "Profile: ${{ inputs.profile }}"

    - name: Install rust
      if: ${{ env.BUILDKIT_ENDPOINT == '' }}
      id: rust-toolchain
      uses: ./.forgejo/actions/rust-toolchain

    - name: Set up Docker Buildx
      uses: docker/setup-buildx-action@d7f5e7f509e45cec5c76c4d5afdd7de93d0b3df5 # v4
      with:
        # Use persistent BuildKit if BUILDKIT_ENDPOINT is set (e.g. tcp://buildkit:8125)
        driver: ${{ env.BUILDKIT_ENDPOINT != '' && 'remote' || 'docker-container' }}
        endpoint: ${{ env.BUILDKIT_ENDPOINT || '' }}

    - name: Set up QEMU
      if: ${{ env.BUILDKIT_ENDPOINT == '' }}
      uses: docker/setup-qemu-action@ce360397dd3f832beb865e1373c09c0e9f86d70a # v4

    - name: Login to builtin registry
      if: ${{ env.BUILTIN_REGISTRY_ENABLED == 'true' }}
      uses: docker/login-action@650006c6eb7dba73a995cc03b0b2d7f5ca915bee # v4
      with:
        registry: ${{ env.BUILTIN_REGISTRY }}
        username: ${{ inputs.registry_user }}
        password: ${{ inputs.registry_password }}

    - name: Extract metadata (labels, annotations) for Docker
      id: meta
      uses: docker/metadata-action@80c7e94dd9b9319bd5eb7a0e0fe9291e23a2a2e9 # v6
      with:
        images: ${{ inputs.images }}
        # default labels & annotations: https://github.com/docker/metadata-action/blob/master/src/meta.ts#L509
      env:
        DOCKER_METADATA_ANNOTATIONS_LEVELS: manifest,index

    - name: Get short git commit SHA
      id: sha
      shell: bash
      run: |
        calculatedSha=$(git rev-parse --short ${{ github.sha }})
        echo "COMMIT_SHORT_SHA=$calculatedSha" >> $GITHUB_ENV
        echo "Short SHA: $calculatedSha"

    - name: Get Git commit timestamps
      shell: bash
      run: |
        timestamp=$(git log -1 --pretty=%ct)
        echo "TIMESTAMP=$timestamp" >> $GITHUB_ENV
        echo "Commit timestamp: $timestamp"

    - uses: ./.forgejo/actions/timelord
      id: timelord