name: Publish Docker image

on:
  push:
    branches: [main]
    tags: ["v*.*.*"]
  workflow_dispatch:

env:
  REGISTRY: ghcr.io
  IMAGE_NAME: ${{ github.repository }}

jobs:
  publish:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
      # Needed to attach a build provenance attestation to the pushed image.
      id-token: write
      attestations: write

    steps:
      - uses: actions/checkout@v4

      # QEMU lets the amd64 runner emulate arm64 so one job produces both
      # architectures (Apple Silicon + typical cloud hosts). The emulated arm64
      # leg is the slow part of this workflow; if it starts to hurt, split into
      # a matrix over ubuntu-latest + ubuntu-24.04-arm and merge the digests.
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v3

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

      - name: Log in to GHCR
        uses: docker/login-action@v3
        with:
          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      # ghcr.io requires a lowercase image path; github.repository keeps the
      # owner's original casing (geneticglitch1/XRayPDF), so normalize it.
      - name: Compute lowercase image name
        id: image
        run: echo "name=${IMAGE_NAME,,}" >> "$GITHUB_OUTPUT"

      - name: Extract metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.REGISTRY }}/${{ steps.image.outputs.name }}
          tags: |
            type=raw,value=latest,enable={{is_default_branch}}
            type=ref,event=branch
            type=semver,pattern={{version}}
            type=semver,pattern={{major}}.{{minor}}
            type=sha,format=long
          labels: |
            org.opencontainers.image.title=XRayPDF
            org.opencontainers.image.description=Strip hidden text and invisible layers out of PDFs
            org.opencontainers.image.licenses=Apache-2.0

      - name: Build and push
        id: build
        uses: docker/build-push-action@v6
        with:
          context: ./client
          platforms: linux/amd64,linux/arm64
          push: true
          tags: ${{ steps.meta.outputs.tags }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha
          cache-to: type=gha,mode=max
          provenance: mode=max
          sbom: true

      - name: Attest build provenance
        uses: actions/attest-build-provenance@v2
        with:
          subject-name: ${{ env.REGISTRY }}/${{ steps.image.outputs.name }}
          subject-digest: ${{ steps.build.outputs.digest }}
          push-to-registry: true