name: Docker

on:
  push:
    branches: [main]
    tags: ['v*.*.*']
  pull_request:
    branches: [main]

permissions:
  contents: read
  packages: write

env:
  IMAGE: ghcr.io/${{ github.repository_owner }}/freellmapi

# Each platform builds NATIVELY (ubuntu-24.04-arm is free for public repos) —
# no QEMU. Emulated arm64 builds took ~20 min cold (better-sqlite3 compiles
# via node-gyp) and their giant gha-cache exports hit backend errors; native
# legs build in ~3 min with small per-arch caches. Pushes are by digest, then
# a merge job stitches the multi-arch manifest. PRs only build (no push).
jobs:
  build:
    name: Build (${{ matrix.platform }})
    runs-on: ${{ matrix.runner }}
    strategy:
      fail-fast: false
      matrix:
        include:
          - platform: linux/amd64
            runner: ubuntu-24.04
          - platform: linux/arm64
            runner: ubuntu-24.04-arm
    steps:
      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1

      - uses: docker/setup-buildx-action@f87e5991a6d7451dcb8d9637bfbc97413f497069 # v4.4.1
        with:
          # Shared runner IPs can exhaust Docker Hub's anonymous pull quota.
          # Use Google's public cache for base images and the Dockerfile frontend;
          # BuildKit retains Docker Hub as the fallback on cache misses.
          buildkitd-config-inline: |
            [registry."docker.io"]
              mirrors = ["mirror.gcr.io"]

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

      - name: Log in to GHCR
        if: github.event_name != 'pull_request'
        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Docker metadata
        id: meta
        uses: docker/metadata-action@dc802804100637a589fabce1cb79ff13a1411302 # v6.2.0
        with:
          images: ${{ env.IMAGE }}

      - name: Build (and push by digest)
        id: build
        uses: docker/build-push-action@c3c9e263c25d99ce0380d002d59b67737d91b0dc # v7.4.0
        with:
          context: .
          file: ./Dockerfile
          platforms: ${{ matrix.platform }}
          build-args: |
            FREELLMAPI_COMMIT_SHA=${{ github.sha }}
          labels: ${{ steps.meta.outputs.labels }}
          cache-from: type=gha,scope=${{ env.PLATFORM_PAIR }}
          cache-to: type=gha,mode=max,scope=${{ env.PLATFORM_PAIR }}
          outputs: type=image,name=${{ env.IMAGE }},push-by-digest=true,name-canonical=true,push=${{ github.event_name != 'pull_request' }}

      - name: Export digest
        if: github.event_name != 'pull_request'
        run: |
          mkdir -p "${{ runner.temp }}/digests"
          digest="${{ steps.build.outputs.digest }}"
          touch "${{ runner.temp }}/digests/${digest#sha256:}"

      - name: Upload digest
        if: github.event_name != 'pull_request'
        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
        with:
          name: digests-${{ env.PLATFORM_PAIR }}
          path: ${{ runner.temp }}/digests/*
          if-no-files-found: error
          retention-days: 1

  merge:
    name: Merge manifest and push
    if: github.event_name != 'pull_request'
    runs-on: ubuntu-24.04
    needs: [build]
    steps:
      - name: Download digests
        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
        with:
          path: ${{ runner.temp }}/digests
          pattern: digests-*
          merge-multiple: true

      - uses: docker/setup-buildx-action@f87e5991a6d7451dcb8d9637bfbc97413f497069 # v4.4.1

      - name: Log in to GHCR
        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4.6.0
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Docker metadata
        id: meta
        uses: docker/metadata-action@dc802804100637a589fabce1cb79ff13a1411302 # v6.2.0
        with:
          images: ${{ env.IMAGE }}
          tags: |
            type=ref,event=branch
            type=ref,event=tag
            type=sha,prefix=sha-
            # `latest` must follow the newest RELEASE, not main. This workflow runs
            # on both main pushes and v* tags, so `{{is_default_branch}}` attached
            # `latest` to every main build and `docker pull ...:latest` served
            # unreleased code — the opposite of what the tag conventionally means,
            # and what sent people to pin `v0.6.5` by hand (discussion #533).
            # Prereleases (v1.2.3-rc1) are excluded so `latest` stays on stable.
            # Main builds keep their `main` and `sha-` tags, so anything tracking
            # the development stream is unaffected.
            type=raw,value=latest,enable=${{ github.ref_type == 'tag' && !contains(github.ref_name, '-') }}

      - name: Create manifest list and push
        working-directory: ${{ runner.temp }}/digests
        run: |
          docker buildx imagetools create \
            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
            $(printf "${IMAGE}@sha256:%s " *)

      - name: Inspect image
        run: docker buildx imagetools inspect "${IMAGE}:${{ steps.meta.outputs.version }}"