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-latest
          - platform: linux/arm64
            runner: ubuntu-24.04-arm
    steps:
      - uses: actions/checkout@v4

      - uses: docker/setup-buildx-action@v3

      - 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@v3
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Docker metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.IMAGE }}

      - name: Build (and push by digest)
        id: build
        uses: docker/build-push-action@v6
        with:
          context: .
          file: ./Dockerfile
          platforms: ${{ matrix.platform }}
          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@v4
        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-latest
    needs: [build]
    steps:
      - name: Download digests
        uses: actions/download-artifact@v4
        with:
          path: ${{ runner.temp }}/digests
          pattern: digests-*
          merge-multiple: true

      - uses: docker/setup-buildx-action@v3

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

      - name: Docker metadata
        id: meta
        uses: docker/metadata-action@v5
        with:
          images: ${{ env.IMAGE }}
          tags: |
            type=ref,event=branch
            type=ref,event=tag
            type=sha,prefix=sha-
            type=raw,value=latest,enable={{is_default_branch}}

      - 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 }}"