name: Publish irtt-server image

on:
  push:
    tags:
      # This repo tags each crate independently (irtt-proto/vX, irtt-client/vX,
      # ...); only the app package's tag corresponds to this image.
      - "irtt-rs/v*"
  workflow_dispatch:
    inputs:
      tag:
        description: >-
          Existing irtt-rs/vX.Y.Z tag to build and publish (backfill a past
          release). Leave empty to build the ref this run was dispatched from.
        required: false
        type: string

env:
  IMAGE_NAME: irtt-server
  IMAGE_OWNER: lochnair
  GITEA_REGISTRY: git.lochnair.net
  GHCR_REGISTRY: ghcr.io
  # Pinned so a floating "latest" release doesn't silently change the build.
  CRANE_VERSION: v0.20.2

jobs:
  publish:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          ref: ${{ github.event.inputs.tag || github.ref }}

      - name: Determine image tags
        id: meta
        run: |
          backfill_tag="${{ github.event.inputs.tag }}"
          if [ -n "${backfill_tag}" ]; then
            ref_name="${backfill_tag}"
            # Backfilling a past release must never move "latest" onto an
            # older build just because it's being published after the fact.
            push_latest=false
          else
            ref_name="${GITHUB_REF_NAME}"
            push_latest=true
          fi

          if [[ "${ref_name}" == irtt-rs/v* ]]; then
            version="${ref_name#irtt-rs/v}"
          else
            # Manual dispatch off a branch, no tag given: tag by commit only.
            version="sha-$(git rev-parse --short HEAD)"
            push_latest=false
          fi

          echo "version=${version}" >> "$GITHUB_OUTPUT"
          if [ "${push_latest}" = true ]; then
            echo "tags=${version},latest" >> "$GITHUB_OUTPUT"
          else
            echo "tags=${version}" >> "$GITHUB_OUTPUT"
          fi

      # Cross-compilation is handled inside the Dockerfile via tonistiigi/xx
      # (native builds, no emulation), but buildx still needs a driver that
      # can assemble a multi-platform manifest list.
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Log in to Gitea Container Registry
        uses: docker/login-action@v3
        with:
          registry: ${{ env.GITEA_REGISTRY }}
          # The automatic per-job token comes back unauthorized for package
          # writes on this instance, so use a PAT (scope: write:package) instead.
          # (Secret names can't start with GITEA_/GITHUB_, hence REGISTRY_*.)
          username: ${{ secrets.REGISTRY_USERNAME }}
          password: ${{ secrets.REGISTRY_TOKEN }}

      - name: Log in to GHCR
        uses: docker/login-action@v3
        with:
          registry: ${{ env.GHCR_REGISTRY }}
          username: ${{ secrets.GHCR_USERNAME }}
          password: ${{ secrets.GHCR_TOKEN }}

      - name: Build tag list
        id: tags
        run: |
          IFS=',' read -ra tag_list <<< "${{ steps.meta.outputs.tags }}"
          gitea_tags=""
          for t in "${tag_list[@]}"; do
            gitea_tags="${gitea_tags}${GITEA_REGISTRY}/${IMAGE_OWNER}/${IMAGE_NAME}:${t},"
          done
          echo "gitea=${gitea_tags%,}" >> "$GITHUB_OUTPUT"

      # Gitea is the primary publish target: this is the only build. Every
      # other registry gets an exact digest copy of this same image (see
      # below), never a separate build, so the hash matches everywhere.
      - name: Build and push to Gitea
        id: build
        uses: docker/build-push-action@v6
        with:
          context: .
          platforms: linux/amd64,linux/arm64
          push: true
          tags: ${{ steps.tags.outputs.gitea }}

      - name: Install crane
        run: |
          mkdir -p "${HOME}/.local/bin"
          curl -sL "https://github.com/google/go-containerregistry/releases/download/${CRANE_VERSION}/go-containerregistry_Linux_x86_64.tar.gz" \
            | tar -xz -C "${HOME}/.local/bin" crane
          echo "${HOME}/.local/bin" >> "$GITHUB_PATH"

      - name: Duplicate image to GHCR (same digest, no rebuild)
        run: |
          source_ref="${GITEA_REGISTRY}/${IMAGE_OWNER}/${IMAGE_NAME}@${{ steps.build.outputs.digest }}"
          IFS=',' read -ra tag_list <<< "${{ steps.meta.outputs.tags }}"
          for t in "${tag_list[@]}"; do
            crane copy "${source_ref}" "${GHCR_REGISTRY}/${IMAGE_OWNER}/${IMAGE_NAME}:${t}"
          done