name: Build Prowlarr Container

on:
  push:
    branches:
      - main
      - develop
  schedule:
    - cron: '0 4 * * *'  # Daily at 4:00 UTC
  workflow_dispatch:

jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        # On schedule/dispatch, build both branches; otherwise only the pushed branch
        branch: ${{ github.event_name == 'schedule' && fromJson('["main", "develop"]') || fromJson(format('["{0}"]', github.ref_name)) }}
    steps:
      - name: Checkout
        uses: actions/checkout@v4
        with:
          ref: ${{ matrix.branch }}

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

      - name: Set build variables
        id: vars
        run: |
          # Date ISO 8601
          echo "build_date=$(date -u +%Y-%m-%dT%H:%M:%S%z)" >> "$GITHUB_OUTPUT"

          # Short SHA of docker-prowlarr repo
          echo "sha_short=$(git rev-parse --short HEAD)" >> "$GITHUB_OUTPUT"

          # Corresponding upstream Prowlarr branch
          PROWLARR_BRANCH="develop"
          if [ "${{ matrix.branch }}" = "main" ]; then
            PROWLARR_BRANCH="master"
          fi
          echo "prowlarr_branch=${PROWLARR_BRANCH}" >> "$GITHUB_OUTPUT"

          # Latest commit SHA on the upstream Prowlarr repo
          UPSTREAM_SHA=$(git ls-remote https://github.com/Prowlarr/Prowlarr.git "refs/heads/${PROWLARR_BRANCH}" | awk '{print $1}')
          UPSTREAM_SHA_SHORT=$(echo "${UPSTREAM_SHA}" | cut -c1-7)
          echo "upstream_sha=${UPSTREAM_SHA}" >> "$GITHUB_OUTPUT"
          echo "upstream_sha_short=${UPSTREAM_SHA_SHORT}" >> "$GITHUB_OUTPUT"
          echo "Prowlarr upstream ${PROWLARR_BRANCH} is at ${UPSTREAM_SHA_SHORT}"

          # Prowlarr version from upstream API
          PROWLARR_VERSION=$(curl -sL "https://prowlarr.servarr.com/v1/update/${PROWLARR_BRANCH}/changes?runtime=netcore&os=linuxmusl" | jq -r '.[0].version')
          echo "prowlarr_version=${PROWLARR_VERSION}" >> "$GITHUB_OUTPUT"

          # Image name
          REGISTRY="${{ vars.OCI_REGISTRY }}"
          REGISTRY="${REGISTRY%/}"
          echo "image_name=${REGISTRY}/prowlarr" >> "$GITHUB_OUTPUT"

          # Channel tag: latest for main, develop for develop
          if [ "${{ matrix.branch }}" = "main" ]; then
            echo "channel_tag=latest" >> "$GITHUB_OUTPUT"
          else
            echo "channel_tag=develop" >> "$GITHUB_OUTPUT"
          fi

      - name: Login to OCI Registry
        uses: docker/login-action@v3
        with:
          registry: ${{ vars.OCI_REGISTRY }}
          username: ${{ vars.OCI_USERNAME }}
          password: ${{ vars.OCI_PASSWORD }}

      - name: Check if upstream version already built
        id: check
        if: github.event_name == 'schedule'
        run: |
          # Check if an image tagged with the upstream SHA already exists
          IMAGE="${{ steps.vars.outputs.image_name }}:${{ steps.vars.outputs.prowlarr_branch }}-${{ steps.vars.outputs.upstream_sha_short }}"
          echo "Checking if ${IMAGE} already exists..."
          if docker manifest inspect "${IMAGE}" > /dev/null 2>&1; then
            echo "Image ${IMAGE} already exists — no upstream changes, skipping build."
            echo "skip=true" >> "$GITHUB_OUTPUT"
          else
            echo "Image ${IMAGE} not found — upstream has changed, proceeding with build."
            echo "skip=false" >> "$GITHUB_OUTPUT"
          fi

      - name: Build and push
        if: steps.check.outputs.skip != 'true'
        uses: docker/build-push-action@v6
        with:
          context: .
          file: ./Dockerfile
          push: true
          build-args: |
            BUILD_DATE=${{ steps.vars.outputs.build_date }}
            VERSION=${{ steps.vars.outputs.prowlarr_version }}-custom
            PROWLARR_BRANCH=${{ steps.vars.outputs.prowlarr_branch }}
          tags: |
            ${{ steps.vars.outputs.image_name }}:${{ steps.vars.outputs.channel_tag }}
            ${{ steps.vars.outputs.image_name }}:${{ steps.vars.outputs.sha_short }}
            ${{ steps.vars.outputs.image_name }}:${{ steps.vars.outputs.prowlarr_version }}-custom
            ${{ steps.vars.outputs.image_name }}:${{ steps.vars.outputs.prowlarr_branch }}-${{ steps.vars.outputs.upstream_sha_short }}
          cache-from: type=gha
          cache-to: type=gha,mode=max