name: Build container image
on:
  pull_request:
    branches:
      - main
  schedule:
    - cron: '05 12 * * 2,5'   
  workflow_dispatch:

env:
  IMAGE_DESC: "Custom Fedora bootc image"
  IMAGE_NAME: "${{ github.event.repository.name }}"
  IMAGE_REGISTRY: "ghcr.io/${{ github.repository_owner }}"
  DEFAULT_TAG: "stable"

concurrency:
  group: ${{ github.workflow }}-${{ github.ref || github.run_id }}
  cancel-in-progress: true

jobs:
  build_push:
    name: Build and push image
    runs-on: ubuntu-24.04

    permissions:
      contents: read
      packages: write
      id-token: write

    steps:
      - name: Prepare environment
        run: |
          echo "IMAGE_REGISTRY=${IMAGE_REGISTRY,,}" >> ${GITHUB_ENV}
          echo "IMAGE_NAME=${IMAGE_NAME,,}" >> ${GITHUB_ENV}

      - name: Checkout
        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v5

      - name: Mount BTRFS for podman storage
        id: container-storage-action
        uses: ublue-os/container-storage-action@911baca08baf30c8654933e9e9723cb399892140 # main
        continue-on-error: true 
        with:
          target-dir: /var/lib/containers
          mount-opts: compress-force=zstd:2

      - name: Image Metadata
        uses: docker/metadata-action@030e881283bb7a6894de51c315a6bfe6a94e05cf # v5
        id: metadata
        with:
          tags: |
            type=raw,value=${{ env.DEFAULT_TAG }}
            type=raw,value=${{ env.DEFAULT_TAG }}.{{date 'YYYYMMDD'}}
            type=raw,value={{date 'YYYYMMDD'}}
            type=sha,enable=${{ github.event_name == 'pull_request' }}
            type=ref,event=pr
          labels: |
            org.opencontainers.image.created={{date 'YYYY-MM-DDTHH:mm:ssZ'}}
            org.opencontainers.image.description=${{ env.IMAGE_DESC }}
            org.opencontainers.image.documentation=https://raw.githubusercontent.com/${{ github.repository_owner }}/${{ env.IMAGE_NAME }}/${{ github.sha }}/README.md
            org.opencontainers.image.source=https://github.com/${{ github.repository_owner }}/${{ env.IMAGE_NAME }}/blob/${{ github.sha }}/Containerfile
            org.opencontainers.image.title=${{ env.IMAGE_NAME }}
            org.opencontainers.image.url=https://github.com/${{ github.repository_owner }}/${{ env.IMAGE_NAME }}/tree/${{ github.sha }}
            org.opencontainers.image.vendor=${{ github.repository_owner }}
            org.opencontainers.image.version=${{ env.DEFAULT_TAG }}.{{date 'YYYYMMDD'}}
            containers.bootc=1
          sep-tags: " "
          sep-annotations: " "

      - name: Cache buildah layers
        uses: actions/cache@v5
        with:
          path: |
            /var/lib/containers/storage/overlay
            ~/.cache/buildah
            /tmp/.buildah-cache
          key: ${{ runner.os }}-${{ github.workflow }}-${{ hashFiles('Containerfile') }}-${{ github.ref }}
          restore-keys: |
            ${{ runner.os }}-${{ github.workflow }}-${{ hashFiles('Containerfile') }}-

      - name: Build Image
        id: build_image
        uses: redhat-actions/buildah-build@7a95fa7ee0f02d552a32753e7414641a04307056 # v2
        with:
          containerfiles: |
            ./Containerfile
          image: ${{ env.IMAGE_NAME }}
          tags: ${{ env.DEFAULT_TAG }}
          labels: ${{ steps.metadata.outputs.labels }}
          oci: true

      - name: Apply chunkah optimization
        id: chunkah
        run: |
          set -x
          BASE_IMAGE="${{ env.IMAGE_NAME }}:${{ env.DEFAULT_TAG }}"
          
          # 1. Das kritische ostree-Label im Runner sichern, bevor wir das Image zerlegen
          OSTREE_DIFFID=$(podman inspect $BASE_IMAGE --format '{{index .Config.Labels "ostree.final-diffid"}}' 2>/dev/null || echo "")
          echo "OSTREE_DIFFID=$OSTREE_DIFFID" >> $GITHUB_ENV

          # Rootfs extrahieren
          CONTAINER_ID=$(podman create $BASE_IMAGE)
          mkdir -p ./chunkah-in ./chunkah-out
          podman export $CONTAINER_ID | tar -xf - -C ./chunkah-in
          podman rm $CONTAINER_ID

          # Die komplette Image-Config sichern
          podman inspect $BASE_IMAGE --format '{{json .Config}}' > ./chunkah-config.json

          # Chunkah-Lauf
          podman run --rm \
            -v ./chunkah-in:/inputs:z \
            -v ./chunkah-out:/outputs:z \
            -v ./chunkah-config.json:/config.json:z \
            quay.io/coreos/chunkah:latest \
            build \
            --config /config.json \
            --prune /sysroot/ \
            --max-layers 128 \
            --compressed \
            --output /outputs/image.ociarchive \
            --rootfs /inputs

      - name: Login to GitHub Container Registry
        uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v3
        if: github.event_name != 'pull_request' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch)
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Push to GHCR via Skopeo
        if: github.event_name != 'pull_request' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch)
        run: |
          set -x
          
          # Skopeo-Authentisierung über die Docker-Config des vorherigen Login-Schritts laden
          export REGISTRY_AUTH_FILE=$HOME/.docker/config.json
          REGISTRY_PATH="${{ env.IMAGE_REGISTRY }}/${{ env.IMAGE_NAME }}"

          # Vorbereitung für das Injezieren des Labels in die OCI Config auf der Registry
          PATCH_ARG=""
          if [ ! -z "${{ env.OSTREE_DIFFID }}" ]; then
            # Erstellt das exakte JSON-Fragment, das Skopeo in die Image-Config patcht
            PATCH_ARG="--patch-config {\"config\":{\"Labels\":{\"ostree.final-diffid\":\"${{ env.OSTREE_DIFFID }}\"}}}"
          fi

          # Loop über alle von metadata-action generierten Tags
          for tag in ${{ steps.metadata.outputs.tags }}; do
            skopeo copy \
              $PATCH_ARG \
              --dest-compress-format=zstd \
              --dest-compress-level=5 \
              oci-archive:./chunkah-out/image.ociarchive \
              docker://$REGISTRY_PATH:$tag
          done

          # Den finalen Digest ermitteln und für den nächsten Schritt in GITHUB_ENV schreiben
          DIGEST=$(skopeo inspect oci-archive:./chunkah-out/image.ociarchive --format '{{.Digest}}')
          echo "FINAL_IMAGE_DIGEST=$DIGEST" >> $GITHUB_ENV

      - name: Install Cosign
        uses: sigstore/cosign-installer@6f9f17788090df1f26f669e9d70d6ae9567deba6 # v4.1.2
        if: github.event_name != 'pull_request' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch)
      
      - name: Sign container image
        if: github.event_name != 'pull_request' && github.ref == format('refs/heads/{0}', github.event.repository.default_branch)
        run: |
          # Nutzt den über Skopeo ermittelten Digest für das statische Signieren
          cosign sign -y --key env://COSIGN_PRIVATE_KEY "${{ env.IMAGE_REGISTRY }}/${{ env.IMAGE_NAME }}@${{ env.FINAL_IMAGE_DIGEST }}"
        env:
          COSIGN_EXPERIMENTAL: false
          COSIGN_PRIVATE_KEY: ${{ secrets.SIGNING_SECRET }}