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: Determine image tag
        run: |
          BRANCH="${GITHUB_REF_NAME}"
          if [[ "$BRANCH" == "main" ]]; then
            echo "IMAGE_TAG=${DEFAULT_TAG}" >> ${GITHUB_ENV}
            echo "IS_TEST_BUILD=false" >> ${GITHUB_ENV}
          else
            SANITIZED=$(echo "$BRANCH" | sed 's/[^a-zA-Z0-9._-]/-/g' | head -c 50)
            echo "IMAGE_TAG=test-${SANITIZED}" >> ${GITHUB_ENV}
            echo "IS_TEST_BUILD=true" >> ${GITHUB_ENV}
          fi

      - 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
        with:
          target-dir: /var/lib/containers
          mount-opts: compress-force=zstd:2

      - name: Image Metadata
        uses: docker/metadata-action@80c7e94dd9b9319bd5eb7a0e0fe9291e23a2a2e9 # v5
        id: metadata
        with:
          tags: |
            type=raw,value=${{ env.IMAGE_TAG }}
            type=raw,value=${{ env.IMAGE_TAG }}.{{date 'YYYYMMDD'}},enable=${{ env.IS_TEST_BUILD == 'false' }}
            type=raw,value={{date 'YYYYMMDD'}},enable=${{ env.IS_TEST_BUILD == 'false' }}
            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.IMAGE_TAG }}.{{date 'YYYYMMDD'}}
            containers.bootc=1
            ostree.bootable=1
          sep-tags: " "
          sep-annotations: " "

      # OPTIMIERUNG 1: Der Cache lauscht jetzt auf Containerfile UND alle Skripte/Configs
      - name: Cache buildah layers
        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
        with:
          path: |
            /var/lib/containers/storage/overlay
            ~/.cache/buildah
            /tmp/.buildah-cache
          key: ${{ runner.os }}-${{ github.workflow }}-${{ hashFiles('Containerfile', 'build/**', 'configs/**', 'scripts/**') }}-${{ github.ref }}
          restore-keys: |
            ${{ runner.os }}-${{ github.workflow }}-${{ hashFiles('Containerfile', 'build/**', 'configs/**', 'scripts/**') }}-
            ${{ runner.os }}-${{ github.workflow }}-

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

      - name: Rechunk with chunkah
        run: |
          set -euo pipefail

          IMG="localhost/${{ env.IMAGE_NAME }}:${{ env.IMAGE_TAG }}"
          CHUNKED_IMG="localhost/${{ env.IMAGE_NAME }}-chunked:${{ env.IMAGE_TAG }}"

          # Image-Config fuer chunkah sichern (Labels, Annotations, etc.)
          CONFIG=$(buildah inspect "$IMG" | jq -c .)

          # Platz schaffen fuer den Rechunk (OCI-Archive + Original passen nicht beide)
          sudo rm -rf /tmp/.buildah-cache/* 2>/dev/null || true

          # chunkah: content-based Layer-Splitting
          # --max-layers 128: Desktop-Images brauchen mehr als Default (64)
          # --prune /sysroot/: entfernt OSTree-Metadaten (optional seit bootc 1.1.3)
          # --label ostree.*: entfernt gueltigkeitsfaehige ostree-Labels
          CHUNKAH_CF=$(mktemp)
          curl -sL https://github.com/coreos/chunkah/releases/download/v0.5.0/Containerfile.splitter -o "$CHUNKAH_CF"

          buildah build --skip-unused-stages=false \
            -f "$CHUNKAH_CF" \
            --from "$IMG" \
            --build-arg CHUNKAH_CONFIG_STR="$CONFIG" \
            --build-arg "CHUNKAH_ARGS=--prune /sysroot/ --max-layers 128 --compressed --label ostree.commit- --label ostree.final-diffid- --label ostree.bootable=true --label containers.bootc=1" \
            -t "$CHUNKED_IMG" \
            .

          rm -f "$CHUNKAH_CF" out.ociarchive

          # Platz freigeben: Original und Zwischenprodukt entfernen
          buildah rmi "$IMG"
          for full_tag in ${{ steps.metadata.outputs.tags }}; do
            tag_only="${full_tag##*:}"
            buildah tag "$CHUNKED_IMG" "localhost/${{ env.IMAGE_NAME }}:${tag_only}"
          done
          buildah rmi "$CHUNKED_IMG"

      - name: Login to GitHub Container Registry
        uses: docker/login-action@650006c6eb7dba73a995cc03b0b2d7f5ca915bee # v3
        if: github.event_name != 'pull_request'
        with:
          registry: ghcr.io
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Push to GHCR
        id: push
        if: github.event_name != 'pull_request'
        uses: redhat-actions/push-to-registry@5ed88d269cf581ea9ef6dd6806d01562096bee9c # v2
        with:
          image: ${{ env.IMAGE_NAME }}
          tags: ${{ steps.metadata.outputs.tags }}
          registry: ${{ env.IMAGE_REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}

      - name: Install Cosign
        uses: sigstore/cosign-installer@6f9f17788090df1f26f669e9d70d6ae9567deba6 # v4.1.2
        if: github.event_name != 'pull_request'
      
      - name: Sign container image
        if: github.event_name != 'pull_request' && env.IS_TEST_BUILD == 'false'
        run: |
          cosign sign -y --key env://COSIGN_PRIVATE_KEY "${{ env.IMAGE_REGISTRY }}/${{ env.IMAGE_NAME }}@${{ steps.push.outputs.digest }}"
        env:
          COSIGN_EXPERIMENTAL: false
          COSIGN_PRIVATE_KEY: ${{ secrets.SIGNING_SECRET }}