name: Check for image compression

on:
  workflow_call:

jobs:
  compress:
    name: Compress and make a PR if needed
    runs-on: ubuntu-24.04

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Install optipng
        run: sudo apt-get update && sudo apt-get install -y optipng

      - name: Optimize PNG files
        id: optimize_png
        run: |
          set -euo pipefail

          FAILED_FILES=""
          while IFS= read -r -d '' file; do
            echo "Compressing: $file"
            if ! optipng -o7 -nc "$file" >/dev/null 2>&1; then
              echo "FAILED: $file (exit code $STATUS)"
              FAILED_FILES+="$file"$'\n'
            fi
          done < <(find . -type f -name "*.png" ! -path "./.git/*" -print0)

          if [[ -n "$FAILED_FILES" ]]; then
            echo "failed_files<<EOF" >> "$GITHUB_OUTPUT"
            echo "$FAILED_FILES" >> "$GITHUB_OUTPUT"
            echo "EOF" >> "$GITHUB_OUTPUT"
            exit 1
          fi
          
      - name: Print files that failed to compress
        if: failure() && steps.optimize_png.outputs.failed_files != ''
        run: |
          echo "The following files failed to compress:"
          echo "${{ steps.optimize_png.outputs.failed_files }}"
      
      - name: Check for changes
        id: check_changes
        run: |
          if [[ -n "$(git status --porcelain)" ]]; then
            echo "needs_compression=true" >> "$GITHUB_OUTPUT"
          else
            echo "needs_compression=false" >> "$GITHUB_OUTPUT"
          fi
          
      - name: Create Pull Request if Needed
        if: ${{ steps.check_changes.outputs.needs_compression == 'true' && github.event_name == 'pull_request' && !github.event.pull_request.draft }}
        run: |
          git config user.name "GitHub GTNH Actions"
          git config user.email "<>"
          git switch -c "${FIXED_BRANCH}"
          git commit -am "optimizing images"
          git push --force-with-lease origin "${FIXED_BRANCH}"
          gh pr create \
            --head "${FIXED_BRANCH}" \
            --base "${PR_BRANCH}" \
            --title "Optimising images contained in ${PR_BRANCH} for #${{ github.event.pull_request.number }}" \
            --body "Automatic image compression, applies to PR #${{ github.event.pull_request.number }}" \
            2>&1 | tee pr-message.log || true
          gh pr comment "${PR_BRANCH}" -F pr-message.log || true
        shell: bash # ensures set -eo pipefail
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          PR_BRANCH: ${{ github.head_ref }}
          FIXED_BRANCH: ${{ github.head_ref }}-image-compression
      - name: Fail if there was compressed files
        if: ${{ steps.check_changes.outputs.needs_compression == 'true' }}
        run: |
          exit 1