action.yml

name: 'Comment on PR with Structurizr Diagrams'
description: 'Automatically comments on PRs with Structurizr diagrams.'
branding:
  icon: 'activity'
  color: 'white'
inputs:
  repo-token:
    description: 'GITHUB_TOKEN from secrets'
    required: true
  output-path:
    description: 'Path to the generated images'
    required: true
    default: 'docs/diagrams'

runs:
  using: 'composite'
  steps:
    - name: Get PR Info
      env:
        GITHUB_TOKEN: ${{ inputs.repo-token }}
        WORKFLOW_RUN_EVENT_OBJ: ${{ toJSON(github.event.workflow_run) }}
      run: |
        PREVIOUS_JOB_ID=$(jq -r '.id' <<< "$WORKFLOW_RUN_EVENT_OBJ")
        echo "Previous Job ID: $PREVIOUS_JOB_ID"
        echo "PREVIOUS_JOB_ID=$PREVIOUS_JOB_ID" >> "$GITHUB_ENV"

        PR_NUMBER=$(jq -r '.pull_requests[0].number' \
        <<< "$WORKFLOW_RUN_EVENT_OBJ")

        echo "PR Number: $PR_NUMBER"
        echo "PR_NUMBER=$PR_NUMBER" >> "$GITHUB_ENV"

        HEAD_SHA=$(jq -r '.pull_requests[0].head.sha' \
        <<< "$WORKFLOW_RUN_EVENT_OBJ")

        echo "Head sha: $HEAD_SHA"
        echo "HEAD_SHA=$HEAD_SHA" >> "$GITHUB_ENV"
      shell: bash

    - name: Checkout Repository
      uses: actions/checkout@v4
      env:
        GITHUB_TOKEN: ${{ inputs.repo-token }}
      with:
        ref: ${{ github.event.workflow_run.head_branch }}

    - name: List Diagram Files
      env:
        HEAD_SHA: ${{ env.HEAD_SHA }}
      run: |
        cd ${{ inputs.output-path }}
        echo 'PNG_FILES_MARKDOWN<<EOF' >> "$GITHUB_ENV"
        for png_file in *.png; do
          # Skip legend files in this loop
          if [[ $png_file == *"-key.png" ]]; then
            continue
          fi

          base_name=$(basename $png_file .png)
          legend_file="${base_name}-key.png"

          # URLs for diagram and its legend
          png_raw_file_path="https://github.com/${{ github.repository }}/blob/${{ github.event.workflow_run.head_branch }}/${{ inputs.output-path }}/${png_file}?raw=true"
          legend_raw_file_path="https://github.com/${{ github.repository }}/blob/${{ github.event.workflow_run.head_branch }}/${{ inputs.output-path }}/${legend_file}?raw=true"
          
          echo "<details>" >> "$GITHUB_ENV"
          clean_base_name=${base_name#structurizr-}
          echo "<summary>${clean_base_name}</summary>" >> "$GITHUB_ENV"
          if [ -f "$legend_file" ]; then
            echo "<img src=\"${legend_raw_file_path}\">" >> "$GITHUB_ENV"
            echo "" >> "$GITHUB_ENV"
            fi
          echo " <img src=\"${png_raw_file_path}\">" >> "$GITHUB_ENV"
          echo "</details>" >> "$GITHUB_ENV"
        done
        echo EOF >> "$GITHUB_ENV"
      shell: bash

    - name: Find Comment
      uses: peter-evans/find-comment@v2
      id: find-comment
      env:
        PR_NUMBER: ${{ env.PR_NUMBER }}
        GITHUB_TOKEN: ${{ inputs.repo-token }}
      with:
        issue-number: ${{ env.PR_NUMBER }}
        comment-author: 'github-actions[bot]'

    - name: Comment on PR
      uses: peter-evans/create-or-update-comment@v3
      env:
        GITHUB_TOKEN: ${{ inputs.repo-token }}
        PR_NUMBER: ${{ env.PR_NUMBER }}
        HEAD_SHA: ${{ env.HEAD_SHA }}
        PREVIOUS_JOB_ID: ${{ env.PREVIOUS_JOB_ID }}
        PNG_FILES_MARKDOWN: ${{ env.PNG_FILES_MARKDOWN }}
        JOB_PATH: "${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ env.PREVIOUS_JOB_ID }}"
      with:
        issue-number: ${{ env.PR_NUMBER }}
        comment-id: ${{ steps.find-comment.outputs.comment-id }}
        edit-mode: replace
        reactions: |
            heart
            hooray
        body: |
            ## C4 Diagrams
            Commit: ${{ env.HEAD_SHA }}
            Logs: ${{ env.JOB_PATH }}
            ${{ env.PNG_FILES_MARKDOWN }}