action.yml

name: Scaffold and Commit Action
description: |
  This action determines the type of repository based on its properties,
  copies the files from the corresponding scaffolding directory,
  overlays them onto the workspace, and commits the changes to a Pull Request.

  A GitHub App is required because scaffolding may need to commit to protected branches and
  any updates of `.github/workflows` needs the `workflows:write` permission, only available via
  a GitHub App. Additionally, if any of the commits should trigger GitHub Actions, the default
  `GITHUB_TOKEN` will not work.

inputs:
  github_app_id:
    description: 'GitHub App ID'
    required: true
  github_app_private_key:
    description: 'GitHub App Private Key'
    required: true

runs:
  using: 'composite'
  steps:
  - uses: actions/create-github-app-token@v1
    id: github-app
    with:
      app-id: ${{ input.github_app_id }}
      private-key: ${{ input.github_app_private_key }}

  - name: Checkout Repository
    uses: actions/checkout@v4
    with:
      token: ${{ steps.github-app.outputs.token }}

  - name: Get Repository Metadata
    id: repo
    shell: bash
    env:
      GH_TOKEN: ${{ steps.github-app.outputs.token }}
    run: |
      response=$(gh api /repos/${{ github.repository }}/properties/values)
      properties=$(echo "$response" | jq -cr 'reduce .[] as $item ({}; .[$item.property_name] = $item.value)')
      type=$(echo "$properties" | jq -r .type)
      echo "properties=$properties" >> $GITHUB_OUTPUT
      echo "type=$type" >> $GITHUB_OUTPUT
      echo "branch=${{ github.event.pull_request.head.ref ||  github.ref_name }}" >> $GITHUB_OUTPUT
      echo "**Ref Name:** ${{ github.ref_name }}" >> $GITHUB_STEP_SUMMARY
      echo "**Default Branch:** ${{github.event.repository.default_branch }}" >> $GITHUB_STEP_SUMMARY
      echo "**Head Ref:** ${{ github.event.pull_request.head.ref }}" >> $GITHUB_STEP_SUMMARY
      echo "**Repo Type**: $type" >> $GITHUB_STEP_SUMMARY

  - name: Run Scaffolding
    id: scaffolding
    shell: bash
    run: |
      type="${{ steps.repo.outputs.type }}"
      scaffolding_path="${{github.action_path}}/scaffolding/$type"
      if [ -f "${scaffolding_path}/Makefile" ]; then
        echo "Running scaffolding for '$type'..."
        echo "## Scaffolding" >> $GITHUB_STEP_SUMMARY
        echo '```shell' >> $GITHUB_STEP_SUMMARY
        cd $scaffolding_path && (make all >> $GITHUB_STEP_SUMMARY 2>&1)
        echo '```' >> $GITHUB_STEP_SUMMARY
      else
        echo "Scaffolding for type '$type' not supported."
        echo '> [!WARNING]' >> $GITHUB_STEP_SUMMARY
        echo '> ## Unsupported Repository Type' >> $GITHUB_STEP_SUMMARY
        echo "> Scaffold for type `'$type'` not found." >> $GITHUB_STEP_SUMMARY
        exit 1
      fi
      
  # Open New PR for scheduled jobs running in the default branch
  - name: Commit and Push Changes to a New Pull Request
    uses: peter-evans/create-pull-request@v6
    if: ${{ steps.repo.outputs.branch == github.event.repository.default_branch }}
    id: auto-pr
    with:
      token: ${{ steps.github-app.outputs.token }}
      commit-message: 'chore: update repo scaffolding'
      branch: 'auto-update/scaffolding'
      base: ${{ steps.repo.outputs.branch }}
      title: 'Update Repository Scaffolding'
      labels: |
        auto-update
        scaffolding
        no-release
      body: |
        ## what
        - This pull request includes the scaffolding files overlaid onto the repository.

        ## why
        - Update the repository whenever the scaffolding files change from the organization's `.github` repository.

  # Update existing PR for jobs running in a PR (e.g. non-default branch)
  # Protected branches will need a GitHub App to update the PR
  - uses: stefanzweifel/git-auto-commit-action@v5
    if: ${{ steps.repo.outputs.branch != github.event.repository.default_branch }}
    name: Commit changes to current Pull Request
    id: auto-commit
    env:
      GITHUB_TOKEN: ${{ steps.github-app.outputs.token }}
    with:
      commit_message: "chore: update repo scaffolding"
      commit_user_name: org-action 🏗️
      commit_user_email: actions@github.com
      commit_author: org-action 🏗️ <actions@github.com>