.github/workflows/diff_shades_comment.yml

name: diff-shades comment

on:
  workflow_run:
    workflows: [diff-shades]
    types: [completed]

permissions: {}

jobs:
  comment:
    runs-on: ubuntu-latest
    # We want to comment even if there were failed files or the stable style changed
    # That would cause the main workflow to "fail"
    if:
      github.event.workflow_run.event == 'pull_request' &&
      contains(fromJSON('["success", "failure"]'), github.event.workflow_run.conclusion)
    permissions:
      pull-requests: write # Needed to comment on PR
    steps:
      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
        with:
          persist-credentials: false

      - uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
        id: artifacts
        with:
          merge-multiple: true
          pattern: ".*.pr-comment.md"
          path: ${{ runner.temp }}/diff-shades-artifacts
          github-token: ${{ github.token }}
          run-id: ${{ github.event.workflow_run.id }}

      - name: Validate downloaded comment artifacts
        id: comment-artifacts
        shell: bash
        run: |
          set -euo pipefail

          artifact_dir="${RUNNER_TEMP}/diff-shades-artifacts"
          preview_artifact="${artifact_dir}/.preview.pr-comment.md"
          stable_artifact="${artifact_dir}/.stable.pr-comment.md"

          if [ ! -d "$artifact_dir" ]; then
              echo "::error::Artifact directory does not exist: ${artifact_dir}"
              exit 1
          fi

          while IFS= read -r -d '' entry; do
              if [ "$(dirname "$entry")" != "$artifact_dir" ]; then
                  echo "::error::Unexpected nested artifact path: ${entry}"
                  exit 1
              fi

              case "$(basename "$entry")" in
                  .preview.pr-comment.md|.stable.pr-comment.md) ;;
                  *)
                      echo "::error::Unexpected artifact path: ${entry}"
                      exit 1
                      ;;
              esac

              if [ ! -f "$entry" ] || [ -L "$entry" ]; then
                  echo "::error::Artifact must be a regular file: ${entry}"
                  exit 1
              fi
          done < <(find "$artifact_dir" -mindepth 1 -print0)

          for artifact in "$preview_artifact" "$stable_artifact"; do
              if [ ! -f "$artifact" ] || [ -L "$artifact" ]; then
                  echo "::error::Missing expected artifact file: ${artifact}"
                  exit 1
              fi
          done

          {
              echo "preview=${preview_artifact}"
              echo "stable=${stable_artifact}"
          } >> "$GITHUB_OUTPUT"

      - name: Set up Python
        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
        with:
          python-version: "3.14"
          pip-version: "25.3"
          pip-install: --group diff-shades-comment

      - name: Get PR number
        id: pr
        run:
          echo pr=$(gh pr list --search $sha --json number --jq ".[0].number") >>
          "$GITHUB_OUTPUT"
        env:
          GITHUB_TOKEN: ${{ github.token }}
          sha: ${{ github.event.workflow_run.head_sha }}

      - name: Get details from initial workflow run
        id: metadata
        run: |
          python scripts/diff_shades_gha_helper.py comment-details \
          "$pr" "$run_id" "$preview_artifact" "$stable_artifact"
        env:
          GITHUB_TOKEN: ${{ github.token }}
          pr: ${{ steps.pr.outputs.pr }}
          run_id: ${{ github.event.workflow_run.id }}
          preview_artifact: ${{ steps.comment-artifacts.outputs.preview }}
          stable_artifact: ${{ steps.comment-artifacts.outputs.stable }}

      - name: Try to find pre-existing PR comment
        id: find-comment
        uses: peter-evans/find-comment@b30e6a3c0ed37e7c023ccd3f1db5c6c0b0c23aad # v4.0.0
        with:
          issue-number: ${{ steps.pr.outputs.pr }}
          comment-author: "github-actions[bot]"
          body-includes: "diff-shades"

      - name: Create or update PR comment
        uses: peter-evans/create-or-update-comment@e8674b075228eee787fea43ef493e45ece1004c9 # v5.0.0
        with:
          comment-id: ${{ steps.find-comment.outputs.comment-id }}
          issue-number: ${{ steps.pr.outputs.pr }}
          body: ${{ steps.metadata.outputs.comment-body }}
          edit-mode: replace