name: Post profile check comment

# NOTE: The workflow name in the 'workflows' filter below must match the 'name'
# field in check_profiles.yml exactly. If that name changes, update it here too.
on:
  workflow_run:
    workflows: ["Check profiles"]
    types:
      - completed

permissions:
  pull-requests: write
  # Needed to delete outdated bot comments via the issues/comments endpoint.
  issues: write

# Serialize handlers per source branch so parallel runs don't race delete-and-post.
concurrency:
  group: ${{ github.workflow }}-${{ github.event.workflow_run.head_repository.full_name }}-${{ github.event.workflow_run.head_branch }}
  cancel-in-progress: false

jobs:
  post_comment:
    name: Post PR comment
    runs-on: ubuntu-24.04
    if: ${{ github.event.workflow_run.event == 'pull_request' && (github.event.workflow_run.conclusion == 'success' || github.event.workflow_run.conclusion == 'failure') }}
    steps:
      - name: Download artifact
        id: download
        uses: actions/download-artifact@v8
        continue-on-error: true
        with:
          name: profile-check-results
          run-id: ${{ github.event.workflow_run.id }}
          github-token: ${{ github.token }}

      - name: Update PR comment
        if: ${{ steps.download.outcome == 'success' }}
        env:
          GH_TOKEN: ${{ github.token }}
          GH_REPO: ${{ github.repository }}
          HEAD_SHA: ${{ github.event.workflow_run.head_sha }}
        run: |
          if [ ! -f pr_number.txt ]; then
            echo "No pr_number.txt in artifact, skipping."
            exit 0
          fi

          PR_NUMBER=$(cat pr_number.txt)
          if ! [[ "$PR_NUMBER" =~ ^[0-9]+$ ]]; then
            echo "Invalid PR number: $PR_NUMBER"
            exit 1
          fi
          # PR code wrote the artifact, so only a run for the named PR's current head may post.
          if [ -z "$HEAD_SHA" ]; then
            echo "The triggering run names no head commit."
            exit 1
          fi
          if ! PR_HEAD=$(gh api "repos/${GH_REPO}/pulls/${PR_NUMBER}" --jq .head.sha); then
            echo "Cannot look up PR #${PR_NUMBER}."
            exit 1
          fi
          if [ "$HEAD_SHA" != "$PR_HEAD" ]; then
            echo "${HEAD_SHA} is not the head of PR #${PR_NUMBER}; skipping."
            exit 0
          fi

          # Lists every bot comment on the PR, one JSON object per line.
          COMMENTS=$(gh api --paginate "repos/${GH_REPO}/issues/${PR_NUMBER}/comments" \
            --jq '.[] | select(.user.login == "github-actions[bot]") | {id, body} | @json')

          # Delete prior comments matching the marker (from check_profiles.yml) or the legacy heading.
          OLD_IDS=$(printf '%s\n' "$COMMENTS" | jq -r 'select((.body | startswith("<!-- profile-validation-comment -->")) or (.body | startswith("## :x: Profile Validation Errors"))) | .id')
          for comment_id in $OLD_IDS; do
            echo "Deleting outdated profile-validation comment ${comment_id}"
            gh api -X DELETE "repos/${GH_REPO}/issues/comments/${comment_id}" || true
          done

          # Post a new comment only when validation failed (pr_comment.md present).
          # A failed post fails the job only after the G-code diff is handled.
          failed=0
          if [ -f pr_comment.md ]; then
            gh pr comment "$PR_NUMBER" --body-file pr_comment.md || failed=1
          else
            echo "Validation succeeded; cleaned up prior comments without posting."
          fi

          # Makes the G-code diff comment match gcode_diff.md, or deletes it if there is none.
          update_gcode_diff_comment() {
            if [ ! -f gcode_diff_done.txt ]; then
              echo "The G-code diff step did not finish; leaving any G-code diff comment as it is."
              return 0
            fi
            GCODE_IDS=$(printf '%s\n' "$COMMENTS" | jq -r 'select(.body | startswith("<!-- profile-gcode-diff-comment -->")) | .id')
            if [ -f gcode_diff.md ] && [ "$(wc -c < gcode_diff.md)" -gt 65536 ]; then
              echo "gcode_diff.md is over GitHub's comment limit; not posting it."
              rm gcode_diff.md
            fi
            if [ -f gcode_diff.md ] && [ "$(echo "$GCODE_IDS" | wc -w)" -eq 1 ]; then
              OLD_BODY=$(printf '%s\n' "$COMMENTS" | jq -r --argjson id "$GCODE_IDS" 'select(.id == $id) | .body' | tr -d '\r')
              NEW_BODY=$(tr -d '\r' < gcode_diff.md)
              if [ "$OLD_BODY" = "$NEW_BODY" ]; then
                echo "G-code diff unchanged; keeping comment ${GCODE_IDS}."
                return 0
              fi
              # Edits in place when only the <sub> line differs, since edits notify nobody.
              if [ "$(grep -v '^<sub>' <<< "$OLD_BODY")" = "$(grep -v '^<sub>' <<< "$NEW_BODY")" ]; then
                echo "G-code diff unchanged at a new commit; updating comment ${GCODE_IDS}."
                gh api -X PATCH "repos/${GH_REPO}/issues/comments/${GCODE_IDS}" -F body=@gcode_diff.md > /dev/null
                return 0
              fi
            fi
            for comment_id in $GCODE_IDS; do
              echo "Deleting outdated G-code diff comment ${comment_id}"
              gh api -X DELETE "repos/${GH_REPO}/issues/comments/${comment_id}" || true
            done
            if [ -f gcode_diff.md ]; then
              gh pr comment "$PR_NUMBER" --body-file gcode_diff.md
            fi
          }
          update_gcode_diff_comment
          exit "$failed"