pr-comment-slack-notify.yml

name: PR Slack Notification

on:
  pull_request:
    types: [opened, reopened]
  issue_comment:
    types: [created]
  pull_request_review_comment:
    types: [created]

jobs:
  notify-slack:
    # For issue_comment, only run if the comment is on a pull request
    if: >
      github.event_name == 'pull_request' ||
      github.event_name == 'pull_request_review_comment' ||
      (github.event_name == 'issue_comment' && github.event.issue.pull_request)
    runs-on: ubuntu-latest
    steps:
      - name: Send Slack notification
        env:
          SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}
          SLACK_CHANNEL_ID: ${{ secrets.SLACK_CHANNEL_ID }}
          EVENT_NAME: ${{ github.event_name }}
          COMMENT_BODY: ${{ github.event.comment.body }}
          COMMENT_URL: ${{ github.event.comment.html_url }}
          COMMENTER: ${{ github.event.comment.user.login }}
          COMMENTER_AVATAR: ${{ github.event.comment.user.avatar_url }}
          REPO: ${{ github.repository }}
          # pull_request event
          PR_URL_PR: ${{ github.event.pull_request.html_url }}
          PR_TITLE_PR: ${{ github.event.pull_request.title }}
          PR_NUMBER_PR: ${{ github.event.pull_request.number }}
          PR_AUTHOR_PR: ${{ github.event.pull_request.user.login }}
          PR_AUTHOR_AVATAR_PR: ${{ github.event.pull_request.user.avatar_url }}
          # pull_request_review_comment event
          PR_URL_REVIEW: ${{ github.event.pull_request.html_url }}
          PR_TITLE_REVIEW: ${{ github.event.pull_request.title }}
          PR_NUMBER_REVIEW: ${{ github.event.pull_request.number }}
          # issue_comment event
          PR_URL_ISSUE: ${{ github.event.issue.pull_request.html_url }}
          PR_TITLE_ISSUE: ${{ github.event.issue.title }}
          PR_NUMBER_ISSUE: ${{ github.event.issue.number }}
        run: |
          # Determine PR details based on event type
          if [ "$EVENT_NAME" = "pull_request" ]; then
            PR_URL="$PR_URL_PR"
            PR_TITLE="$PR_TITLE_PR"
            PR_NUMBER="$PR_NUMBER_PR"
          elif [ "$EVENT_NAME" = "pull_request_review_comment" ]; then
            PR_URL="$PR_URL_REVIEW"
            PR_TITLE="$PR_TITLE_REVIEW"
            PR_NUMBER="$PR_NUMBER_REVIEW"
          else
            PR_URL="$PR_URL_ISSUE"
            PR_TITLE="$PR_TITLE_ISSUE"
            PR_NUMBER="$PR_NUMBER_ISSUE"
          fi

          REPO_SHORT="${REPO#*/}"

          # Ensure bot has joined the channel
          curl -s -X POST "https://slack.com/api/conversations.join" \
            -H "Authorization: Bearer $SLACK_BOT_TOKEN" \
            -H "Content-Type: application/json" \
            -d "{\"channel\": \"$SLACK_CHANNEL_ID\"}" > /dev/null

          # Search channel history for an existing thread about this PR
          find_thread_ts() {
            HISTORY=$(curl -s "https://slack.com/api/conversations.history?channel=$SLACK_CHANNEL_ID&limit=200" \
              -H "Authorization: Bearer $SLACK_BOT_TOKEN")

            # Look for a message containing this PR's URL
            THREAD_TS=$(echo "$HISTORY" | jq -r --arg pr_url "$PR_URL" '
              .messages[]
              | select(.text != null and (.text | contains($pr_url)))
              | .ts' | tail -1)

            if [ -n "$THREAD_TS" ] && [ "$THREAD_TS" != "null" ]; then
              echo "$THREAD_TS"
            fi
          }

          if [ "$EVENT_NAME" = "pull_request" ]; then
            # PR opened/reopened — post a new top-level thread-starting message
            PAYLOAD=$(jq -n \
              --arg channel "$SLACK_CHANNEL_ID" \
              --arg repo_short "$REPO_SHORT" \
              --arg pr_url "$PR_URL" \
              --arg pr_number "$PR_NUMBER" \
              --arg pr_title "$PR_TITLE" \
              --arg author "$PR_AUTHOR_PR" \
              --arg avatar "$PR_AUTHOR_AVATAR_PR" \
              '{
                "channel": $channel,
                "username": $author,
                "icon_url": $avatar,
                "text": ("New pull request [" + $repo_short + "#" + $pr_number + "] <" + $pr_url + "|" + $pr_title + "> by " + $author),
                "unfurl_links": false,
                "blocks": [
                  {
                    "type": "section",
                    "text": {
                      "type": "mrkdwn",
                      "text": ("New pull request [" + $repo_short + "#" + $pr_number + "] <" + $pr_url + "|" + $pr_title + "> by " + $author)
                    }
                  }
                ]
              }')

            curl -s -X POST "https://slack.com/api/chat.postMessage" \
              -H "Authorization: Bearer $SLACK_BOT_TOKEN" \
              -H "Content-Type: application/json" \
              -d "$PAYLOAD"
          else
            # Comment event — try to find existing thread, then reply in it
            THREAD_TS=$(find_thread_ts)

            # Clean comment body:
            # 1. Remove HTML comments (<!-- ... -->)
            # 2. Remove GitHub admonitions (> [!TIP], > [!NOTE], etc. and their continuation lines)
            # 3. Trim leading/trailing whitespace
            CLEANED_BODY=$(echo "$COMMENT_BODY" | perl -0777 -pe '
              s/<!--.*?-->//gs;
              s/^>\s*\[!(TIP|NOTE|WARNING|CAUTION|IMPORTANT)\]\s*\n(^>.*\n)*//gm;
              s/^\s+|\s+$//g;
            ')

            # Truncate to 200 chars
            if [ ${#CLEANED_BODY} -gt 200 ]; then
              TRUNCATED_BODY="${CLEANED_BODY:0:200}..."
            else
              TRUNCATED_BODY="$CLEANED_BODY"
            fi

            if [ -n "$THREAD_TS" ]; then
              # Thread reply — just show the comment text, no header
              PAYLOAD=$(jq -n \
                --arg channel "$SLACK_CHANNEL_ID" \
                --arg commenter "$COMMENTER" \
                --arg comment_body "$TRUNCATED_BODY" \
                --arg avatar "$COMMENTER_AVATAR" \
                --arg thread_ts "$THREAD_TS" \
                '{
                  "channel": $channel,
                  "username": $commenter,
                  "icon_url": $avatar,
                  "thread_ts": $thread_ts,
                  "text": $comment_body,
                  "unfurl_links": false,
                  "blocks": [
                    {
                      "type": "rich_text",
                      "elements": [
                        {
                          "type": "rich_text_quote",
                          "elements": [
                            {
                              "type": "text",
                              "text": $comment_body
                            }
                          ]
                        }
                      ]
                    }
                  ]
                }')
            else
              # No thread found — post top-level with full context
              PAYLOAD=$(jq -n \
                --arg channel "$SLACK_CHANNEL_ID" \
                --arg repo_short "$REPO_SHORT" \
                --arg pr_url "$PR_URL" \
                --arg pr_number "$PR_NUMBER" \
                --arg pr_title "$PR_TITLE" \
                --arg commenter "$COMMENTER" \
                --arg comment_body "$TRUNCATED_BODY" \
                --arg avatar "$COMMENTER_AVATAR" \
                '{
                  "channel": $channel,
                  "username": $commenter,
                  "icon_url": $avatar,
                  "text": ($commenter + " commented on [" + $repo_short + "#" + $pr_number + "] <" + $pr_url + "|" + $pr_title + ">"),
                  "unfurl_links": false,
                  "blocks": [
                    {
                      "type": "section",
                      "text": {
                        "type": "mrkdwn",
                        "text": ($commenter + " commented on [" + $repo_short + "#" + $pr_number + "] <" + $pr_url + "|" + $pr_title + ">")
                      }
                    },
                    {
                      "type": "rich_text",
                      "elements": [
                        {
                          "type": "rich_text_quote",
                          "elements": [
                            {
                              "type": "text",
                              "text": $comment_body
                            }
                          ]
                        }
                      ]
                    }
                  ]
                }')
            fi

            curl -s -X POST "https://slack.com/api/chat.postMessage" \
              -H "Authorization: Bearer $SLACK_BOT_TOKEN" \
              -H "Content-Type: application/json" \
              -d "$PAYLOAD"
          fi