inline-comments-to-slack.yml

name: Notify Slack on Inline Review Comments

on:
  pull_request_review_comment:
    types:
      - created

jobs:
  notify-slack:
    runs-on: ubuntu-latest
    env:
      SLACK_BOT_TOKEN: ${{ secrets.SLACK_BOT_TOKEN }}
      SLACK_CHANNEL_ID: ${{ secrets.SLACK_CHANNEL_ID }}
    steps:
      - name: Find PR thread in Slack
        id: find-thread
        run: |
          PR_NUMBER="${{ github.event.pull_request.number }}"
          PR_TITLE="${{ github.event.pull_request.title }}"
          REPO_FULL="${{ github.repository }}"

          # Search channel history for the original GitHub app message about this PR
          # Look through recent messages for one containing the PR URL or PR reference
          CURSOR=""
          THREAD_TS=""

          for i in 1 2 3 4 5; do
            if [ -n "$CURSOR" ]; then
              RESPONSE=$(curl -s -H "Authorization: Bearer $SLACK_BOT_TOKEN" \
                "https://slack.com/api/conversations.history?channel=$SLACK_CHANNEL_ID&limit=50&cursor=$CURSOR")
            else
              RESPONSE=$(curl -s -H "Authorization: Bearer $SLACK_BOT_TOKEN" \
                "https://slack.com/api/conversations.history?channel=$SLACK_CHANNEL_ID&limit=50")
            fi

            # Look for messages from the official GitHub app that mention this PR
            # The official GitHub app posts messages containing the PR URL like:
            # github.com/org/repo/pull/123 or "#123 PR Title"
            THREAD_TS=$(echo "$RESPONSE" | jq -r --arg pr_num "#${PR_NUMBER} " --arg pr_title "$PR_TITLE" '
              .messages[] |
              select(
                (.bot_profile.name == "GitHub" or .username == "GitHub") and
                (
                  (.text // "" | contains($pr_num)) or
                  (.text // "" | contains($pr_title)) or
                  (.attachments // [] | .[].text // "" | contains($pr_num)) or
                  (.attachments // [] | .[].text // "" | contains($pr_title)) or
                  (.blocks // [] | .[].text.text // "" | contains($pr_num)) or
                  (.blocks // [] | .[].text.text // "" | contains($pr_title))
                )
              ) | .ts' 2>/dev/null | head -1)

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

            CURSOR=$(echo "$RESPONSE" | jq -r '.response_metadata.next_cursor // empty')
            if [ -z "$CURSOR" ]; then
              break
            fi
          done

          if [ -n "$THREAD_TS" ] && [ "$THREAD_TS" != "null" ]; then
            echo "thread_ts=$THREAD_TS" >> "$GITHUB_OUTPUT"
            echo "Found PR thread: $THREAD_TS"
          else
            echo "thread_ts=" >> "$GITHUB_OUTPUT"
            echo "No existing thread found for PR #$PR_NUMBER"
          fi

      - name: Post comment to Slack thread
        run: |
          PR_NUMBER="${{ github.event.pull_request.number }}"
          PR_TITLE="${{ github.event.pull_request.title }}"
          PR_URL="${{ github.event.pull_request.html_url }}"
          COMMENT_URL="${{ github.event.comment.html_url }}"
          COMMENT_BODY="${{ github.event.comment.body }}"
          COMMENT_USER="${{ github.event.comment.user.login }}"
          COMMENT_USER_URL="${{ github.event.comment.user.html_url }}"
          COMMENT_PATH="${{ github.event.comment.path }}"
          COMMENT_LINE="${{ github.event.comment.line }}"
          REPO_FULL="${{ github.repository }}"
          THREAD_TS="${{ steps.find-thread.outputs.thread_ts }}"

          # Build the payload matching the official GitHub app's comment format
          # The official app shows: "Comment on pull request by <user>"
          # With an attachment containing the PR title and comment body
          PAYLOAD=$(jq -n \
            --arg channel "$SLACK_CHANNEL_ID" \
            --arg thread_ts "$THREAD_TS" \
            --arg comment_url "$COMMENT_URL" \
            --arg comment_user "$COMMENT_USER" \
            --arg comment_user_url "$COMMENT_USER_URL" \
            --arg pr_number "$PR_NUMBER" \
            --arg pr_title "$PR_TITLE" \
            --arg pr_url "$PR_URL" \
            --arg comment_body "$COMMENT_BODY" \
            --arg comment_path "$COMMENT_PATH" \
            --arg comment_line "$COMMENT_LINE" \
            --arg repo_full "$REPO_FULL" \
            '{
              channel: $channel,
              unfurl_links: false,
              unfurl_media: false,
              text: "<\($comment_url)|Comment> on pull request by <\($comment_user_url)|\($comment_user)>",
              blocks: [
                {
                  type: "section",
                  text: {
                    type: "mrkdwn",
                    text: "<\($comment_url)|Comment> on pull request by <\($comment_user_url)|\($comment_user)>"
                  }
                }
              ],
              attachments: [
                {
                  color: "#24292e",
                  blocks: [
                    {
                      type: "section",
                      text: {
                        type: "mrkdwn",
                        text: "<\($pr_url)|#\($pr_number) \($pr_title)>\n`\($comment_path)` (line \($comment_line))\n\($comment_body)"
                      }
                    },
                    {
                      type: "context",
                      elements: [
                        {
                          type: "mrkdwn",
                          text: "\($repo_full)"
                        }
                      ]
                    }
                  ]
                }
              ]
            } | if $thread_ts != "" then .thread_ts = $thread_ts else . end')

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

          OK=$(echo "$RESPONSE" | jq -r '.ok')
          if [ "$OK" != "true" ]; then
            echo "Error posting to Slack: $(echo "$RESPONSE" | jq -r '.error')"
            exit 1
          fi

          echo "Comment posted successfully"