name: Post Gas Diff Comment

on:
  workflow_run:
    workflows: ["ci"]
    types:
      - completed

jobs:
  comment:
    if: >-
      github.event.workflow_run.event == 'pull_request' &&
      github.event.workflow_run.conclusion != 'cancelled'
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
      actions: read
    steps:
      - name: Download gas diff artifact
        id: download
        continue-on-error: true
        uses: actions/download-artifact@v8.0.1
        with:
          name: gas-diff
          github-token: ${{ secrets.GITHUB_TOKEN }}
          run-id: ${{ github.event.workflow_run.id }}

      - name: Read PR number
        if: steps.download.outcome == 'success'
        id: pr
        run: echo "number=$(cat pr-number.txt)" >> "$GITHUB_OUTPUT"

      - name: Read gas diff
        if: steps.download.outcome == 'success'
        id: gas_diff
        run: |
          if [ -f comment.md ] && [ -s comment.md ]; then
            {
              echo "markdown<<__GASDIFF_EOF__"
              cat comment.md
              echo "__GASDIFF_EOF__"
            } >> "$GITHUB_OUTPUT"
          fi

      - name: Add gas diff to sticky comment
        if: steps.download.outcome == 'success'
        uses: marocchino/sticky-pull-request-comment@v2
        with:
          number: ${{ steps.pr.outputs.number }}
          delete: ${{ !steps.gas_diff.outputs.markdown }}
          message: ${{ steps.gas_diff.outputs.markdown }}