name: E2E Label Help

# When an E2E label is applied, post a PR comment
# telling the maintainer the next manual step. We don't dispatch the workflow
# ourselves: a workflow_dispatch-triggered run does not surface in the PR's
# Checks tab, so we'd lose in-progress visibility. Instead we point the
# maintainer at either the existing run (re-run from the UI) or the
# `/ok to test <SHA>` command needed to refresh the mirror.
#
# Uses `pull_request_target` so forked PRs get a token capable of posting
# comments. The job never checks out PR code; it only calls the GitHub API.

on:
  pull_request_target:
    types: [labeled]

permissions: {}

jobs:
  hint:
    name: Post next-step hint for E2E label
    if: github.event.label.name == 'test:e2e' || github.event.label.name == 'test:e2e-gpu' || github.event.label.name == 'test:e2e-kubernetes'
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
      actions: read
      contents: read
    steps:
      - name: Post comment
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          GH_REPO: ${{ github.repository }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
          PR_HEAD_SHA: ${{ github.event.pull_request.head.sha }}
          LABEL_NAME: ${{ github.event.label.name }}
        shell: bash
        run: |
          set -euo pipefail

          workflow_file=branch-e2e.yml
          workflow_name="Branch E2E Checks"
          case "$LABEL_NAME" in
            test:e2e)
              suite_summary="the standard E2E suite"
              build_summary="gateway and supervisor images"
              status_summary="The matching required CI gate status on this PR will flip green automatically once the run finishes."
              ;;
            test:e2e-gpu)
              suite_summary="GPU E2E"
              build_summary="supervisor image"
              status_summary="The matching required CI gate status on this PR will flip green automatically once the run finishes."
              ;;
            test:e2e-kubernetes)
              suite_summary="Kubernetes HA E2E"
              build_summary="gateway and supervisor images"
              status_summary="This is an optional proof-of-life suite; failures are visible in the workflow run but do not publish a required CI gate status."
              ;;
            *) echo "Unrecognized label $LABEL_NAME"; exit 1 ;;
          esac

          mirror_ref="pull-request/$PR_NUMBER"
          mirror_sha=$(gh api "repos/$GH_REPO/git/ref/heads/$mirror_ref" --jq '.object.sha' 2>/dev/null || true)
          if [[ ! "$mirror_sha" =~ ^[0-9a-f]{40}$ ]]; then mirror_sha=""; fi
          short_pr=${PR_HEAD_SHA:0:7}

          if [ -z "$mirror_sha" ]; then
            body="Label \`$LABEL_NAME\` applied, but \`$mirror_ref\` does not exist yet. A maintainer needs to comment \`/ok to test $PR_HEAD_SHA\` to mirror this PR. Once the mirror exists, re-apply the label or re-run [$workflow_name](https://github.com/$GH_REPO/actions/workflows/$workflow_file) from the Actions tab."
          elif [ "$mirror_sha" != "$PR_HEAD_SHA" ]; then
            short_mirror=${mirror_sha:0:7}
            body="Label \`$LABEL_NAME\` applied, but \`$mirror_ref\` is at \`$short_mirror\` while the PR head is \`$short_pr\`. A maintainer needs to comment \`/ok to test $PR_HEAD_SHA\` to refresh the mirror. Once the mirror catches up, re-run [$workflow_name](https://github.com/$GH_REPO/actions/workflows/$workflow_file) from the Actions tab."
          else
            run_id=$(gh api "repos/$GH_REPO/actions/workflows/$workflow_file/runs?head_sha=$PR_HEAD_SHA&event=push" \
              --jq '.workflow_runs | sort_by(.created_at) | reverse | .[0].id // empty')
            if [ -n "$run_id" ]; then
              instructions="Open [the existing run](https://github.com/$GH_REPO/actions/runs/$run_id) and click **Re-run all jobs** to execute with the label set."
            else
              workflow_link="[$workflow_name](https://github.com/$GH_REPO/actions/workflows/$workflow_file)"
              instructions="Open $workflow_link, find the run for commit \`$short_pr\`, and click **Re-run all jobs** to execute with the label set."
            fi
            body="Label \`$LABEL_NAME\` applied for \`$short_pr\`. $instructions The run will execute $suite_summary after building the required $build_summary once. $status_summary"
          fi

          gh pr comment "$PR_NUMBER" --body "$body"