# Runs after "SPIRV Compiler CI" completes successfully on a PR, then enables
# auto-merge with a merge commit. Avoids racing pull_request automerge before
# required checks have queued, and bypasses the
# block-merge-commit-on-amd-*-branches ruleset (which forbids merge-commit
# auto-merge for non-bypass actors) by enabling auto-merge as the
# bypass-eligible GitHub App.
#
# Trigger workflow name must match exactly (see `name:` in spirv-ci.yml):
#   .github/workflows/spirv-ci.yml -> "SPIRV Compiler CI"
#
# Title pattern matches what upstream-merge.yml produces:
#   "Upstream merge YYYY-MM-DD HH:MM TZ"
#
# Requires:
#   - Secret MERGE_APP_ID (existing, used by upstream-merge.yml)
#   - Secret MERGE_APP_PRIVATE_KEY (existing, used by upstream-merge.yml)
#   - The MERGE_APP App must be a bypass actor on the
#     block-merge-commit-on-amd-*-branches ruleset, otherwise auto-merge
#     will sit indefinitely as it does today.
#   - Repository setting "Allow auto-merge" enabled.

name: Auto-merge upstream-merge PRs after SPIRV Compiler CI

on:
  workflow_run:
    workflows: ["SPIRV Compiler CI"]
    types: [completed]

permissions:
  contents: read
  pull-requests: read
  checks: read

concurrency:
  group: automerge-after-spirv-ci-${{ github.event.workflow_run.head_sha }}
  cancel-in-progress: true

jobs:
  enable-automerge:
    name: Enable auto-merge after successful SPIRV Compiler CI
    runs-on: ubuntu-latest
    if: >-
      github.event.workflow_run.conclusion == 'success' &&
      github.event.workflow_run.event == 'pull_request' &&
      github.event.workflow_run.head_repository.full_name == github.repository &&
      startsWith(github.event.workflow_run.display_title, 'Upstream merge ')
    steps:
      - name: Generate App token
        id: app-token
        uses: actions/create-github-app-token@v1
        with:
          app-id: ${{ secrets.MERGE_APP_ID }}
          private-key: ${{ secrets.MERGE_APP_PRIVATE_KEY }}

      - name: Resolve PR and enable auto-merge (merge commit)
        env:
          GH_TOKEN: ${{ steps.app-token.outputs.token }}
          HEAD_BRANCH: ${{ github.event.workflow_run.head_branch }}
          REPO: ${{ github.repository }}
          PULL_REQUESTS_JSON: ${{ toJSON(github.event.workflow_run.pull_requests) }}
        run: |
          set -euo pipefail

          # Prefer workflow_run.pull_requests when GitHub attaches it
          # (same-repo PRs). Fall back to a head-branch lookup.
          PR=""
          if command -v jq >/dev/null 2>&1; then
            PR=$(echo "${PULL_REQUESTS_JSON}" | jq -r '
              if . == null or . == [] then empty
              elif type == "array" then .[0].number | tostring
              else empty end' 2>/dev/null || true)
          fi
          if [ -z "${PR}" ] || [ "${PR}" = "null" ]; then
            PR="$(gh pr list --repo "${REPO}" --head "${HEAD_BRANCH}" --base amd-staging --state open \
              --json number -q '.[0].number // empty' 2>/dev/null || true)"
          fi
          if [ -z "${PR}" ] || [ "${PR}" = "null" ]; then
            echo "No open PR found for head branch ${HEAD_BRANCH} -> amd-staging; skipping."
            exit 0
          fi

          BASE="$(gh pr view "${PR}" --repo "${REPO}" --json baseRefName -q .baseRefName)"
          if [ "${BASE}" != "amd-staging" ]; then
            echo "PR #${PR} base is ${BASE}, not amd-staging; skipping."
            exit 0
          fi

          DRAFT="$(gh pr view "${PR}" --repo "${REPO}" --json isDraft -q .isDraft)"
          if [ "${DRAFT}" = "true" ]; then
            echo "PR #${PR} is draft; skipping."
            exit 0
          fi

          echo "Enabling auto-merge (merge commit) for PR #${PR} (${REPO}) after successful SPIRV Compiler CI."
          gh pr merge "${PR}" --repo "${REPO}" --merge --auto