name: Enable auto-merge

on:
  pull_request:
    types: [opened, ready_for_review, reopened, synchronize]
    branches: [main]
  pull_request_review:
    types: [submitted]

concurrency:
  group: enable-auto-merge-${{ github.event.pull_request.number }}
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  enable:
    if: >-
      github.event.pull_request.draft == false
      && github.event.pull_request.base.ref == 'main'
      && github.event.pull_request.head.repo.full_name == github.repository
      && github.event.pull_request.user.login != 'dependabot[bot]'
      && github.event.pull_request.user.login != 'renovate[bot]'
      && (github.event_name != 'pull_request_review' || github.event.review.state == 'approved')
    runs-on: ubuntu-latest
    steps:
      - name: Mint seahaven-bot token
        id: app-token
        uses: actions/create-github-app-token@bcd2ba49218906704ab6c1aa796996da409d3eb1 # v3.2.0
        with:
          app-id: ${{ secrets.SEAHAVEN_BOT_APP_ID }}
          private-key: ${{ secrets.SEAHAVEN_BOT_PRIVATE_KEY }}
          owner: Sea-Haven-Industries
          repositories: ${{ github.event.repository.name }}

      - name: Enqueue or arm auto-merge
        env:
          GH_TOKEN: ${{ steps.app-token.outputs.token }}
          PR: ${{ github.event.pull_request.number }}
          REPO: ${{ github.repository }}
          PR_NODE_ID: ${{ github.event.pull_request.node_id }}
        run: |
          set -euo pipefail
          in_queue="$(gh api graphql -f query='query($id:ID!) { node(id:$id) { ... on PullRequest { isInMergeQueue } } }' -f id="$PR_NODE_ID" --jq '.data.node.isInMergeQueue')"
          if [ "$in_queue" = "true" ]; then
            echo "already in merge queue"
            exit 0
          fi
          set +e
          out="$(gh api graphql -f query='mutation($id:ID!) { enqueuePullRequest(input:{pullRequestId:$id}) { mergeQueueEntry { state } } }' -f id="$PR_NODE_ID" 2>&1)"
          status=$?
          set -e
          if [ "$status" -eq 0 ]; then
            printf '%s\n' "$out"
            exit 0
          fi
          echo "$out"
          # Re-arm as seahaven-bot. A leftover GITHUB_TOKEN auto-merge would
          # enqueue without starting merge_group.
          gh pr merge "$PR" --repo "$REPO" --disable-auto || true
          if ! gh pr merge "$PR" --repo "$REPO" --auto; then
            if [ "$(gh pr view "$PR" --repo "$REPO" --json autoMergeRequest --jq '.autoMergeRequest != null')" = "true" ]; then
              echo "auto-merge already enabled"
              exit 0
            fi
            exit 1
          fi