name: Cancel CI on PR close

on:
  pull_request:
    types: [closed]

permissions:
  actions: write
  pull-requests: read

concurrency:
  group: cancel-pr-${{ github.event.pull_request.number }}
  cancel-in-progress: false

jobs:
  cancel:
    name: Cancel queued and in-progress PR runs
    runs-on: ubuntu-latest
    timeout-minutes: 5
    if: ${{ github.event.pull_request.head.repo.full_name == github.repository }}
    steps:
      - name: Cancel queued and in-progress runs for the PR branch
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          HEAD_REF: ${{ github.event.pull_request.head.ref }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
          MERGED: ${{ github.event.pull_request.merged }}
          SELF_RUN_ID: ${{ github.run_id }}
        run: |
          set -euo pipefail
          if [ "$MERGED" = "true" ]; then
            echo "PR #$PR_NUMBER merged — cancelling residual runs for branch $HEAD_REF"
          else
            echo "PR #$PR_NUMBER closed without merge — cancelling residual runs for branch $HEAD_REF"
          fi

          ids=$(gh api --paginate \
            "repos/$GITHUB_REPOSITORY/actions/runs?branch=$HEAD_REF&per_page=100" \
            --jq ".workflow_runs[]
              | select(.status==\"queued\" or .status==\"in_progress\")
              | select(.id != $SELF_RUN_ID)
              | select(any(.pull_requests[]?; .number == $PR_NUMBER))
              | .id")

          if [ -z "$ids" ]; then
            echo "Nothing to cancel."
            exit 0
          fi

          echo "$ids" | while read -r id; do
            [ -n "$id" ] || continue
            echo "Cancelling run $id"
            gh run cancel "$id" --repo "$GITHUB_REPOSITORY" || true
          done