---
name: Lint commit

on:
  push:
  pull_request:
  merge_group:

# Don't grant any access by default
permissions: {}

jobs:
  commitlint:
    runs-on: ubuntu-latest
    permissions:
      contents: read
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Check if the pull request contains a single commit
        if: github.event_name == 'pull_request'
        run: |
          commit_count=${{ github.event.pull_request.commits }}

          if [ -z ${commit_count} ]; then
            echo "[ERROR] commit_count is empty"
            exit 1
          fi

          if [[ ${commit_count} -ne 1 ]]; then
            echo "[ERROR] This pull request contains ${commit_count} commits. Squash these commits into a single commit."
            exit 1
          else
            echo "This pull request contains ${commit_count} commit."
          fi