name: Sync Upstream

on:
  workflow_dispatch:   # 手动触发
  schedule:
    - cron: "0 19 * * *"   # 每天(utc+8)凌晨3点自动同步（可自行设置）

permissions:
  contents: write

jobs:
  sync:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout your repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0   # 必须拉取完整历史
          token: ${{ secrets.GITHUB_TOKEN }}

      # 配置 Git 信息
      - name: Configure Git
        run: |
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"

      # 添加 upstream（如果不存在）
      - name: Add upstream remote
        run: |
          git remote add upstream https://github.com/PKUFlyingPig/cs-self-learning || true
          git fetch upstream

#      # 方法1：merge（推荐，最稳定）
#      - name: Merge upstream into main
#        run: |
#          git checkout master
#          git merge upstream/master --no-edit || true

      # 方法2：rebase（更干净的历史）
      - name: Rebase onto upstream
        run: |
          git checkout master
          git rebase upstream/master || true

      # 推送到你的仓库
      - name: Push changes
        run: |
          git push origin master