name: Upstream Sync

permissions:
  contents: write
  issues: write

on:
  schedule:
    - cron: "0 */6 * * *"
  workflow_dispatch:

jobs:
  sync_latest_from_upstream:
    name: Sync latest commits from upstream repo
    runs-on: ubuntu-latest
    if: ${{ github.event.repository.fork }}

    steps:
      - uses: actions/checkout@v4
        with:
          ref: master
          fetch-depth: 0
          # Must use a PAT with repo scope — GITHUB_TOKEN cannot push in fork scheduled workflows
          token: ${{ secrets.UPSTREAM_TOKEN }}

      - name: Check UPSTREAM_TOKEN
        run: |
          if [ -z "$UPSTREAM_TOKEN" ]; then
            echo "::error::UPSTREAM_TOKEN secret is not set. Please add a Personal Access Token with repo scope to your repository secrets."
            exit 1
          fi
        env:
          UPSTREAM_TOKEN: ${{ secrets.UPSTREAM_TOKEN }}

      - name: Sync upstream changes
        id: sync
        run: |
          git remote add upstream https://github.com/alexta69/metube.git 2>/dev/null || true
          git fetch upstream master

          LOCAL=$(git rev-parse HEAD)
          UPSTREAM=$(git rev-parse upstream/master)

          if [ "$LOCAL" = "$UPSTREAM" ]; then
            echo "Already up-to-date"
            echo "has_changes=false" >> "$GITHUB_OUTPUT"
            exit 0
          fi

          echo "Local:  $LOCAL"
          echo "Upstream: $UPSTREAM"
          echo "has_changes=true" >> "$GITHUB_OUTPUT"

          # Configure git for the merge commit
          git config user.name "github-actions[bot]"
          git config user.email "github-actions[bot]@users.noreply.github.com"

          # Try merge first (preserves both histories)
          if git merge upstream/master --no-edit; then
            git push origin master
            echo "Merge succeeded"
            echo "sync_result=success" >> "$GITHUB_OUTPUT"
          else
            echo "Merge conflict detected, aborting"
            git merge --abort
            echo "sync_result=conflict" >> "$GITHUB_OUTPUT"
            exit 1
          fi

      - name: Sync check — create issue on failure
        if: failure()
        uses: actions/github-script@v7
        with:
          script: |
            await github.rest.issues.create({
              owner: context.repo.owner,
              repo: context.repo.repo,
              title: "🚨 同步失败 | Sync Fail",
              labels: ["🚨 Sync Fail"],
              body: `Due to conflicts or workflow changes in the [alexta69/metube](https://github.com/alexta69/metube) upstream repository, the automatic sync has failed. Please manually sync your fork and resolve any conflicts.

            由于上游仓库 [alexta69/metube](https://github.com/alexta69/metube) 存在冲突或 workflow 变更，自动同步失败。请手动 Sync Fork 并解决冲突。`
            });