name: Check Line Counts
on:
  pull_request_target:

# Cancel the workflow in progress in newer build is about to start.
concurrency:
  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
  cancel-in-progress: true

jobs:
  checkbranch:
    name: Check PR Branch status
    runs-on: ubuntu-latest
    outputs:
      branchstat: ${{ steps.brstat.outputs.stat}}
    steps:
      - name: Check code from PR branch 
        uses: actions/checkout@v6
        with:
          repository: ${{ github.event.pull_request.head.repo.full_name }}
          ref: ${{ github.event.pull_request.head.sha }}
          fetch-depth: 0
      - name: Check whether branch is up-to-date
        id: brstat
        run: |
          git remote add tinygrad https://github.com/tinygrad/tinygrad
          git fetch tinygrad master
          echo "${{ github.event.pull_request.head.sha }}"
          git rev-list --left-right --count  tinygrad/master...${{ github.event.pull_request.head.sha }} | awk '{print "Behind "$1" - Ahead "$2""}'
          count=$(git rev-list --left-right --count  tinygrad/master...${{ github.event.pull_request.head.sha }} | awk '{print $1}')
          if [ $count -gt 0 ]
          then
            echo "Current branch is behind tinygrad master branch!"
            echo "stat=true" >> "$GITHUB_OUTPUT"
          else
            echo "stat=false" >> "$GITHUB_OUTPUT"
          fi

  szdiff:
    name: Core Library Line Difference
    permissions:
      contents: read
      pull-requests: write
    runs-on: ubuntu-latest
    needs: checkbranch
    if: needs.checkbranch.outputs.branchstat == 'false'
    steps:
      - name: Checkout code from PR branch
        uses: actions/checkout@v6
        with:
          repository: ${{ github.event.pull_request.head.repo.full_name }}
          ref: ${{ github.event.pull_request.head.sha }}
          path: pr
        # the base default to tinygrad master and cannot be other fork branch for security purpose
      - name: Checkout code from tinygrad master
        uses: actions/checkout@v6
        with:
          path: base
      - name: Set up Python 3.12
        uses: actions/setup-python@v6
        with:
          python-version: '3.12'
      - name: Count Line Diff
        run: |
          BASE="$GITHUB_WORKSPACE/base"
          PR="$GITHUB_WORKSPACE/pr"
          pip install tabulate $BASE
          cp "$BASE/sz.py" .
          python sz.py "$BASE" "$PR" > loc_content.txt
      - name: Comment Code Line Diff
        continue-on-error: false
        uses: marocchino/sticky-pull-request-comment@v3
        with:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          ignore_empty: true
          skip_unchanged: true
          recreate: true
          path: loc_content.txt

  rebase:
    name: Core Library Line Difference
    permissions:
      pull-requests: write
    runs-on: ubuntu-latest
    needs: checkbranch
    if: needs.checkbranch.outputs.branchstat == 'true'
    steps:
      - name: Comment Rebase
        continue-on-error: false
        uses: marocchino/sticky-pull-request-comment@v3
        with:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          skip_unchanged: true
          recreate: true
          message: |
            This branch currently is behind tinygrad/master. The line count difference bot is disabled.
