name: Check Clang-Format on Diff

on: [pull_request]

jobs:
  clang-format:
    runs-on: ubuntu-latest

    steps:
    - name: Checkout code
      uses: actions/checkout@v2

    - name: Import LLVM GPG Key
      run: |
        sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 15CF4D18AF4F7421

    - name: Add LLVM Repository
      run: |
        sudo add-apt-repository "deb http://apt.llvm.org/jammy llvm-toolchain-jammy-17 main"
        sudo apt-get update

    - name: Install clang-format 17
      run: |
        sudo apt-get install clang-format-17

    - name: Fetch branches to check
      run: |
        git fetch origin ${{ github.base_ref }}
        if [ "${{ github.repository_owner }}" != "${{ github.event.pull_request.head.repo.owner.login }}" ]; then
          fork_owner="${{ github.event.pull_request.head.repo.owner.login }}"
          fork_repo="${{ github.event.pull_request.head.repo.full_name }}"
          echo "Fork repo: ${fork_repo}"
          fork_url="https://github.com/${fork_repo}.git"
          echo "Fork URL: ${fork_url}"
          git remote add fork "${fork_url}"
          git fetch fork ${{ github.head_ref }}
        else
          git fetch origin ${{ github.head_ref }}
        fi

    - name: Apply clang-format locally
      if: github.event_name == 'pull_request'
      run: |
        if [ "${{ github.repository_owner }}" != "${{ github.event.pull_request.head.repo.owner.login }}" ]; then
          ./scripts/clang-format/clang-format-apply.sh origin/${{ github.base_ref }} fork/${{ github.head_ref }}
        else
          ./scripts/clang-format/clang-format-apply.sh origin/${{ github.base_ref }} origin/${{ github.head_ref }}
        fi

    - name: Save clang-format changes as patch
      run: |
        git diff -U0
        git diff -U0 > clang_format.patch

    - name: Check if patch is not empty
      run: |
        if [ -s clang_format.patch ]; then
          echo "Patch is not empty"
          echo "patch_not_empty=true" >> $GITHUB_STATE
        else
          echo "Patch is empty"
          echo "patch_not_empty=false" >> $GITHUB_STATE
        fi

    - name: Post patch as comment
      if: env.GITHUB_STATE.patch_not_empty == 'true'
      run: |
        API_URL="https://api.github.com/repos/${{ github.repository }}/issues/${{ github.event.pull_request.number }}/comments"
        curl -X POST \
          -H "Accept: application/vnd.github+json" \
          -H "Authorization: token ${{ secrets.GH_ACTION_TOKEN_CLANG_FORMAT }}" \
          -H "X-GitHub-Api-Version: 2022-11-28" \
          -d "{\"body\": \"clang-format has detected some changes that need formatting\"}" \
          "${API_URL}"