name: Markdown (Fail Fast)

on:
  push:
  pull_request:

jobs:
  changedfiles:
    name: changed files
    runs-on: ubuntu-latest
    outputs:
      md: ${{ steps.changes.outputs.md }}
    steps:
      - name: Checkout Repo
        uses: actions/checkout@v3
        with:
          fetch-depth: 0
      - name: Get changed files
        id: changes
        run: |
          echo "::set-output name=md::$(git diff --name-only --diff-filter=ACMRTUXB origin/${{ github.event.pull_request.base.ref }} ${{ github.event.pull_request.head.sha }} | grep .md$ | xargs)"

  lint:
    name: lint markdown files
    runs-on: ubuntu-latest
    needs: changedfiles
    if: ${{needs.changedfiles.outputs.md}}
    steps:
    - name: Checkout Repo
      uses: actions/checkout@v3
    - name: Run linter
      uses: docker://avtodev/markdown-lint:v1
      with:
        args: ${{needs.changedfiles.outputs.md}}