name: backport
on:
  pull_request_target:
    branches:
      - main
    types:
      - opened
      - reopened
      - unlabeled
      - labeled
      - closed

jobs:
  label:
    runs-on: ubuntu-latest
    if: |
      github.event.pull_request.state == 'open' && !github.event.pull_request.draft
    steps:
      - name: 'Apply default "backport: auto" label'
        uses: actions/github-script@v4
        if: |
          !contains(github.event.pull_request.labels.*.name, 'backport: auto') &&
          !contains(github.event.pull_request.labels.*.name, 'backport: skip')
        with:
          script: |
            github.issues.addLabels({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              labels: ['backport: auto']
            })
      - name: 'Remove "backport: auto" if "backport: skip" is set'
        uses: actions/github-script@v4
        if: |
          contains(github.event.pull_request.labels.*.name, 'backport: auto') &&
          contains(github.event.pull_request.labels.*.name, 'backport: skip')
        with:
          script: |
            github.issues.removeLabel({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              name: 'backport: auto'
            })


  commit:
    if: |
      github.event.pull_request.merged == true
      && contains(github.event.pull_request.labels.*.name, 'backport: auto')
      && (
        (github.event.action == 'labeled' && github.event.label.name == 'backport: auto')
        || (github.event.action == 'closed')
      )
    runs-on: ubuntu-latest
    strategy:
      max-parallel: 1
      matrix:
        target_branch: [7.13]

    steps:
      - name: Checkout repo
        uses: actions/checkout@v2
        with:
          token: ${{ secrets.PROTECTIONS_MACHINE_TOKEN }}
          ref: ${{matrix.target_branch}}

      - name: Set github config
        run: |
          git config --global user.email "41898282+github-actions[bot]@users.noreply.github.com"
          git config --global user.name "github-actions[bot]"

      - name: Get branch histories
        run: |
          git fetch origin main --unshallow
          git status
          git log -1 --format='%H'

      - name: Backport commit
        run: |
          echo "Cherry-pick from $GITHUB_SHA to ${{matrix.target_branch}}"
          git cherry-pick -x ${{github.event.pull_request.merge_commit_sha}}

          # See https://github.com/elastic/detection-rules/issues/1171
          # Eventually, this cherry pick command will be:
          # git-cherry-pick --no-commit
          # <python code to remove irrelevant rules>
          # git commit --author ... --message ...

      - name: Push changes
        run: |
          git push