# This workflow runs after a release of the action.
# It merges any changes from the release back into the
# main branch. Typically, this is just a single commit
# that updates the changelog.
name: Tag release and merge back

on:
  workflow_dispatch:
    inputs:
      baseBranch:
        description: 'The base branch to merge into'
        default: main
        required: false

  push:
    branches:
      - v1
      - v2

jobs:
  merge-back:
    runs-on: ubuntu-latest
    if: github.repository == 'github/codeql-action'
    env:
      BASE_BRANCH: "${{ github.event.inputs.baseBranch || 'main' }}"
      HEAD_BRANCH: "${{ github.head_ref || github.ref }}"

    steps:
      - name: Dump environment
        run: env

      - name: Dump GitHub context
        env:
          GITHUB_CONTEXT: '${{ toJson(github) }}'
        run: echo "$GITHUB_CONTEXT"

      - uses: actions/checkout@v3
      - uses: actions/setup-node@v2

      - name: Update git config
        run: |
          git config --global user.email "github-actions@github.com"
          git config --global user.name "github-actions[bot]"

      - name: Get version and new branch
        id: getVersion
        run: |
          VERSION="v$(jq '.version' -r 'package.json')"
          SHORT_SHA="${GITHUB_SHA:0:8}"
          echo "::set-output name=version::$VERSION"
          NEW_BRANCH="mergeback/${VERSION}-to-${BASE_BRANCH}-${SHORT_SHA}"
          echo "::set-output name=newBranch::$NEW_BRANCH"


      - name: Dump branches
        env:
          NEW_BRANCH: "${{ steps.getVersion.outputs.newBranch }}"
        run: |
          echo "BASE_BRANCH $BASE_BRANCH"
          echo "HEAD_BRANCH $HEAD_BRANCH"
          echo "NEW_BRANCH $NEW_BRANCH"

      - name: Create mergeback branch
        env:
          NEW_BRANCH: "${{ steps.getVersion.outputs.newBranch }}"
        run: |
          git checkout -b "$NEW_BRANCH"

      - name: Check for tag
        id: check
        env:
          VERSION: "${{ steps.getVersion.outputs.version }}"
        run: |
          set +e # don't fail on an errored command
          git ls-remote --tags origin | grep "$VERSION"
          EXISTS="$?"
          if [ "$EXISTS" -eq 0 ]; then
            echo "Tag $TAG exists. Not going to re-release."
            echo "::set-output name=exists::true"
          else
            echo "Tag $TAG does not exist yet."
          fi

      # we didn't tag the release during the update-release-branch workflow because the
      # commit that actually makes it to the release branch is a merge commit,
      # and not yet known during the first workflow. We tag now because we know the correct commit.
      - name: Tag release
        if: steps.check.outputs.exists != 'true'
        env:
          VERSION: ${{ steps.getVersion.outputs.version }}
        run: |
          git tag -a "$VERSION" -m "$VERSION"
          git fetch --unshallow  # unshallow the repo in order to allow pushes
          git push origin --follow-tags "$VERSION"

      - name: Create mergeback branch
        if: steps.check.outputs.exists != 'true' && contains(github.ref, 'v2')
        env:
          VERSION: "${{ steps.getVersion.outputs.version }}"
          NEW_BRANCH: "${{ steps.getVersion.outputs.newBranch }}"
          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
        run: |
          set -exu
          PR_TITLE="Mergeback $VERSION $HEAD_BRANCH into $BASE_BRANCH"
          PR_BODY="Updates version and changelog."

          # Update the version number ready for the next release
          npm version patch --no-git-tag-version

          # Update the changelog
          perl -i -pe 's/^/## \[UNRELEASED\]\n\nNo user facing changes.\n\n/ if($.==3)' CHANGELOG.md
          git add .
          git commit -m "Update changelog and version after $VERSION"

          git push origin "$NEW_BRANCH"

          # PR checks won't be triggered on PRs created by Actions. Therefore mark the PR as draft
          # so that a maintainer can take the PR out of draft, thereby triggering the PR checks.
          gh pr create \
            --head "$NEW_BRANCH" \
            --base "$BASE_BRANCH" \
            --title "$PR_TITLE" \
            --label "Update dependencies" \
            --body "$PR_BODY" \
            --draft