name: Commit Bot

# Instructions
#
# - One-time setup: create a personal access token with permissions. Then configure it here
#   as secrets.CI_PAT. https://github.com/boostorg/boost/settings/secrets/actions
#   The reason is explained in https://github.com/orgs/community/discussions/25702
#   "If an action pushes code using the repository's GITHUB_TOKEN, a new workflow will not run"
#
# - Processing of either the 'master' or 'develop' branch may be stopped by creating the variables
#   vars.block_master or vars.block_develop with any value.
#   https://github.com/boostorg/boost/settings/variables/actions
#

# To avoid infinite loops, don't trigger on "push"
on:
  schedule:
    - cron: "0,30 * * * *"

concurrency:
  group: ${{format('commit-bot-{0}:{1}', github.repository, github.ref)}}
  cancel-in-progress: true

jobs:
  update-modules:
    runs-on: ubuntu-latest
    name: Commit Bot
    if: github.repository == 'boostorg/boost'

    steps:
      - name: Check for module updates
        id: branches
        run: |
            set -xe
            branches=""
            if [[ "${{ github.event_name }}" == "push" ]]; then
                if [[ ! -n "${{ vars.block_master }}" && "${{ github.ref_name }}" == "master" ]]; then
                    branches="master"
                elif [[ ! -n "${{ vars.block_develop }}" && "${{ github.ref_name }}" == "develop" ]]; then
                    branches="develop"
                else
                    branches="${{ github.ref_name }}"
                fi
            else
                # from a schedule:
                if [[ ! -n "${{ vars.block_master }}" ]]; then
                    branches="master"
                fi
                if [[ ! -n "${{ vars.block_develop }}" ]]; then
                    branches="${branches} develop"
                fi
            fi
            echo "branches=$branches" >> $GITHUB_OUTPUT

      - name: Checkout master repository
        uses: actions/checkout@v4
        if: contains(steps.branches.outputs.branches, 'master')
        with:
          ref: master
          path: master
          persist-credentials: false

      - name: Checkout develop repository
        uses: actions/checkout@v4
        if: contains(steps.branches.outputs.branches, 'develop')
        with:
          ref: develop
          path: develop
          persist-credentials: false

      - name: Check for module updates
        run: |
          branches="${{ steps.branches.outputs.branches }}"

          # Set up Git
          git config --global user.name "boost-commitbot"
          git config --global user.email "boost-commitbot@example.com"

          # Update each branch
          for branch in $branches; do
            cd $branch
            module_paths=$(git config --file .gitmodules --get-regexp '^submodule\..*\.path$')
            while IFS=' ' read -r key path; do
              submodule_name=$(echo "$key" | awk -F '.' '{print $2}')
              submodule_path=$(echo "$path")
              url=$(git config --file .gitmodules --get-regexp "^submodule\.$submodule_name\.url$" | awk '{print $2}')
              if [[ ! "$url" =~ ^https:// ]]; then
                  basicreponame=$(basename $url)
                  url=${GITHUB_SERVER_URL}/${GITHUB_REPOSITORY_OWNER}/${basicreponame}
              fi
              hash=$(git ls-remote "$url" "refs/heads/$branch" | cut -f 1)
              hash="${hash#"${hash%%[![:space:]]*}"}"
              hash="${hash%"${hash##*[![:space:]]}"}"
              commit_id="${hash:0:8}"
              previous_hash=$(git ls-tree HEAD "$submodule_path" | awk '{print $3}')
              previous_hash="${previous_hash#"${previous_hash%%[![:space:]]*}"}"
              previous_hash="${previous_hash%"${previous_hash##*[![:space:]]}"}"
              previous_commit_id="${previous_hash:0:8}"
              if [ "$hash" == "$previous_hash" ]; then
                  echo "$submodule_name ($commit_id): OK"
              else
                  echo "$submodule_name: $previous_commit_id -> $commit_id"
                  set -x
                  set +e
                  git submodule update --init "$submodule_path"
                  git submodule update --remote "$submodule_path"
                  git add "$submodule_path"
                  git commit -m "Update $submodule_name from $branch"
                  set -e
                  set +x
              fi
            done <<< "$module_paths"
            cd ..
          done

      - name: Push changes from master
        uses: ad-m/github-push-action@v0.8.0
        if: contains(steps.branches.outputs.branches, 'master')
        with:
          # github_token: ${{ secrets.GITHUB_TOKEN }}
          github_token: ${{ secrets.CI_PAT }}
          branch: master
          directory: master

      - name: Push changes from develop
        uses: ad-m/github-push-action@v0.8.0
        if: contains(steps.branches.outputs.branches, 'develop')
        with:
          # github_token: ${{ secrets.GITHUB_TOKEN }}
          github_token: ${{ secrets.CI_PAT }}
          branch: develop
          directory: develop