name: Validate Branch Name on Pull Request

on:
    pull_request:
        branches:
            - main
    workflow_dispatch: # Allows manual execution of the workflow.

jobs:
    validate-branch-name-on-pull-request:
        runs-on: ubuntu-latest

        steps:
            - name: Check out repository
              uses: actions/checkout@v2

            - name: Read Config File
              id: config
              run: |
                  VALID_PREFIXES=$(grep 'valid_prefixes' .github/config.conf | cut -d '=' -f2 | tr -d ' ')
                  echo "VALID_PREFIXES=$VALID_PREFIXES" >> $GITHUB_ENV

            - name: Validate Branch Name on Pull Request
              run: |
                  BRANCH_NAME=${{ github.head_ref }}
                  VALID_PREFIXES_ARRAY=(${VALID_PREFIXES//,/ })
                  VALID=false

                  for PREFIX in "${VALID_PREFIXES_ARRAY[@]}"; do
                    if [[ "$BRANCH_NAME" =~ ^$PREFIX ]]; then
                      VALID=true
                      break
                    fi
                  done

                  if [ "$VALID" = false ]; then
                    echo "Invalid branch name: $BRANCH_NAME"
                    echo "Branch name must start with one of the following prefixes: $VALID_PREFIXES"
                    exit 1
                  fi