# Cloud Foundry Java Buildpack
# Copyright 2013-2017 the original author or authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

require 'pathname'
require 'java_buildpack/util'

module JavaBuildpack
  module Util

    # Utilities for dealing with Groovy applications
    class GroovyUtils

      private_class_method :new

      class << self

        # Indicates whether a file is a +beans+style configuration
        #
        # @param [File] file the file to scan
        # @return [Boolean] +true+ if the file is a +beans+style configuration, +false+ otherwise.
        def beans?(file)
          safe_read(file) { Pathname.new(file).read =~ /beans[\s]*\{/ }
        end

        # Indicates whether a file has a +main()+ method in it
        #
        # @param [File] file the file to scan
        # @return [Boolean] +true+ if the file contains a +main()+ method, +false+ otherwise.
        def main_method?(file)
          safe_read(file) { Pathname.new(file).read =~ /static void main\(/ }
        end

        # Indicates whether a file is a POGO
        #
        # @param [File] file the file to scan
        # @return [Boolean] +true+ if the file is a POGO, +false+ otherwise.
        def pogo?(file)
          safe_read(file) { Pathname.new(file).read =~ /class [\w]+[\s\w]*\{/ }
        end

        # Indicates whether a file has a shebang
        #
        # @param [File] file the file to scan
        # @return [Boolean] +true+ if the file has a shebang, +false+ otherwise.
        def shebang?(file)
          safe_read(file) { Pathname.new(file).read =~ /#!/ }
        end

        # Returns all the Ruby files in the given directory
        #
        # @param [JavaBuildpack::Component::Application] application the application to search
        # @return [Array] a possibly empty list of files
        def groovy_files(application)
          (application.root + GROOVY_FILE_PATTERN).glob.reject(&:directory?).sort
        end

        private

        GROOVY_FILE_PATTERN = '**/*.groovy'.freeze

        private_constant :GROOVY_FILE_PATTERN

        def safe_read(file)
          yield
        rescue => e
          raise "Unable to read file #{file.path}: #{e.message}"
        end

      end

    end

  end
end
