# frozen_string_literal: true

# Copyright 2019 Google LLC
#
# 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
#
#     https://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 "fileutils"
require "action_controller"
require "active_support/inflector"

module Gapic
  ##
  # The builder created files for new extension gems.
  class GemBuilder
    ##
    # Initializes the builder.
    #
    # @param name [String] The name of the new extension gem.
    # @param path [String] The directory to write the gem files.
    #
    def initialize name, path
      @name = name
      @path = path
    end

    ##
    # Writes all the files for the gem.
    #
    def bootstrap
      gen "readme.erb",     "README.md"
      gen "gemspec.erb",    "gapic-generator-#{gem_name}.gemspec"
      gen "rakefile.erb",   "Rakefile"
      gen "gemfile.erb",    "Gemfile"
      gen "gitignore.erb",  ".gitignore"
      gen "rubocop.erb",    ".rubocop.yml"
      gen "dockerfile.erb", "Dockerfile"
      gen "entrypoint.erb", "docker-entrypoint.sh"
      gen "gapic_sh.erb",   "gapic.sh"
      gen "binary.erb",     "bin/protoc-gen-ruby_#{gem_name}"
      gen "generator.erb",
          "lib/gapic/generators/#{gem_name}_generator.rb"
      gen "version.erb",
          "lib/gapic/generator/#{gem_name}/version.rb"
      gen "test_helper.erb",    "test/test_helper.rb"
      gen "test_generator.erb", "test/generators/#{gem_name}_test.rb"
      cp  "speech_desc.bin",    "proto_input/speech_desc.bin"
    end

    private

    def template_path
      File.join __dir__, "../../gem_templates"
    end

    def gem_name
      ActiveSupport::Inflector.underscore @name
    end

    def gem_class_prefix
      ActiveSupport::Inflector.camelize @name
    end

    def controller
      @controller ||= Class.new(ActionController::Base).new.tap do |c|
        # Configure the controller to know about the templates
        c.prepend_view_path template_path
      end
    end

    def cp from, to
      input_path = File.join template_path, from
      target_path = File.join @path, to
      FileUtils.mkdir_p File.dirname(target_path)
      FileUtils.cp input_path, target_path
    end

    def gen template, filename
      content = controller.render_to_string(
        template: template,
        formats:  :text,
        locals:   { gem_name: gem_name, gem_class_prefix: gem_class_prefix }
      )
      target_path = File.join @path, filename
      FileUtils.mkdir_p File.dirname(target_path)
      File.write target_path, content
    end
  end
end