# -*- encoding: utf-8 -*-
#
# Author:: Fletcher Nichol (<fnichol@nichol.ca>)
#
# Copyright (C) 2013, Fletcher Nichol
#
# 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 "thor/group"
require "thor/util"

module Kitchen
  module Generator
    # A generator to create a new Kitchen Driver gem project.
    #
    # @author Fletcher Nichol <fnichol@nichol.ca>
    class DriverCreate < Thor::Group
      include Thor::Actions

      argument :name, type: :string

      class_option :license,
                   aliases: "-l",
                   default: "apachev2",
                   desc: "License type for gem (apachev2, mit, lgplv3, reserved)"

      # Invoke the command.
      def create
        self.class.source_root(Kitchen.source_root.join("templates", "driver"))

        create_core_files
        create_source_files
        initialize_git
      end

      private

      # Creates top-level project files.
      #
      # @api private
      def create_core_files
        empty_directory(target_dir)

        create_template("CHANGELOG.md.erb", "CHANGELOG.md")
        create_template("Gemfile.erb", "Gemfile")
        create_template("Rakefile.erb", "Rakefile")
        create_template("README.md.erb", "README.md")
        create_template("gemspec.erb", "#{config[:gem_name]}.gemspec")
        create_template("license_#{config[:license]}.erb", license_filename)
        create_template("gitignore.erb", ".gitignore")
        create_template("tailor.erb", ".tailor")
        create_template("travis.yml.erb", ".travis.yml")
        create_file(File.join(target_dir, ".cane"))
      end

      # Creates source code files.
      #
      # @api private
      def create_source_files
        empty_directory(File.join(target_dir, "lib/kitchen/driver"))

        create_template(
          "version.rb.erb",
          "lib/kitchen/driver/#{name}_version.rb"
        )
        create_template(
          "driver.rb.erb",
          "lib/kitchen/driver/#{name}.rb"
        )
      end

      # Initialize a git repository.
      #
      # @api private
      def initialize_git
        inside(target_dir) do
          run("git init", capture: true)
          run("git add .", capture: true)
        end
      end

      # Render an ERb template to a destination file.
      #
      # @param erb [String] path to an ERb file
      # @param dest [String] destination path for the rendered template
      # @api private
      def create_template(erb, dest)
        template(erb, File.join(target_dir, dest), config)
      end

      # @return [String] the path to the gem skeleton project
      # @api private
      def target_dir
        File.join(Dir.pwd, "kitchen-#{name}")
      end

      # @return [Hash] a configuration hash which can be used by templates as
      #   context
      # @api private
      def config
        @config ||= {
          name: name,
          gem_name: "kitchen-#{name}",
          gemspec: "kitchen-#{name}.gemspec",
          klass_name: ::Thor::Util.camel_case(name),
          constant_name: ::Thor::Util.snake_case(name).upcase,
          author: author,
          email: email,
          license: options[:license],
          license_string: license_string,
          year: Time.now.year,
        }
      end

      # @return [String] a default author name taken from git configuration if
      #   found
      # @api private
      def author
        git_user_name = `git config user.name`.chomp
        git_user_name.empty? ? "TODO: Write your name" : git_user_name
      end

      # @return [String] a default email address taken from git configuration
      #   if found
      # @api private
      def email
        git_user_email = `git config user.email`.chomp
        git_user_email.empty? ? "TODO: Write your email" : git_user_email
      end

      # @return [String] a rendered license string for a given license
      # @api private
      def license_string
        case options[:license]
        when "mit" then "MIT"
        when "apachev2" then "Apache 2.0"
        when "lgplv3" then "LGPL 3.0"
        when "reserved" then "All rights reserved"
        else
          raise ArgumentError, "No such license #{options[:license]}"
        end
      end

      # @return [String] the filename to use for the license file
      # @api private
      def license_filename
        case options[:license]
        when "mit" then "LICENSE.txt"
        when "apachev2", "reserved" then "LICENSE"
        when "lgplv3" then "COPYING"
        else
          raise ArgumentError, "No such license #{options[:license]}"
        end
      end

      # @return [String] the license comment/preamble
      # @api private
      def license_comment
        @license_comment ||= IO.read(File.join(target_dir, license_filename))
                               .gsub(/^/, "# ").gsub(/\s+$/, "")
      end
    end
  end
end