require 'rails/generators/base'
require 'rails/generators/active_record'
require 'generators/authenticate/helpers'

module Authenticate
  module Generators
    class InstallGenerator < Rails::Generators::Base
      include Rails::Generators::Migration
      include Authenticate::Generators::Helpers

      source_root File.expand_path('../templates', __FILE__)
      class_option :model,
                   optional: true,
                   type: :string,
                   banner: 'model',
                   desc: "Specify the model class name if you will use anything other than 'User'"

      class_option :allow_sign_up,
                   optional: true,
                   type: :boolean,
                   banner: 'allow_sign_up',
                   desc: 'Disable the sign up route'

      def initialize(*)
        super
        assign_names!(model_class_name)
      end

      def verify
        if options[:model] && !File.exist?(model_path)
          puts "Exiting: the model class you specified, #{options[:model]}, is not found."
          exit 1
        end
      end

      def create_or_inject_into_user_model
        if File.exist? model_path
          inject_into_class(model_path, model_class_name, "  include Authenticate::User\n\n")
        else
          @model_base_class = model_base_class
          template 'user.rb.erb', 'app/models/user.rb'
        end
      end

      def create_authenticate_user_migration
        if users_table_exists?
          create_add_columns_migration
        else
          create_new_users_migration
        end
      end

      def copy_migration_files
        copy_migration 'add_authenticate_brute_force_to_users.rb'
        copy_migration 'add_authenticate_timeoutable_to_users.rb'
        copy_migration 'add_authenticate_password_reset_to_users.rb'
      end

      def inject_into_application_controller
        inject_into_class(
          'app/controllers/application_controller.rb',
          ApplicationController,
          "  include Authenticate::Controller\n\n"
        )
      end

      def create_initializer
        copy_file 'authenticate.rb', 'config/initializers/authenticate.rb'
        if options[:model]
          inject_into_file(
            'config/initializers/authenticate.rb',
            "  config.user_model = '#{options[:model]}'\n",
            after: "Authenticate.configure do |config|\n"
          )
        end

        if options.key? :allow_sign_up
          inject_into_file(
            'config/initializers/authenticate.rb',
            "  config.allow_sign_up = #{options['allow_sign_up']}\n",
            after: "Authenticate.configure do |config|\n"
          )
        end
      end

      private

      def create_new_users_migration
        config = {
          new_columns: new_columns,
          new_indexes: new_indexes
        }
        copy_migration 'create_users.rb', config
      end

      def create_add_columns_migration
        if migration_needed?
          config = {
            new_columns: new_columns,
            new_indexes: new_indexes
          }
          copy_migration('add_authenticate_to_users.rb', config)
        end
      end

      def copy_migration(migration_name, config = {})
        unless migration_exists?(migration_name)
          migration_template(
            "db/migrate/#{migration_name}",
            "db/migrate/#{migration_name}",
            config.merge(migration_version: migration_version)
          )
        end
      end

      def migration_needed?
        new_columns.any? || new_indexes.any?
      end

      def new_columns
        @new_columns ||= {
          email: 't.string :email',
          encrypted_password: 't.string :encrypted_password, limit: 128',
          session_token: 't.string :session_token, limit: 128',

          # trackable, lifetimed
          current_sign_in_at: 't.datetime :current_sign_in_at',
          current_sign_in_ip: 't.string :current_sign_in_ip, limit: 128',
          last_sign_in_at: 't.datetime :last_sign_in_at',
          last_sign_in_ip: 't.string :last_sign_in_ip, limit: 128',
          sign_in_count: 't.integer :sign_in_count'
        }.reject { |column| existing_users_columns.include?(column.to_s) }
      end

      def new_indexes
        @new_indexes ||= {
          index_users_on_email: "add_index :#{table_name}, :email, unique: true",
          index_users_on_session_token: "add_index :#{table_name}, :session_token"
        }.reject { |index| existing_users_indexes.include?(index.to_s) }
      end

      def migration_exists?(name)
        existing_migrations.include?(name)
      end

      def existing_migrations
        @existing_migrations ||= Dir.glob('db/migrate/*.rb').map do |file|
          migration_name_without_timestamp(file)
        end
      end

      def migration_name_without_timestamp(file)
        file.sub(%r{^.*(db/migrate/)(?:\d+_)?}, '')
      end

      # def users_table_exists?
      #   ActiveRecord::Base.connection.table_exists?(table_name)
      # end

      def users_table_exists?
        # Rails 5 uses 'data sources'
        if ActiveRecord::Base.connection.respond_to?(:data_source_exists?)
          ActiveRecord::Base.connection.data_source_exists?(table_name)
        else
          # Rails 4 uses 'tables'
          ActiveRecord::Base.connection.table_exists?(table_name)
        end
      end


      def existing_users_columns
        return [] unless users_table_exists?
        ActiveRecord::Base.connection.columns(table_name).map(&:name)
      end

      def existing_users_indexes
        return [] unless users_table_exists?
        ActiveRecord::Base.connection.indexes(table_name).map(&:name)
      end

      # for generating a timestamp when using `create_migration`
      def self.next_migration_number(dir)
        ActiveRecord::Generators::Base.next_migration_number(dir)
      end

      def model_base_class
        (Rails.version >= '5.0.0') ? 'ApplicationRecord' : 'ActiveRecord::Base'
      end

      def migration_version
        if Rails.version >= '5.0.0'
          "[#{Rails::VERSION::MAJOR}.#{Rails::VERSION::MINOR}]"
        end
      end
    end
  end
end