class ScaffoldingSandbox
  include ActionView::Helpers::ActiveRecordHelper

  attr_accessor :form_action, :singular_name, :suffix, :model_instance

  def sandbox_binding
    binding
  end
end

class ActionView::Helpers::InstanceTag
  def to_input_field_tag(field_type, options={})
    field_meth = "#{field_type}_field"
    "<%= #{field_meth} '#{@object_name}', '#{@method_name}' #{options.empty? ? '' : ', '+options.inspect} %>"
  end

  def to_text_area_tag(options = {})
    "<%= text_area '#{@object_name}', '#{@method_name}' #{options.empty? ? '' : ', '+ options.inspect} %>"
  end

  def to_date_select_tag(options = {})
    "<%= date_select '#{@object_name}', '#{@method_name}' #{options.empty? ? '' : ', '+ options.inspect} %>"
  end

  def to_datetime_select_tag(options = {})
    "<%= datetime_select '#{@object_name}', '#{@method_name}' #{options.empty? ? '' : ', '+ options.inspect} %>"
  end
end

class ScaffoldGenerator < Rails::Generator::NamedBase
  attr_reader   :controller_name,
                :controller_class_path,
                :controller_class_nesting,
                :controller_class_name,
                :controller_singular_name,
                :controller_plural_name
  alias_method  :controller_file_name,  :controller_singular_name
  alias_method  :controller_table_name, :controller_plural_name

  def initialize(runtime_args, runtime_options = {})
    super
    @controller_name = args.shift || @name.pluralize
    base_name, @controller_class_path, @controller_class_nesting = extract_modules(@controller_name)
    @controller_class_name_without_nesting, @controller_singular_name, @controller_plural_name = inflect_names(base_name)
    if @controller_class_nesting.empty?
      @controller_class_name = @controller_class_name_without_nesting
    else
      @controller_class_name = "#{@controller_class_nesting}::#{@controller_class_name_without_nesting}"
    end
  end

  def manifest
    record do |m|
      # Depend on model generator but skip if the model exists.
      m.dependency 'model', [@name], :collision => :skip

      # Check for class naming collisions.
      m.class_collisions "#{controller_class_name}Controller", "#{controller_class_name}ControllerTest", "#{controller_class_name}Helper"

      # Controller, helper, views, and test directories.
      m.directory File.join('app/controllers', controller_class_path)
      m.directory File.join('app/helpers', controller_class_path)
      m.directory File.join('app/views', controller_class_path, controller_file_name)
      m.directory File.join('test/functional', controller_class_path)


      # Controller class, functional test, helper, and views.
      m.template 'controller.rb',
                  File.join('app/controllers',
                            controller_class_path,
                            "#{controller_file_name}_controller.rb")

      m.template 'functional_test.rb',
                  File.join('test/functional',
                            controller_class_path,
                            "#{controller_file_name}_controller_test.rb")

      m.template 'controller:helper.rb',
                  File.join('app/helpers',
                            controller_class_path,
                            "#{controller_file_name}_helper.rb")

      # Layout and stylesheet.
      m.template 'layout.rhtml',  "app/views/layouts/#{controller_file_name}.rhtml"
      m.template 'style.css',     'public/stylesheets/scaffold.css'

      # Scaffolded views.
      scaffold_views.each do |action|
        m.template "view_#{action}.rhtml",
                   File.join('app/views',
                             controller_class_path,
                             controller_file_name,
                             "#{action}.rhtml"),
                   :assigns => { :action => action }
      end

      # Scaffolded forms.
      scaffold_forms.each do |action|
        m.complex_template "view_#{action}.rhtml",
          File.join('app/views',
                    controller_class_path,
                    controller_file_name,
                    "#{action}.rhtml"),
          :assigns => { :action => action },
          :insert => 'form.rhtml',
          :sandbox => lambda { create_sandbox(action) },
          :begin_mark => 'form',
          :end_mark => 'eoform',
          :mark_id => singular_name
      end

      # Unscaffolded views.
      unscaffolded_actions.each do |action|
        m.template "controller:view.rhtml",
                   File.join('app/views',
                             controller_class_path,
                             controller_file_name,
                             "#{action}.rhtml"),
                   :assigns => { :action => action }
      end
    end
  end

  protected
    # Override with your own usage banner.
    def banner
      "Usage: #{$0} scaffold ModelName [ControllerName] [action, ...]"
    end

    def scaffold_views
      %w(list show)
    end

    def scaffold_forms
      %w(new edit)
    end

    def scaffold_actions
      scaffold_views + %w(index create update destroy)
    end

    def unscaffolded_actions
      args - scaffold_actions
    end

    def suffix
      "_#{singular_name}" if options[:suffix]
    end

    def create_sandbox(action)
      sandbox = ScaffoldingSandbox.new
      action = if action == 'edit' then 'update' else 'create' end
      sandbox.form_action = action
      sandbox.singular_name = singular_name
      begin
        sandbox.model_instance = model_instance
        sandbox.instance_variable_set("@#{singular_name}", sandbox.model_instance)
      rescue ActiveRecord::StatementInvalid => e
        logger.error "Before updating scaffolding from new DB schema, try creating a table for your model (#{class_name})"
        raise SystemExit
      end
      sandbox.suffix = suffix
      sandbox
    end

    def model_instance
      base = class_nesting.split('::').inject(Object) do |base, nested|
        break base.const_get(nested) if base.const_defined?(nested)
        base.const_set(nested, Module.new)
      end
      unless base.const_defined?(@class_name_without_nesting)
        base.const_set(@class_name_without_nesting, Class.new(ActiveRecord::Base))
      end
      class_name.constantize.new
    end
end