activesupport_path = "#{File.dirname(__FILE__)}/../../../activesupport/lib"
$LOAD_PATH.unshift(activesupport_path) if File.directory?(activesupport_path)
require 'active_support'
require 'active_support/core_ext/object/blank'
require 'active_support/core_ext/object/metaclass'
require 'active_support/core_ext/array'
require 'active_support/core_ext/hash'
require 'active_support/core_ext/module/attribute_accessors'
require 'active_support/core_ext/string/inflections'

# TODO: Do not always push on vendored thor
$LOAD_PATH.unshift("#{File.dirname(__FILE__)}/vendor/thor-0.12.0/lib")
require 'rails/generators/base'
require 'rails/generators/named_base'

module Rails
  module Generators
    DEFAULT_ALIASES = {
      :rails => {
        :actions => '-a',
        :orm => '-o',
        :resource_controller => '-c',
        :scaffold_controller => '-c',
        :stylesheets => '-y',
        :template_engine => '-e',
        :test_framework => '-t'
      },

      :test_unit => {
        :fixture_replacement => '-r',
      },

      :plugin => {
        :generator => '-g',
        :tasks => '-r'
      }
    }

    DEFAULT_OPTIONS = {
      :active_record => {
        :migration  => true,
        :timestamps => true
      },

      :erb => {
        :layout => true
      },

      :rails => {
        :force_plural => false,
        :helper => true,
        :layout => true,
        :orm => :active_record,
        :integration_tool => :test_unit,
        :performance_tool => :test_unit,
        :resource_controller => :controller,
        :scaffold_controller => :scaffold_controller,
        :singleton => false,
        :stylesheets => true,
        :template_engine => :erb,
        :test_framework => :test_unit
      },

      :test_unit => {
        :fixture => true,
        :fixture_replacement => nil
      },

      :plugin => {
        :generator => false,
        :tasks => false
      }
    }

    def self.configure!(config = Rails.application.config.generators) #:nodoc:
      no_color! unless config.colorize_logging
      aliases.deep_merge! config.aliases
      options.deep_merge! config.options
    end

    def self.aliases #:nodoc:
      @aliases ||= DEFAULT_ALIASES.dup
    end

    def self.options #:nodoc:
      @options ||= DEFAULT_OPTIONS.dup
    end

    def self.gems_generators_paths #:nodoc:
      return [] unless defined?(Gem) && Gem.respond_to?(:loaded_specs)
      Gem.loaded_specs.inject([]) do |paths, (name, spec)|
        paths += Dir[File.join(spec.full_gem_path, "lib/{generators,rails_generators}")]
      end
    end

    def self.plugins_generators_paths #:nodoc:
      return [] unless Rails.root
      Dir[File.join(Rails.root, "vendor", "plugins", "*", "lib", "{generators,rails_generators}")]
    end

    # Hold configured generators fallbacks. If a plugin developer wants a
    # generator group to fallback to another group in case of missing generators,
    # they can add a fallback.
    #
    # For example, shoulda is considered a test_framework and is an extension
    # of test_unit. However, most part of shoulda generators are similar to
    # test_unit ones.
    #
    # Shoulda then can tell generators to search for test_unit generators when
    # some of them are not available by adding a fallback:
    #
    #   Rails::Generators.fallbacks[:shoulda] = :test_unit
    #
    def self.fallbacks
      @fallbacks ||= {}
    end

    # Remove the color from output.
    #
    def self.no_color!
      Thor::Base.shell = Thor::Shell::Basic
    end

    # Generators load paths used on lookup. The lookup happens as:
    #
    #   1) lib generators
    #   2) vendor/plugin generators
    #   3) vendor/gems generators
    #   4) ~/rails/generators
    #   5) rubygems generators
    #   6) builtin generators
    #
    # TODO Remove hardcoded paths for all, except (6).
    #
    def self.load_paths
      @load_paths ||= begin
        paths = []
        paths += Dir[File.join(Rails.root, "lib", "{generators,rails_generators}")] if Rails.root
        paths += Dir[File.join(Thor::Util.user_home, ".rails", "{generators,rails_generators}")]
        paths += self.plugins_generators_paths
        paths += self.gems_generators_paths
        paths << File.expand_path(File.join(File.dirname(__FILE__), "generators"))
        paths.uniq!
        paths
      end
    end
    load_paths # Cache load paths. Needed to avoid __FILE__ pointing to wrong paths.

    # Rails finds namespaces exactly as thor, with three conveniences:
    #
    #  1) If your generator name ends with generator, as WebratGenerator, it sets
    #     its namespace to "webrat", so it can be invoked as "webrat" and not
    #     "webrat_generator";
    #
    #  2) If your generator has a generators namespace, as Rails::Generators::WebratGenerator,
    #     the namespace is set to "rails:generators:webrat", but Rails allows it
    #     to be invoked simply as "rails:webrat". The "generators" is added
    #     automatically when doing the lookup;
    #
    #  3) Rails looks in load paths and loads the generator just before it's going to be used.
    #
    # ==== Examples
    #
    #   find_by_namespace :webrat, :rails, :integration
    #
    # Will search for the following generators:
    #
    #   "rails:generators:webrat", "webrat:generators:integration", "webrat"
    #
    # On the other hand, if "rails:webrat" is given, it will search for:
    #
    #   "rails:generators:webrat", "rails:webrat"
    #
    # Notice that the "generators" namespace is handled automatically by Rails,
    # so you don't need to type it when you want to invoke a generator in specific.
    #
    def self.find_by_namespace(name, base=nil, context=nil) #:nodoc:
      name, attempts = name.to_s, [ ]

      case name.count(':')
        when 1
          base, name = name.split(':')
          return find_by_namespace(name, base)
        when 0
          attempts += generator_names(base, name)    if base
          attempts += generator_names(name, context) if context
      end

      attempts << name
      attempts += generator_names(name, name) unless name.include?(?:)
      attempts.uniq!

      unloaded = attempts - namespaces
      lookup(unloaded)

      attempts.each do |namespace|
        klass = Thor::Util.find_by_namespace(namespace)
        return klass if klass
      end

      invoke_fallbacks_for(name, base) || invoke_fallbacks_for(context, name)
    end

    # Receives a namespace, arguments and the behavior to invoke the generator.
    # It's used as the default entry point for generate, destroy and update
    # commands.
    #
    def self.invoke(namespace, args=ARGV, config={})
      if klass = find_by_namespace(namespace, "rails")
        args << "--help" if klass.arguments.any? { |a| a.required? } && args.empty?
        klass.start args, config
      else
        puts "Could not find generator #{namespace}."
      end
    end

    # Show help message with available generators.
    #
    def self.help
      rails = Rails::Generators.builtin.map do |group, name|
        name if group == "rails"
      end
      rails.compact!
      rails.sort!

      puts "Please select a generator."
      puts "Builtin: #{rails.join(', ')}."

      # Load paths and remove builtin
      paths, others = load_paths.dup, []
      paths.pop

      paths.each do |path|
        tail = [ "*", "*", "*_generator.rb" ]

        until tail.empty?
          others += Dir[File.join(path, *tail)].collect do |file|
            name = file.split('/')[-tail.size, 2]
            name.last.sub!(/_generator\.rb$/, '')
            name.uniq!
            name.join(':')
          end
          tail.shift
        end
      end

      others.sort!
      puts "Others: #{others.join(', ')}." unless others.empty?
    end

    protected

      # Return all defined namespaces.
      #
      def self.namespaces #:nodoc:
        Thor::Base.subclasses.map { |klass| klass.namespace }
      end

      # Keep builtin generators in an Array[Array[group, name]].
      #
      def self.builtin #:nodoc:
        Dir[File.dirname(__FILE__) + '/generators/*/*'].collect do |file|
          file.split('/')[-2, 2]
        end
      end

      # By default, Rails strips the generator namespace to make invocations
      # easier. This method generaters the both possibilities names.
      def self.generator_names(first, second) #:nodoc:
        [ "#{first}:generators:#{second}", "#{first}:#{second}" ]
      end

      # Try callbacks for the given base.
      #
      def self.invoke_fallbacks_for(name, base) #:nodoc:
        return nil unless base && fallbacks[base.to_sym]
        invoked_fallbacks = []

        Array(fallbacks[base.to_sym]).each do |fallback|
          next if invoked_fallbacks.include?(fallback)
          invoked_fallbacks << fallback

          klass = find_by_namespace(name, fallback)
          return klass if klass
        end

        nil
      end

      # Receives namespaces in an array and tries to find matching generators
      # in the load path.
      #
      def self.lookup(attempts) #:nodoc:
        attempts = attempts.map { |a| "#{a.split(":").last}_generator" }.uniq
        attempts = "{#{attempts.join(',')}}.rb"

        self.load_paths.each do |path|
          Dir[File.join(path, '**', attempts)].each do |file|
            begin
              require file
            rescue NameError => e
              raise unless e.message =~ /Rails::Generator/
              warn "[WARNING] Could not load generator at #{file.inspect} because it's a Rails 2.x generator, which is not supported anymore"
            rescue Exception => e
              warn "[WARNING] Could not load generator at #{file.inspect}. Error: #{e.message}"
            end
          end
        end
      end

  end
end