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# Redmine - project management software

# Copyright (C) 2006-2008  Jean-Philippe Lang

#

# This program is free software; you can redistribute it and/or

# modify it under the terms of the GNU General Public License

# as published by the Free Software Foundation; either version 2

# of the License, or (at your option) any later version.

# 

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

# 

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

module Redmine

  module Hook

    include ActionController::UrlWriter

    @@listener_classes = []

    @@listeners = nil

    @@hook_listeners = {}

    class << self

      # Adds a listener class.

      # Automatically called when a class inherits from Redmine::Hook::Listener.

      def add_listener(klass)

        raise "Hooks must include Singleton module." unless klass.included_modules.include?(Singleton)

        @@listener_classes << klass

        clear_listeners_instances

      end

      # Returns all the listerners instances.

      def listeners

        @@listeners ||= @@listener_classes.collect {|listener| listener.instance}

      end

      # Returns the listeners instances for the given hook.

      def hook_listeners(hook)

        @@hook_listeners[hook] ||= listeners.select {|listener| listener.respond_to?(hook)}

      end

      # Clears all the listeners.

      def clear_listeners

        @@listener_classes = []

        clear_listeners_instances

      end

      # Clears all the listeners instances.

      def clear_listeners_instances

        @@listeners = nil

        @@hook_listeners = {}

      end

      # Calls a hook.

      # Returns the listeners response.

      def call_hook(hook, context={})

        [].tap do |response|

          hls = hook_listeners(hook)

          if hls.any?

            hls.each {|listener| response << listener.send(hook, context)}

          end

        end

      end

    end

    # Base class for hook listeners.

    class Listener

      include Singleton

      include Redmine::I18n

      # Registers the listener

      def self.inherited(child)

        Redmine::Hook.add_listener(child)

        super

      end

    end

    # Listener class used for views hooks.

    # Listeners that inherit this class will include various helpers by default.

    class ViewListener < Listener

      include ERB::Util

      include ActionView::Helpers::TagHelper

      include ActionView::Helpers::FormHelper

      include ActionView::Helpers::FormTagHelper

      include ActionView::Helpers::FormOptionsHelper

      include ActionView::Helpers::JavaScriptHelper

      include ActionView::Helpers::PrototypeHelper

      include ActionView::Helpers::NumberHelper

      include ActionView::Helpers::UrlHelper

      include ActionView::Helpers::AssetTagHelper

      include ActionView::Helpers::TextHelper

      include ActionController::UrlWriter

      include ApplicationHelper

      # Default to creating links using only the path.  Subclasses can

      # change this default as needed

      def self.default_url_options

        {:only_path => true }

      end

      # Helper method to directly render a partial using the context:

      # 

      #   class MyHook < Redmine::Hook::ViewListener

      #     render_on :view_issues_show_details_bottom, :partial => "show_more_data" 

      #   end

      #

      def self.render_on(hook, options={})

        define_method hook do |context|

          context[:controller].send(:render_to_string, {:locals => context}.merge(options))

        end

      end

    end

    # Helper module included in ApplicationHelper and ActionControllerso that

    # hooks can be called in views like this:

    # 

    #   <%= call_hook(:some_hook) %>

    #   <%= call_hook(:another_hook, :foo => 'bar' %>

    # 

    # Or in controllers like:

    #   call_hook(:some_hook)

    #   call_hook(:another_hook, :foo => 'bar'

    # 

    # Hooks added to views will be concatenated into a string.  Hooks added to

    # controllers will return an array of results.

    #

    # Several objects are automatically added to the call context:

    # 

    # * project => current project

    # * request => Request instance

    # * controller => current Controller instance

    # 

    module Helper

      def call_hook(hook, context={})

        if is_a?(ActionController::Base)

          default_context = {:controller => self, :project => @project, :request => request}

          Redmine::Hook.call_hook(hook, default_context.merge(context))

        else

          default_context = {:controller => controller, :project => @project, :request => request}

          Redmine::Hook.call_hook(hook, default_context.merge(context)).join(' ')

        end        

      end

    end

  end

end

ApplicationHelper.send(:include, Redmine::Hook::Helper)

ActionController::Base.send(:include, Redmine::Hook::Helper)