# redMine - project management software
# Copyright (C) 2006-2007  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.

require 'coderay'
require 'coderay/helpers/file_type'
require 'forwardable'
require 'cgi'

module ApplicationHelper
  include Redmine::WikiFormatting::Macros::Definitions
  include Redmine::I18n
  include GravatarHelper::PublicMethods

  extend Forwardable
  def_delegators :wiki_helper, :wikitoolbar_for, :heads_for_wiki_formatter

  # Return true if user is authorized for controller/action, otherwise false
  def authorize_for(controller, action)
    User.current.allowed_to?({:controller => controller, :action => action}, @project)
  end

  # Display a link if user is authorized
  def link_to_if_authorized(name, options = {}, html_options = nil, *parameters_for_method_reference)
    link_to(name, options, html_options, *parameters_for_method_reference) if authorize_for(options[:controller] || params[:controller], options[:action])
  end

  # Display a link to remote if user is authorized
  def link_to_remote_if_authorized(name, options = {}, html_options = nil)
    url = options[:url] || {}
    link_to_remote(name, options, html_options) if authorize_for(url[:controller] || params[:controller], url[:action])
  end

  # Displays a link to user's account page if active
  def link_to_user(user, options={})
    if user.is_a?(User)
      name = h(user.name(options[:format]))
      if user.active?
        link_to name, :controller => 'users', :action => 'show', :id => user
      else
        name
      end
    else
      h(user.to_s)
    end
  end

  # Displays a link to +issue+ with its subject.
  # Examples:
  # 
  #   link_to_issue(issue)                        # => Defect #6: This is the subject
  #   link_to_issue(issue, :truncate => 6)        # => Defect #6: This i...
  #   link_to_issue(issue, :subject => false)     # => Defect #6
  #   link_to_issue(issue, :project => true)      # => Foo - Defect #6
  #
  def link_to_issue(issue, options={})
    title = nil
    subject = nil
    if options[:subject] == false
      title = truncate(issue.subject, :length => 60)
    else
      subject = issue.subject
      if options[:truncate]
        subject = truncate(subject, :length => options[:truncate])
      end
    end
    s = link_to "#{issue.tracker} ##{issue.id}", {:controller => "issues", :action => "show", :id => issue}, 
                                                 :class => issue.css_classes,
                                                 :title => title
    s << ": #{h subject}" if subject
    s = "#{h issue.project} - " + s if options[:project]
    s
  end

  # Generates a link to an attachment.
  # Options:
  # * :text - Link text (default to attachment filename)
  # * :download - Force download (default: false)
  def link_to_attachment(attachment, options={})
    text = options.delete(:text) || attachment.filename
    action = options.delete(:download) ? 'download' : 'show'

    link_to(h(text), {:controller => 'attachments', :action => action, :id => attachment, :filename => attachment.filename }, options)
  end

  # Generates a link to a SCM revision
  # Options:
  # * :text - Link text (default to the formatted revision)
  def link_to_revision(revision, project, options={})
    text = options.delete(:text) || format_revision(revision)

    link_to(text, {:controller => 'repositories', :action => 'revision', :id => project, :rev => revision}, :title => l(:label_revision_id, revision))
  end

  def toggle_link(name, id, options={})
    onclick = "Element.toggle('#{id}'); "
    onclick << (options[:focus] ? "Form.Element.focus('#{options[:focus]}'); " : "this.blur(); ")
    onclick << "return false;"
    link_to(name, "#", :onclick => onclick)
  end

  def image_to_function(name, function, html_options = {})
    html_options.symbolize_keys!
    tag(:input, html_options.merge({
        :type => "image", :src => image_path(name),
        :onclick => (html_options[:onclick] ? "#{html_options[:onclick]}; " : "") + "#{function};"
        }))
  end

  def prompt_to_remote(name, text, param, url, html_options = {})
    html_options[:onclick] = "promptToRemote('#{text}', '#{param}', '#{url_for(url)}'); return false;"
    link_to name, {}, html_options
  end
  
  def format_activity_title(text)
    h(truncate_single_line(text, :length => 100))
  end
  
  def format_activity_day(date)
    date == Date.today ? l(:label_today).titleize : format_date(date)
  end
  
  def format_activity_description(text)
    h(truncate(text.to_s, :length => 120).gsub(%r{[\r\n]*<(pre|code)>.*$}m, '...')).gsub(/[\r\n]+/, "<br />")
  end

  def format_version_name(version)
    if version.project == @project
    	h(version)
    else
      h("#{version.project} - #{version}")
    end
  end
  
  def due_date_distance_in_words(date)
    if date
      l((date < Date.today ? :label_roadmap_overdue : :label_roadmap_due_in), distance_of_date_in_words(Date.today, date))
    end
  end

  def render_page_hierarchy(pages, node=nil)
    content = ''
    if pages[node]
      content << "<ul class=\"pages-hierarchy\">\n"
      pages[node].each do |page|
        content << "<li>"
        content << link_to(h(page.pretty_title), {:controller => 'wiki', :action => 'index', :id => page.project, :page => page.title},
                           :title => (page.respond_to?(:updated_on) ? l(:label_updated_time, distance_of_time_in_words(Time.now, page.updated_on)) : nil))
        content << "\n" + render_page_hierarchy(pages, page.id) if pages[page.id]
        content << "</li>\n"
      end
      content << "</ul>\n"
    end
    content
  end
  
  # Renders flash messages
  def render_flash_messages
    s = ''
    flash.each do |k,v|
      s << content_tag('div', v, :class => "flash #{k}")
    end
    s
  end
  
  # Renders tabs and their content
  def render_tabs(tabs)
    if tabs.any?
      render :partial => 'common/tabs', :locals => {:tabs => tabs}
    else
      content_tag 'p', l(:label_no_data), :class => "nodata"
    end
  end
  
  # Renders the project quick-jump box
  def render_project_jump_box
    # Retrieve them now to avoid a COUNT query
    projects = User.current.projects.all
    if projects.any?
      s = '<select onchange="if (this.value != \'\') { window.location = this.value; }">' +
            "<option value=''>#{ l(:label_jump_to_a_project) }</option>" +
            '<option value="" disabled="disabled">---</option>'
      s << project_tree_options_for_select(projects, :selected => @project) do |p|
        { :value => url_for(:controller => 'projects', :action => 'show', :id => p, :jump => current_menu_item) }
      end
      s << '</select>'
      s
    end
  end
  
  def project_tree_options_for_select(projects, options = {})
    s = ''
    project_tree(projects) do |project, level|
      name_prefix = (level > 0 ? ('&nbsp;' * 2 * level + '&#187; ') : '')
      tag_options = {:value => project.id, :selected => ((project == options[:selected]) ? 'selected' : nil)}
      tag_options.merge!(yield(project)) if block_given?
      s << content_tag('option', name_prefix + h(project), tag_options)
    end
    s
  end
  
  # Yields the given block for each project with its level in the tree
  def project_tree(projects, &block)
    ancestors = []
    projects.sort_by(&:lft).each do |project|
      while (ancestors.any? && !project.is_descendant_of?(ancestors.last)) 
        ancestors.pop
      end
      yield project, ancestors.size
      ancestors << project
    end
  end
  
  def project_nested_ul(projects, &block)
    s = ''
    if projects.any?
      ancestors = []
      projects.sort_by(&:lft).each do |project|
        if (ancestors.empty? || project.is_descendant_of?(ancestors.last))
          s << "<ul>\n"
        else
          ancestors.pop
          s << "</li>"
          while (ancestors.any? && !project.is_descendant_of?(ancestors.last)) 
            ancestors.pop
            s << "</ul></li>\n"
          end
        end
        s << "<li>"
        s << yield(project).to_s
        ancestors << project
      end
      s << ("</li></ul>\n" * ancestors.size)
    end
    s
  end
  
  def principals_check_box_tags(name, principals)
    s = ''
    principals.sort.each do |principal|
      s << "<label>#{ check_box_tag name, principal.id, false } #{h principal}</label>\n"
    end
    s 
  end

  # Truncates and returns the string as a single line
  def truncate_single_line(string, *args)
    truncate(string.to_s, *args).gsub(%r{[\r\n]+}m, ' ')
  end

  def html_hours(text)
    text.gsub(%r{(\d+)\.(\d+)}, '<span class="hours hours-int">\1</span><span class="hours hours-dec">.\2</span>')
  end

  def authoring(created, author, options={})
    l(options[:label] || :label_added_time_by, :author => link_to_user(author), :age => time_tag(created))
  end
  
  def time_tag(time)
    text = distance_of_time_in_words(Time.now, time)
    if @project
      link_to(text, {:controller => 'projects', :action => 'activity', :id => @project, :from => time.to_date}, :title => format_time(time))
    else
      content_tag('acronym', text, :title => format_time(time))
    end
  end

  def syntax_highlight(name, content)
    type = CodeRay::FileType[name]
    type ? CodeRay.scan(content, type).html : h(content)
  end

  def to_path_param(path)
    path.to_s.split(%r{[/\\]}).select {|p| !p.blank?}
  end

  def pagination_links_full(paginator, count=nil, options={})
    page_param = options.delete(:page_param) || :page
    url_param = params.dup
    # don't reuse query params if filters are present
    url_param.merge!(:fields => nil, :values => nil, :operators => nil) if url_param.delete(:set_filter)

    html = ''
    if paginator.current.previous
      html << link_to_remote_content_update('&#171; ' + l(:label_previous), url_param.merge(page_param => paginator.current.previous)) + ' '
    end

    html << (pagination_links_each(paginator, options) do |n|
      link_to_remote_content_update(n.to_s, url_param.merge(page_param => n))
    end || '')
    
    if paginator.current.next
      html << ' ' + link_to_remote_content_update((l(:label_next) + ' &#187;'), url_param.merge(page_param => paginator.current.next))
    end

    unless count.nil?
      html << [
        " (#{paginator.current.first_item}-#{paginator.current.last_item}/#{count})",
        per_page_links(paginator.items_per_page)
      ].compact.join(' | ')
    end

    html
  end
  
  def per_page_links(selected=nil)
    url_param = params.dup
    url_param.clear if url_param.has_key?(:set_filter)

    links = Setting.per_page_options_array.collect do |n|
      n == selected ? n : link_to_remote(n, {:update => "content",
                                             :url => params.dup.merge(:per_page => n),
                                             :method => :get},
                                            {:href => url_for(url_param.merge(:per_page => n))})
    end
    links.size > 1 ? l(:label_display_per_page, links.join(', ')) : nil
  end
  
  def reorder_links(name, url)
    link_to(image_tag('2uparrow.png',   :alt => l(:label_sort_highest)), url.merge({"#{name}[move_to]" => 'highest'}), :method => :post, :title => l(:label_sort_highest)) +
    link_to(image_tag('1uparrow.png',   :alt => l(:label_sort_higher)),  url.merge({"#{name}[move_to]" => 'higher'}),  :method => :post, :title => l(:label_sort_higher)) +
    link_to(image_tag('1downarrow.png', :alt => l(:label_sort_lower)),   url.merge({"#{name}[move_to]" => 'lower'}),   :method => :post, :title => l(:label_sort_lower)) +
    link_to(image_tag('2downarrow.png', :alt => l(:label_sort_lowest)),  url.merge({"#{name}[move_to]" => 'lowest'}),  :method => :post, :title => l(:label_sort_lowest))
  end

  def breadcrumb(*args)
    elements = args.flatten
    elements.any? ? content_tag('p', args.join(' &#187; ') + ' &#187; ', :class => 'breadcrumb') : nil
  end
  
  def other_formats_links(&block)
    concat('<p class="other-formats">' + l(:label_export_to))
    yield Redmine::Views::OtherFormatsBuilder.new(self)
    concat('</p>')
  end
  
  def page_header_title
    if @project.nil? || @project.new_record?
      h(Setting.app_title)
    else
      b = []
      ancestors = (@project.root? ? [] : @project.ancestors.visible)
      if ancestors.any?
        root = ancestors.shift
        b << link_to(h(root), {:controller => 'projects', :action => 'show', :id => root, :jump => current_menu_item}, :class => 'root')
        if ancestors.size > 2
          b << '&#8230;'
          ancestors = ancestors[-2, 2]
        end
        b += ancestors.collect {|p| link_to(h(p), {:controller => 'projects', :action => 'show', :id => p, :jump => current_menu_item}, :class => 'ancestor') }
      end
      b << h(@project)
      b.join(' &#187; ')
    end
  end

  def html_title(*args)
    if args.empty?
      title = []
      title << @project.name if @project
      title += @html_title if @html_title
      title << Setting.app_title
      title.select {|t| !t.blank? }.join(' - ')
    else
      @html_title ||= []
      @html_title += args
    end
  end

  def accesskey(s)
    Redmine::AccessKeys.key_for s
  end

  # Formats text according to system settings.
  # 2 ways to call this method:
  # * with a String: textilizable(text, options)
  # * with an object and one of its attribute: textilizable(issue, :description, options)
  def textilizable(*args)
    options = args.last.is_a?(Hash) ? args.pop : {}
    case args.size
    when 1
      obj = options[:object]
      text = args.shift
    when 2
      obj = args.shift
      text = obj.send(args.shift).to_s
    else
      raise ArgumentError, 'invalid arguments to textilizable'
    end
    return '' if text.blank?

    only_path = options.delete(:only_path) == false ? false : true

    # when using an image link, try to use an attachment, if possible
    attachments = options[:attachments] || (obj && obj.respond_to?(:attachments) ? obj.attachments : nil)

    if attachments
      attachments = attachments.sort_by(&:created_on).reverse
      text = text.gsub(/!((\<|\=|\>)?(\([^\)]+\))?(\[[^\]]+\])?(\{[^\}]+\})?)(\S+\.(bmp|gif|jpg|jpeg|png))!/i) do |m|
        style = $1
        filename = $6.downcase
        # search for the picture in attachments
        if found = attachments.detect { |att| att.filename.downcase == filename }
          image_url = url_for :only_path => only_path, :controller => 'attachments', :action => 'download', :id => found
          desc = found.description.to_s.gsub(/^([^\(\)]*).*$/, "\\1")
          alt = desc.blank? ? nil : "(#{desc})"
          "!#{style}#{image_url}#{alt}!"
        else
          m
        end
      end
    end

    text = Redmine::WikiFormatting.to_html(Setting.text_formatting, text) { |macro, args| exec_macro(macro, obj, args) }

    # different methods for formatting wiki links
    case options[:wiki_links]
    when :local
      # used for local links to html files
      format_wiki_link = Proc.new {|project, title, anchor| "#{title}.html" }
    when :anchor
      # used for single-file wiki export
      format_wiki_link = Proc.new {|project, title, anchor| "##{title}" }
    else
      format_wiki_link = Proc.new {|project, title, anchor| url_for(:only_path => only_path, :controller => 'wiki', :action => 'index', :id => project, :page => title, :anchor => anchor) }
    end

    project = options[:project] || @project || (obj && obj.respond_to?(:project) ? obj.project : nil)

    # Wiki links
    #
    # Examples:
    #   [[mypage]]
    #   [[mypage|mytext]]
    # wiki links can refer other project wikis, using project name or identifier:
    #   [[project:]] -> wiki starting page
    #   [[project:|mytext]]
    #   [[project:mypage]]
    #   [[project:mypage|mytext]]
    text = text.gsub(/(!)?(\[\[([^\]\n\|]+)(\|([^\]\n\|]+))?\]\])/) do |m|
      link_project = project
      esc, all, page, title = $1, $2, $3, $5
      if esc.nil?
        if page =~ /^([^\:]+)\:(.*)$/
          link_project = Project.find_by_name($1) || Project.find_by_identifier($1)
          page = $2
          title ||= $1 if page.blank?
        end

        if link_project && link_project.wiki
          # extract anchor
          anchor = nil
          if page =~ /^(.+?)\#(.+)$/
            page, anchor = $1, $2
          end
          # check if page exists
          wiki_page = link_project.wiki.find_page(page)
          link_to((title || page), format_wiki_link.call(link_project, Wiki.titleize(page), anchor),
                                   :class => ('wiki-page' + (wiki_page ? '' : ' new')))
        else
          # project or wiki doesn't exist
          all
        end
      else
        all
      end
    end

    # Redmine links
    #
    # Examples:
    #   Issues:
    #     #52 -> Link to issue #52
    #   Changesets:
    #     r52 -> Link to revision 52
    #     commit:a85130f -> Link to scmid starting with a85130f
    #   Documents:
    #     document#17 -> Link to document with id 17
    #     document:Greetings -> Link to the document with title "Greetings"
    #     document:"Some document" -> Link to the document with title "Some document"
    #   Versions:
    #     version#3 -> Link to version with id 3
    #     version:1.0.0 -> Link to version named "1.0.0"
    #     version:"1.0 beta 2" -> Link to version named "1.0 beta 2"
    #   Attachments:
    #     attachment:file.zip -> Link to the attachment of the current object named file.zip
    #   Source files:
    #     source:some/file -> Link to the file located at /some/file in the project's repository
    #     source:some/file@52 -> Link to the file's revision 52
    #     source:some/file#L120 -> Link to line 120 of the file
    #     source:some/file@52#L120 -> Link to line 120 of the file's revision 52
    #     export:some/file -> Force the download of the file
    #  Forum messages:
    #     message#1218 -> Link to message with id 1218
    text = text.gsub(%r{([\s\(,\-\>]|^)(!)?(attachment|document|version|commit|source|export|message)?((#|r)(\d+)|(:)([^"\s<>][^\s<>]*?|"[^"]+?"))(?=(?=[[:punct:]]\W)|,|\s|<|$)}) do |m|
      leading, esc, prefix, sep, identifier = $1, $2, $3, $5 || $7, $6 || $8
      link = nil
      if esc.nil?
        if prefix.nil? && sep == 'r'
          if project && (changeset = project.changesets.find_by_revision(identifier))
            link = link_to("r#{identifier}", {:only_path => only_path, :controller => 'repositories', :action => 'revision', :id => project, :rev => changeset.revision},
                                      :class => 'changeset',
                                      :title => truncate_single_line(changeset.comments, :length => 100))
          end
        elsif sep == '#'
          oid = identifier.to_i
          case prefix
          when nil
            if issue = Issue.visible.find_by_id(oid, :include => :status)
              link = link_to("##{oid}", {:only_path => only_path, :controller => 'issues', :action => 'show', :id => oid},
                                        :class => issue.css_classes,
                                        :title => "#{truncate(issue.subject, :length => 100)} (#{issue.status.name})")
            end
          when 'document'
            if document = Document.find_by_id(oid, :include => [:project], :conditions => Project.visible_by(User.current))
              link = link_to h(document.title), {:only_path => only_path, :controller => 'documents', :action => 'show', :id => document},
                                                :class => 'document'
            end
          when 'version'
            if version = Version.find_by_id(oid, :include => [:project], :conditions => Project.visible_by(User.current))
              link = link_to h(version.name), {:only_path => only_path, :controller => 'versions', :action => 'show', :id => version},
                                              :class => 'version'
            end
          when 'message'
            if message = Message.find_by_id(oid, :include => [:parent, {:board => :project}], :conditions => Project.visible_by(User.current))
              link = link_to h(truncate(message.subject, :length => 60)), {:only_path => only_path,
                                                                :controller => 'messages',
                                                                :action => 'show',
                                                                :board_id => message.board,
                                                                :id => message.root,
                                                                :anchor => (message.parent ? "message-#{message.id}" : nil)},
                                                 :class => 'message'
            end
          end
        elsif sep == ':'
          # removes the double quotes if any
          name = identifier.gsub(%r{^"(.*)"$}, "\\1")
          case prefix
          when 'document'
            if project && document = project.documents.find_by_title(name)
              link = link_to h(document.title), {:only_path => only_path, :controller => 'documents', :action => 'show', :id => document},
                                                :class => 'document'
            end
          when 'version'
            if project && version = project.versions.find_by_name(name)
              link = link_to h(version.name), {:only_path => only_path, :controller => 'versions', :action => 'show', :id => version},
                                              :class => 'version'
            end
          when 'commit'
            if project && (changeset = project.changesets.find(:first, :conditions => ["scmid LIKE ?", "#{name}%"]))
              link = link_to h("#{name}"), {:only_path => only_path, :controller => 'repositories', :action => 'revision', :id => project, :rev => changeset.revision},
                                           :class => 'changeset',
                                           :title => truncate_single_line(changeset.comments, :length => 100)
            end
          when 'source', 'export'
            if project && project.repository
              name =~ %r{^[/\\]*(.*?)(@([0-9a-f]+))?(#(L\d+))?$}
              path, rev, anchor = $1, $3, $5
              link = link_to h("#{prefix}:#{name}"), {:controller => 'repositories', :action => 'entry', :id => project,
                                                      :path => to_path_param(path),
                                                      :rev => rev,
                                                      :anchor => anchor,
                                                      :format => (prefix == 'export' ? 'raw' : nil)},
                                                     :class => (prefix == 'export' ? 'source download' : 'source')
            end
          when 'attachment'
            if attachments && attachment = attachments.detect {|a| a.filename == name }
              link = link_to h(attachment.filename), {:only_path => only_path, :controller => 'attachments', :action => 'download', :id => attachment},
                                                     :class => 'attachment'
            end
          end
        end
      end
      leading + (link || "#{prefix}#{sep}#{identifier}")
    end

    text
  end

  # Same as Rails' simple_format helper without using paragraphs
  def simple_format_without_paragraph(text)
    text.to_s.
      gsub(/\r\n?/, "\n").                    # \r\n and \r -> \n
      gsub(/\n\n+/, "<br /><br />").          # 2+ newline  -> 2 br
      gsub(/([^\n]\n)(?=[^\n])/, '\1<br />')  # 1 newline   -> br
  end

  def lang_options_for_select(blank=true)
    (blank ? [["(auto)", ""]] : []) +
      valid_languages.collect{|lang| [ ll(lang.to_s, :general_lang_name), lang.to_s]}.sort{|x,y| x.last <=> y.last }
  end

  def label_tag_for(name, option_tags = nil, options = {})
    label_text = l(("field_"+field.to_s.gsub(/\_id$/, "")).to_sym) + (options.delete(:required) ? @template.content_tag("span", " *", :class => "required"): "")
    content_tag("label", label_text)
  end

  def labelled_tabular_form_for(name, object, options, &proc)
    options[:html] ||= {}
    options[:html][:class] = 'tabular' unless options[:html].has_key?(:class)
    form_for(name, object, options.merge({ :builder => TabularFormBuilder, :lang => current_language}), &proc)
  end

  def back_url_hidden_field_tag
    back_url = params[:back_url] || request.env['HTTP_REFERER']
    back_url = CGI.unescape(back_url.to_s)
    hidden_field_tag('back_url', CGI.escape(back_url)) unless back_url.blank?
  end

  def check_all_links(form_name)
    link_to_function(l(:button_check_all), "checkAll('#{form_name}', true)") +
    " | " +
    link_to_function(l(:button_uncheck_all), "checkAll('#{form_name}', false)")
  end

  def progress_bar(pcts, options={})
    pcts = [pcts, pcts] unless pcts.is_a?(Array)
    pcts = pcts.collect(&:round)
    pcts[1] = pcts[1] - pcts[0]
    pcts << (100 - pcts[1] - pcts[0])
    width = options[:width] || '100px;'
    legend = options[:legend] || ''
    content_tag('table',
      content_tag('tr',
        (pcts[0] > 0 ? content_tag('td', '', :style => "width: #{pcts[0]}%;", :class => 'closed') : '') +
        (pcts[1] > 0 ? content_tag('td', '', :style => "width: #{pcts[1]}%;", :class => 'done') : '') +
        (pcts[2] > 0 ? content_tag('td', '', :style => "width: #{pcts[2]}%;", :class => 'todo') : '')
      ), :class => 'progress', :style => "width: #{width};") +
      content_tag('p', legend, :class => 'pourcent')
  end

  def context_menu_link(name, url, options={})
    options[:class] ||= ''
    if options.delete(:selected)
      options[:class] << ' icon-checked disabled'
      options[:disabled] = true
    end
    if options.delete(:disabled)
      options.delete(:method)
      options.delete(:confirm)
      options.delete(:onclick)
      options[:class] << ' disabled'
      url = '#'
    end
    link_to name, url, options
  end

  def calendar_for(field_id)
    include_calendar_headers_tags
    image_tag("calendar.png", {:id => "#{field_id}_trigger",:class => "calendar-trigger"}) +
    javascript_tag("Calendar.setup({inputField : '#{field_id}', ifFormat : '%Y-%m-%d', button : '#{field_id}_trigger' });")
  end

  def include_calendar_headers_tags
    unless @calendar_headers_tags_included
      @calendar_headers_tags_included = true
      content_for :header_tags do
        start_of_week = case Setting.start_of_week.to_i
        when 1
          'Calendar._FD = 1;' # Monday
        when 7
          'Calendar._FD = 0;' # Sunday
        else
          '' # use language
        end
        
        javascript_include_tag('calendar/calendar') +
        javascript_include_tag("calendar/lang/calendar-#{current_language.to_s.downcase}.js") +
        javascript_tag(start_of_week) +  
        javascript_include_tag('calendar/calendar-setup') +
        stylesheet_link_tag('calendar')
      end
    end
  end

  def content_for(name, content = nil, &block)
    @has_content ||= {}
    @has_content[name] = true
    super(name, content, &block)
  end

  def has_content?(name)
    (@has_content && @has_content[name]) || false
  end

  # Returns the avatar image tag for the given +user+ if avatars are enabled
  # +user+ can be a User or a string that will be scanned for an email address (eg. 'joe <joe@foo.bar>')
  def avatar(user, options = { })
    if Setting.gravatar_enabled?
      options.merge!({:ssl => Setting.protocol == 'https', :default => Setting.gravatar_default})
      email = nil
      if user.respond_to?(:mail)
        email = user.mail
      elsif user.to_s =~ %r{<(.+?)>}
        email = $1
      end
      return gravatar(email.to_s.downcase, options) unless email.blank? rescue nil
    end
  end

  private

  def wiki_helper
    helper = Redmine::WikiFormatting.helper_for(Setting.text_formatting)
    extend helper
    return self
  end
  
  def link_to_remote_content_update(text, url_params)
    link_to_remote(text,
      {:url => url_params, :method => :get, :update => 'content', :complete => 'window.scrollTo(0,0)'},
      {:href => url_for(:params => url_params)}
    )
  end
  
end
