module Padrino
  module Helpers
    module AssetTagHelpers

      ##
      # Creates a div to display the flash of given type if it exists
      # 
      # Examples:
      # 
      #   flash_tag(:notice, :class => 'flash', :id => 'flash-notice')
      def flash_tag(kind, options={})
        flash_text = flash[kind]
        return '' if flash_text.blank?
        options.reverse_merge!(:class => 'flash')
        content_tag(:div, flash_text, options)
      end

      ##
      # Creates a link element with given name, url and options
      # 
      # Examples:
      # 
      #   link_to 'click me', '/dashboard', :class => 'linky'
      #   link_to 'click me', '/dashboard', :if => @foo.present?
      #   link_to 'click me', '/dashboard', :unless => @foo.empty?
      #   link_to 'click me', '/dashboard', :unless => :current
      #   link_to('/dashboard', :class => 'blocky') do ... end
      # 
      # Note that you can pass :+if+ or :+unless+ conditions, but if you provide :current as
      # condition padrino return true/false if the request.path_info match the given url
      # 
      def link_to(*args, &block)
        options = args.extract_options!
        anchor  = "##{CGI.escape options.delete(:anchor).to_s}" if options[:anchor]
        options["data-remote"] = "true" if options.delete(:remote)
        if block_given?
          url = args[0] ? args[0] + anchor.to_s : anchor || 'javascript:void(0);'
          options.reverse_merge!(:href => url)
          link_content = capture_html(&block)
          return name unless parse_conditions(url, options)
          result_link = content_tag(:a, link_content, options)
          block_is_template?(block) ? concat_content(result_link) : result_link
        else
          name, url = args[0], (args[1] ? args[1] + anchor.to_s : anchor || 'javascript:void(0);')
          return name unless parse_conditions(url, options)
          options.reverse_merge!(:href => url)
          content_tag(:a, name, options)
        end
      end

      ##
      # Creates a mail link element with given name and caption
      # 
      # Examples:
      #   mail_to "me@demo.com"             => <a href="mailto:me@demo.com">me@demo.com</a>
      #   mail_to "me@demo.com", "My Email" => <a href="mailto:me@demo.com">My Email</a>
      # 
      def mail_to(email, caption=nil, mail_options={})
        html_options = mail_options.slice!(:cc, :bcc, :subject, :body)
        mail_query = Rack::Utils.build_query(mail_options).gsub(/\+/, '%20').gsub('%40', '@')
        mail_href = "mailto:#{email}"; mail_href << "?#{mail_query}" if mail_query.present?
        link_to (caption || email), mail_href, html_options
      end

      ##
      # Creates a meta element with the content and given options
      # 
      # Examples:
      # 
      #   meta_tag "weblog,news", :name => "keywords"                         => <meta name="keywords" content="weblog,news">
      #   meta_tag "text/html; charset=UTF-8", :http-equiv => "Content-Type"  => <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
      # 
      def meta_tag(content, options={})
        options.reverse_merge!("content" => content)
        tag(:meta, options)
      end

      ##
      # Creates an image element with given url and options
      # 
      # Example:
      # 
      #   image_tag('icons/avatar.png')
      # 
      def image_tag(url, options={})
        options.reverse_merge!(:src => image_path(url))
        tag(:img, options)
      end

      ##
      # Returns an html script tag for each of the sources provided. 
      # You can pass in the filename without extension or a symbol and we search it in your +appname.public+ 
      # like app/public/stylesheets for inclusion. You can provide also a full path.
      # 
      # Example:
      # 
      #   stylesheet_link_tag 'style', 'application', 'layout'
      # 
      def stylesheet_link_tag(*sources)
        options = sources.extract_options!.symbolize_keys
        sources.collect { |sheet| stylesheet_tag(sheet, options) }.join("\n")
      end

      ##
      # Returns an html script tag for each of the sources provided. 
      # You can pass in the filename without extension or a symbol and we search it in your +appname.public+ 
      # like app/public/javascript for inclusion. You can provide also a full path.
      # 
      # Example:
      # 
      #   javascript_include_tag 'application', :extjs
      # 
      def javascript_include_tag(*sources)
        options = sources.extract_options!.symbolize_keys
        sources.collect { |script| javascript_tag(script, options) }.join("\n")
      end

      ##
      # Returns the path to the image, either relative or absolute. We search it in your +appname.public+ 
      # like app/public/images for inclusion. You can provide also a full path.
      # 
      # Example:
      # 
      #   image_path("foo.jpg") => "yourapp/public/images/foo.jpg" 
      # 
      def image_path(src)
        src.gsub!(/\s/, '')
        src =~ %r{^\s*(/|http)} ? src : uri_root_path('images', src)
      end

      protected
        # stylesheet_tag('style', :media => 'screen')
        def stylesheet_tag(source, options={})
          options = options.dup.reverse_merge!(:href => stylesheet_path(source), :media => 'screen', :rel => 'stylesheet', :type => 'text/css')
          tag(:link, options)
        end

        # javascript_tag 'application', :src => '/javascripts/base/application.js'
        def javascript_tag(source, options={})
          options = options.dup.reverse_merge!(:src => javascript_path(source), :type => 'text/javascript', :content => "")
          tag(:script, options)
        end

        # Returns the javascript_path appending the default javascripts path if necessary
        def javascript_path(source)
          return source if source =~ /^http/
          source        = source.to_s.gsub(/\.js$/, '')
          source_name   = source; source_name << ".js" unless source =~ /\.js/
          result_path   = source_name if source =~ %r{^/} # absolute path
          result_path ||= uri_root_path("javascripts", source_name)
          return result_path if result_path =~ /\?/
          public_path = Padrino.root("public", result_path)
          stamp = File.exist?(public_path) ? File.mtime(public_path).to_i : Time.now.to_i
          "#{result_path}?#{stamp}"
        end

        # Returns the stylesheet_path appending the default stylesheets path if necessary
        def stylesheet_path(source)
          return source if source =~ /^http/
          source        = source.to_s.gsub(/\.css$/, '')
          source_name   = source; source_name << ".css" unless source =~ /\.css/
          result_path   = source_name if source =~ %r{^/} # absolute path
          result_path ||= uri_root_path("stylesheets", source_name)
          return result_path if result_path =~ /\?/
          public_path   = Padrino.root("public", result_path)
          stamp         = File.exist?(public_path) ? File.mtime(public_path).to_i : Time.now.to_i
          "#{result_path}?#{stamp}"
        end

        # Returns the uri root of the application, defaulting to '/'
        def uri_root_path(*paths)
          root_uri = self.class.uri_root if self.class.respond_to?(:uri_root)
          File.join(root_uri || '/', *paths)
        end

        # Parse link_to options for give correct conditions
        def parse_conditions(url, options)
          if options.has_key?(:if)
            condition = options.delete(:if)
            condition == :current ? url == request.path_info : condition
          elsif condition = options.delete(:unless)
            condition == :current ? url != request.path_info : !condition
          else
            true
          end
        end
    end
  end
end