require 'table_helper/cell'

module PluginAWeek #:nodoc:
  module TableHelper
    # Provides a blank class that can be used to build the cells for a row
    class RowBuilder < BlankSlate
      reveal :respond_to?
      
      attr_reader :row
      
      # Creates a builder for the given row
      def initialize(row)
        @row = row
      end
      
      # Proxies all missed methods to the row
      def method_missing(*args)
        row.send(*args)
      end
      
      # Defines the builder method for the given cell name.  For example, if
      # a cell with the name :title was defined, then the cell would be able
      # to be read and written like so:
      # 
      #   row.title               #=> Accesses the title
      #   row.title "Page Title"  #=> Creates a new cell with "Page Title" as the content
      def define_cell(name)
        method_name = name.gsub('-', '_')
        
        klass = class << self; self; end
        klass.class_eval do
          define_method(method_name) do |*args|
            if args.empty?
              row.cells[name]
            else
              row.cell(name, *args)
            end
          end
        end unless klass.method_defined?(method_name)
      end
      
      # Removes the definition for the given cell
      def undef_cell(name)
        method_name = name.gsub('-', '_')
        
        klass = class << self; self; end
        klass.class_eval do
          remove_method(method_name)
        end
      end
    end
    
    # Represents a single row within a table.  A row can consist of either
    # data cells or header cells.
    class Row < HtmlElement
      # The proxy class used externally to build the actual cells
      attr_reader :builder
      
      # The current cells in this row, in the order in which they will be built
      attr_reader :cells
      
      def initialize #:nodoc:
        super
        
        @cells = ActiveSupport::OrderedHash.new
        @builder = RowBuilder.new(self)
      end
      
      # Creates a new cell with the given name and generates shortcut
      # accessors for the method.
      def cell(name, *args)
        name = name.to_s if name
        
        cell = Cell.new(name, *args)
        cells[name] = cell
        builder.define_cell(name) if name
        
        cell
      end
      
      # The names of all cells in this row
      def cell_names
        cells.keys
      end
      
      # Clears all of the current cells from the row
      def clear
        # Remove all of the shortcut methods
        cell_names.each {|name| builder.undef_cell(name)}
        cells.clear
      end
      
      private
        def tag_name
          'tr'
        end
        
        def content
          cells.values.map(&:html).join
        end
    end
  end
end