##
# This is yet another library to convert an ActiveRecord array (or any struct) 
# to an HTML table.
#
# You get a table with a bunch of CSS classes automatically applied (or 
# customize it with your own classes and ids). For example, first_row (is also
# a th tag), first_column, last_column, even & odd (for rows).
#
# Other tags like thead and tbody may be added in the future.
#
# Simple example with an ActiveRecord object:
#
#   <%= TidyTable.new(@records).to_html(%w(title description created_at)) %>
#
# You also format the row values with a block:
#
#   <%= TidyTable.new(@records, :table_class => "revenue_report").to_html(%w(resource visits min max)) do |row|
#     [
#       row.resource,
#       number_with_delimiter(row.visit_count),
#       row.min,
#       row.max
#     ]
#   end %>
#
# Or in HAML:
#
#   = TidyTable.new(@records, :table_class => "revenue_report").to_html(%w(resource visits min max)) do |row|
#     - [ row.resource, number_with_delimiter(row.visit_count), row.min, row.max ]

class TidyTable

  VERSION = '0.0.5'

  ##
  # Make a new TidyTable with a data array and CSS options.
  #
  # * :table_class -- Defaults to 'tidy_table'
  # * :first_row_class -- Defaults to 'first_row'
  # * :first_column_class -- Defaults to 'first_column'
  # * :last_column_class -- Defaults to 'last_column'
  # * :title -- Title for this table. Emits an extra header row 
  #             spanning all columns.
  # * :title_class -- CSS class for the title th. Default: 'title'
  #
  # You also get 'even' and 'odd' for free (rows only).
  
  def initialize(array, options={})
    @rows = array
    @options = {
      :table_class => "tidy_table",
      :first_row_class => "first_row",
      :first_column_class => "first_column",
      :last_column_class => "last_column",
      :title_class => "title"
    }.merge(options)
  end

  ##
  # First argument is an array of column names.
  # Will also be called as methods on each row object if no block is provided.
  #
  # If given, a block will be called for each row of the array. You should
  # return an Array with the values formatted in the format that you want to see
  # in the resulting cells.
  #
  # Or, return a Hash where
  #
  #   :data  => ['contents', 'for', 'cells'],
  #   :id    => 'id_for_this_row',
  #   :class => 'extra_classes for_this row'

  def to_html(fields)      
    output = []
    output << %(<table class="#{@options[:table_class]}">)

    # Title
    if @options.has_key?(:title)
      output << %(<tr class="#{@options[:first_row_class]}">)
      output << %(<th class="#{@options[:title_class]} #{@options[:first_row_class]} #{@options[:first_column_class]}" colspan="#{fields.length}">#{@options[:title]}</th>)
      output << %(</tr>)
    end

    # First row (header)
    output << %(<tr class="#{@options[:first_row_class]}">)
    fields.each_with_index do |field, index|
      output << %(<th class="#{@options[:first_row_class]} #{column_classes(fields, index)}">#{field}</th>)
    end
    output << "</tr>"

    @rows.each_with_index do |row, row_index|
      if block_given?
        yield_output = yield(row)

        data = []
        row_options = {}
        case yield_output
        when Array
          data = yield_output
        when Hash
          data = yield_output.delete(:data)
          row_options = yield_output
        else
          raise ArgumentError, "TidyTable block expects an Array or Hash, but a #{yield_output.class} was returned."
        end

        row_classes = [row_index % 2 == 0 ? 'even': 'odd', row_options[:class]].select {|i| !i.nil?}.join(' ')
        output << %(<tr class="#{row_classes}" #{"id=\"#{row_options[:id]}\"" if row_options.has_key?(:id)}>)
        data.each_with_index do |item, index|
          output << %(<td class="#{column_classes(data, index)}">#{item}</td>)
        end
      else
        output << %(<tr class="#{row_index % 2 == 0 ? 'even': 'odd'}">)
        fields.each_with_index do |field, index|
          output << %(<td class="#{column_classes(fields, index)}">#{row.send(field.to_sym)}</td>)
        end
      end
      output << "</tr>"
    end
    output << "</table>"
    output.join
  end

  private
  
  ##
  # Returns "first_column", "last_column", or both.
  #
  # additional_class_names is a string of other class names to append to the 
  # autogenerated classes.
  
  def column_classes(fields_array, index, additional_class_names=nil)
    classes = (index == 0 ? @options[:first_column_class] : '')
    classes += (index == fields_array.length - 1 ? @options[:last_column_class] : '')
    if additional_class_names
      classes += " " + additional_class_names
    end
    classes
  end
  
end