# coding: utf-8

require 'highline/template_renderer'
require 'highline/wrapper'
require 'highline/list'

#
# This class is a utility for quickly and easily laying out lists
# to be used by HighLine.
#
class HighLine::ListRenderer
  # Items list
  # @return [Array]
  attr_reader :items

  # @return [Symbol] the current mode the List is being rendered
  # @see #initialize for more details see mode parameter of #initialize
  attr_reader :mode

  # Changes the behaviour of some modes. Example, in :inline mode
  # the option is treated as the 'end separator' (defaults to " or ")
  # @return option parameter that changes the behaviour of some modes.
  attr_reader :option

  # @return [HighLine] context
  attr_reader :highline

  # The only required parameters are _items_ and _highline_.
  # @param items [Array] the Array of items to list
  # @param mode [Symbol] controls how that list is formed
  # @param option has different effects, depending on the _mode_.
  # @param highline [HighLine] a HighLine instance to direct the output to.
  #
  # Recognized modes are:
  #
  # <tt>:columns_across</tt>::         _items_ will be placed in columns,
  #                                    flowing from left to right.  If given,
  #                                    _option_ is the number of columns to be
  #                                    used.  When absent, columns will be
  #                                    determined based on _wrap_at_ or a
  #                                    default of 80 characters.
  # <tt>:columns_down</tt>::           Identical to <tt>:columns_across</tt>,
  #                                    save flow goes down.
  # <tt>:uneven_columns_across</tt>::  Like <tt>:columns_across</tt> but each
  #                                    column is sized independently.
  # <tt>:uneven_columns_down</tt>::    Like <tt>:columns_down</tt> but each
  #                                    column is sized independently.
  # <tt>:inline</tt>::                 All _items_ are placed on a single line.
  #                                    The last two _items_ are separated by
  #                                    _option_ or a default of " or ".  All
  #                                    other _items_ are separated by ", ".
  # <tt>:rows</tt>::                   The default mode.  Each of the _items_ is
  #                                    placed on its own line.  The _option_
  #                                    parameter is ignored in this mode.
  #
  # Each member of the _items_ Array is passed through ERb and thus can contain
  # their own expansions.  Color escape expansions do not contribute to the
  # final field width.

  def initialize(items, mode = :rows, option = nil, highline)
    @highline = highline
    @mode     = mode
    @option   = option
    @items    = render_list_items(items)
  end

  # Render the list using the appropriate mode and options.
  # @return [String] rendered list as String
  def render
    return "" if items.empty?

    case mode
    when :inline
      list_inline_mode
    when :columns_across
      list_columns_across_mode
    when :columns_down
      list_columns_down_mode
    when :uneven_columns_across
      list_uneven_columns_mode
    when :uneven_columns_down
      list_uneven_columns_down_mode
    else
      list_default_mode
    end
  end

  private

  def render_list_items(items)
    items.to_ary.map do |item|
      item = String(item)
      template = ERB.new(item, nil, "%")
      template_renderer = HighLine::TemplateRenderer.new(template, self, highline)
      template_renderer.render
    end
  end

  def list_default_mode
    items.map { |i| "#{i}\n" }.join
  end

  def list_inline_mode
    end_separator = option || " or "

    if items.size == 1
      items.first
    else
      items[0..-2].join(", ") + "#{end_separator}#{items.last}"
    end
  end

  def list_columns_across_mode
    HighLine::List.new(right_padded_items, cols: col_count).to_s
  end

  def list_columns_down_mode
    HighLine::List.new(right_padded_items, cols: col_count, col_down: true).to_s
  end

  def list_uneven_columns_mode(list=nil)
    list ||= HighLine::List.new(items)

    col_max = option || items.size
    col_max.downto(1) do |column_count|
      list.cols = column_count
      widths = get_col_widths(list)

      if column_count == 1 or # last guess
        inside_line_size_limit?(widths) or # good guess
        option # defined by user
        return pad_uneven_rows(list, widths)
      end
    end
  end

  def list_uneven_columns_down_mode
    list = HighLine::List.new(items, col_down: true)
    list_uneven_columns_mode(list)
  end

  def pad_uneven_rows(list, widths)
    right_padded_list = Array(list).map do |row|
      right_pad_row(row.compact, widths)
    end
    stringfy_list(right_padded_list)
  end

  def stringfy_list(list)
    list.map { |row| row_to_s(row) }.join
  end

  def row_to_s(row)
    row.compact.join(row_join_string) + "\n"
  end

  def right_pad_row(row, widths)
    row.zip(widths).map do |field, width|
      right_pad_field(field, width)
    end
  end

  def right_pad_field(field, width)
    field = String(field) # nil protection
    pad_size = width - actual_length(field)
    field + (pad_char * pad_size)
  end

  def get_col_widths(lines)
    lines = transpose(lines)
    get_segment_widths(lines)
  end

  def get_row_widths(lines)
    get_segment_widths(lines)
  end

  def get_segment_widths(lines)
    lines.map do |col|
      actual_lengths_for(col).max
    end
  end

  def actual_lengths_for(line)
    line.map do |item|
      actual_length(item)
    end
  end

  def transpose(lines)
    lines = Array(lines)
    first_line = lines.shift
    first_line.zip(*lines)
  end

  def inside_line_size_limit?(widths)
    line_size = widths.inject(0) { |sum, n| sum + n + row_join_str_size }
    line_size <= line_size_limit + row_join_str_size
  end

  def actual_length(text)
    HighLine::Wrapper.actual_length text
  end

  def items_max_length
    @items_max_length ||= max_length(items)
  end

  def max_length(items)
    items.map { |item| actual_length(item) }.max
  end

  def line_size_limit
    @line_size_limit ||= ( highline.wrap_at || 80 )
  end

  def row_join_string
    @row_join_string ||= "  "
  end

  def row_join_string=(string)
    @row_join_string = string
  end

  def row_join_str_size
    row_join_string.size
  end

  def get_col_count
    (line_size_limit + row_join_str_size) /
      (items_max_length + row_join_str_size)
  end

  def col_count
    option || get_col_count
  end

  def right_padded_items
    items.map do |item|
      right_pad_field(item, items_max_length)
    end
  end

  def pad_char
    " "
  end

  def row_count
    (items.count / col_count.to_f).ceil
  end
end