# encoding: UTF-8

# Copyright 2012 Twitter, Inc
# http://www.apache.org/licenses/LICENSE-2.0

module TwitterCldr
  module Shared

    CODE_POINT_FIELDS = [
      :code_point,
      :name,
      :category,
      :combining_class,
      :bidi_class,
      :decomposition,
      :digit_value,
      :non_decimal_digit_value,
      :numeric_value,
      :bidi_mirrored,
      :unicode1_name,
      :iso_comment,
      :simple_uppercase_map,
      :simple_lowercase_map,
      :simple_titlecase_map
    ]

    CodePoint = Struct.new(*CODE_POINT_FIELDS) do
      DECOMPOSITION_DATA_INDEX = 5

      def hangul_type
        CodePoint.hangul_type(code_point)
      end

      def excluded_from_composition?
        CodePoint.excluded_from_composition?(code_point)
      end

      class << self

        def for_hex(code_point)
          target = get_block(code_point.rjust(4, "0").upcase)

          if target && target.first
            block_data = TwitterCldr.get_resource(:unicode_data, target.first)
            code_point_data = block_data.fetch(code_point.to_sym) { |code_point_sym| get_range_start(code_point_sym, block_data) }
            CodePoint.new(*code_point_data) if code_point_data
          else
            nil
          end
        end

        def for_decomposition(code_points)
          @decomposition_map ||= TwitterCldr.get_resource(:unicode_data, :decomposition_map)
          key = code_points.join(" ").to_sym

          if @decomposition_map.include?(key)
            for_hex(@decomposition_map[key])
          else
            nil
          end
        end

        def hangul_type(code_point)
          if code_point
            code_point_int = code_point.hex
            [:lparts, :vparts, :tparts, :compositions, :decompositions].each do |type|
              hangul_blocks[type].each do |range|
                return type if range.include?(code_point_int)
              end
            end
          end
          nil
        end

        def excluded_from_composition?(code_point)
          code_point_int = code_point.hex
          composition_exclusions.any? { |excl| excl.include?(code_point_int) }
        end

        protected

        def hangul_blocks
          @hangul_blocks ||= TwitterCldr.get_resource(:unicode_data, :blocks_hangul)
        end

        def composition_exclusions
          @composition_exclusions ||= TwitterCldr.get_resource(:unicode_data, :composition_exclusions)
        end

        def get_block(code_point)
          blocks = TwitterCldr.get_resource(:unicode_data, :blocks)
          code_point_int = code_point.hex

          # Find the target block
          blocks.find do |block_name, range|
            range.include?(code_point_int)
          end
        end

        # Check if block constitutes a range. The code point beginning a range will have a name enclosed in <>, ending with 'First'
        # eg: <CJK Ideograph Extension A, First>
        # http://unicode.org/reports/tr44/#Code_Point_Ranges
        def get_range_start(code_point, block_data)
          start_code_point = block_data.keys.sort_by { |key| key.to_s.hex }.first
          start_data = block_data[start_code_point].clone
          if start_data[1] =~ /<.*, First>/
            start_data[0] = code_point.to_s
            start_data[1] = start_data[1].sub(', First', '')
            start_data
          end
        end

      end
    end
  end
end