#!/usr/bin/env ruby

begin
  $:.unshift(File.expand_path("../lib", __dir__))
  require "active_support"
rescue IOError
end

require "open-uri"
require "tmpdir"
require "fileutils"

module ActiveSupport
  module Multibyte
    module Unicode
      class UnicodeDatabase
        def load; end
      end

      class DatabaseGenerator
        BASE_URI = "http://www.unicode.org/Public/#{UNICODE_VERSION}/ucd/"
        SOURCES = {
          codepoints: BASE_URI + "UnicodeData.txt",
          composition_exclusion: BASE_URI + "CompositionExclusions.txt",
          grapheme_break_property: BASE_URI + "auxiliary/GraphemeBreakProperty.txt",
          cp1252: "http://unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WINDOWS/CP1252.TXT"
        }

        def initialize
          @ucd = Unicode::UnicodeDatabase.new
        end

        def parse_codepoints(line)
          codepoint = Codepoint.new
          raise "Could not parse input." unless line =~ /^
            ([0-9A-F]+);        # code
            ([^;]+);            # name
            ([A-Z]+);           # general category
            ([0-9]+);           # canonical combining class
            ([A-Z]+);           # bidi class
            (<([A-Z]*)>)?       # decomposition type
            ((\ ?[0-9A-F]+)*);  # decomposition mapping
            ([0-9]*);           # decimal digit
            ([0-9]*);           # digit
            ([^;]*);            # numeric
            ([YN]*);            # bidi mirrored
            ([^;]*);            # unicode 1.0 name
            ([^;]*);            # iso comment
            ([0-9A-F]*);        # simple uppercase mapping
            ([0-9A-F]*);        # simple lowercase mapping
            ([0-9A-F]*)$/ix     # simple titlecase mapping
          codepoint.code              = $1.hex
          codepoint.combining_class   = Integer($4)
          codepoint.decomp_type       = $7
          codepoint.decomp_mapping    = ($8 == "") ? nil : $8.split.collect(&:hex)
          codepoint.uppercase_mapping = ($16 == "") ? 0 : $16.hex
          codepoint.lowercase_mapping = ($17 == "") ? 0 : $17.hex
          @ucd.codepoints[codepoint.code] = codepoint
        end

        def parse_grapheme_break_property(line)
          if line =~ /^([0-9A-F.]+)\s*;\s*([\w]+)\s*#/
            type = $2.downcase.intern
            @ucd.boundary[type] ||= []
            if $1.include? ".."
              parts = $1.split ".."
              @ucd.boundary[type] << (parts[0].hex..parts[1].hex)
            else
              @ucd.boundary[type] << $1.hex
            end
          end
        end

        def parse_composition_exclusion(line)
          if line =~ /^([0-9A-F]+)/i
            @ucd.composition_exclusion << $1.hex
          end
        end

        def parse_cp1252(line)
          if line =~ /^([0-9A-Fx]+)\s([0-9A-Fx]+)/i
            @ucd.cp1252[$1.hex] = $2.hex
          end
        end

        def create_composition_map
          @ucd.codepoints.each do |_, cp|
            if !cp.nil? && cp.combining_class == 0 && cp.decomp_type.nil? && !cp.decomp_mapping.nil? && cp.decomp_mapping.length == 2 && @ucd.codepoints[cp.decomp_mapping[0]].combining_class == 0 && !@ucd.composition_exclusion.include?(cp.code)
              @ucd.composition_map[cp.decomp_mapping[0]] ||= {}
              @ucd.composition_map[cp.decomp_mapping[0]][cp.decomp_mapping[1]] = cp.code
            end
          end
        end

        def normalize_boundary_map
          @ucd.boundary.each do |k, v|
            if [:lf, :cr].include? k
              @ucd.boundary[k] = v[0]
            end
          end
        end

        def parse
          SOURCES.each do |type, url|
            filename = File.join(Dir.tmpdir, UNICODE_VERSION, "#{url.split('/').last}")
            unless File.exist?(filename)
              $stderr.puts "Downloading #{url.split('/').last}"
              FileUtils.mkdir_p(File.dirname(filename))
              File.open(filename, "wb") do |target|
                open(url) do |source|
                  source.each_line { |line| target.write line }
                end
              end
            end
            File.open(filename) do |file|
              file.each_line { |line| send "parse_#{type}".intern, line }
            end
          end
          create_composition_map
          normalize_boundary_map
        end

        def dump_to(filename)
          File.open(filename, "wb") do |f|
            f.write Marshal.dump([@ucd.codepoints, @ucd.composition_exclusion, @ucd.composition_map, @ucd.boundary, @ucd.cp1252])
          end
        end
      end
    end
  end
end

if __FILE__ == $0
  filename = ActiveSupport::Multibyte::Unicode::UnicodeDatabase.filename
  generator = ActiveSupport::Multibyte::Unicode::DatabaseGenerator.new
  generator.parse
  print "Writing to: #{filename}"
  generator.dump_to filename
  puts " (#{File.size(filename)} bytes)"
end