# -*- coding: utf-8 -*- #
# frozen_string_literal: true

require_relative "../task_helper"

VIML_KEYWORDS_FILE = "./lib/rouge/lexers/viml/keywords.rb"

namespace :builtins do
  task :viml do
    VimLBuiltins.process(VIML_KEYWORDS_FILE)
  end
end

class VimLBuiltins < BuiltinsGenerator
  VIML_SYNTAX_URI = "https://raw.githubusercontent.com/vim/vim/master/runtime/syntax/vim.vim"

  def fetch
    URI.open(VIML_SYNTAX_URI) { |f| f.read }
  end

  def parse
    keywords = Hash.new { |h,k| h[k] = Set.new }

    @input.each_line do |line|
      line =~ %r(^
        (?: syn[ ]keyword[ ](vim(?:AutoEvent|Command|FuncName|Option))[ ]contained )
        (.*)
      $)x

      next unless $1

      name = $1
      functions = $2

      key = case name
            when "vimAutoEvent"
              :auto
            when "vimCommand"
              :command
            when "vimFuncName"
              :function
            when "vimOption"
              :option
            end

      functions.scan(/([\w:]+)(?:\[(\w+)\])?/) do
        keywords[key].merge [$1, "#{$1}#{$2}"]
      end
    end

    keywords.transform_values { |v| v.sort.uniq }
  end

  def generate
    yield   "# -*- coding: utf-8 -*- #"
    yield   "# frozen_string_literal: true"
    yield   ""
    yield   "# DO NOT EDIT"
    yield   "# This file is automatically generated by `rake builtins:viml`."
    yield   "# See tasks/builtins/viml.rake for more info."
    yield   ""
    yield   "module Rouge"
    yield   "  module Lexers"
    yield   "    class VimL"
    yield   "      KEYWORDS = {}.tap do |kw|"
    @keywords.each do |k,v|
      yield "          kw[#{k.inspect}] = Set.new #{v.to_a.inspect}"
    end
    yield   "      end"
    yield   "    end"
    yield   "  end"
    yield   "end"
  end
end
