module Rugments
  module Lexers
    class Lua < RegexLexer
      title 'Lua'
      desc 'Lua (http://www.lua.org)'
      tag 'lua'
      filenames '*.lua', '*.wlua'

      mimetypes 'text/x-lua', 'application/x-lua'

      def initialize(opts = {})
        @function_highlighting = opts.delete(:function_highlighting) { true }
        @disabled_modules = opts.delete(:disabled_modules) { [] }
        super(opts)
      end

      def self.analyze_text(text)
        return 1 if text.shebang? 'lua'
      end

      def self.builtins
        load Pathname.new(__FILE__).dirname.join('lua/builtins.rb')
        builtins
      end

      def builtins
        return [] unless @function_highlighting

        @builtins ||= Set.new.tap do |builtins|
          self.class.builtins.each do |mod, fns|
            next if @disabled_modules.include? mod
            builtins.merge(fns)
          end
        end
      end

      state :root do
        # lua allows a file to start with a shebang
        rule %r{#!(.*?)$}, Comment::Preproc
        rule //, Text, :base
      end

      state :base do
        rule %r{--\[(=*)\[.*?\]\1\]}m, Comment::Multiline
        rule %r{--.*$}, Comment::Single

        rule %r{(?i)(\d*\.\d+|\d+\.\d*)(e[+-]?\d+)?'}, Num::Float
        rule %r{(?i)\d+e[+-]?\d+}, Num::Float
        rule %r{(?i)0x[0-9a-f]*}, Num::Hex
        rule %r{\d+}, Num::Integer

        rule %r{\n}, Text
        rule %r{[^\S\n]}, Text
        # multiline strings
        rule %r{\[(=*)\[.*?\]\1\]}m, Str

        rule %r{(==|~=|<=|>=|\.\.\.|\.\.|[=+\-*/%^<>#])}, Operator
        rule %r([\[\]\{\}\(\)\.,:;]), Punctuation
        rule %r{(and|or|not)\b}, Operator::Word

        rule %r{(break|do|else|elseif|end|for|if|in|repeat|return|then|until|while)\b}, Keyword
        rule %r{(local)\b}, Keyword::Declaration
        rule %r{(true|false|nil)\b}, Keyword::Constant

        rule %r{(function)\b}, Keyword, :function_name

        rule %r{[A-Za-z_][A-Za-z0-9_]*(\.[A-Za-z_][A-Za-z0-9_]*)?} do |m|
          name = m[0]
          if self.builtins.include?(name)
            token Name::Builtin
          elsif name =~ /\./
            a, b = name.split('.', 2)
            token Name, a
            token Punctuation, '.'
            token Name, b
          else
            token Name
          end
        end

        rule %r{'}, Str::Single, :escape_sqs
        rule %r{"}, Str::Double, :escape_dqs
      end

      state :function_name do
        rule /\s+/, Text
        rule %r{(?:([A-Za-z_][A-Za-z0-9_]*)(\.))?([A-Za-z_][A-Za-z0-9_]*)} do
          groups Name::Class, Punctuation, Name::Function
          pop!
        end
        # inline function
        rule %r{\(}, Punctuation, :pop!
      end

      state :escape_sqs do
        mixin :string_escape
        mixin :sqs
      end

      state :escape_dqs do
        mixin :string_escape
        mixin :dqs
      end

      state :string_escape do
        rule %r(\\([abfnrtv\\"']|\d{1,3})), Str::Escape
      end

      state :sqs do
        rule %r{'}, Str::Single, :pop!
        rule %r{[^']+}, Str::Single
      end

      state :dqs do
        rule %r{"}, Str::Double, :pop!
        rule %r{[^"]+}, Str::Double
      end
    end
  end
end
