module Rouge
  module Lexers
    class Python < RegexLexer
      desc "The Python programming language (python.org)"
      tag 'python'
      aliases 'py'
      filenames '*.py', '*.pyw', '*.sc', 'SConstruct', 'SConscript', '*.tac'
      mimetypes 'text/x-python', 'application/x-python'

      def self.analyze_text(text)
        return 1 if text.shebang?(/pythonw?(3|2(\.\d)?)?/)
      end

      keywords = %w(
        assert break continue del elif else except exec
        finally for global if lambda pass print raise
        return try while yield as with
      )

      builtins = %w(
        __import__ abs all any apply basestring bin bool buffer
        bytearray bytes callable chr classmethod cmp coerce compile
        complex delattr dict dir divmod enumerate eval execfile exit
        file filter float frozenset getattr globals hasattr hash hex id
        input int intern isinstance issubclass iter len list locals
        long map max min next object oct open ord pow property range
        raw_input reduce reload repr reversed round set setattr slice
        sorted staticmethod str sum super tuple type unichr unicode
        vars xrange zip
      )

      builtins_pseudo = %w(self None Ellipsis NotImplemented False True)

      exceptions = %w(
        ArithmeticError AssertionError AttributeError
        BaseException DeprecationWarning EOFError EnvironmentError
        Exception FloatingPointError FutureWarning GeneratorExit IOError
        ImportError ImportWarning IndentationError IndexError KeyError
        KeyboardInterrupt LookupError MemoryError NameError
        NotImplemented NotImplementedError OSError OverflowError
        OverflowWarning PendingDeprecationWarning ReferenceError
        RuntimeError RuntimeWarning StandardError StopIteration
        SyntaxError SyntaxWarning SystemError SystemExit TabError
        TypeError UnboundLocalError UnicodeDecodeError
        UnicodeEncodeError UnicodeError UnicodeTranslateError
        UnicodeWarning UserWarning ValueError VMSError Warning
        WindowsError ZeroDivisionError
      )

      identifier =        /[a-z_][a-z0-9_]*/i
      dotted_identifier = /[a-z_.][a-z0-9_.]*/i
      state :root do
        rule /\n+/m, Text
        rule /^(:)(\s*)([ru]{,2}""".*?""")/mi do
          group Punctuation
          group Text
          group Str::Doc
        end

        rule /[^\S\n]+/, Text
        rule /#.*$/, Comment
        rule /[\[\]{}:(),;]/, Punctuation
        rule /\\\n/, Text
        rule /\\/, Text

        rule /(in|is|and|or|not)\b/, Operator::Word
        rule /!=|==|<<|>>|[-~+\/*%=<>&^|.]/, Operator

        rule /(?:#{keywords.join('|')})\b/, Keyword

        rule /(def)((?:\s|\\\s)+)/ do
          group Keyword # def
          group Text # whitespae
          push :funcname
        end

        rule /(class)((?:\s|\\\s)+)/ do
          group Keyword
          group Text
          push :classname
        end

        rule /(from)((?:\s|\\\s)+)/ do
          group Keyword::Namespace
          group Text
          push :fromimport
        end

        rule /(import)((?:\s|\\\s)+)/ do
          group Keyword::Namespace
          group Text
          push :import
        end

        # using negative lookbehind so we don't match property names
        rule /(?<!\.)(?:#{builtins.join('|')})/, Name::Builtin
        rule /(?<!\.)(?:#{builtins_pseudo.join('|')})/, Name::Builtin::Pseudo

        # TODO: not in python 3
        rule /`.*?`/, Str::Backtick
        rule /(?:r|ur|ru)"""/i, Str, :tdqs
        rule /(?:r|ur|ru)'''/i, Str, :tsqs
        rule /(?:r|ur|ru)"/i,   Str, :dqs
        rule /(?:r|ur|ru)'/i,   Str, :sqs
        rule /u?"""/i,          Str, :escape_tdqs
        rule /u?'''/i,          Str, :escape_tsqs
        rule /u?"/i,            Str, :escape_dqs
        rule /u?'/i,            Str, :escape_sqs

        rule /@#{dotted_identifier}/i, Name::Decorator
        rule identifier, Name

        rule /(\d+\.\d*|\d*\.\d+)(e[+-]?[0-9]+)?/i, Num::Float
        rule /\d+e[+-]?[0-9]+/i, Num::Float
        rule /0[0-7]+/, Num::Oct
        rule /0x[a-f0-9]+/i, Num::Hex
        rule /\d+L/, Num::Integer::Long
        rule /\d+/, Num::Integer
      end

      state :funcname do
        rule identifier, Name::Function, :pop!
      end

      state :classname do
        rule identifier, Name::Class, :pop!
      end

      state :import do
        # non-line-terminating whitespace
        rule /(?:[ \t]|\\\n)+/, Text

        rule /as\b/, Keyword::Namespace
        rule /,/, Operator
        rule dotted_identifier, Name::Namespace
        rule(//) { pop! } # anything else -> go back
      end

      state :fromimport do
        # non-line-terminating whitespace
        rule /(?:[ \t]|\\\n)+/, Text

        rule /import\b/, Keyword::Namespace, :pop!
        rule dotted_identifier, Name::Namespace
      end

      state :strings do
        rule /%(\([a-z0-9_]+\))?[-#0 +]*([0-9]+|[*])?(\.([0-9]+|[*]))?/i, Str::Interpol
      end

      state :strings_double do
        rule /[^\\"%\n]+/, Str
        mixin :strings
      end

      state :strings_single do
        rule /[^\\'%\n]+/, Str
        mixin :strings
      end

      state :nl do
        rule /\n/, Str
      end

      state :escape do
        rule %r(\\
          ( [\\abfnrtv"']
          | \n
          | N{.*?}
          | u[a-fA-F0-9]{4}
          | U[a-fA-F0-9]{8}
          | x[a-fA-F0-9]{2}
          | [0-7]{1,3}
          )
        )x, Str::Escape
      end

      state :dqs do
        rule /"/, Str, :pop!
        rule /\\\\|\\"|\\\n/, Str::Escape
        mixin :strings_double
      end

      state :sqs do
        rule /'/, Str, :pop!
        rule /\\\\|\\'|\\\n/, Str::Escape
        mixin :strings_single
      end

      state :tdqs do
        rule /"""/, Str, :pop!
        rule /"/, Str
        mixin :strings_double
        mixin :nl
      end

      state :tsqs do
        rule /'''/, Str, :pop!
        rule /'/, Str
        mixin :strings_single
        mixin :nl
      end

      %w(tdqs tsqs dqs sqs).each do |qtype|
        state :"escape_#{qtype}" do
          mixin :escape
          mixin :"#{qtype}"
        end
      end

    end
  end
end