module CodeRay module Scanners
  
  # by Josh Goebel
  class SQL < Scanner

    register_for :sql
    
    RESERVED_WORDS = %w(
      all and as before begin by case collate
      constraint create else end engine exists
      for foreign from group if inner is join key
      like not on or order outer primary references replace
      then to trigger union using values when where
      left right distinct
    )
    
    OBJECTS = %w(
      database databases table tables column columns index
    )
    
    COMMANDS = %w(
      add alter comment create delete drop grant insert into select update set
      show
    )
    
    PREDEFINED_TYPES = %w(
      char varchar enum binary text tinytext mediumtext
      longtext blob tinyblob mediumblob longblob timestamp
      date time datetime year double decimal float int
      integer tinyint mediumint bigint smallint unsigned bit
      bool boolean hex bin oct
    )
    
    PREDEFINED_FUNCTIONS = %w( sum cast substring abs pi count min max avg now )
    
    DIRECTIVES = %w( auto_increment unique default charset )
    
    PREDEFINED_CONSTANTS = %w( null true false )
    
    IDENT_KIND = CaseIgnoringWordList.new(:ident).
      add(RESERVED_WORDS, :reserved).
      add(OBJECTS, :type).
      add(COMMANDS, :class).
      add(PREDEFINED_TYPES, :pre_type).
      add(PREDEFINED_CONSTANTS, :pre_constant).
      add(PREDEFINED_FUNCTIONS, :predefined).
      add(DIRECTIVES, :directive)
    
    ESCAPE = / [rbfntv\n\\\/'"] | x[a-fA-F0-9]{1,2} | [0-7]{1,3} | . /mx
    UNICODE_ESCAPE =  / u[a-fA-F0-9]{4} | U[a-fA-F0-9]{8} /x
    
    STRING_PREFIXES = /[xnb]|_\w+/i
    
    def scan_tokens tokens, options
      
      state = :initial
      string_type = nil
      string_content = ''
      
      until eos?
        
        kind = nil
        match = nil
        
        if state == :initial
          
          if scan(/ \s+ | \\\n /x)
            kind = :space
          
          elsif scan(/^(?:--\s?|#).*/)
            kind = :comment
            
          elsif scan(%r( /\* (!)? (?: .*? \*/ | .* ) )mx)
            kind = self[1] ? :directive : :comment
            
          elsif scan(/ [-+*\/=<>;,!&^|()\[\]{}~%] | \.(?!\d) /x)
            kind = :operator
            
          elsif scan(/(#{STRING_PREFIXES})?([`"'])/o)
            prefix = self[1]
            string_type = self[2]
            tokens << [:open, :string]
            tokens << [prefix, :modifier] if prefix
            match = string_type
            state = :string
            kind = :delimiter
            
          elsif match = scan(/ @? [A-Za-z_][A-Za-z_0-9]* /x)
            # FIXME: Don't match keywords after "."
            kind = match[0] == ?@ ? :variable : IDENT_KIND[match.downcase]
            
          elsif scan(/0[xX][0-9A-Fa-f]+/)
            kind = :hex
            
          elsif scan(/0[0-7]+(?![89.eEfF])/)
            kind = :oct
            
          elsif scan(/(?>\d+)(?![.eEfF])/)
            kind = :integer
            
          elsif scan(/\d[fF]|\d*\.\d+(?:[eE][+-]?\d+)?|\d+[eE][+-]?\d+/)
            kind = :float
          
          elsif scan(/\\N/)
            kind = :pre_constant
            
          else
            getch
            kind = :error
            
          end
          
        elsif state == :string
          if match = scan(/[^\\"'`]+/)
            string_content << match
            next
          elsif match = scan(/["'`]/)
            if string_type == match
              if peek(1) == string_type  # doubling means escape
                string_content << string_type << getch
                next
              end
              unless string_content.empty?
                tokens << [string_content, :content]
                string_content = ''
              end
              tokens << [matched, :delimiter]
              tokens << [:close, :string]
              state = :initial
              string_type = nil
              next
            else
              string_content << match
            end
            next
          elsif scan(/ \\ (?: #{ESCAPE} | #{UNICODE_ESCAPE} ) /mox)
            unless string_content.empty?
              tokens << [string_content, :content]
              string_content = ''
            end
            kind = :char
          elsif match = scan(/ \\ . /mox)
            string_content << match
            next
          elsif scan(/ \\ | $ /x)
            unless string_content.empty?
              tokens << [string_content, :content]
              string_content = ''
            end
            kind = :error
            state = :initial
          else
            raise "else case \" reached; %p not handled." % peek(1), tokens
          end
          
        else
          raise 'else-case reached', tokens
          
        end
        
        match ||= matched
        unless kind
          raise_inspect 'Error token %p in line %d' %
            [[match, kind], line], tokens, state
        end
        raise_inspect 'Empty token', tokens unless match
        
        tokens << [match, kind]
        
      end
      tokens
      
    end
    
  end
  
end end