module Erubis::JavascriptGenerator

def self.supported_properties()   # :nodoc:
  list = []
  #list << [:indent,   '',       "indent spaces (ex. '  ')"]
  #list << [:bufvar,      '_buf',   "output buffer variable name"]
  list << [:docwrite, true,     "use 'document.write()' when true"]
  return list
end

def add_expr_debug(src, code)
  add_indent(src, @indent)
  code.strip!
  src << "alert(\"*** debug: #{code}=\"+(#{code}));"
end

def add_expr_escaped(src, code)
  add_expr_literal(src, escaped_expr(code))
end

def add_expr_literal(src, code)
  add_indent(src, @indent)
  code.strip!
  src << "#{@bufvar}.push(#{code});"
end

def add_indent(src, indent)
  src << (src.empty? || src[-1] == ?\n ? indent : ' ')
end

def add_postamble(src)
  src << "\n" if src[-1] == ?;
  if @docwrite
    src << @indent << 'document.write(' << @bufvar << ".join(\"\"));\n"
  else
    src << @indent << @bufvar << ".join(\"\");\n"
  end
end

def add_preamble(src)
  src << "#{@indent}var #{@bufvar} = [];"
end

def add_stmt(src, code)
  src << code
end

def add_text(src, text)
  return if text.empty?
  add_indent(src, @indent)
  src << @bufvar << '.push("'
  s = escape_text(text)
  if s[-1] == ?\n
    s[-2, 2] = ''
    src << s << "\");\n"
  else
    src << s << "\");"
  end
end

def escape_text(text)
  @@table_ ||= { "\r"=>"\\r", "\n"=>"\\n\\\n", "\t"=>"\\t", '"'=>'\\"', "\\"=>"\\\\" }
  return text.gsub!(/[\r\n\t"\\]/) { |m| @@table_[m] } || text
end

def init_generator(properties={})
  super
  @escapefunc ||= 'escape'
  @indent = properties[:indent] || ''
  @bufvar = properties[:bufvar] || '_buf'
  @docwrite = properties[:docwrite] != false  # '!= false' will be removed in the next release
end