module LightIO::Library
  class IO
    include Base
    include LightIO::Wrap::IOWrapper

    mock ::IO
    extend LightIO::Module::IO::ClassMethods

    def to_io
      self
    end

    # abstract for io-like operations
    module IOMethods
      class << self
        def included(base)
          base.send(:wrap_blocking_methods, :read, :write)
          base.send(:alias_method, :<<, :write)
        end
      end

      def wait(timeout = nil, mode = :read)
        io_watcher.wait(timeout, mode) && self
      end

      def wait_readable(timeout = nil)
        wait(timeout, :read) && self
      end

      def wait_writable(timeout = nil)
        wait(timeout, :write) && self
      end

      def read(length=nil, outbuf=nil)
        raise ArgumentError, "negative length #{length} given" if length && length < 0
        (outbuf ||= "").clear
        loop do
          readlen = length.nil? ? 4096 : length - outbuf.size
          if (data = wait_nonblock(:read_nonblock, readlen))
            outbuf << data
            if length == outbuf.size
              return outbuf
            end
          else
            return outbuf.empty? && length ? nil : outbuf
          end
        end
      end

      def readpartial(maxlen, outbuf=nil)
        (outbuf ||= "").clear
        if (data = wait_nonblock(:read_nonblock, maxlen))
          outbuf << data
        else
          raise EOFError, 'end of file reached'
        end
        outbuf
      end

      def getbyte
        read(1)
      end

      def getc
        wait_readable
        @obj.getc
      end

      def readline(*args)
        line = gets(*args)
        raise EOFError, 'end of file reached' if line.nil?
        line
      end

      def readlines(*args)
        result = []
        until eof?
          result << readline(*args)
        end
        result
      end

      def readchar
        c = getc
        raise EOFError, 'end of file reached' if c.nil?
        c
      end

      def readbyte
        b = getbyte
        raise EOFError, 'end of file reached' if b.nil?
        b
      end

      def eof
        wait_readable
        @obj.eof
      end

      alias eof? eof

      def gets(*args)
        raise ArgumentError, "wrong number of arguments (given #{args.size}, expected 0..2)" if args.size > 2
        sep = $/
        if args[0].is_a?(Numeric)
          limit = args.shift
        else
          sep = args.shift if args.size > 0
          limit = args.shift if args.first.is_a?(Numeric)
        end
        s = ''
        while (c = getbyte)
          s << c
          break if limit && s.size == limit
          break if c == sep
        end
        s = nil if s.empty?
        $_ = s
      end

      def print(*obj)
        obj.each do |s|
          write(s)
        end
      end

      def printf(*args)
        write(sprintf(*args))
      end

      def puts(*obj)
        obj.each do |s|
          write(s)
          write($/)
        end
      end

      def close(*args)
        # close watcher before io closed
        io_watcher.close
        @obj.close
      end
    end

    prepend IOMethods
  end
end