Add telnet file with support to send and receive text from Merc MUD

diff --git a/telnet.go b/telnet.go
new file mode 100644 (file)
index 0000000..f674e01
--- /dev/null
+++ b/telnet.go
@@ -0,0 +1,90 @@
+/*
+midgaard_bot, a Telegram bot which sets a bridge to Midgaard Merc MUD
+Copyright (C) 2017 by Javier Sancho Fernandez <jsf at jsancho dot org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package main
+
+import (
+       "bytes"
+       "time"
+
+       "github.com/reiver/go-oi"
+       "github.com/reiver/go-telnet"
+)
+
+type TelnetCaller struct {
+       Input chan string
+       Output chan string
+}
+
+func (caller TelnetCaller) CallTELNET(ctx telnet.Context, writer telnet.Writer, reader telnet.Reader) {
+
+       // Send text to MUD
+       go func() {
+               var buffer bytes.Buffer
+               var p []byte
+
+               crlfBuffer := [2]byte{'\r', '\n'}
+               crlf := crlfBuffer[:]
+
+               for {
+                       message := <-caller.Input
+                       buffer.Write([]byte(message))
+                       buffer.Write(crlf)
+
+                       p = buffer.Bytes()
+                       oi.LongWrite(writer, p)
+                       buffer.Reset()
+               }
+       }()
+
+       // Receive text from MUD
+       chunks := make(chan string)
+       chunk := ""
+       
+       go func() {
+               var buffer [1]byte
+               p := buffer[:]
+
+               for {
+                       n, err := reader.Read(p)
+                       if n <= 0 && err == nil {
+                               continue
+                       } else if n <= 0 && err != nil {
+                               break
+                       }
+
+                       chunks <- string(p)
+               }
+       }()
+
+       for {
+               select {
+               case input := <-chunks:
+                       chunk = input
+                       for chunk != "" {
+                               select {
+                               case input := <-chunks:
+                                       chunk = chunk + input
+                               case <-time.After(time.Millisecond * 500):
+                                       caller.Output <- chunk
+                                       chunk = ""
+                               }
+                       }
+               }
+       }
+}