From a7c21e81476b7565e46a378403ec0d4129446538 Mon Sep 17 00:00:00 2001
From: Merlijn Wajer <merlijn@wizzup.org>
Date: Tue, 25 Jul 2017 12:30:51 +0200
Subject: [PATCH] Add serial protocol code

---
 protocol/main.go |  20 ++++++++
 protocol/tbm.go  | 141 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 161 insertions(+)
 create mode 100644 protocol/main.go
 create mode 100644 protocol/tbm.go

diff --git a/protocol/main.go b/protocol/main.go
new file mode 100644
index 0000000..3352527
--- /dev/null
+++ b/protocol/main.go
@@ -0,0 +1,20 @@
+package main
+
+import (
+	"log"
+)
+
+func main() {
+	t := &TBM{}
+	err := t.Connect("/dev/ttyUSB0")
+	if err != nil {
+		log.Fatal(err)
+	}
+	t.Handle()
+	defer t.Close()
+
+	//cmd := &Command{"Hi", []string{"v20170802 testing"}}
+	//t.Commands <- cmd
+	res := <-t.Results
+	log.Printf("Got result: %q", res)
+}
diff --git a/protocol/tbm.go b/protocol/tbm.go
new file mode 100644
index 0000000..9242efe
--- /dev/null
+++ b/protocol/tbm.go
@@ -0,0 +1,141 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/tarm/serial"
+)
+
+type TBM struct {
+	Commands chan *Command
+	Results  chan *Result
+	Port     *serial.Port
+}
+
+type Command struct {
+	command string
+	args    []string
+}
+
+type Result struct {
+	output  []byte
+	errcode []byte
+}
+
+func (t *TBM) Connect(device string) error {
+	t.Commands = make(chan *Command)
+	t.Results = make(chan *Result)
+
+	serialconfig := &serial.Config{Name: device, Baud: 9600}
+
+	port, err := serial.OpenPort(serialconfig)
+	if err != nil {
+		return err
+	}
+
+	t.Port = port
+
+	return nil
+}
+
+func (t *TBM) Handle() error {
+	go handleResults(t.Port, t.Results)
+	go handleCommands(t.Port, t.Commands)
+
+	return nil
+}
+
+func (t *TBM) Close() {
+	t.Port.Close()
+}
+
+func deserialise(in io.Reader, init []byte) (*Result, []byte, error) {
+	var (
+		output, errorcode []byte
+		data, rest        []byte
+	)
+
+	want_output := true
+	_ = copy(data, init)
+
+	for {
+		buf := make([]byte, 4096)
+		n, err := in.Read(buf)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		n2 := n + len(data)
+
+		data = append(data, buf[:n]...)
+
+		for i := 0; i < n2; i++ {
+			if data[i] == 0x4 {
+				if want_output {
+					want_output = false
+					output = data[:i]
+					data = data[i+1:]
+					break
+				} else {
+					errorcode = data[:i]
+					rest = data[i+1:]
+					return &Result{output, errorcode}, rest, nil
+				}
+			}
+		}
+
+	}
+
+}
+
+func handleResults(in io.Reader, c chan *Result) {
+	var (
+		res  *Result
+		rest []byte
+		err  error
+	)
+
+	for {
+		res, rest, err = deserialise(in, rest)
+
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		c <- res
+	}
+}
+
+func serialise(out io.Writer, command string, args []string) error {
+	var quoted_args []string
+
+	quoted_args = append(quoted_args, command)
+
+	for _, arg := range args {
+		quoted_args = append(quoted_args, fmt.Sprintf("\"%s\"", arg))
+	}
+
+	out_string := strings.Join(quoted_args, " ")
+
+	output := []byte(out_string)
+	output = append(output, 0x4)
+
+	_, err := out.Write(output)
+	// err is non nil if n != len(output)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func handleCommands(out io.Writer, c chan *Command) {
+	for command := range c {
+		err := serialise(out, command.command, command.args)
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+}