doorgo/door/door.go

/*
Package door: a golang implementation of a BBS door for linux that
support door32.sys.

    import (
			"door"
		)

		int main() {
			d = door.Door{}
			d.Init() // Process commandline switches, initialize door, detect screen size.

			d.Write("Welcome to my awesome door, written in "+door.ColorText("BLINK BOLD WHITE")+"golang"+door.Reset+"."+door.CRNL)
			d.Write("Press a key...")
			d.Key()
			d.Write(door.CRNL)
		}
*/
package door

import (
	"bufio"
	"flag"
	"fmt"
	"os"
	"strconv"
	"strings"
	"syscall"
	"time"
)

const CRNL = "\r\n"                   // BBS Line Ending
const Clrscr = "\x1b[0m\x1b[2J\x1b[H" // Clear screen, home cursor
const HideCursor = "\x1b[?25l"        // Hide Cursor
const ShowCursor = "\x1b[?25h"        // Show Cursor
var Reset string = Color(0)           // ANSI Color Reset
var Unicode bool                      // Unicode support detected
var CP437 bool                        // CP437 support detected
var Full_CP437 bool                   // Full CP437 support detected (handles control codes properly)
var Height int                        // Screen height detected
var Width int                         // Screen width detected
var Inactivity int64 = 120            // Inactivity timeout

type LIFOBuffer struct {
	data  []int
	index int
}

func (b *LIFOBuffer) Empty() bool {
	return b.index == 0
}

func (b *LIFOBuffer) Push(value int) {
	if b.index+1 > len(b.data) {
		b.data = append(b.data, value)
		b.index++
	} else {
		b.data[b.index] = value
		b.index++
	}
}

func (b *LIFOBuffer) Pop() int {
	if b.index == 0 {
		panic("Attempting to Pop from empty LIFOBuffer.")
	}

	b.index--
	return b.data[b.index]
}

/*
door32.sys:

0                            Line 1 : Comm type (0=local, 1=serial, 2=telnet)
0                            Line 2 : Comm or socket handle
38400                        Line 3 : Baud rate
Mystic 1.07                  Line 4 : BBSID (software name and version)
1                            Line 5 : User record position (1-based)
James Coyle                  Line 6 : User's real name
g00r00                       Line 7 : User's handle/alias
255                          Line 8 : User's security level
58                           Line 9 : User's time left (in minutes)
1                            Line 10: Emulation *See Below
1                            Line 11: Current node number
*/

type DropfileConfig struct {
	Comm_type      int
	Comm_handle    int
	Baudrate       int
	BBSID          string
	User_number    int
	Real_name      string
	Handle         string
	Security_level int
	Time_left      int
	Emulation      int
	Node           int
}

type Door struct {
	Config       DropfileConfig
	READFD       int
	WRITEFD      int
	Disconnected bool
	TimeOut      time.Time // Fixed point in time, when time expires
	StartTime    time.Time
	Pushback     LIFOBuffer
}

// Return the amount of time left as time.Duration
func (d *Door) TimeLeft() time.Duration {
	return d.TimeOut.Sub(time.Now())
}

func (d *Door) TimeUsed() time.Duration {
	return time.Now().Sub(d.StartTime)
}

// Read the BBS door file.  We only support door32.sys.
func (d *Door) ReadDropfile(filename string) {
	file, err := os.Open(filename)
	if err != nil {
		panic(fmt.Sprintf("Open(%s): %s\n", filename, err))
		// os.Exit(2)
	}

	defer file.Close()

	var lines []string
	// read line by line

	// The scanner handles DOS and linux file endings.

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()
		lines = append(lines, line)
	}

	d.Config.Comm_type, err = strconv.Atoi(lines[0])
	d.Config.Comm_handle, err = strconv.Atoi(lines[1])
	d.Config.Baudrate, err = strconv.Atoi(lines[2])
	d.Config.BBSID = lines[3]
	d.Config.User_number, err = strconv.Atoi(lines[4])
	d.Config.Real_name = lines[5]
	d.Config.Handle = lines[6]
	d.Config.Security_level, err = strconv.Atoi(lines[7])
	d.Config.Time_left, err = strconv.Atoi(lines[8])
	d.Config.Emulation, err = strconv.Atoi(lines[9])
	d.Config.Node, err = strconv.Atoi(lines[10])

	d.READFD = d.Config.Comm_handle
	d.WRITEFD = d.Config.Comm_handle

	// Calculate the time when time expires.
	d.StartTime = time.Now()
	d.TimeOut = time.Now().Add(time.Duration(d.Config.Time_left) * time.Minute)
}

// Detect client terminal capabilities, Unicode, CP437, Full_CP437,
// screen Height and Width.
func (d *Door) detect() {
	d.Write("\x1b[0;30;40m\x1b[2J\x1b[H")                          // black on black, clrscr, go home
	d.Write("\x03\x04\x1b[6n")                                     // hearts and diamonds does CP437 work?
	d.Write(CRNL + "\u2615\x1b[6n")                                // hot beverage
	d.Write("\x1b[999C\x1b[999B\x1b[6n" + Reset + "\x1b[2J\x1b[H") // goto end of screen + cursor pos
	// time.Sleep(50 * time.Millisecond)
	time.Sleep(250 * time.Millisecond)
	// read everything
	// telnet term isn't in RAW mode, so keys are buffer until <CR>
	var results string

	if d.HasKey() {
		buffer := make([]byte, 100)
		r, err := syscall.Read(d.READFD, buffer)
		results = string(buffer[:r])
		output := strings.Replace(results, "\x1b", "^[", -1)
		fmt.Println("DETECT:", r, err, output)
	} else {
		// local telnet echos the reply  :()
		fmt.Println("DETECT: Nothing received.")
		return
	}

	if ((strings.Index(results, "1;1R") != -1) ||
		(strings.Index(results, "1;3R") != -1)) &&
		((strings.Index(results, "2:2R") != -1) ||
			(strings.Index(results, "2;3R") != -1)) {
		Unicode = true
	} else {
		Unicode = false
		CP437 = true
	}
	if strings.Index(results, "1;3R") != -1 {
		Full_CP437 = true
	}

	// get screen size
	var err error

	pos := strings.LastIndex(results, "\x1b")
	if pos != -1 {
		pos++
		if results[pos] == '[' {
			pos++
			results = results[pos:]
			pos = strings.Index(results, ";")
			if pos != -1 {
				height := results[:pos]
				Height, err = strconv.Atoi(height)
				pos++
				results = results[pos:]

				pos = strings.Index(results, "R")
				if pos != -1 {
					width := results[:pos]

					Width, err = strconv.Atoi(width)
					fmt.Printf("Width: %s, %d, %v\n", results, Width, err)
				}
			} else {
				Height = 0
				Width = 0
			}
		}
	}
	fmt.Printf("Unicode %v Screen: %d X %d\n", Unicode, Width, Height)
}

// Initialize door framework.  Parse commandline, read dropfile,
// detect terminal capabilities.
func (d *Door) Init() {
	var dropfile string

	flag.StringVar(&dropfile, "d", "", "Path to dropfile")
	flag.Parse()
	if len(dropfile) == 0 {
		flag.PrintDefaults()
		os.Exit(2)
	}
	fmt.Printf("Loading: %s\n", dropfile)

	d.ReadDropfile(dropfile)

	fmt.Printf("BBS %s, User %s / Handle %s / File %d\n", d.Config.BBSID, d.Config.Real_name, d.Config.Handle, d.Config.Comm_handle)
	d.detect()
	if Unicode {
		BOXES = BOXES_UNICODE
		BARS = BARS_UNICODE
	} else {
		BOXES = BOXES_CP437
		BARS = BARS_CP437
	}
}

// Write string to client.
func (d *Door) Write(output string) {
	if d.Disconnected {
		return
	}
	buffer := []byte(output)
	n, err := syscall.Write(d.WRITEFD, buffer)
	if err != nil {
		fmt.Println("Write error/HANGUP?", n)
		d.Disconnected = true
	}
	// No, this isn't it.  The # of bytes in buffer == bytes written.
	if n != len(buffer) {
		fmt.Printf("Write fail: %d != %d\n", len(buffer), n)
	}
}

func Goto(x int, y int) string {
	return fmt.Sprintf("\x1b[%d;%dH", y, x)
}