commit 7fb6b76119d72813843914b9539372bd478beeda
Author: Kevin Cotugno <kevin@kevincotugno.com>
Date:   Sun Dec 24 14:41:04 2017 -0800

    Init

diff --git a/main.go b/main.go
new file mode 100644
index 0000000..c7f2be8
--- /dev/null
+++ b/main.go
@@ -0,0 +1,1232 @@
+package main
+
+import (
+	"github.com/emirpasic/gods/trees/redblacktree"
+	"github.com/gorilla/websocket"
+	"github.com/shopspring/decimal"
+	"golang.org/x/sys/unix"
+
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"os"
+	"sync"
+	"time"
+	"unicode/utf8"
+)
+
+type Queue struct {
+	data         []interface{}
+	begin, end   int
+	length, size int
+}
+
+type Terminal struct {
+	Event <-chan Event
+
+	in *os.File
+
+	outLock sync.Mutex
+	out     *os.File
+
+	bufLock sync.Mutex
+	buffer  *bytes.Buffer
+
+	sizeLock sync.Mutex
+	size     Size
+
+	displayLock sync.Mutex
+	display     [][]Cell
+
+	interLock sync.Mutex
+	interBuf  []Cell
+
+	currentAttributes Attributes
+	cursorPosition    Position
+	cursorVisible     bool
+
+	termios unix.Termios
+
+	doneLock sync.Mutex
+	done     bool
+
+	shutdown chan struct{}
+	event    chan Event
+}
+
+type Cell struct {
+	Pos   Position
+	Value rune
+	Attrs Attributes
+}
+
+type Attributes struct {
+	ForegroundColor ForegroundColor
+	BackgroundColor BackgroundColor
+	Bold            bool
+	Italics         bool
+	Blink           bool
+	Underline       bool
+}
+
+type Scene struct {
+	Terminal *Terminal
+	Window   Widget
+}
+
+type Widget interface {
+	Render() [][]Cell
+}
+
+type WindowWidget struct {
+	Constraints Constraints
+	Border      Border
+
+	widgets []Widget
+}
+
+type ListWidget struct {
+	Constraints Constraints
+	Attrs       Attributes
+
+	cellLock sync.Mutex
+	cells    [][]Cell
+
+	rightAlign bool
+	border     bool
+
+	listLock sync.Mutex
+	list     [][]rune
+
+	lastSize Size
+}
+
+type Constraints struct {
+	Top    bool
+	Bottom bool
+	Left   bool
+	Right  bool
+}
+
+type Border Constraints
+
+type ForegroundColor int
+type BackgroundColor int
+type Event byte
+
+type Sub struct {
+	Type       string   `json:"type"`
+	ProductIds []string `json:"product_ids"`
+	Channels   []string `json:"channels"`
+}
+
+type Message struct {
+	Sequence      int64           `json:"sequence"`
+	Type          string          `json:"type"`
+	Side          string          `json:"side"`
+	Price         decimal.Decimal `json:"price"`
+	Size          decimal.Decimal `json:"size"`
+	OrderId       string          `json:"order_id"`
+	MakerOrderId  string          `json:"maker_order_id"`
+	RemainingSize decimal.Decimal `json:"remaining_size"`
+	NewSize       decimal.Decimal `json:"new_size"`
+	ProductId     string          `json:"product_id"`
+	Time          time.Time       `json:"time"`
+	Reason        string          `json:"reason"`
+	OrderType     string          `json:"order_type"`
+	ClientOid     string          `json:"client_oid"`
+}
+
+type LevelThree struct {
+	Sequence int64             `json:"sequence"`
+	Bids     []LevelThreeEntry `json:"bids"`
+	Asks     []LevelThreeEntry `json:"asks"`
+}
+
+type Entry struct {
+	Id    string
+	Price decimal.Decimal
+	Size  decimal.Decimal
+}
+
+type Position struct {
+	X int
+	Y int
+}
+
+type Size Position
+
+type Entries map[string]Entry
+
+type LevelThreeEntry []string
+
+const (
+	CtrC = Event(3)
+)
+
+const (
+	Normal = iota
+	Bold
+	_
+	_
+	Underline
+	SlowBlink
+)
+
+const (
+	FGBlack = ForegroundColor(iota + 30)
+	FGRed
+	FGGreen
+	FGYellow
+	FGBlue
+	FGMagenta
+	FGCyan
+	FGWhite
+)
+
+const (
+	BGBlack = BackgroundColor(iota + 40)
+	BGRed
+	BGGreen
+	BGYellow
+	BGBlue
+	BGMagenta
+	BGCyan
+	BGWhite
+)
+
+const (
+	coin = "ETH-USD"
+
+	timeFormat = "15:04:05"
+	smcup      = "\x1b[?1049h"
+	rmcup      = "\x1b[?1049l"
+	civis      = "\x1b[?25l"
+	cvvis      = "\x1b[?12;25h"
+	clear      = "\x1b[2J"
+	sgr        = "\x1b[%vm"
+	cup        = "\x1b[%v;%vH"
+)
+
+var sub = Sub{"subscribe", []string{coin}, []string{"full"}}
+
+var asks = redblacktree.NewWith(DecimalComparator)
+var bids = redblacktree.NewWith(ReverseDecimalComparator)
+var trades = NewQueue()
+
+var terminal *Terminal
+
+var window *WindowWidget
+var topAsks *ListWidget
+var topBids *ListWidget
+var midPrice *ListWidget
+
+func NewQueue() *Queue {
+	q := Queue{}
+	q.data = make([]interface{}, 256)
+	q.size = 256
+	q.end = -1
+
+	return &q
+}
+
+func (q *Queue) Length() int {
+	return q.length
+}
+
+func (q *Queue) Enqueue(v interface{}) {
+	if q.length == 256 {
+		fmt.Println("Queue Full")
+		os.Exit(1)
+	}
+
+	q.end++
+
+	if len(q.data) == q.end {
+		q.end = 0
+	}
+
+	q.length++
+	q.data[q.end] = v
+}
+
+func (q *Queue) Dequeue() interface{} {
+	if q.length == 0 {
+		return nil
+	}
+
+	v := q.data[q.begin]
+
+	q.begin++
+	q.length--
+
+	if q.size == q.begin {
+		q.begin = 0
+	}
+
+	if q.length == 0 {
+		q.begin = 0
+		q.end = -1
+	}
+
+	return v
+}
+
+func (q *Queue) Element(i int) interface{} {
+	var v interface{}
+
+	if q.begin == 0 {
+		v = q.data[i]
+	} else {
+		if q.begin+i >= q.size {
+			j := (q.begin + i) - q.size
+			v = q.data[j]
+		} else {
+			v = q.data[q.begin+i]
+		}
+	}
+
+	return v
+}
+
+func main() {
+	terminal = Init()
+	defer terminal.Shutdown()
+	terminal.HideCursor()
+
+	window = &WindowWidget{}
+	topAsks = &ListWidget{}
+	window.Constraints.Bottom = true
+	topAsks.SetBorder(true)
+	topAsks.SetRightAlign(true)
+	topAsks.Attrs.ForegroundColor = FGRed
+
+	topBids = &ListWidget{}
+	topBids.SetBorder(true)
+	topBids.SetRightAlign(true)
+	topBids.Attrs.ForegroundColor = FGGreen
+
+	midPrice = &ListWidget{}
+	midPrice.SetRightAlign(true)
+
+	window.AddWidget(topAsks)
+	//         window.AddWidget(midPrice)
+	//         window.AddWidget(topBids)
+
+	scene := Scene{terminal, window}
+
+	conn, _, err := websocket.DefaultDialer.Dial("wss://ws-feed.gdax.com", nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer conn.Close()
+
+	go func() {
+		for e := range terminal.Event {
+			if e == CtrC {
+				conn.WriteMessage(websocket.CloseMessage,
+					websocket.FormatCloseMessage(websocket.
+						CloseNormalClosure, ""))
+				break
+			}
+		}
+	}()
+
+	err = conn.WriteJSON(sub)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	go renderLoop(&scene, 100*time.Millisecond)
+
+	sequence := loadOrderBook()
+
+	for {
+		var msg Message
+		err := conn.ReadJSON(&msg)
+		if err != nil {
+			if websocket.IsCloseError(err, websocket.CloseNormalClosure) {
+				break
+			} else {
+				log.Fatal(err)
+			}
+		}
+
+		if msg.Type == "subscriptions" {
+			continue
+		}
+
+		if msg.Sequence <= sequence {
+			continue
+		}
+
+		if msg.Sequence != sequence+1 {
+			sequence = loadOrderBook()
+			continue
+		}
+
+		sequence = msg.Sequence
+
+		switch msg.Type {
+		case "received":
+		case "open":
+			open(msg)
+		case "done":
+			done(msg)
+		case "match":
+			match(msg)
+		case "change":
+			change(msg)
+		default:
+			log.Fatal("Unknown message type")
+		}
+
+		sz := terminal.Size()
+
+		num := numOfOrderPerSide(sz.Y)
+
+		aIt := asks.Iterator()
+		s := make([]string, num)
+
+		var low, high decimal.Decimal
+		for i := num - 1; i >= 0; i-- {
+			aIt.Next()
+
+			entries := aIt.Value().(Entries)
+			price, size := flatten(entries)
+
+			s[i] = fmt.Sprintf("%v - %v ", price.StringFixed(2), size.StringFixed(8))
+
+			if i == num-1 {
+				low = price
+			}
+		}
+		topAsks.SetList(append([]string{}, s...))
+
+		bIt := bids.Iterator()
+		for i := 0; i < num; i++ {
+			bIt.Next()
+
+			entries := bIt.Value().(Entries)
+			price, size := flatten(entries)
+
+			s[i] = fmt.Sprintf("%v - %v ", price.StringFixed(2), size.StringFixed(8))
+
+			if i == 0 {
+				high = price
+			}
+		}
+
+		topBids.SetList(append([]string(nil), s...))
+
+		diff := low.Sub(high)
+
+		s = []string{"", fmt.Sprintf("%v  Spread: %v",
+			high.Add(diff.Div(decimal.New(2, 0))).StringFixed(3),
+			diff.StringFixed(2)), ""}
+
+		midPrice.SetList(append([]string(nil), s...))
+	}
+}
+
+func open(msg Message) {
+	tree := sideTree(msg.Side)
+
+	var entries Entries
+	var entry Entry
+
+	entries, ok := treeEntries(tree, msg.Price)
+	if !ok {
+		entries = Entries{}
+
+		tree.Put(msg.Price, entries)
+	}
+
+	entry.Id = msg.OrderId
+	entry.Price = msg.Price
+	entry.Size = msg.RemainingSize
+
+	entries[entry.Id] = entry
+}
+
+func done(msg Message) {
+	if msg.OrderType == "market" {
+		return
+	}
+	tree := sideTree(msg.Side)
+
+	entries, ok := treeEntries(tree, msg.Price)
+	if !ok {
+		return
+	}
+
+	delete(entries, msg.OrderId)
+	if len(entries) == 0 {
+		tree.Remove(msg.Price)
+	} else {
+		tree.Put(msg.Price, entries)
+	}
+}
+
+func match(msg Message) {
+	tree := sideTree(msg.Side)
+
+	entries, ok := treeEntries(tree, msg.Price)
+	if !ok {
+		return
+	}
+
+	entry, ok := entries[msg.MakerOrderId]
+	if !ok {
+		return
+	}
+
+	entry.Size = entry.Size.Sub(msg.Size)
+	entries[msg.MakerOrderId] = entry
+
+	if trades.Length() == 256 {
+		trades.Dequeue()
+	}
+
+	trades.Enqueue(msg)
+}
+
+func change(msg Message) {
+	tree := sideTree(msg.Side)
+
+	entries, ok := treeEntries(tree, msg.Price)
+	if !ok {
+		return
+	}
+
+	entry, ok := entries[msg.OrderId]
+	if !ok {
+		return
+	}
+
+	entry.Size = msg.NewSize
+	entries[msg.OrderId] = entry
+}
+
+func loadOrderBook() int64 {
+	bids.Clear()
+	asks.Clear()
+
+	resp, err := http.Get(fmt.Sprintf("https://api.gdax.com/products/%v/book?level=3", coin))
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer resp.Body.Close()
+
+	buf, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	var parsed LevelThree
+
+	err = json.Unmarshal(buf, &parsed)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	for _, e := range parsed.Bids {
+		var entry Entry
+
+		entry.Price, err = decimal.NewFromString(e[0])
+		if err != nil {
+			log.Fatal(err)
+		}
+		entry.Size, err = decimal.NewFromString(e[1])
+		if err != nil {
+			log.Fatal(err)
+		}
+		entry.Id = e[2]
+
+		var entries Entries
+		values, ok := bids.Get(entry.Price)
+		if !ok {
+			entries = Entries{}
+
+			bids.Put(entry.Price, entries)
+		} else {
+			entries = values.(Entries)
+		}
+
+		entries[entry.Id] = entry
+	}
+
+	for _, e := range parsed.Asks {
+		var entry Entry
+
+		entry.Price, err = decimal.NewFromString(e[0])
+		if err != nil {
+			log.Fatal(err)
+		}
+		entry.Size, err = decimal.NewFromString(e[1])
+		if err != nil {
+			log.Fatal(err)
+		}
+		entry.Id = e[2]
+
+		var entries Entries
+		values, ok := asks.Get(entry.Price)
+		if !ok {
+			entries = Entries{}
+
+			asks.Put(entry.Price, entries)
+		} else {
+			entries = values.(Entries)
+		}
+
+		entries[entry.Id] = entry
+	}
+
+	return parsed.Sequence
+}
+
+func sideTree(side string) *redblacktree.Tree {
+	switch side {
+	case "buy":
+		return bids
+	case "sell":
+		return asks
+	}
+
+	return nil
+}
+
+func treeEntries(tree *redblacktree.Tree, key decimal.Decimal) (Entries, bool) {
+	values, ok := tree.Get(key)
+
+	if ok {
+		return values.(Entries), true
+	} else {
+		return nil, false
+	}
+}
+
+func numOfOrderPerSide(y int) int {
+	total := y - 3 - 4
+
+	return (total / 2)
+}
+
+func flatten(entries Entries) (decimal.Decimal, decimal.Decimal) {
+	var price, size decimal.Decimal
+
+	for _, v := range entries {
+		price = v.Price
+		size = size.Add(v.Size)
+	}
+
+	return price, size
+}
+
+func renderLoop(scene *Scene, interval time.Duration) {
+	timer := time.NewTicker(interval)
+
+	for {
+		select {
+		case <-timer.C:
+			scene.Render()
+		}
+	}
+}
+
+func Init() *Terminal {
+	var t Terminal
+
+	out, err := os.OpenFile("/dev/tty", os.O_WRONLY|unix.O_NOCTTY, os.ModeCharDevice)
+	if err != nil {
+		log.Panic(err)
+	}
+
+	in, err := os.OpenFile("/dev/tty", os.O_RDONLY|unix.O_NOCTTY, os.ModeCharDevice)
+	if err != nil {
+		log.Panic(err)
+	}
+
+	termios, err := unix.IoctlGetTermios(int(out.Fd()), unix.TCGETS)
+	if err != nil {
+		out.Close()
+		in.Close()
+		log.Panic(err)
+	}
+
+	t.buffer = &bytes.Buffer{}
+	t.out = out
+	t.in = in
+	t.termios = *termios
+	t.shutdown = make(chan struct{})
+	t.event = make(chan Event, 1024)
+	t.Event = t.event
+
+	x, y := t.sizeInternal()
+	if x != 0 && y != 0 {
+		t.setSize(x, y)
+	}
+
+	t.enterAlt()
+	t.enterRaw()
+	t.SetCursor(0, 0)
+	t.Render()
+
+	t.watchSize()
+	t.watchInput()
+
+	return &t
+}
+
+func (t *Terminal) Shutdown() {
+	t.shutdown <- struct{}{}
+
+	t.doneLock.Lock()
+	t.done = true
+	t.doneLock.Unlock()
+
+	t.resetBuffer()
+	t.ShowCursor()
+	t.Render()
+
+	t.exitRaw()
+	t.exitAlt()
+	t.out.Close()
+	t.in.Close()
+	close(t.event)
+}
+
+func (t *Terminal) Clear() {
+	t.writeBuffer([]byte(clear))
+}
+
+func (t *Terminal) SetCursor(x, y int) {
+	t.writeBuffer([]byte(fmt.Sprintf(cup, y+1, x+1)))
+	t.cursorPosition.X = x
+	t.cursorPosition.Y = y
+}
+
+func (t *Terminal) ShowCursor() {
+	t.writeBuffer([]byte(cvvis))
+	t.cursorVisible = true
+}
+
+func (t *Terminal) HideCursor() {
+	t.writeBuffer([]byte(civis))
+	t.cursorVisible = false
+}
+
+func (t *Terminal) CursorVisible() bool {
+	return t.cursorVisible
+}
+
+func (t *Terminal) Size() Size {
+	t.sizeLock.Lock()
+	defer t.sizeLock.Unlock()
+
+	return t.size
+}
+
+func (t *Terminal) setSize(x, y int) {
+	t.sizeLock.Lock()
+	defer t.sizeLock.Unlock()
+
+	if t.size.X == x && t.size.Y == y {
+		return
+	}
+
+	t.displayLock.Lock()
+	defer t.displayLock.Unlock()
+
+	t.size.X = x
+	t.size.Y = y
+
+	if t.display == nil {
+		t.display = make([][]Cell, x)
+	} else if len(t.display) < x {
+		t.display = append(t.display, make([][]Cell, x-len(t.display))...)
+	}
+
+	for i := 0; i < x; i++ {
+		if t.display[i] == nil {
+			t.display[i] = make([]Cell, y)
+		} else if len(t.display[i]) < y {
+			t.display[i] = append(t.display[i],
+				make([]Cell, y-len(t.display[i]))...)
+		}
+	}
+
+	t.Clear()
+}
+
+func (t *Terminal) WriteString(s string, x, y int, attrs Attributes) {
+	if len(s) == 0 || len(t.display) < x+1 || len(t.display[0]) < y+1 {
+		return
+	}
+
+	var j int
+	for i := 0; i < len(s); i++ {
+		r, sz := utf8.DecodeRuneInString(s[j:])
+
+		if sz > 0 {
+
+			cell := Cell{Position{x + i, y}, r, attrs}
+
+			if t.display[x+i][y] != cell {
+				t.interBuf = append(t.interBuf, cell)
+			}
+
+			j = j + sz
+		}
+	}
+}
+
+func (t *Terminal) WriteCells(cells []Cell) {
+	if len(cells) == 0 {
+		return
+	}
+
+	t.interLock.Lock()
+	defer t.interLock.Unlock()
+
+	for _, cell := range cells {
+		t.interBuf = append(t.interBuf, cell)
+	}
+}
+
+func (t *Terminal) Render() {
+	t.doneLock.Lock()
+	defer t.doneLock.Unlock()
+
+	if t.done {
+		return
+	}
+
+	t.reconcileCells()
+	t.flush()
+	t.resetBuffer()
+}
+
+func (t *Terminal) writeBuffer(b []byte) {
+	t.bufLock.Lock()
+	defer t.bufLock.Unlock()
+
+	t.buffer.Write(b)
+}
+
+func (t *Terminal) resetBuffer() {
+	t.bufLock.Lock()
+	defer t.bufLock.Unlock()
+
+	t.buffer.Reset()
+}
+
+func (t *Terminal) flush() {
+	t.bufLock.Lock()
+	defer t.bufLock.Unlock()
+
+	t.outLock.Lock()
+	defer t.outLock.Unlock()
+
+	io.Copy(t.out, t.buffer)
+}
+
+func (t *Terminal) reconcileCells() {
+	t.displayLock.Lock()
+	defer t.displayLock.Unlock()
+	t.interLock.Lock()
+	defer t.interLock.Unlock()
+
+	var changed bool
+	sz := t.Size()
+
+	for _, c := range t.interBuf {
+		if c.Pos.X >= sz.X || c.Pos.Y >= sz.Y {
+			continue
+		}
+
+		t.display[c.Pos.X][c.Pos.Y] = c
+
+		if t.currentAttributes != c.Attrs {
+			changed = true
+			t.writeAttrs(c.Attrs)
+		}
+
+		if t.cursorPosition.X+1 != c.Pos.X {
+			t.SetCursor(c.Pos.X, c.Pos.Y)
+		}
+
+		t.writeRune(c.Value)
+	}
+
+	if changed {
+		t.writeAttrs(Attributes{})
+	}
+
+	t.SetCursor(0, 0)
+
+	t.interBuf = make([]Cell, 0)
+}
+
+func (t *Terminal) writeRune(r rune) {
+
+	t.writeBuffer([]byte(string(r)))
+
+	if t.cursorPosition.X+1 <= t.size.X {
+		t.cursorPosition.X = 1
+	} else {
+		t.cursorPosition.X++
+	}
+
+	if t.cursorPosition.Y+1 <= t.size.Y {
+		t.cursorPosition.Y = 1
+	} else {
+		t.cursorPosition.Y++
+	}
+}
+
+func (t *Terminal) writeAttrs(attrs Attributes) {
+	if t.currentAttributes.ForegroundColor != attrs.ForegroundColor {
+		t.writeBuffer([]byte(fmt.Sprintf(sgr, attrs.ForegroundColor)))
+		t.currentAttributes.ForegroundColor = attrs.ForegroundColor
+	}
+
+	if t.currentAttributes.BackgroundColor != attrs.BackgroundColor {
+		t.writeBuffer([]byte(fmt.Sprintf(sgr, attrs.BackgroundColor)))
+		t.currentAttributes.BackgroundColor = attrs.BackgroundColor
+	}
+}
+
+func (t *Terminal) watchInput() {
+	go func() {
+		buf := make([]byte, 1)
+		for {
+			_, err := t.in.Read(buf)
+			if err != nil {
+				break
+			}
+
+			select {
+			case t.event <- Event(buf[0]):
+			default:
+			}
+		}
+	}()
+}
+
+func (t *Terminal) watchSize() {
+	go func() {
+		timer := time.NewTicker(1 * time.Second)
+
+		for {
+			select {
+			case <-t.shutdown:
+				timer.Stop()
+				break
+			case <-timer.C:
+				x, y := t.sizeInternal()
+				if x != 0 && y != 0 {
+					t.setSize(x, y)
+				}
+
+				continue
+			}
+
+			break
+		}
+	}()
+}
+
+func (t *Terminal) sizeInternal() (x, y int) {
+	sz, err := unix.IoctlGetWinsize(int(t.in.Fd()), unix.TIOCGWINSZ)
+	if err != nil {
+		return 0, 0
+	}
+
+	return int(sz.Col), int(sz.Row)
+}
+
+func (t *Terminal) writeOut(b []byte) {
+	t.outLock.Lock()
+	defer t.outLock.Unlock()
+
+	t.out.Write(b)
+}
+
+func (t *Terminal) outFd() int {
+	t.outLock.Lock()
+	defer t.outLock.Unlock()
+
+	return int(t.out.Fd())
+}
+
+func (t *Terminal) enterAlt() {
+	t.writeOut([]byte(smcup))
+	t.resetBuffer()
+}
+
+func (t *Terminal) exitAlt() {
+	t.writeOut([]byte(rmcup))
+	t.resetBuffer()
+}
+
+func (t *Terminal) enterRaw() {
+	termios := t.termios
+
+	termios.Iflag &^= unix.IGNBRK | unix.BRKINT | unix.PARMRK | unix.ISTRIP |
+		unix.INLCR | unix.IGNCR | unix.ICRNL | unix.IXON
+
+	termios.Oflag &^= unix.OPOST
+
+	termios.Lflag &^= unix.ECHO | unix.ECHONL | unix.ICANON | unix.ISIG |
+		unix.IEXTEN
+
+	termios.Cflag &^= unix.CSIZE | unix.PARENB
+	termios.Cflag |= unix.CS8
+	termios.Cc[unix.VMIN] = 1
+	termios.Cc[unix.VTIME] = 0
+
+	err := unix.IoctlSetTermios(t.outFd(), unix.TCSETS, &termios)
+	if err != nil {
+		t.exitAlt()
+		t.out.Close()
+		t.in.Close()
+		log.Panic(err)
+	}
+}
+
+func (t *Terminal) exitRaw() {
+	err := unix.IoctlSetTermios(t.outFd(), unix.TCSETS, &t.termios)
+	if err != nil {
+		t.out.Close()
+		t.in.Close()
+		log.Panic(err)
+	}
+}
+
+func (s *Scene) Render() {
+	c := make([]Cell, 0)
+
+	for _, row := range s.Window.Render() {
+		for _, col := range row {
+			c = append(c, col)
+		}
+	}
+
+	s.Terminal.WriteCells(c)
+	s.Terminal.Render()
+}
+
+func (w *WindowWidget) AddWidget(widget Widget) {
+	if w.widgets == nil {
+		w.widgets = make([]Widget, 0)
+	}
+
+	w.widgets = append(w.widgets, widget)
+}
+
+func (w *WindowWidget) Render() [][]Cell {
+	c := make([][]Cell, 0)
+
+	var y int
+	for _, w := range w.widgets {
+		for _, row := range w.Render() {
+			t := make([]Cell, len(row))
+			c = append(c, t)
+
+			for j, col := range row {
+				col.Pos.Y = y
+				c[y][j] = col
+			}
+
+			y++
+		}
+	}
+
+	return c
+}
+
+func (l *ListWidget) Render() [][]Cell {
+	l.cellLock.Lock()
+	defer l.cellLock.Unlock()
+
+	var sx int
+	sy := len(l.cells)
+
+	if sy > 0 {
+		sx = len(l.cells[0])
+	} else {
+		return make([][]Cell, 0)
+	}
+
+	dx := 0
+	dy := 0
+	if l.lastSize.X > sx {
+		dx = l.lastSize.X - sx
+	}
+
+	if l.lastSize.Y > sy {
+		dy = l.lastSize.Y - sy
+	}
+
+	for y := 0; y < sy+dy; y++ {
+		if y >= sy {
+			l.cells = append(l.cells, []Cell{})
+		}
+
+		for x := 0; x < sx+dx; x++ {
+			if x >= sx || y >= sy {
+				c := Cell{}
+				c.Pos.X = x
+				c.Pos.Y = y
+				c.Value = ' '
+				l.cells[y] = append(l.cells[y], c)
+			} else {
+				l.cells[y][x].Attrs = l.Attrs
+				l.cells[y][x].Pos.X = x
+				l.cells[y][x].Pos.Y = y
+			}
+		}
+	}
+
+	l.lastSize.X = sx
+	l.lastSize.Y = sy
+	return append([][]Cell(nil), l.cells...)
+}
+
+func (l *ListWidget) SetList(list []string) {
+	buf := make([][]rune, len(list))
+
+	for i, s := range list {
+		buf[i] = make([]rune, 0)
+
+		for _, r := range s {
+			buf[i] = append(buf[i], r)
+		}
+	}
+
+	l.listLock.Lock()
+	l.list = buf
+	l.listLock.Unlock()
+
+	l.recalculateCells()
+}
+
+func (l *ListWidget) SetBorder(b bool) {
+	if l.border == b {
+		return
+	}
+
+	l.border = b
+
+	l.recalculateCells()
+}
+
+func (l *ListWidget) SetRightAlign(b bool) {
+	if l.rightAlign == b {
+		return
+	}
+
+	l.rightAlign = b
+
+	l.recalculateCells()
+}
+
+func (l *ListWidget) recalculateCells() {
+	l.listLock.Lock()
+	defer l.listLock.Unlock()
+
+	var longest int
+	var border int
+
+	for _, s := range l.list {
+		if longest < len(s) {
+			longest = len(s)
+		}
+	}
+
+	cells := make([][]Cell, len(l.list))
+
+	if l.border {
+		border = 1
+
+		top := make([]Cell, longest+2)
+		top[0] = Cell{Value: '┏'}
+		top[longest+1] = Cell{Value: '┓'}
+		for i := 1; i <= longest; i++ {
+			top[i] = Cell{Value: '━'}
+		}
+
+		bottom := append([]Cell(nil), top...)
+		bottom[0] = Cell{Value: '┗'}
+		bottom[longest+1] = Cell{Value: '┛'}
+
+		cells = append([][]Cell{top}, cells...)
+		cells = append(cells, bottom)
+	}
+
+	for i, s := range l.list {
+		cells[i+border] = make([]Cell, longest+border+border)
+
+		var start int
+		if l.rightAlign {
+			start = longest - len(s)
+		} else {
+			start = 0
+		}
+
+		if l.border {
+			c := Cell{Value: '┃'}
+			cells[i+border][0] = c
+			cells[i+border][longest+1] = c
+		}
+
+		for j := 0; j < longest; j++ {
+			c := Cell{}
+			if j > start+len(s)-1 || j < start {
+				c.Value = ' '
+			} else {
+				c.Value = s[j-start]
+			}
+
+			cells[i+border][j+border] = c
+		}
+	}
+
+	l.cellLock.Lock()
+	defer l.cellLock.Unlock()
+
+	l.cells = cells
+}
+
+func DecimalComparator(a, b interface{}) int {
+	aAsserted := a.(decimal.Decimal)
+	bAsserted := b.(decimal.Decimal)
+
+	switch {
+	case aAsserted.GreaterThan(bAsserted):
+		return 1
+	case aAsserted.LessThan(bAsserted):
+		return -1
+	default:
+		return 0
+	}
+}
+
+func ReverseDecimalComparator(a, b interface{}) int {
+	aAsserted := a.(decimal.Decimal)
+	bAsserted := b.(decimal.Decimal)
+
+	switch {
+	case aAsserted.GreaterThan(bAsserted):
+		return -1
+	case aAsserted.LessThan(bAsserted):
+		return 1
+	default:
+		return 0
+	}
+}