2 files changed, 134 insertions, 12 deletions

diff --git a/ui/context.go b/ui/context.go
index e7d9ebe..ae9e561 100644
--- a/ui/context.go
+++ b/ui/context.go
@@ -3,7 +3,8 @@ package ui
 import (
 	"fmt"
 
-	"github.com/nsf/termbox-go"
+	"github.com/mattn/go-runewidth"
+	tb "github.com/nsf/termbox-go"
 )
 
 // A context allows you to draw in a sub-region of the terminal
@@ -38,15 +39,15 @@ func (ctx *Context) Subcontext(x, y, width, height int) *Context {
 	}
 }
 
-func (ctx *Context) SetCell(x, y int, ch rune, fg, bg termbox.Attribute) {
+func (ctx *Context) SetCell(x, y int, ch rune, fg, bg tb.Attribute) {
 	if x >= ctx.width || y >= ctx.height {
 		panic(fmt.Errorf("Attempted to draw outside of context"))
 	}
-	termbox.SetCell(ctx.x+x, ctx.y+y, ch, fg, bg)
+	tb.SetCell(ctx.x+x, ctx.y+y, ch, fg, bg)
 }
 
-func (ctx *Context) Printf(x, y int, ref termbox.Cell,
-	format string, a ...interface{}) {
+func (ctx *Context) Printf(x, y int, ref tb.Cell,
+	format string, a ...interface{}) int {
 
 	if x >= ctx.width || y >= ctx.height {
 		panic(fmt.Errorf("Attempted to draw outside of context"))
@@ -64,29 +65,35 @@ func (ctx *Context) Printf(x, y int, ref termbox.Cell,
 		return y < ctx.height
 	}
 	for _, ch := range str {
+		if str == " こんにちは " {
+			fmt.Printf("%c\n", ch)
+		}
 		switch ch {
 		case '\n':
 			if !newline() {
-				return
+				return runewidth.StringWidth(str)
 			}
 		case '\r':
 			x = old_x
 		default:
-			termbox.SetCell(x, y, ch, ref.Fg, ref.Bg)
-			x++
+			tb.SetCell(x, y, ch, ref.Fg, ref.Bg)
+			x += runewidth.RuneWidth(ch)
 			if x == old_x+ctx.width {
 				if !newline() {
-					return
+					return runewidth.StringWidth(str)
 				}
 			}
 		}
 	}
+
+	return runewidth.StringWidth(str)
 }
 
-func (ctx *Context) Fill(x, y, width, height int, ref termbox.Cell) {
+func (ctx *Context) Fill(x, y, width, height int, ref tb.Cell) {
 	_x := x
-	for ; y < height && y < ctx.height; y++ {
-		for ; x < width && x < ctx.width; x++ {
+	_y := y
+	for ; y < _y+height && y < ctx.height; y++ {
+		for ; x < _x+width && x < ctx.width; x++ {
 			ctx.SetCell(x, y, ref.Ch, ref.Fg, ref.Bg)
 		}
 		x = _x
diff --git a/ui/tab.go b/ui/tab.go
new file mode 100644
index 0000000..e6a8aa5
--- /dev/null
+++ b/ui/tab.go
@@ -0,0 +1,115 @@
+package ui
+
+import (
+	tb "github.com/nsf/termbox-go"
+)
+
+type Tabs struct {
+	Tabs       []*Tab
+	TabStrip   *TabStrip
+	TabContent *TabContent
+	Selected   int
+
+	onInvalidateStrip   func(d Drawable)
+	onInvalidateContent func(d Drawable)
+}
+
+type Tab struct {
+	Content Drawable
+	Name    string
+	invalid bool
+}
+
+type TabStrip Tabs
+type TabContent Tabs
+
+func NewTabs() *Tabs {
+	tabs := &Tabs{}
+	tabs.TabStrip = (*TabStrip)(tabs)
+	tabs.TabContent = (*TabContent)(tabs)
+	return tabs
+}
+
+func (tabs *Tabs) Add(content Drawable, name string) {
+	tabs.Tabs = append(tabs.Tabs, &Tab{
+		Content: content,
+		Name:    name,
+	})
+	tabs.TabStrip.Invalidate()
+	content.OnInvalidate(tabs.invalidateChild)
+}
+
+func (tabs *Tabs) invalidateChild(d Drawable) {
+	for i, tab := range tabs.Tabs {
+		if tab.Content == d {
+			if i == tabs.Selected {
+				tabs.TabContent.Invalidate()
+			}
+			return
+		}
+	}
+}
+
+func (tabs *Tabs) Remove(content Drawable) {
+	for i, tab := range tabs.Tabs {
+		if tab.Content == content {
+			tabs.Tabs = append(tabs.Tabs[:i], tabs.Tabs[i+1:]...)
+			break
+		}
+	}
+	tabs.TabStrip.Invalidate()
+}
+
+func (tabs *Tabs) Select(index int) {
+	if tabs.Selected != index {
+		tabs.Selected = index
+		tabs.TabStrip.Invalidate()
+		tabs.TabContent.Invalidate()
+	}
+}
+
+// TODO: Color repository
+func (strip *TabStrip) Draw(ctx *Context) {
+	x := 0
+	for i, tab := range strip.Tabs {
+		cell := tb.Cell{
+			Fg: tb.ColorBlack,
+			Bg: tb.ColorWhite,
+		}
+		if strip.Selected == i {
+			cell.Fg = tb.ColorDefault
+			cell.Bg = tb.ColorDefault
+		}
+		x += ctx.Printf(x, 0, cell, " %s ", tab.Name)
+	}
+	cell := tb.Cell{
+		Fg: tb.ColorBlack,
+		Bg: tb.ColorWhite,
+	}
+	ctx.Fill(x, 0, ctx.Width()-x, 1, cell)
+}
+
+func (strip *TabStrip) Invalidate() {
+	if strip.onInvalidateStrip != nil {
+		strip.onInvalidateStrip(strip)
+	}
+}
+
+func (strip *TabStrip) OnInvalidate(onInvalidate func(d Drawable)) {
+	strip.onInvalidateStrip = onInvalidate
+}
+
+func (content *TabContent) Draw(ctx *Context) {
+	tab := content.Tabs[content.Selected]
+	tab.Content.Draw(ctx)
+}
+
+func (content *TabContent) Invalidate() {
+	if content.onInvalidateContent != nil {
+		content.onInvalidateContent(content)
+	}
+}
+
+func (content *TabContent) OnInvalidate(onInvalidate func(d Drawable)) {
+	content.onInvalidateContent = onInvalidate
+}