8 files changed, 663 insertions, 0 deletions
diff --git a/lib/ui/borders.go b/lib/ui/borders.go
new file mode 100644
index 0000000..08071ad
--- /dev/null
+++ b/lib/ui/borders.go
@@ -0,0 +1,73 @@
+package ui
+
+import (
+	tb "github.com/nsf/termbox-go"
+)
+
+const (
+	BORDER_LEFT   = 1 << iota
+	BORDER_TOP    = 1 << iota
+	BORDER_RIGHT  = 1 << iota
+	BORDER_BOTTOM = 1 << iota
+)
+
+type Bordered struct {
+	borders      uint
+	content      Drawable
+	onInvalidate func(d Drawable)
+}
+
+func NewBordered(content Drawable, borders uint) *Bordered {
+	b := &Bordered{
+		borders: borders,
+		content: content,
+	}
+	content.OnInvalidate(b.contentInvalidated)
+	return b
+}
+
+func (bordered *Bordered) contentInvalidated(d Drawable) {
+	bordered.Invalidate()
+}
+
+func (bordered *Bordered) Invalidate() {
+	if bordered.onInvalidate != nil {
+		bordered.onInvalidate(bordered)
+	}
+}
+
+func (bordered *Bordered) OnInvalidate(onInvalidate func(d Drawable)) {
+	bordered.onInvalidate = onInvalidate
+}
+
+func (bordered *Bordered) Draw(ctx *Context) {
+	x := 0
+	y := 0
+	width := ctx.Width()
+	height := ctx.Height()
+	cell := tb.Cell{
+		Ch: ' ',
+		Fg: tb.ColorBlack,
+		Bg: tb.ColorWhite,
+	}
+	if bordered.borders&BORDER_LEFT != 0 {
+		ctx.Fill(0, 0, 1, ctx.Height(), cell)
+		x += 1
+		width -= 1
+	}
+	if bordered.borders&BORDER_TOP != 0 {
+		ctx.Fill(0, 0, ctx.Width(), 1, cell)
+		y += 1
+		height -= 1
+	}
+	if bordered.borders&BORDER_RIGHT != 0 {
+		ctx.Fill(ctx.Width()-1, 0, 1, ctx.Height(), cell)
+		width -= 1
+	}
+	if bordered.borders&BORDER_BOTTOM != 0 {
+		ctx.Fill(0, ctx.Height()-1, ctx.Width(), 1, cell)
+		height -= 1
+	}
+	subctx := ctx.Subcontext(x, y, width, height)
+	bordered.content.Draw(subctx)
+}
diff --git a/lib/ui/context.go b/lib/ui/context.go
new file mode 100644
index 0000000..ca3f452
--- /dev/null
+++ b/lib/ui/context.go
@@ -0,0 +1,109 @@
+package ui
+
+import (
+	"fmt"
+
+	"github.com/mattn/go-runewidth"
+	tb "github.com/nsf/termbox-go"
+)
+
+// A context allows you to draw in a sub-region of the terminal
+type Context struct {
+	x      int
+	y      int
+	width  int
+	height int
+}
+
+func (ctx *Context) X() int {
+	return ctx.x
+}
+
+func (ctx *Context) Y() int {
+	return ctx.y
+}
+
+func (ctx *Context) Width() int {
+	return ctx.width
+}
+
+func (ctx *Context) Height() int {
+	return ctx.height
+}
+
+func NewContext(width, height int) *Context {
+	return &Context{0, 0, width, height}
+}
+
+func (ctx *Context) Subcontext(x, y, width, height int) *Context {
+	if x+width > ctx.width || y+height > ctx.height {
+		panic(fmt.Errorf("Attempted to create context larger than parent"))
+	}
+	return &Context{
+		x:      ctx.x + x,
+		y:      ctx.y + y,
+		width:  width,
+		height: height,
+	}
+}
+
+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"))
+	}
+	tb.SetCell(ctx.x+x, ctx.y+y, ch, fg, bg)
+}
+
+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"))
+	}
+
+	str := fmt.Sprintf(format, a...)
+
+	x += ctx.x
+	y += ctx.y
+	old_x := x
+
+	newline := func() bool {
+		x = old_x
+		y++
+		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 runewidth.StringWidth(str)
+			}
+		case '\r':
+			x = old_x
+		default:
+			tb.SetCell(x, y, ch, ref.Fg, ref.Bg)
+			x += runewidth.RuneWidth(ch)
+			if x == old_x+ctx.width {
+				if !newline() {
+					return runewidth.StringWidth(str)
+				}
+			}
+		}
+	}
+
+	return runewidth.StringWidth(str)
+}
+
+func (ctx *Context) Fill(x, y, width, height int, ref tb.Cell) {
+	_x := 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/lib/ui/drawable.go b/lib/ui/drawable.go
new file mode 100644
index 0000000..ef09451
--- /dev/null
+++ b/lib/ui/drawable.go
@@ -0,0 +1,10 @@
+package ui
+
+type Drawable interface {
+	// Called when this renderable should draw itself
+	Draw(ctx *Context)
+	// Specifies a function to call when this cell needs to be redrawn
+	OnInvalidate(callback func(d Drawable))
+	// Invalidates the drawable
+	Invalidate()
+}
diff --git a/lib/ui/grid.go b/lib/ui/grid.go
new file mode 100644
index 0000000..ede7d0c
--- /dev/null
+++ b/lib/ui/grid.go
@@ -0,0 +1,191 @@
+package ui
+
+import (
+	"fmt"
+	"math"
+)
+
+type Grid struct {
+	rows         []GridSpec
+	rowLayout    []gridLayout
+	columns      []GridSpec
+	columnLayout []gridLayout
+	Cells        []*GridCell
+	onInvalidate func(d Drawable)
+	invalid      bool
+}
+
+const (
+	SIZE_EXACT  = iota
+	SIZE_WEIGHT = iota
+)
+
+// Specifies the layout of a single row or column
+type GridSpec struct {
+	// One of SIZE_EXACT or SIZE_WEIGHT
+	Strategy int
+	// If Strategy = SIZE_EXACT, this is the number of cells this row/col shall
+	// occupy. If SIZE_WEIGHT, the space left after all exact rows/cols are
+	// measured is distributed amonst the remainder weighted by this value.
+	Size int
+}
+
+// Used to cache layout of each row/column
+type gridLayout struct {
+	Offset int
+	Size   int
+}
+
+type GridCell struct {
+	Row     int
+	Column  int
+	RowSpan int
+	ColSpan int
+	Content Drawable
+	invalid bool
+}
+
+func NewGrid() *Grid {
+	return &Grid{invalid: true}
+}
+
+func (cell *GridCell) At(row, col int) *GridCell {
+	cell.Row = row
+	cell.Column = col
+	return cell
+}
+
+func (cell *GridCell) Span(rows, cols int) *GridCell {
+	cell.RowSpan = rows
+	cell.ColSpan = cols
+	return cell
+}
+
+func (grid *Grid) Rows(spec []GridSpec) *Grid {
+	grid.rows = spec
+	return grid
+}
+
+func (grid *Grid) Columns(spec []GridSpec) *Grid {
+	grid.columns = spec
+	return grid
+}
+
+func (grid *Grid) Draw(ctx *Context) {
+	invalid := grid.invalid
+	if invalid {
+		grid.reflow(ctx)
+	}
+	for _, cell := range grid.Cells {
+		if !cell.invalid && !invalid {
+			continue
+		}
+		rows := grid.rowLayout[cell.Row : cell.Row+cell.RowSpan]
+		cols := grid.columnLayout[cell.Column : cell.Column+cell.ColSpan]
+		x := cols[0].Offset
+		y := rows[0].Offset
+		width := 0
+		height := 0
+		for _, col := range cols {
+			width += col.Size
+		}
+		for _, row := range rows {
+			height += row.Size
+		}
+		subctx := ctx.Subcontext(x, y, width, height)
+		cell.Content.Draw(subctx)
+	}
+}
+
+func (grid *Grid) reflow(ctx *Context) {
+	grid.rowLayout = nil
+	grid.columnLayout = nil
+	flow := func(specs *[]GridSpec, layouts *[]gridLayout, extent int) {
+		exact := 0
+		weight := 0
+		nweights := 0
+		for _, spec := range *specs {
+			if spec.Strategy == SIZE_EXACT {
+				exact += spec.Size
+			} else if spec.Strategy == SIZE_WEIGHT {
+				nweights += 1
+				weight += spec.Size
+			}
+		}
+		offset := 0
+		for _, spec := range *specs {
+			layout := gridLayout{Offset: offset}
+			if spec.Strategy == SIZE_EXACT {
+				layout.Size = spec.Size
+			} else if spec.Strategy == SIZE_WEIGHT {
+				size := float64(spec.Size) / float64(weight)
+				size *= float64(extent - exact)
+				layout.Size = int(math.Floor(size))
+			}
+			offset += layout.Size
+			*layouts = append(*layouts, layout)
+		}
+	}
+	flow(&grid.rows, &grid.rowLayout, ctx.Height())
+	flow(&grid.columns, &grid.columnLayout, ctx.Width())
+	grid.invalid = false
+}
+
+func (grid *Grid) invalidateLayout() {
+	grid.invalid = true
+	if grid.onInvalidate != nil {
+		grid.onInvalidate(grid)
+	}
+}
+
+func (grid *Grid) Invalidate() {
+	grid.invalidateLayout()
+	for _, cell := range grid.Cells {
+		cell.Content.Invalidate()
+	}
+}
+
+func (grid *Grid) OnInvalidate(onInvalidate func(d Drawable)) {
+	grid.onInvalidate = onInvalidate
+}
+
+func (grid *Grid) AddChild(content Drawable) *GridCell {
+	cell := &GridCell{
+		RowSpan: 1,
+		ColSpan: 1,
+		Content: content,
+		invalid: true,
+	}
+	grid.Cells = append(grid.Cells, cell)
+	cell.Content.OnInvalidate(grid.cellInvalidated)
+	cell.invalid = true
+	grid.invalidateLayout()
+	return cell
+}
+
+func (grid *Grid) RemoveChild(cell *GridCell) {
+	for i, _cell := range grid.Cells {
+		if _cell == cell {
+			grid.Cells = append(grid.Cells[:i], grid.Cells[i+1:]...)
+			break
+		}
+	}
+	grid.invalidateLayout()
+}
+
+func (grid *Grid) cellInvalidated(drawable Drawable) {
+	var cell *GridCell
+	for _, cell = range grid.Cells {
+		if cell.Content == drawable {
+			break
+		}
+		cell = nil
+	}
+	if cell == nil {
+		panic(fmt.Errorf("Attempted to invalidate unknown cell"))
+	}
+	cell.invalid = true
+	if grid.onInvalidate != nil {
+		grid.onInvalidate(grid)
+	}
+}
diff --git a/lib/ui/interactive.go b/lib/ui/interactive.go
new file mode 100644
index 0000000..8bdf592
--- /dev/null
+++ b/lib/ui/interactive.go
@@ -0,0 +1,15 @@
+package ui
+
+import (
+	tb "github.com/nsf/termbox-go"
+)
+
+type Interactive interface {
+	// Returns true if the event was handled by this component
+	Event(event tb.Event) bool
+}
+
+type Simulator interface {
+	// Queues up the given input events for simulation
+	Simulate(events []tb.Event)
+}
diff --git a/lib/ui/tab.go b/lib/ui/tab.go
new file mode 100644
index 0000000..e6a8aa5
--- /dev/null
+++ b/lib/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
+}
diff --git a/lib/ui/text.go b/lib/ui/text.go
new file mode 100644
index 0000000..6164837
--- /dev/null
+++ b/lib/ui/text.go
@@ -0,0 +1,71 @@
+package ui
+
+import (
+	"github.com/mattn/go-runewidth"
+	tb "github.com/nsf/termbox-go"
+)
+
+const (
+	TEXT_LEFT   = iota
+	TEXT_CENTER = iota
+	TEXT_RIGHT  = iota
+)
+
+type Text struct {
+	text         string
+	strategy     uint
+	fg           tb.Attribute
+	bg           tb.Attribute
+	onInvalidate func(d Drawable)
+}
+
+func NewText(text string) *Text {
+	return &Text{text: text}
+}
+
+func (t *Text) Text(text string) *Text {
+	t.text = text
+	t.Invalidate()
+	return t
+}
+
+func (t *Text) Strategy(strategy uint) *Text {
+	t.strategy = strategy
+	t.Invalidate()
+	return t
+}
+
+func (t *Text) Color(fg tb.Attribute, bg tb.Attribute) *Text {
+	t.fg = fg
+	t.bg = bg
+	t.Invalidate()
+	return t
+}
+
+func (t *Text) Draw(ctx *Context) {
+	size := runewidth.StringWidth(t.text)
+	cell := tb.Cell{
+		Ch: ' ',
+		Fg: t.fg,
+		Bg: t.bg,
+	}
+	x := 0
+	if t.strategy == TEXT_CENTER {
+		x = (ctx.Width() - size) / 2
+	}
+	if t.strategy == TEXT_RIGHT {
+		x = ctx.Width() - size
+	}
+	ctx.Fill(0, 0, ctx.Width(), ctx.Height(), cell)
+	ctx.Printf(x, 0, cell, "%s", t.text)
+}
+
+func (t *Text) OnInvalidate(onInvalidate func(d Drawable)) {
+	t.onInvalidate = onInvalidate
+}
+
+func (t *Text) Invalidate() {
+	if t.onInvalidate != nil {
+		t.onInvalidate(t)
+	}
+}
diff --git a/lib/ui/ui.go b/lib/ui/ui.go
new file mode 100644
index 0000000..9ea037c
--- /dev/null
+++ b/lib/ui/ui.go
@@ -0,0 +1,79 @@
+package ui
+
+import (
+	tb "github.com/nsf/termbox-go"
+
+	"git.sr.ht/~sircmpwn/aerc2/config"
+)
+
+type UI struct {
+	Exit    bool
+	Content Drawable
+	ctx     *Context
+
+	interactive []Interactive
+
+	tbEvents      chan tb.Event
+	invalidations chan interface{}
+}
+
+func Initialize(conf *config.AercConfig, content Drawable) (*UI, error) {
+	if err := tb.Init(); err != nil {
+		return nil, err
+	}
+	width, height := tb.Size()
+	state := UI{
+		Content: content,
+		ctx:     NewContext(width, height),
+
+		tbEvents:      make(chan tb.Event, 10),
+		invalidations: make(chan interface{}),
+	}
+	tb.SetInputMode(tb.InputEsc | tb.InputMouse)
+	tb.SetOutputMode(tb.Output256)
+	go (func() {
+		for !state.Exit {
+			state.tbEvents <- tb.PollEvent()
+		}
+	})()
+	go (func() { state.invalidations <- nil })()
+	content.OnInvalidate(func(_ Drawable) {
+		go (func() { state.invalidations <- nil })()
+	})
+	return &state, nil
+}
+
+func (state *UI) Close() {
+	tb.Close()
+}
+
+func (state *UI) Tick() bool {
+	select {
+	case event := <-state.tbEvents:
+		switch event.Type {
+		case tb.EventKey:
+			if event.Key == tb.KeyEsc {
+				state.Exit = true
+			}
+		case tb.EventResize:
+			tb.Clear(tb.ColorDefault, tb.ColorDefault)
+			state.ctx = NewContext(event.Width, event.Height)
+			state.Content.Invalidate()
+		}
+		if state.interactive != nil {
+			for _, i := range state.interactive {
+				i.Event(event)
+			}
+		}
+	case <-state.invalidations:
+		state.Content.Draw(state.ctx)
+		tb.Flush()
+	default:
+		return false
+	}
+	return true
+}
+
+func (state *UI) AddInteractive(i Interactive) {
+	state.interactive = append(state.interactive, i)
+}