Add arrow keys

internal/editor/editor.go

@@ -16,8 +16,8 @@ const (
 )
 
 type Editor struct {
-	scr        *Screen
-	kb         *Keyboard
+	scr        *screen
+	kb         *keyboard
 	col, row   int
 	x, y       int
 	lines      []string
@@ -29,8 +29,8 @@ type Editor struct {
 func Init() *Editor {
 	console.Raw()
 
-	scr := NewScreen()
-	kb := NewKeyboard()
+	scr := newScreen()
+	kb := newKeyboard()
 
 	return &Editor{
 		scr:    &scr,
@@ -58,42 +58,85 @@ func (ed *Editor) runeCount() int {
 	return utf8.RuneCountInString(ed.lines[ed.row])
 }
 
+func (ed *Editor) lineHeight(line string) int {
+	w, _ := ed.scr.size()
+	rc := utf8.RuneCountInString(line)
+	width := util.StringWidth(line, rc)
+	return 1 + max(width-1, 0)/w
+}
+
 func (ed *Editor) drawBuffer() {
+	_, h := ed.scr.size()
+
+	y := 0
 	for i := 0; i < len(ed.lines); i++ {
-		console.MoveCursor(0, i)
+		var line string
 		if ed.mode == modeInsert && i == ed.row {
-			console.Print(ed.head)
-			console.Print(ed.insert.String())
-			console.Print(ed.tail)
+			line = ed.head + ed.insert.String() + ed.tail
 		} else {
-			console.Print(ed.lines[i])
+			line = ed.lines[i]
 		}
+
+		console.MoveCursor(0, y)
+		console.Print(line)
+
+		y += ed.lineHeight(line)
+		if y >= h-1 {
+			break
+		}
+	}
+
+	for ; y < h-1; y++ {
+		console.MoveCursor(0, y)
+		console.Print("~")
 	}
 }
 
 func (ed *Editor) drawStatus() {
-	_, h := console.Size()
+	_, h := ed.scr.size()
 
-	console.MoveCursor(0, h-2)
+	console.MoveCursor(0, h-1)
 	switch ed.mode {
 	case modeCommand:
-		console.Print("-- [command] q: quit, i: insert, a: insert after --")
+		console.Print("c")
 	case modeInsert:
-		console.Print("-- [insert] Esc: command mode --")
+		console.Print("i")
 	}
 }
 
 func (ed *Editor) updateCursor() {
+	w, _ := ed.scr.size()
+
+	var dy int
 	switch ed.mode {
 	case modeCommand:
 		ed.row = min(max(ed.row, 0), max(len(ed.lines)-1, 0))
 		len := ed.runeCount()
 		ed.col = min(ed.col, max(len-1, 0))
-		ed.x = util.StringWidth(ed.lines[ed.row], ed.col)
+
+		// XXX approximation
+		width := util.StringWidth(ed.lines[ed.row], ed.col)
+		ed.x = width % w
+		dy = width / w
 	case modeInsert:
-		ed.x = util.StringWidth(ed.head+ed.insert.String(), ed.col)
+		// XXX approximation
+		width := util.StringWidth(ed.head+ed.insert.String(), ed.col)
+		ed.x = width % w
+		dy = width / w
 	}
-	ed.y = ed.row
+
+	y := 0
+	for i := 0; i < ed.row; i++ {
+		var line string
+		if ed.mode == modeInsert && i == ed.row {
+			line = ed.head + ed.insert.String() + ed.tail
+		} else {
+			line = ed.lines[i]
+		}
+
+		y += ed.lineHeight(line)
+	}
+	ed.y = y + dy
 }
 
 func (ed *Editor) repaint() {
@@ -120,11 +163,18 @@ func (ed *Editor) exitInsert() {
 }
 
 func (ed *Editor) insertNewline() {
-	ed.lines[ed.row] = ed.head + ed.insert.String()
-	ed.lines = append(ed.lines, "")
-	copy(ed.lines[ed.row+1:], ed.lines[ed.row:])
+	lines := make([]string, 0, len(ed.lines)+1)
+	lines = append(lines, ed.lines[:ed.row+1]...)
+	lines = append(lines, "")
+	if ed.row+1 < len(ed.lines) {
+		lines = append(lines, ed.lines[ed.row+1:]...)
+	}
+
+	lines[ed.row] = ed.head + ed.insert.String()
+	lines[ed.row+1] = ed.tail
+	ed.lines = lines
 	ed.row++
-	ed.lines[ed.row] = ed.tail
+
 	ed.col = 0
 	ed.head = ""
 	ed.insert = new(strings.Builder)
@@ -139,33 +189,63 @@ func (ed *Editor) Main() {
 	for {
 		ed.repaint()
 
-		r := ed.kb.ReadRune()
+		k, r := ed.kb.readKey()
 		switch ed.mode {
 		case modeCommand:
-			switch r {
-			case 'q':
-				return
-			case 'i':
-				ed.enterInsert()
-			case 'a':
-				ed.enterInsertAfter()
-			case 'h':
-				ed.moveLeft(1)
-			case 'l':
-				ed.moveRight(1)
-			case 'j':
-				ed.moveDown(1)
-			case 'k':
+			switch k {
+			case keyNormal:
+				switch r {
+				case 'q':
+					return
+				case 'i':
+					ed.enterInsert()
+				case 'a':
+					ed.enterInsertAfter()
+				case 'h':
+					ed.moveLeft(1)
+				case 'l':
+					ed.moveRight(1)
+				case 'j':
+					ed.moveDown(1)
+				case 'k':
+					ed.moveUp(1)
+				}
+			case keyUp:
 				ed.moveUp(1)
+			case keyDown:
+				ed.moveDown(1)
+			case keyRight:
+				ed.moveRight(1)
+			case keyLeft:
+				ed.moveLeft(1)
+			default:
+				// TODO ring
 			}
 		case modeInsert:
-			switch r {
-			case Escape:
+			switch k {
+			case keyNormal:
+				switch r {
+				case runeEscape:
+					ed.exitInsert()
+				case runeEnter:
+					ed.insertNewline()
+				default:
+					ed.insertRune(r)
+				}
+			case keyUp:
 				ed.exitInsert()
-			case Enter:
-				ed.insertNewline()
+				ed.moveUp(1)
+			case keyDown:
+				ed.exitInsert()
+				ed.moveDown(1)
+			case keyRight:
+				ed.exitInsert()
+				ed.moveRight(1)
+			case keyLeft:
+				ed.exitInsert()
+				ed.moveLeft(1)
 			default:
-				ed.insertRune(r)
+				// TODO ring
 			}
 		}
 	}

internal/editor/keyboard.go

@@ -4,15 +4,56 @@ import (
 	"tea.kareha.org/lab/levi/internal/console"
 )
 
-const Escape rune = 0x1b
-const Enter rune = '\r'
+const runeEscape rune = 0x1b
+const runeEnter rune = '\r'
 
-type Keyboard struct{}
+type key int
 
-func NewKeyboard() Keyboard {
-	return Keyboard{}
+const (
+	keyNormal = iota
+	keyUp
+	keyDown
+	keyRight
+	keyLeft
+)
+
+type keyboard struct {
+	buf []rune
 }
 
-func (kb *Keyboard) ReadRune() rune {
-	return console.ReadRune()
+func newKeyboard() keyboard {
+	return keyboard{
+		buf: make([]rune, 0),
+	}
+}
+
+func (kb *keyboard) readKey() (key, rune) {
+	if len(kb.buf) > 0 {
+		r := kb.buf[0]
+		kb.buf = kb.buf[1:]
+		return keyNormal, r
+	}
+	r := console.ReadRune()
+	if r != runeEscape {
+		return keyNormal, r
+	}
+	r2 := console.ReadRune()
+	if r2 != '[' {
+		kb.buf = append(kb.buf, r2)
+		return keyNormal, r
+	}
+	r3 := console.ReadRune()
+	switch r3 {
+	case 'A':
+		return keyUp, 0
+	case 'B':
+		return keyDown, 0
+	case 'C':
+		return keyRight, 0
+	case 'D':
+		return keyLeft, 0
+	}
+	kb.buf = append(kb.buf, r2)
+	kb.buf = append(kb.buf, r3)
+	return keyNormal, r
 }

internal/editor/screen.go

@@ -4,18 +4,18 @@ import (
 	"tea.kareha.org/lab/levi/internal/console"
 )
 
-type Screen struct {
+type screen struct {
 	w, h int
 }
 
-func NewScreen() Screen {
+func newScreen() screen {
 	w, h := console.Size()
-	return Screen{
+	return screen{
 		w: w,
 		h: h,
 	}
 }
 
-func (scr *Screen) Size() (int, int) {
+func (scr *screen) size() (int, int) {
 	return scr.w, scr.h
 }