Files
levi/internal/editor/editor.go
2026-03-25 17:11:08 +09:00

173 lines
2.9 KiB
Go

package editor
import (
"strings"
"unicode/utf8"
"tea.kareha.org/lab/levi/internal/console"
"tea.kareha.org/lab/levi/internal/util"
)
type mode int
const (
modeCommand = iota
modeInsert
)
type Editor struct {
scr *Screen
kb *Keyboard
col, row int
x, y int
lines []string
head, tail string
insert *strings.Builder
mode mode
}
func Init() *Editor {
console.Raw()
scr := NewScreen()
kb := NewKeyboard()
return &Editor{
scr: &scr,
kb: &kb,
col: 0,
row: 0,
x: 0,
y: 0,
lines: make([]string, 1),
head: "",
tail: "",
insert: new(strings.Builder),
mode: modeCommand,
}
}
func (ed *Editor) Finish() {
console.Clear()
console.HomeCursor()
console.Cooked()
console.ShowCursor()
}
func (ed *Editor) runeCount() int {
return utf8.RuneCountInString(ed.lines[ed.row])
}
func (ed *Editor) drawBuffer() {
for i := 0; i < len(ed.lines); i++ {
console.MoveCursor(0, i)
if ed.mode == modeInsert && i == ed.row {
console.Print(ed.head)
console.Print(ed.insert.String())
console.Print(ed.tail)
} else {
console.Print(ed.lines[i])
}
}
}
func (ed *Editor) drawStatus() {
_, h := console.Size()
console.MoveCursor(0, h-2)
switch ed.mode {
case modeCommand:
console.Print("-- [command] q: quit, i: insert, a: insert after --")
case modeInsert:
console.Print("-- [insert] Esc: command mode --")
}
}
func (ed *Editor) updateCursor() {
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)
case modeInsert:
ed.x = util.StringWidth(ed.head+ed.insert.String(), ed.col)
}
ed.y = ed.row
}
func (ed *Editor) repaint() {
console.HideCursor()
console.Clear()
console.HomeCursor()
ed.drawBuffer()
ed.drawStatus()
ed.updateCursor()
console.MoveCursor(ed.x, ed.y)
console.ShowCursor()
}
func (ed *Editor) exitInsert() {
ed.lines[ed.row] = ed.head + ed.insert.String() + ed.tail
ed.tail = ""
ed.insert = new(strings.Builder)
ed.mode = modeCommand
ed.moveLeft(1)
}
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:])
ed.row++
ed.lines[ed.row] = ed.tail
ed.col = 0
ed.head = ""
ed.insert = new(strings.Builder)
}
func (ed *Editor) insertRune(r rune) {
ed.insert.WriteRune(r)
ed.col++
}
func (ed *Editor) Main() {
for {
ed.repaint()
r := ed.kb.ReadRune()
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':
ed.moveUp(1)
}
case modeInsert:
switch r {
case Escape:
ed.exitInsert()
case Enter:
ed.insertNewline()
default:
ed.insertRune(r)
}
}
}
}