Files
levi/internal/console/input.go
2026-03-26 12:21:48 +09:00

96 lines
1.4 KiB
Go

package console
import (
"io"
"os"
"unicode/utf8"
)
type Key int
const (
KeyNormal Key = iota
KeyUp
KeyDown
KeyRight
KeyLeft
)
const RuneEscape rune = 0x1b
const RuneEnter rune = '\r'
const RuneBackspace rune = '\b'
const RuneDelete rune = 0x7f
var buf []rune = make([]rune, 0)
func runeSize(b byte) int {
switch {
case b&0x80 == 0:
return 1
case b&0xe0 == 0xc0:
return 2
case b&0xf0 == 0xe0:
return 3
case b&0xf8 == 0xf0:
return 4
default:
return -1 // invalid
}
}
func readRune() rune {
buf := make([]byte, 1)
_, err := io.ReadFull(os.Stdin, buf)
if err != nil {
panic(err)
}
expected := runeSize(buf[0])
if expected == -1 {
panic("Invalid UTF-8 head")
}
full := make([]byte, expected)
full[0] = buf[0]
if expected > 1 {
_, err := io.ReadFull(os.Stdin, full[1:])
if err != nil {
panic(err)
}
}
r, size := utf8.DecodeRune(full)
if r == utf8.RuneError && size == 1 {
panic("Invalid UTF-8 body")
}
return r
}
func ReadKey() (Key, rune) {
if len(buf) > 0 {
r := buf[0]
buf = buf[1:]
return KeyNormal, r
}
r := readRune()
if r != RuneEscape {
return KeyNormal, r
}
r2 := readRune()
if r2 != '[' {
buf = append(buf, r2)
return KeyNormal, r
}
r3 := readRune()
switch r3 {
case 'A':
return KeyUp, 0
case 'B':
return KeyDown, 0
case 'C':
return KeyRight, 0
case 'D':
return KeyLeft, 0
}
buf = append(buf, r2)
buf = append(buf, r3)
return KeyNormal, r
}