Refactor

internal/console/console.go

@@ -2,9 +2,7 @@ package console
 
 import (
 	"fmt"
-	"io"
 	"os"
-	"unicode/utf8"
 
 	"golang.org/x/term"
 )
@@ -25,7 +23,7 @@ func Raw() {
 
 func Cooked() {
 	if state == nil {
-		panic("state is nil")
+		panic("invalid state")
 	}
 	term.Restore(int(os.Stdin.Fd()), state)
 }
@@ -53,47 +51,7 @@ func ShowCursor() {
 func Size() (int, int) {
 	w, h, err := term.GetSize(int(os.Stdout.Fd()))
 	if err != nil {
-		panic(err)
+		return 80, 24
 	}
 	return w, h
 }
-
-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
-}

internal/console/input.go

@@ -0,0 +1,95 @@
+package console
+
+import (
+	"io"
+	"os"
+	"unicode/utf8"
+)
+
+type Key int
+
+const (
+	KeyNormal = 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
+}

internal/console/output.go

@@ -0,0 +1,92 @@
+package console
+
+import (
+	"fmt"
+	"unicode"
+)
+
+func isWide(r rune) bool {
+	return r >= 0x1100 && (r <= 0x115f || // Hangul Jamo
+		r == 0x2329 || r == 0x232a ||
+		(r >= 0x2e80 && r <= 0xa4cf) ||
+		(r >= 0xac00 && r <= 0xd7a3) ||
+		(r >= 0xf900 && r <= 0xfaff) ||
+		(r >= 0xfe10 && r <= 0xfe19) ||
+		(r >= 0xfe30 && r <= 0xfe6f) ||
+		(r >= 0xff00 && r <= 0xff60) ||
+		(r >= 0xffe0 && r <= 0xffe6))
+}
+
+func isEmoji(r rune) bool {
+	return r >= 0x1f300 && r <= 0x1faff
+}
+
+const tabWidth = 4
+
+func runeWidth(r rune, x int) int {
+	// tab
+	if r == '\t' {
+		return tabWidth - (x % tabWidth)
+	}
+
+	// control code
+	if r == 0 {
+		return 0
+	}
+	if r < 32 || (r >= 0x7f && r < 0xa0) {
+		return 0
+	}
+
+	// combining mark
+	if unicode.Is(unicode.Mn, r) {
+		return 0
+	}
+
+	// wide (loose CJK)
+	if isWide(r) {
+		return 2
+	}
+
+	// emoji
+	if isEmoji(r) {
+		return 2
+	}
+
+	return 1
+}
+
+func StringWidth(s string, col int) int {
+	sum := 0
+	i := 0
+	for _, r := range s {
+		if i >= col {
+			break
+		}
+		w := runeWidth(r, sum)
+		sum += w
+		i++
+	}
+	return sum
+}
+
+func Print(s string) {
+	x := 0
+	for _, r := range s {
+		if r == '\t' {
+			spaces := tabWidth - (x % tabWidth)
+			for i := 0; i < spaces; i++ {
+				fmt.Print(" ")
+			}
+			x += spaces
+		} else {
+			fmt.Printf("%c", r)
+			x += runeWidth(r, x)
+		}
+	}
+}
+
+func Printf(format string, a ...any) (n int, err error) {
+	s := fmt.Sprintf(format, a...)
+	Print(s)
+	return len(s), nil
+}