Squashed some bugs, still working out right arrow and having the cursor start at the end of a seed.

main.go

@@ -36,6 +36,7 @@ type Buffer struct {
 	maxWidth int
 	offset int
 	cursorStart int
+	prompt string
 }
 
 func (lb Buffer) String() string {
@@ -47,10 +48,11 @@ func (lb *Buffer) deleteChar() {
 		return
 	} else if lb.cursor == len(lb.buf)-1 {
 		lb.buf = lb.buf[:len(lb.buf)-1]
-		fmt.Printf("\033[0K")
 	} else {
 		lb.buf = append(lb.buf[:lb.cursor], lb.buf[lb.cursor+1:]...)
-		fmt.Printf("%s\033[0K\033[%dD", string(lb.buf[lb.cursor:]), len(lb.buf)-lb.cursor)
+	}
+	if lb.offset > 0 {
+		lb.offset--
 	}
 }
 
@@ -64,17 +66,13 @@ func (lb *Buffer) addChar(c rune, echo bool) {
 	if lb.cursor == len(lb.buf) {
 		lb.buf = append(lb.buf, c)
 		lb.cursor++
-		// if echo {
-			// fmt.Printf("%c", c)
-		// }
 	} else {
 		lb.buf = append(lb.buf[:lb.cursor+1], lb.buf[lb.cursor:]...)
 		lb.buf[lb.cursor] = c
 		lb.cursor++
-		// if echo {
-			// s := string(lb.buf[lb.cursor-1:])
-			// fmt.Printf("%s\033[%dD", s, len(s)-1)
-		// }
+	}
+	if lb.cursor - lb.offset > lb.maxWidth {
+		lb.offset++
 	}
 	if echo {
 		lb.printBuf()
@@ -88,12 +86,16 @@ func min(a, b int) int {
 	return b
 }
 
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
 func (lb Buffer) printBuf() {
 	out := lb.buf[lb.offset:min(len(lb.buf), lb.offset+lb.maxWidth)]
-	if lb.cursor - 1 != 0 {
-		fmt.Printf("\033[%dD", lb.cursor-1)
-	}
-	fmt.Printf("%s\033[%dD\033[%dC", string(out), len(out), lb.cursor)
+	fmt.Printf("\r%s%s\033[0K\r\033[%dC", lb.prompt, string(out), lb.cursor - lb.offset + len(lb.prompt))
 }
 
 func (lb *Buffer) controlInput(c rune) {
@@ -103,30 +105,33 @@ func (lb *Buffer) controlInput(c rune) {
 	case BackSpace:
 		if lb.cursor > 0 {
 			lb.cursor--
-			fmt.Print("\033[1D")
 			lb.deleteChar()
 		}
 	case LeftArrow:
+		if lb.offset > 0 && lb.cursor - lb.offset == 0 {
+			lb.offset--
+		}
 		if lb.cursor > 0 {
 			lb.cursor--
-			fmt.Print("\033[1D")
 		}
 	case RightArrow:
+		// FIXME: This still isnt working quite right...
+		for ;lb.cursor - lb.offset >= lb.maxWidth && lb.cursor < len(lb.buf); {
+			lb.offset++
+		}
 		if lb.cursor < len(lb.buf) {
 			lb.cursor++
-			fmt.Print("\033[1C")
 		}
 	case Home:
-		if lb.cursor > 0 {
-			fmt.Printf("\033[%dD", lb.cursor)
+			lb.offset = 0
 			lb.cursor = 0
-		}
 	case End:
 		if lb.cursor < len(lb.buf) {
-			fmt.Printf("\033[%dC", len(lb.buf)-lb.cursor)
 			lb.cursor = len(lb.buf)
+			lb.offset = max(lb.cursor - lb.maxWidth, 0)
 		}
 	}
+	lb.printBuf()
 }
 
 func (lb *Buffer) seedContent(s string) {
@@ -144,12 +149,12 @@ func parseCursorPosition(esc string) (int, int, error) {
 
 func GetText(prompt string, content string) string {
 	cols, _ := termios.GetWindowSize()
-	b := Buffer{make([]rune, 0, (len(content)+1)*2), 0, cols-len(prompt), 0, 0}
+	b := Buffer{make([]rune, 0, (len(content)+1)*2), 0, cols-len(prompt), 0, 0, prompt}
 	b.seedContent(content)
 
 	fmt.Print(prompt)
 	fmt.Print("\033[6n")
-	fmt.Print(b.String())
+	b.printBuf()
 
 	var ch rune
 	var err error