dynamic line update in watch mode

Overrides existing lines based on first column, which is
assumed to be an identifier. This greatly simplifies the
output as it's immediately obvious how many resources
exist and what state they are in.

main/builtin-get.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"strings"
 	"regexp"
+	"github.com/k0kubun/go-ansi"
+	"io/ioutil"
 )
 
 var (
@@ -23,15 +25,41 @@ func (b builtinGet) filter(command string) bool {
 
 func (b builtinGet) run(command string) error {
 	variableIndex := 0
+
+	lines := make(map[string]int, 0)
+
 	return shHandler(kubectl(command), func(line string) {
-		if strings.HasPrefix(line, "NAME ") {
+		firstColumn := strings.Split(line, " ")[0]
+		lineOffset, lineDefined := lines[firstColumn]
+
+		if lineDefined {
+			ansi.CursorPreviousLine(lineOffset)
+			ansi.EraseInLine(2) // clear entire line
 			fmt.Printf("   \t%s\n", line)
+
 		} else {
-			variableIndex++
-			key := fmt.Sprintf("%d", variableIndex)
-			printIndexedLine(key, line)
+			if strings.HasPrefix(line, "NAME ") {
+				fmt.Printf("   \t%s\n", line)
+
+			} else {
+				variableIndex++
+				key := fmt.Sprintf("%d", variableIndex)
+
+				// shift existing lines
+				for k, _ := range lines {
+					lines[k] += 1
+				}
+
+				lines[firstColumn] = 1
+				printIndexedLine(key, line)
+			}
 		}
+
+		ioutil.WriteFile("/dev/ttys012", []byte(fmt.Sprintf("%#v\n", lines)), 777)
+		ansi.CursorNextLine(999) // reset cursor
+
+		// save variable
 		key := fmt.Sprintf("%d", variableIndex)
-		variables[key] = strings.Split(line, " ")[0]
+		variables[key] = firstColumn
 	})
 }