feat: handling stdin ansi sexies for better ux

* feat: working on handling stdin ansi sexies

* feat: add ANSI escape code handling and history

* feat: handle scroll

* fix: small cleanup

Author: UltimateForm

README.md

@@ -161,7 +161,7 @@ tcprcon-cli --profile="my_server" --port=27015
 
 ## Protocol Compliance
 
-While `tcprcon-cli` follows the standard Source RCON Protocol, some game servers (like Rust) have non-standard implementations that might cause unexpected behavior, such as duplicated responses or incorrect packet IDs, the cli should still work, you might just have to deal with an overly chatty server.
+While `tcprcon-cli` follows the standard Source RCON Protocol, some game servers (like Rust) have non-standard implementations that might introduce unexpected behaviors, such as duplicated responses or incorrect packet IDs, the cli should still work, you might just have to deal with an overly chatty server.
 
 For a detailed breakdown of known server quirks and how they are handled, see the [Caveats section in the core library documentation](https://github.com/UltimateForm/tcprcon#caveats).
 

internal/ansi/constants.go

@@ -1,6 +1,10 @@
 package ansi
 
 const (
+	ArrowKeyUp     = "\033[A"
+	ArrowKeyDown   = "\033[B"
+	PageUpKey      = "\033[5~"
+	PageDownKey    = "\033[6~"
 	ClearScreen    = "\033[2J"
 	CursorHome     = "\033[H"
 	CursorToPos    = "\033[%d;%dH" // use with fmt.Sprintf, the two ds are for the row and column coordinates

internal/fullterm/app.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"os"
 	"os/signal"
+	"strings"
 	"sync"
 	"syscall"
 
@@ -20,10 +21,13 @@ type app struct {
 	stdinChannel     chan byte
 	fd               int
 	prevState        *term.State
-	cmdLine          []byte
 	content          []string
 	commandSignature string
 	once             sync.Once
+	ansiMachine      stdinAnsi
+	history          [][]byte
+	historyCursor    int
+	scrollOffset     int
 }
 
 func (src *app) Write(bytes []byte) (int, error) {
@@ -47,15 +51,29 @@ func (src *app) ListenStdin(context context.Context) {
 		}
 	}
 }
+
+func (src *app) setHistoryTail(b []byte) {
+	src.history[len(src.history)-1] = b
+}
+
+func (src *app) historyTail() []byte {
+	return src.history[len(src.history)-1]
+}
+
+func (src *app) currentCmd() []byte {
+	return src.history[src.historyCursor]
+}
+
 func (src *app) Submissions() <-chan string {
 	return src.submissionChan
 }
 
-func visibleContent(content []string, height int) []string {
+func visibleContent(content []string, height int, scrollOffset int) []string {
 	currentRows := len(content)
+	endRow := max(currentRows-scrollOffset, 0)
 	// ngl i forgot why we adding plus 1.. oh well
-	startRow := max(currentRows-(height+1), 0)
-	return content[startRow:]
+	startRow := max(endRow-(height+1), 0)
+	return content[startRow:endRow]
 }
 
 func formatCommandEcho(cmd string) string {
@@ -70,7 +88,7 @@ func (src *app) DrawContent(finalDraw bool) error {
 	if !finalDraw {
 		fmt.Print(ansi.ClearScreen + ansi.CursorHome)
 	}
-	drawableRows := visibleContent(src.content, height)
+	drawableRows := visibleContent(src.content, height, src.scrollOffset)
 	for i := range drawableRows {
 		fmt.Print(drawableRows[i])
 	}
@@ -79,11 +97,18 @@ func (src *app) DrawContent(finalDraw bool) error {
 		return nil
 	}
 	ansi.MoveCursorTo(height, 0)
+	if src.scrollOffset > 0 {
+		fmt.Print(ansi.Format(fmt.Sprintf("[↑ %d] ", src.scrollOffset), ansi.Yellow, ansi.Bold))
+	}
 	fmt.Printf(ansi.Format("%v> ", ansi.Blue), src.commandSignature)
-	fmt.Print(string(src.cmdLine))
+	fmt.Print(string(src.currentCmd()))
 	return nil
 }
 
+func (src *app) traverseHistory(delta int) {
+	src.historyCursor = clamp(0, src.historyCursor+delta, len(src.history)-1)
+}
+
 func (src *app) Run(context context.Context) error {
 
 	// this could be an argument but i aint feeling yet
@@ -122,19 +147,57 @@ func (src *app) Run(context context.Context) error {
 		case <-context.Done():
 			return nil
 		case newStdinInput := <-src.stdinChannel:
-			newCmd, isSubmission := constructCmdLine(newStdinInput, src.cmdLine)
-			if isSubmission {
-				src.content = append(src.content, formatCommandEcho(string(newCmd)))
-				src.cmdLine = []byte{}
-				src.submissionChan <- string(newCmd)
-			} else {
-				src.cmdLine = newCmd
+			ansiSeq, ansiState := src.ansiMachine.handle(newStdinInput)
+			// src.content = append(src.content, fmt.Sprintf("ansi machine handling %v, at state %v\n", ansiSeq, ansiState))
+			switch ansiState {
+			case ansiStateIdle:
+				// no ansi sequence ongoing so its just presentation bytes
+				newCmd, isSubmission := constructCmdLine(newStdinInput, src.currentCmd())
+				if isSubmission {
+					src.content = append(src.content, formatCommandEcho(string(newCmd)))
+					if len(src.historyTail()) > 0 {
+						src.history = append(src.history, []byte{})
+					}
+					src.scrollOffset = 0
+					src.submissionChan <- string(newCmd)
+				} else {
+					src.setHistoryTail(newCmd)
+				}
+				// feel a bit awkward doing this every input stroke, we can get back to it later
+				src.historyCursor = len(src.history) - 1
+			case ansiStateCSITerm:
+				switch string(ansiSeq) {
+				case ansi.ArrowKeyUp:
+					src.traverseHistory(-1)
+				case ansi.ArrowKeyDown:
+					src.traverseHistory(1)
+				case ansi.PageUpKey:
+					if _, h, err := term.GetSize(src.fd); err == nil {
+						maxOffset := max(len(src.content)-(h+1), 0)
+						// substract one cuz we need to account for persistent command line
+						src.scrollOffset = min(src.scrollOffset+h-1, maxOffset)
+					} else {
+						// TODO: do something here idk
+					}
+				case ansi.PageDownKey:
+					if _, h, err := term.GetSize(src.fd); err == nil {
+						// ditto subtraction
+						src.scrollOffset = max(src.scrollOffset-(h-1), 0)
+					}
+				default:
+					// src.content = append(src.content, fmt.Sprintf("unhandled csi %v, %v\n", strconv.Itoa(int(ansiState)), ansiSeq))
+				}
+			default:
+				// src.content = append(src.content, fmt.Sprintf("unhandled state %v, %v\n", strconv.Itoa(int(ansiState)), ansiSeq))
 			}
+
 			if err := src.DrawContent(false); err != nil {
 				return err
 			}
 		case newDisplayInput := <-src.DisplayChannel:
-			src.content = append(src.content, newDisplayInput)
+			for line := range strings.Lines(newDisplayInput) {
+				src.content = append(src.content, line)
+			}
 			if err := src.DrawContent(false); err != nil {
 				return err
 			}
@@ -164,5 +227,8 @@ func CreateApp(commandSignature string) *app {
 		submissionChan:   submissionChan,
 		content:          make([]string, 0),
 		commandSignature: commandSignature,
+		ansiMachine:      newStdinAnsi(),
+		history:          [][]byte{[]byte{}},
+		historyCursor:    0,
 	}
 }

internal/fullterm/app_test.go

@@ -6,7 +6,7 @@ import (
 
 func TestVisibleContentShorterThanWindow(t *testing.T) {
 	content := []string{"line1\n", "line2\n", "line3\n"}
-	result := visibleContent(content, 10)
+	result := visibleContent(content, 10, 0)
 	if len(result) != len(content) {
 		t.Fatalf("expected %d rows, got %d", len(content), len(result))
 	}
@@ -20,7 +20,7 @@ func TestVisibleContentShorterThanWindow(t *testing.T) {
 func TestVisibleContentExactlyFitsWindow(t *testing.T) {
 	content := []string{"line1\n", "line2\n", "line3\n"}
 	// height+1 == len(content), so startRow == 0
-	result := visibleContent(content, len(content)-1)
+	result := visibleContent(content, len(content)-1, 0)
 	if len(result) != len(content) {
 		t.Fatalf("expected %d rows, got %d", len(content), len(result))
 	}
@@ -29,7 +29,7 @@ func TestVisibleContentExactlyFitsWindow(t *testing.T) {
 func TestVisibleContentOverflowsWindow(t *testing.T) {
 	content := []string{"line1\n", "line2\n", "line3\n", "line4\n", "line5\n"}
 	height := 2
-	result := visibleContent(content, height)
+	result := visibleContent(content, height, 0)
 	// startRow = max(5 - 3, 0) = 2, so rows 2,3,4
 	expectedLen := height + 1
 	if len(result) != expectedLen {
@@ -44,15 +44,15 @@ func TestVisibleContentOverflowsWindow(t *testing.T) {
 }
 
 func TestVisibleContentEmpty(t *testing.T) {
-	result := visibleContent([]string{}, 10)
+	result := visibleContent([]string{}, 10, 0)
 	if len(result) != 0 {
 		t.Fatalf("expected empty result, got %d rows", len(result))
 	}
 }
 
 func TestVisibleContentZeroHeight(t *testing.T) {
 	content := []string{"line1\n", "line2\n", "line3\n"}
-	result := visibleContent(content, 0)
+	result := visibleContent(content, 0, 0)
 	// startRow = max(3 - 1, 0) = 2, so only last row
 	if len(result) != 1 {
 		t.Fatalf("expected 1 row, got %d", len(result))
@@ -61,3 +61,42 @@ func TestVisibleContentZeroHeight(t *testing.T) {
 		t.Errorf("expected 'line3\\n', got %q", result[0])
 	}
 }
+
+func TestVisibleContentScrolled(t *testing.T) {
+	content := []string{"line1\n", "line2\n", "line3\n", "line4\n", "line5\n"}
+	height := 2
+	// scrollOffset=2: endRow = 5-2 = 3, startRow = max(3-3, 0) = 0, so rows 0,1,2
+	result := visibleContent(content, height, 2)
+	expectedLen := height + 1
+	if len(result) != expectedLen {
+		t.Fatalf("expected %d rows, got %d", expectedLen, len(result))
+	}
+	if result[0] != "line1\n" {
+		t.Errorf("expected first visible row to be 'line1\\n', got %q", result[0])
+	}
+	if result[len(result)-1] != "line3\n" {
+		t.Errorf("expected last visible row to be 'line3\\n', got %q", result[len(result)-1])
+	}
+}
+
+func TestVisibleContentScrollOffsetPastTop(t *testing.T) {
+	content := []string{"line1\n", "line2\n", "line3\n"}
+	// scrollOffset larger than content — should return empty, not panic
+	result := visibleContent(content, 2, 100)
+	if len(result) != 0 {
+		t.Fatalf("expected empty result when scrolled past top, got %d rows", len(result))
+	}
+}
+
+func TestVisibleContentScrolledPartial(t *testing.T) {
+	content := []string{"line1\n", "line2\n", "line3\n", "line4\n", "line5\n"}
+	height := 10
+	// scrollOffset=1: endRow = 4, startRow = max(4-11, 0) = 0, all 4 rows visible
+	result := visibleContent(content, height, 1)
+	if len(result) != 4 {
+		t.Fatalf("expected 4 rows, got %d", len(result))
+	}
+	if result[len(result)-1] != "line4\n" {
+		t.Errorf("expected last row to be 'line4\\n', got %q", result[len(result)-1])
+	}
+}

internal/fullterm/stdin_ansi.go

@@ -0,0 +1,50 @@
+package fullterm
+
+type ansiState int
+
+const (
+	ansiStateIdle ansiState = iota
+	ansiStateEscape
+	ansiStateCSI
+	ansiStateCSITerm
+)
+
+type stdinAnsi struct {
+	buf   []byte
+	state ansiState
+}
+
+func newStdinAnsi() stdinAnsi {
+	return stdinAnsi{
+		buf:   make([]byte, 0, 8),
+		state: ansiStateIdle,
+	}
+}
+
+func (src *stdinAnsi) reset() {
+	src.buf = make([]byte, 0, 8)
+	src.state = ansiStateIdle
+}
+
+func (src *stdinAnsi) handle(b byte) ([]byte, ansiState) {
+	switch {
+	case b == 27:
+		src.reset()
+		src.buf = append(src.buf, b)
+		src.state = ansiStateEscape
+	case b == 91 && src.state == ansiStateEscape:
+		src.buf = append(src.buf, b)
+		src.state = ansiStateCSI
+	case src.state == ansiStateCSI:
+		src.buf = append(src.buf, b)
+		if b > 63 && b < 127 {
+			defer func() {
+				src.state = ansiStateIdle
+			}()
+			src.state = ansiStateCSITerm
+		}
+	default:
+		src.reset()
+	}
+	return src.buf, src.state
+}

internal/fullterm/util.go

@@ -15,3 +15,7 @@ func constructCmdLine(newByte byte, cmdLine []byte) ([]byte, bool) {
 	}
 	return cmdLine, isSubmission
 }
+
+func clamp(minBound int, n int, maxBound int) int {
+	return max(minBound, min(maxBound, n))
+}

internal/fullterm/util_test.go

@@ -73,3 +73,33 @@ func TestConstructCmdLineSubmissionLF(t *testing.T) {
 		t.Errorf("expected 'test', got '%s'", newLine)
 	}
 }
+
+func TestClamp(t *testing.T) {
+	minBound := 4
+	maxBound := 23
+	n := 11
+	r := clamp(minBound, n, maxBound)
+	if r != n {
+		t.Fatalf("expect r to equal %v but instead it is %v", n, r)
+	}
+}
+
+func TestClampGreaterThanMax(t *testing.T) {
+	minBound := 2
+	maxBound := 5
+	n := 12
+	r := clamp(minBound, n, maxBound)
+	if r != maxBound {
+		t.Fatalf("expect r to equal %v but instead it is %v", maxBound, r)
+	}
+}
+
+func TestClampLesserThanMin(t *testing.T) {
+	minBound := 202
+	maxBound := 582
+	n := 105
+	r := clamp(minBound, n, maxBound)
+	if r != minBound {
+		t.Fatalf("expect r to equal %v but instead it is %v", minBound, r)
+	}
+}