[Init] Initial commit - NetMesh terminal manager

domain/terminalScroll.ts

@@ -0,0 +1,86 @@
+import type { TerminalSettings } from "./models";
+
+type TerminalScrollTarget = {
+  buffer: {
+    active: {
+      baseY: number;
+      viewportY: number;
+    };
+  };
+  scrollToBottom: () => void;
+};
+
+const hasPrintableTerminalInput = (data: string): boolean => {
+  if (data.includes("\x1b")) {
+    return false;
+  }
+
+  for (const char of data) {
+    const codePoint = char.codePointAt(0);
+    if (codePoint === undefined) {
+      continue;
+    }
+    if (codePoint >= 0x20 && codePoint !== 0x7f && codePoint !== 0x1b) {
+      return true;
+    }
+  }
+  return false;
+};
+
+export const shouldEnableNativeUserInputAutoScroll = (
+  settings?: Partial<TerminalSettings> | null,
+): boolean => settings?.scrollOnInput ?? true;
+
+export const shouldScrollOnTerminalInput = (
+  settings: Partial<TerminalSettings> | null | undefined,
+  data: string,
+): boolean => {
+  const scrollOnInput = settings?.scrollOnInput ?? true;
+  const scrollOnKeyPress = settings?.scrollOnKeyPress ?? false;
+
+  if (!scrollOnInput && !scrollOnKeyPress) {
+    return false;
+  }
+
+  // Ctrl+C (SIGINT) is handled by our urgent-interrupt path, which bypasses
+  // xterm's native scrollOnUserInput. Map it to scroll-on-input so the default
+  // "Scroll on input" setting returns the viewport to the bottom after the user
+  // interrupts a scrolled-up stream (e.g. tail logs). #2287
+  if (data === "\x03") {
+    return scrollOnInput || scrollOnKeyPress;
+  }
+
+  return hasPrintableTerminalInput(data) ? scrollOnInput : scrollOnKeyPress;
+};
+
+export const shouldScrollOnTerminalOutput = (
+  settings?: Partial<TerminalSettings> | null,
+): boolean => settings?.scrollOnOutput ?? false;
+
+export const shouldScrollOnTerminalPaste = (
+  settings?: Partial<TerminalSettings> | null,
+): boolean => settings?.scrollOnPaste ?? true;
+
+export const scrollTerminalToBottomIfNeeded = (
+  terminal: TerminalScrollTarget,
+): boolean => {
+  const { baseY, viewportY } = terminal.buffer.active;
+  if (viewportY >= baseY) {
+    return false;
+  }
+
+  terminal.scrollToBottom();
+  return true;
+};
+
+export const scrollTerminalToBottomAfterInputIfEnabled = (
+  terminal: TerminalScrollTarget,
+  settings: Partial<TerminalSettings> | null | undefined,
+  data: string,
+): boolean => {
+  if (!shouldScrollOnTerminalInput(settings, data)) {
+    return false;
+  }
+
+  return scrollTerminalToBottomIfNeeded(terminal);
+};