[Init] Initial commit - NetMesh terminal manager

components/terminal/runtime/shiftEnterText.ts

@@ -0,0 +1,113 @@
+import type { TerminalSettings } from "../../../domain/models";
+
+export const DEFAULT_SHIFT_ENTER_TEXT = "\\n";
+
+/** Kitty CSI-u encoding for Shift+Enter (keycode 13, modifier shift → 2). */
+export const SHIFT_ENTER_CSI_U_SEQUENCE = "\u001b[13;2u";
+
+type ShiftEnterEvent = Pick<
+  KeyboardEvent,
+  "altKey" | "ctrlKey" | "key" | "metaKey" | "shiftKey" | "type"
+> & {
+  isComposing?: boolean;
+};
+
+export function decodeTerminalTextEscapes(text: string): string {
+  let decoded = "";
+
+  for (let index = 0; index < text.length; index += 1) {
+    const char = text[index];
+    if (char !== "\\" || index >= text.length - 1) {
+      decoded += char;
+      continue;
+    }
+
+    const next = text[index + 1];
+    switch (next) {
+      case "n":
+        decoded += "\n";
+        index += 1;
+        break;
+      case "r":
+        decoded += "\r";
+        index += 1;
+        break;
+      case "t":
+        decoded += "\t";
+        index += 1;
+        break;
+      case "\\":
+        decoded += "\\";
+        index += 1;
+        break;
+      default:
+        decoded += char;
+        break;
+    }
+  }
+
+  return decoded;
+}
+
+export function shouldSendShiftEnterText(
+  event: ShiftEnterEvent,
+  settings?: Pick<TerminalSettings, "shiftEnterNewlineEnabled">,
+): boolean {
+  return (
+    settings?.shiftEnterNewlineEnabled !== false &&
+    event.type === "keydown" &&
+    event.key === "Enter" &&
+    event.shiftKey &&
+    !event.altKey &&
+    !event.ctrlKey &&
+    !event.metaKey &&
+    !event.isComposing
+  );
+}
+
+export function resolveShiftEnterText(
+  settings?: Pick<TerminalSettings, "shiftEnterNewlineText">,
+): string {
+  const configured = settings?.shiftEnterNewlineText;
+  return decodeTerminalTextEscapes(
+    typeof configured === "string" ? configured : DEFAULT_SHIFT_ENTER_TEXT,
+  );
+}
+
+export function isBareShiftEnterLineEnding(text: string): boolean {
+  return text === "\n" || text === "\r" || text === "\r\n";
+}
+
+/**
+ * True when Kitty encoding already keeps Shift+Enter distinct from plain Enter.
+ * Non-preserving flag sets (e.g. alternate-key or associated-text alone) still
+ * encode Shift+Enter as a bare CR/LF, so the alternate-screen remap must run.
+ */
+export function doesKittyEncodingPreserveShiftEnter(
+  encoded: string | null | undefined,
+): boolean {
+  return typeof encoded === "string"
+    && encoded.length > 0
+    && !isBareShiftEnterLineEnding(encoded);
+}
+
+export function isShiftEnterLineContinuationText(text: string): boolean {
+  return /\\(?:\r\n|\r|\n)$/.test(text);
+}
+
+export type ShiftEnterSubmittedInput = {
+  text: string;
+  lineEnding: "\r\n" | "\r" | "\n";
+};
+
+export function getShiftEnterSubmittedInput(
+  text: string,
+): ShiftEnterSubmittedInput | null {
+  if (isShiftEnterLineContinuationText(text)) return null;
+  const match = text.match(/^([^\r\n]*)(\r\n|\r|\n)$/);
+  if (!match) return null;
+  return {
+    text: match[1],
+    lineEnding: match[2] as ShiftEnterSubmittedInput["lineEnding"],
+  };
+}