refactor: dedupe core lowercase helpers

src/tui/commands.ts

@@ -2,6 +2,7 @@ import type { SlashCommand } from "@mariozechner/pi-tui";
 import { listChatCommands, listChatCommandsForConfig } from "../auto-reply/commands-registry.js";
 import { formatThinkingLevels, listThinkingLevelLabels } from "../auto-reply/thinking.js";
 import type { OpenClawConfig } from "../config/types.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 
 const VERBOSE_LEVELS = ["on", "off"];
 const FAST_LEVELS = ["status", "on", "off"];
@@ -31,7 +32,7 @@ function createLevelCompletion(
 ): NonNullable<SlashCommand["getArgumentCompletions"]> {
   return (prefix) =>
     levels
-      .filter((value) => value.startsWith(prefix.toLowerCase()))
+      .filter((value) => value.startsWith(normalizeLowercaseStringOrEmpty(prefix)))
       .map((value) => ({
         value,
         label: value,
@@ -44,7 +45,7 @@ export function parseCommand(input: string): ParsedCommand {
     return { name: "", args: "" };
   }
   const [name, ...rest] = trimmed.split(/\s+/);
-  const normalized = name.toLowerCase();
+  const normalized = normalizeLowercaseStringOrEmpty(name);
   return {
     name: COMMAND_ALIASES[normalized] ?? normalized,
     args: rest.join(" ").trim(),
@@ -77,7 +78,7 @@ export function getSlashCommands(options: SlashCommandOptions = {}): SlashComman
       description: "Set thinking level",
       getArgumentCompletions: (prefix) =>
         thinkLevels
-          .filter((v) => v.startsWith(prefix.toLowerCase()))
+          .filter((v) => v.startsWith(normalizeLowercaseStringOrEmpty(prefix)))
           .map((value) => ({ value, label: value })),
     },
     {

src/tui/components/filterable-select-list.ts

@@ -7,6 +7,7 @@ import {
   type SelectListTheme,
 } from "@mariozechner/pi-tui";
 import chalk from "chalk";
+import { normalizeLowercaseStringOrEmpty } from "../../shared/string-coerce.js";
 import { fuzzyFilterLower, prepareSearchItems } from "./fuzzy-filter.js";
 
 export interface FilterableSelectItem extends SelectItem {
@@ -44,7 +45,7 @@ export class FilterableSelectList implements Component {
   }
 
   private applyFilter(): void {
-    const queryLower = this.filterText.toLowerCase();
+    const queryLower = normalizeLowercaseStringOrEmpty(this.filterText);
     if (!queryLower.trim()) {
       this.selectList = new SelectList(this.allItems, this.maxVisible, this.theme);
       return;

src/tui/components/fuzzy-filter.ts

@@ -2,6 +2,8 @@
  * Shared fuzzy filtering utilities for select list components.
  */
 
+import { normalizeLowercaseStringOrEmpty } from "../../shared/string-coerce.js";
+
 /**
  * Word boundary characters for matching.
  */
@@ -22,8 +24,8 @@ export function findWordBoundaryIndex(text: string, query: string): number | nul
   if (!query) {
     return null;
   }
-  const textLower = text.toLowerCase();
-  const queryLower = query.toLowerCase();
+  const textLower = normalizeLowercaseStringOrEmpty(text);
+  const queryLower = normalizeLowercaseStringOrEmpty(query);
   const maxIndex = textLower.length - queryLower.length;
   if (maxIndex < 0) {
     return null;
@@ -133,6 +135,6 @@ export function prepareSearchItems<
     if (item.searchText) {
       parts.push(item.searchText);
     }
-    return { ...item, searchTextLower: parts.join(" ").toLowerCase() };
+    return { ...item, searchTextLower: normalizeLowercaseStringOrEmpty(parts.join(" ")) };
   });
 }

src/tui/components/searchable-select-list.ts

@@ -7,6 +7,7 @@ import {
   type SelectListTheme,
   truncateToWidth,
 } from "@mariozechner/pi-tui";
+import { normalizeLowercaseStringOrEmpty } from "../../shared/string-coerce.js";
 import { stripAnsi, visibleWidth } from "../../terminal/ansi.js";
 import { findWordBoundaryIndex, fuzzyFilterLower } from "./fuzzy-filter.js";
 
@@ -80,7 +81,7 @@ export class SearchableSelectList implements Component {
    * 4. Fuzzy match (lowest priority)
    */
   private smartFilter(query: string): SelectItem[] {
-    const q = query.toLowerCase();
+    const q = normalizeLowercaseStringOrEmpty(query);
     type ScoredItem = { item: SelectItem; tier: number; score: number };
     type FuzzyCandidate = { item: SelectItem; searchTextLower: string };
     const scoredItems: ScoredItem[] = [];
@@ -89,8 +90,8 @@ export class SearchableSelectList implements Component {
     for (const item of this.items) {
       const rawLabel = this.getItemLabel(item);
       const rawDesc = item.description ?? "";
-      const label = stripAnsi(rawLabel).toLowerCase();
-      const desc = stripAnsi(rawDesc).toLowerCase();
+      const label = normalizeLowercaseStringOrEmpty(stripAnsi(rawLabel));
+      const desc = normalizeLowercaseStringOrEmpty(stripAnsi(rawDesc));
 
       // Tier 1: Exact substring in label
       const labelIndex = label.indexOf(q);
@@ -114,11 +115,12 @@ export class SearchableSelectList implements Component {
       const searchText = (item as { searchText?: string }).searchText ?? "";
       fuzzyCandidates.push({
         item,
-        searchTextLower: [rawLabel, rawDesc, searchText]
-          .map((value) => stripAnsi(value))
-          .filter(Boolean)
-          .join(" ")
-          .toLowerCase(),
+        searchTextLower: normalizeLowercaseStringOrEmpty(
+          [rawLabel, rawDesc, searchText]
+            .map((value) => stripAnsi(value))
+            .filter(Boolean)
+            .join(" "),
+        ),
       });
     }
 
@@ -171,7 +173,7 @@ export class SearchableSelectList implements Component {
     const tokens = query
       .trim()
       .split(/\s+/)
-      .map((token) => token.toLowerCase())
+      .map((token) => normalizeLowercaseStringOrEmpty(token))
       .filter((token) => token.length > 0);
     if (tokens.length === 0) {
       return text;

src/tui/tui-submit.ts

@@ -1,3 +1,5 @@
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
+
 export function createEditorSubmitHandler(params: {
   editor: {
     setText: (value: string) => void;
@@ -44,7 +46,7 @@ export function shouldEnableWindowsGitBashPasteFallback(params?: {
 }): boolean {
   const platform = params?.platform ?? process.platform;
   const env = params?.env ?? process.env;
-  const termProgram = (env.TERM_PROGRAM ?? "").toLowerCase();
+  const termProgram = normalizeLowercaseStringOrEmpty(env.TERM_PROGRAM);
 
   // Some macOS terminals emit multiline paste as rapid single-line submits.
   // Enable burst coalescing so pasted blocks stay as one user message.
@@ -64,7 +66,7 @@ export function shouldEnableWindowsGitBashPasteFallback(params?: {
   if (msystem.startsWith("MINGW") || msystem.startsWith("MSYS")) {
     return true;
   }
-  if (shell.toLowerCase().includes("bash")) {
+  if (normalizeLowercaseStringOrEmpty(shell).includes("bash")) {
     return true;
   }
   return termProgram.includes("mintty");

src/tui/tui.ts

@@ -16,6 +16,7 @@ import {
   normalizeMainKey,
   parseAgentSessionKey,
 } from "../routing/session-key.js";
+import { normalizeLowercaseStringOrEmpty } from "../shared/string-coerce.js";
 import { getSlashCommands } from "./commands.js";
 import { ChatLog } from "./components/chat-log.js";
 import { CustomEditor } from "./components/custom-editor.js";
@@ -69,9 +70,9 @@ export function resolveTuiSessionKey(params: {
     return trimmed;
   }
   if (trimmed.startsWith("agent:")) {
-    return trimmed.toLowerCase();
+    return normalizeLowercaseStringOrEmpty(trimmed);
   }
-  return `agent:${params.currentAgentId}:${trimmed.toLowerCase()}`;
+  return `agent:${params.currentAgentId}:${normalizeLowercaseStringOrEmpty(trimmed)}`;
 }
 
 export function resolveInitialTuiAgentId(params: {