fix(tui): chapter phase survives trailing-space deletion

src/tui/reader/reader-reducer.test.ts

@@ -596,6 +596,55 @@ describe("readerReducer", () => {
       if (next.kind !== "awaiting") throw new Error("expected awaiting");
       expect(next.phase).toBe("chapter");
     });
+
+    it("preserves chapter phase when the trailing space is deleted (query equals book name exactly)", () => {
+      // Bug: backspacing the trailing space after picking "John" used to drop
+      // the user out of chapter phase, hiding the chapter grid. Deleting the
+      // space alone is not a signal that the user wants to re-search books.
+      const state = makeAwaiting({
+        phase: "chapter",
+        bookChosen: { alias: "john", canonical: "JHN", displayName: "John" },
+        chapters: Array.from({ length: 21 }, (_, i) => i + 1),
+        selectedIndex: 0,
+        query: "John ",
+      });
+      const next = dispatch(state, { type: "QueryTyped", query: "John" });
+      if (next.kind !== "awaiting") throw new Error("expected awaiting");
+      expect(next.phase).toBe("chapter");
+      expect(next.bookChosen).not.toBeNull();
+      expect(next.chapters.length).toBe(21);
+    });
+
+    it("highlights the chapter when digits follow the book name without a space", () => {
+      // Bug follow-up: after deleting the trailing space, typing a digit
+      // produces "John1" (no space). The chapter grid should still highlight
+      // chapter 1, matching the "John 1" behavior.
+      const state = makeAwaiting({
+        phase: "chapter",
+        bookChosen: { alias: "john", canonical: "JHN", displayName: "John" },
+        chapters: Array.from({ length: 21 }, (_, i) => i + 1),
+        selectedIndex: 0,
+        query: "John",
+      });
+      const next = dispatch(state, { type: "QueryTyped", query: "John1" });
+      if (next.kind !== "awaiting") throw new Error("expected awaiting");
+      expect(next.phase).toBe("chapter");
+      expect(next.selectedIndex).toBe(0);
+    });
+
+    it("highlights chapter 10 for 'John10' (multi-digit, no space)", () => {
+      const state = makeAwaiting({
+        phase: "chapter",
+        bookChosen: { alias: "john", canonical: "JHN", displayName: "John" },
+        chapters: Array.from({ length: 21 }, (_, i) => i + 1),
+        selectedIndex: 0,
+        query: "John",
+      });
+      const next = dispatch(state, { type: "QueryTyped", query: "John10" });
+      if (next.kind !== "awaiting") throw new Error("expected awaiting");
+      expect(next.phase).toBe("chapter");
+      expect(next.selectedIndex).toBe(9);
+    });
   });
 
   describe("PassageFetched (intent branches)", () => {

src/tui/reader/reader-reducer.ts

@@ -47,25 +47,29 @@ export type ReaderAction =
 const handlers = {
   QueryTyped: (s: ReaderState, a: Extract<ReaderAction, { type: "QueryTyped" }>): ReaderState => {
     if (s.kind !== "awaiting") return s;
-    // Stay in chapter phase if the new query still has the chosen book's display
-    // name as a prefix. Without this, OpenTUI's controlled <input> kicks us out
-    // of chapter mode the instant SuggestionAccepted programmatically rewrites
-    // the query, because the value-prop change synthesizes an onInput event.
-    if (
-      s.phase === "chapter" &&
-      s.bookChosen !== null &&
-      a.query.toLowerCase().startsWith(`${s.bookChosen.displayName.toLowerCase()} `)
-    ) {
-      // Decode trailing digit suffix → grid selection. Multi-digit naturally works:
-      // "John 1" highlights chapter 1, "John 10" highlights chapter 10.
-      const suffix = a.query.slice(s.bookChosen.displayName.length + 1);
-      const digitMatch = /^(\d+)/.exec(suffix);
-      let selectedIndex = s.selectedIndex;
-      if (digitMatch) {
-        const n = parseInt(digitMatch[1], 10);
-        if (n >= 1 && n <= s.chapters.length) selectedIndex = n - 1;
+    // Stay in chapter phase when the new query is the chosen book's display
+    // name, optionally followed by a space and/or digits (e.g. "John", "John ",
+    // "John 1", "John1"). Deleting just the trailing space must NOT kick the
+    // user back to book phase — that hides the chapter grid mid-edit and is
+    // what produced the "sometimes the chapter menu doesn't show up" bug.
+    if (s.phase === "chapter" && s.bookChosen !== null) {
+      const dn = s.bookChosen.displayName.toLowerCase();
+      const q = a.query.toLowerCase();
+      if (q.startsWith(dn)) {
+        const rest = q.slice(dn.length);
+        if (rest === "" || rest.startsWith(" ") || /^\d/.test(rest)) {
+          // Decode digit suffix → grid selection. Optional space between name
+          // and digits; multi-digit naturally works ("John 10" / "John10").
+          const afterBook = a.query.slice(s.bookChosen.displayName.length);
+          const digitMatch = /^\s*(\d+)/.exec(afterBook);
+          let selectedIndex = s.selectedIndex;
+          if (digitMatch) {
+            const n = parseInt(digitMatch[1], 10);
+            if (n >= 1 && n <= s.chapters.length) selectedIndex = n - 1;
+          }
+          return { ...s, query: a.query, parseError: null, selectedIndex };
+        }
       }
-      return { ...s, query: a.query, parseError: null, selectedIndex };
     }
     // Book phase: re-suggest and auto-highlight the top match so Tab/Enter
     // accept the obvious choice without arrow-down first (fzf-style).