fix: prevent slow FAQ parsing, stale drafts, and dropped responsibilities

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 All notable Doc2FAQ changes are recorded here. Version numbers follow semantic versioning; entries describe shipped source functionality and do not imply an external AI service.
 
+## Unreleased
+
+### Fixed
+
+- Avoid excessive regex backtracking on whitespace-heavy input in both FAQ modes.
+- Discard pending draft results and errors after the source, example, imported text, or mode changes.
+- Preserve separate client and provider responsibility suggestions while still filtering duplicates for the same party.
+
 ## 0.3.0
 
 ### Added

src/main/java/com/okansoftware/doc2faq/service/FaqDraftService.java

@@ -19,8 +19,8 @@
 public class FaqDraftService {
     private static final int MAX_CHARACTERS = 50_000;
     private static final int MAX_ITEMS = 30;
-    private static final Pattern QUESTION = Pattern.compile(
-            "^(?:#{1,6}\\s+|(?:Q|Question):\\s*)(.+\\?)\\s*$",
+    private static final Pattern QUESTION_PREFIX = Pattern.compile(
+            "^(?:#{1,6}\\s+|(?:Q|Question):\\s*)",
             Pattern.CASE_INSENSITIVE);
     private static final Pattern ANSWER_PREFIX = Pattern.compile(
             "^(?:A|Answer):\\s*", Pattern.CASE_INSENSITIVE);
@@ -42,10 +42,10 @@ public PreviewResponse preview(String content) {
 
         for (String rawLine : content.split("\\R", -1)) {
             String line = rawLine.strip();
-            Matcher match = QUESTION.matcher(line);
-            if (match.matches()) {
+            String nextQuestion = questionFrom(line);
+            if (nextQuestion != null) {
                 addIfValid(items, seen, question, answer);
-                question = match.group(1).strip();
+                question = nextQuestion;
                 answer.setLength(0);
                 continue;
             }
@@ -74,6 +74,16 @@ public PreviewResponse preview(String content) {
         return new PreviewResponse(List.copyOf(items), items.size(), NOTICE);
     }
 
+    private static String questionFrom(String line) {
+        if (!line.endsWith("?")) return null;
+        // Match only the prefix: overlapping whitespace and question captures can
+        // otherwise backtrack quadratically on a long line without a question mark.
+        Matcher prefix = QUESTION_PREFIX.matcher(line);
+        if (!prefix.find()) return null;
+        String question = line.substring(prefix.end()).strip();
+        return question.length() > 1 ? question : null;
+    }
+
     private static void addIfValid(List<FaqItem> items, Set<String> seen,
                                    String question, StringBuilder answer) {
         if (question == null || answer.isEmpty() || items.size() >= MAX_ITEMS) {

src/main/java/com/okansoftware/doc2faq/service/FaqGenerateService.java

@@ -156,7 +156,7 @@ private static Topic topicForHeading(String heading) {
         if (h.contains("terminat") || h.contains("cancellat")) return Topic.TERMINATION;
         if (h.contains("payment") || h.contains("invoic")) return Topic.PAYMENT;
         if (h.contains("fee") || h.contains("pricing") || h.contains("cost")) return Topic.FEES;
-        if (h.contains("responsibilit") || h.contains("obligation")) return Topic.RESPONSIBILITIES;
+        if (h.contains("responsibilit") || h.contains("obligation")) return responsibilityTopic(h);
         if (h.contains("ownership") || h.contains("intellectual property")) return Topic.OWNERSHIP;
         if (h.contains("confidential")) return Topic.CONFIDENTIALITY;
         if (h.contains("scope") || h.contains("service")) return Topic.SERVICES;
@@ -178,7 +178,7 @@ private static Topic topicForQuestion(String question) {
                 || q.contains("invoice") || q.contains("how are payments")) return Topic.PAYMENT;
         if (q.contains("fee") || q.contains("pricing") || q.contains("price")
                 || q.contains("cost")) return Topic.FEES;
-        if (q.contains("responsibilit") || q.contains("obligation")) return Topic.RESPONSIBILITIES;
+        if (q.contains("responsibilit") || q.contains("obligation")) return responsibilityTopic(q);
         if (q.contains("ownership") || q.contains("owns the work") || q.contains("deliverables"))
             return Topic.OWNERSHIP;
         if (q.contains("confidential")) return Topic.CONFIDENTIALITY;
@@ -194,6 +194,14 @@ private static Topic topicForQuestion(String question) {
         return Topic.OTHER;
     }
 
+    private static Topic responsibilityTopic(String text) {
+        // Separate parties so an explicit or generated client FAQ cannot hide
+        // the provider's distinct obligations (and vice versa).
+        if (text.contains("client") && !text.contains("provider")) return Topic.CLIENT_RESPONSIBILITIES;
+        if (text.contains("provider") && !text.contains("client")) return Topic.PROVIDER_RESPONSIBILITIES;
+        return Topic.RESPONSIBILITIES;
+    }
+
     private static String questionFor(String heading) {
         String h = heading.toLowerCase(Locale.ROOT);
         if (h.contains("termination") || h.contains("cancellation"))
@@ -231,6 +239,7 @@ private static String questionFor(String heading) {
 
     private enum Topic {
         SERVICES, TERM, FEES, PAYMENT, TERMINATION, RESPONSIBILITIES,
+        CLIENT_RESPONSIBILITIES, PROVIDER_RESPONSIBILITIES,
         OWNERSHIP, CONFIDENTIALITY, SUMMARY, SKILLS, EXPERIENCE, EDUCATION, OTHER
     }
 

src/main/resources/static/app.js

@@ -44,6 +44,7 @@ const formatSelect = $("export-format");
 const addButton = $("add-item-btn");
 const modeSelect = $("draft-mode");
 let items = [];
+let draftRevision = 0;
 
 function setStatus(message, kind = "") {
   status.textContent = message;
@@ -231,6 +232,7 @@ function exportData() {
 }
 
 function clearDraft() {
+  draftRevision++;
   items = [];
   search.value = "";
   render();
@@ -333,7 +335,11 @@ draftButton.addEventListener("click", async () => {
     return;
   }
 
-  const generating = selectedMode() === "generate";
+  const mode = selectedMode();
+  const generating = mode === "generate";
+  const revision = draftRevision;
+  const isCurrentDraft = () => revision === draftRevision
+    && source.value === content && selectedMode() === mode;
   draftButton.disabled = true;
   draftButton.textContent = generating ? "Generating draft…" : "Extracting pairs…";
   setStatus(generating ? "Building source-grounded FAQ suggestions…" : "Extracting explicit Q&A pairs…");
@@ -344,6 +350,7 @@ draftButton.addEventListener("click", async () => {
       body: JSON.stringify({content})
     });
     const data = await response.json().catch(() => ({}));
+    if (!isCurrentDraft()) return;
     if (!response.ok) throw new Error(data.message || "Could not create an FAQ draft.");
     items = Array.isArray(data.items)
       ? data.items.filter((item) =>
@@ -357,7 +364,9 @@ draftButton.addEventListener("click", async () => {
       : "No complete Q&A pairs found. Switch to Generate Mode for ordinary documents.",
       items.length ? "success" : "");
   } catch (error) {
-    setStatus(error.message || "The FAQ service is unavailable.", "error");
+    if (isCurrentDraft()) {
+      setStatus(error.message || "The FAQ service is unavailable.", "error");
+    }
   } finally {
     draftButton.disabled = false;
     updateModeText();

src/test/java/com/okansoftware/doc2faq/service/FaqDraftServiceTest.java

@@ -1,6 +1,7 @@
 package com.okansoftware.doc2faq.service;
 
 import com.okansoftware.doc2faq.model.PreviewResponse;
+import java.time.Duration;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.*;
@@ -87,4 +88,38 @@ void capsNumberOfExtractedPairs() {
         }
         assertEquals(30, service.preview(input.toString()).count());
     }
+
+    @Test
+    void handlesLongWhitespacePrefixesWithoutExcessiveBacktracking() {
+        assertTimeoutPreemptively(Duration.ofSeconds(2), () -> {
+            for (String prefix : new String[]{"Q:", "Question:", "######"}) {
+                String whitespace = " ".repeat(49_900);
+                assertEquals(0, service.preview(prefix + whitespace + "x").count());
+                PreviewResponse result = service.preview(prefix + whitespace + "Why?\nA: Yes.");
+                assertEquals(1, result.count());
+                assertEquals("Why?", result.items().getFirst().question());
+            }
+        });
+    }
+
+    @Test
+    void preservesSupportedQuestionPrefixesAndRejectsUnrelatedLines() {
+        PreviewResponse result = service.preview("""
+                q:Why now?
+                A: Today.
+                qUeStIoN:\tWhere next?
+                A: Fairfax.
+                ######\tWho decides?
+                A: The team.
+                # Unrelated heading
+                ####### Invalid heading?
+                Ignored answer.
+                An ordinary question?
+                Ignored answer.
+                """);
+        assertEquals(3, result.count());
+        assertEquals("Why now?", result.items().get(0).question());
+        assertEquals("Where next?", result.items().get(1).question());
+        assertEquals("Who decides?", result.items().get(2).question());
+    }
 }

src/test/java/com/okansoftware/doc2faq/service/FaqGenerateServiceTest.java

@@ -1,6 +1,7 @@
 package com.okansoftware.doc2faq.service;
 
 import com.okansoftware.doc2faq.model.PreviewResponse;
+import java.time.Duration;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.*;
@@ -200,4 +201,52 @@ void usesNaturalQuestionsForResponsibilitiesAndOwnership() {
                 result.items().get(1).answer());
     }
 
+    @Test
+    void retainsClientAndProviderResponsibilitiesInEitherOrder() {
+        for (boolean clientFirst : new boolean[]{true, false}) {
+            String client = "## Client Responsibilities\nThe client supplies backups.\n";
+            String provider = "## Provider Responsibilities\nThe provider patches software.\n";
+            PreviewResponse result = service.generate(clientFirst ? client + provider : provider + client);
+            assertEquals(2, result.count());
+            assertTrue(result.items().stream().anyMatch(item ->
+                    item.question().contains("client") && item.answer().equals("The client supplies backups.")));
+            assertTrue(result.items().stream().anyMatch(item ->
+                    item.question().contains("provider") && item.answer().equals("The provider patches software.")));
+        }
+    }
+
+    @Test
+    void explicitClientFaqOnlySuppressesDuplicateClientSuggestions() {
+        PreviewResponse result = service.generate("""
+                ## Client Responsibilities
+                The client supplies backups.
+                ## Provider Responsibilities
+                The provider patches software.
+                ## FAQ
+                Q: What responsibilities does the client have under the agreement?
+                A: The client retains backups.
+                """);
+        assertEquals(2, result.count());
+        assertEquals("The client retains backups.", result.items().getFirst().answer());
+        assertEquals("What responsibilities does the provider have under the agreement?",
+                result.items().get(1).question());
+        assertEquals("The provider patches software.", result.items().get(1).answer());
+    }
+
+    @Test
+    void stillDeduplicatesRepeatedResponsibilitiesForTheSameParty() {
+        PreviewResponse result = service.generate("""
+                ## Provider Responsibilities
+                The provider patches software.
+                ## Provider Obligations
+                The provider monitors uptime.
+                """);
+        assertEquals(1, result.count());
+    }
+
+    @Test
+    void generationAlsoHandlesWhitespaceHeavyInputPromptly() {
+        assertTimeoutPreemptively(Duration.ofSeconds(2), () ->
+                assertEquals(1, service.generate("Q:" + " ".repeat(49_990) + "x").count()));
+    }
 }

src/test/js/app-requests.test.cjs

@@ -0,0 +1,128 @@
+const {readFileSync} = require("node:fs");
+const path = require("node:path");
+const test = require("node:test");
+const assert = require("node:assert/strict");
+const vm = require("node:vm");
+
+const source = readFileSync(path.resolve(__dirname, "../../main/resources/static/app.js"), "utf8");
+const withoutBoot = source.replace(/updateModeText\(\);\s*updateCount\(\);\s*render\(\);\s*$/, "");
+
+function pendingDraft() {
+  const elements = new Map();
+  function element(id) {
+    if (!elements.has(id)) elements.set(id, {
+      value: "", disabled: false, textContent: "", handlers: {},
+      addEventListener(type, handler) { this.handlers[type] = handler; },
+      focus() {}
+    });
+    return elements.get(id);
+  }
+  let complete;
+  let fail;
+  const response = new Promise((resolve, reject) => { complete = resolve; fail = reject; });
+  const context = {document: {getElementById: element}, fetch: () => response};
+  // Keep the actual event handlers and export controls; these tests do not need card layout.
+  vm.runInNewContext(withoutBoot + "\nrender = () => updateControls();", context);
+  element("source-text").value = "Q: Old question?\nA: Old answer.";
+  element("draft-mode").value = "extract";
+  const finished = element("generate-btn").handlers.click();
+  return {
+    element, finished,
+    fail() { fail(new Error("Network unavailable.")); },
+    complete(ok = true) {
+      complete({ok, json: async () => ({
+        items: [{question: "Old question?", answer: "Old answer."}],
+        message: "Old request failed."
+      })});
+    }
+  };
+}
+
+test("a response for unchanged source enables export", async () => {
+  const draft = pendingDraft();
+  draft.complete();
+  await draft.finished;
+  assert.equal(draft.element("faq-count").textContent, "1 ITEM");
+  assert.equal(draft.element("copy-btn").disabled, false);
+  assert.equal(draft.element("generate-btn").disabled, false);
+});
+
+test("editing the source discards an in-flight response even if the text is restored", async () => {
+  const draft = pendingDraft();
+  const input = draft.element("source-text");
+  const original = input.value;
+  input.value = "A different document.";
+  input.handlers.input();
+  input.value = original;
+  input.handlers.input();
+  draft.complete();
+  await draft.finished;
+  assert.equal(draft.element("faq-count").textContent, "0 ITEMS");
+  assert.equal(draft.element("copy-btn").disabled, true);
+  assert.equal(draft.element("download-btn").disabled, true);
+  assert.equal(draft.element("generate-btn").disabled, false);
+});
+
+test("switching modes discards results and preserves the new mode status", async () => {
+  const draft = pendingDraft();
+  const mode = draft.element("draft-mode");
+  mode.value = "generate";
+  mode.handlers.change();
+  const status = draft.element("status").textContent;
+  draft.complete();
+  await draft.finished;
+  assert.equal(draft.element("faq-count").textContent, "0 ITEMS");
+  assert.equal(draft.element("copy-btn").disabled, true);
+  assert.equal(draft.element("status").textContent, status);
+});
+
+test("loading an example invalidates the previous request", async () => {
+  const draft = pendingDraft();
+  draft.element("sample-btn").handlers.click();
+  draft.complete();
+  await draft.finished;
+  assert.equal(draft.element("faq-count").textContent, "0 ITEMS");
+  assert.equal(draft.element("copy-btn").disabled, true);
+});
+
+test("an outdated failure cannot overwrite the current mode status", async () => {
+  const draft = pendingDraft();
+  draft.element("draft-mode").value = "generate";
+  draft.element("draft-mode").handlers.change();
+  const status = draft.element("status").textContent;
+  draft.complete(false);
+  await draft.finished;
+  assert.equal(draft.element("status").textContent, status);
+  assert.equal(draft.element("generate-btn").disabled, false);
+});
+
+test("importing replacement text invalidates the previous request", async () => {
+  const draft = pendingDraft();
+  const input = draft.element("file-input");
+  input.files = [{name: "replacement.txt", size: 30, text: async () => "New imported document."}];
+  await input.handlers.change({target: input});
+  draft.complete();
+  await draft.finished;
+  assert.equal(draft.element("source-text").value, "New imported document.");
+  assert.equal(draft.element("faq-count").textContent, "0 ITEMS");
+  assert.equal(draft.element("copy-btn").disabled, true);
+});
+
+test("an outdated network failure cannot replace the current status", async () => {
+  const draft = pendingDraft();
+  draft.element("sample-btn").handlers.click();
+  const status = draft.element("status").textContent;
+  draft.fail();
+  await draft.finished;
+  assert.equal(draft.element("status").textContent, status);
+  assert.equal(draft.element("generate-btn").disabled, false);
+});
+
+test("a current network failure remains visible and allows retry", async () => {
+  const draft = pendingDraft();
+  draft.fail();
+  await draft.finished;
+  assert.equal(draft.element("status").textContent, "Network unavailable.");
+  assert.equal(draft.element("status").className, "status error");
+  assert.equal(draft.element("generate-btn").disabled, false);
+});