增加pdf中划句或段ai伴读功能

src/modules/lecture/application/matchPreparedSentence.ts

@@ -0,0 +1,87 @@
+import type {
+  StoredParagraph,
+  StoredSentence,
+} from "../infrastructure/storage/lectureStore";
+
+export function normalizeSelectionText(text: string): string {
+  return text
+    .replace(/[\u0000-\u001f\f]/g, " ")
+    .replace(/\s+/g, " ")
+    .trim()
+    .toLowerCase();
+}
+
+export interface PreparedSentenceMatch {
+  paragraph: StoredParagraph;
+  sentence: StoredSentence;
+}
+
+function overlapScore(a: string, b: string): number {
+  const na = normalizeSelectionText(a);
+  const nb = normalizeSelectionText(b);
+  if (!na || !nb) return 0;
+  if (na === nb) return 100;
+  if (na.includes(nb) || nb.includes(na)) {
+    const shorter = Math.min(na.length, nb.length);
+    const longer = Math.max(na.length, nb.length);
+    return Math.round((shorter / longer) * 90);
+  }
+
+  const aWords = new Set(na.split(/\s+/).filter((w) => w.length > 2));
+  const bWords = nb.split(/\s+/).filter((w) => w.length > 2);
+  if (!aWords.size || !bWords.length) return 0;
+  let shared = 0;
+  for (const w of bWords) {
+    if (aWords.has(w)) shared += 1;
+  }
+  return Math.round((shared / bWords.length) * 70);
+}
+
+export function findMatchingPreparedSentence(
+  paragraphs: StoredParagraph[] | undefined,
+  selectedText: string,
+  options?: { requireTts?: boolean },
+): PreparedSentenceMatch | undefined {
+  if (!paragraphs?.length || !selectedText.trim()) return undefined;
+
+  const requireTts = options?.requireTts !== false;
+  let best: PreparedSentenceMatch | undefined;
+  let bestScore = 0;
+
+  for (const paragraph of paragraphs) {
+    if (paragraph.genStatus !== "ready") continue;
+
+    for (const sentence of paragraph.sentences ?? []) {
+      if (requireTts && sentence.ttsZhStatus !== "ready") continue;
+      const score = overlapScore(selectedText, sentence.text);
+      if (score > bestScore) {
+        bestScore = score;
+        best = { paragraph, sentence };
+      }
+    }
+
+    if (!paragraph.sentences?.length) {
+      const score = overlapScore(selectedText, paragraph.originalText);
+      if (score > bestScore && (!requireTts || paragraph.ttsZhStatus === "ready")) {
+        bestScore = score;
+        best = {
+          paragraph,
+          sentence: {
+            id: `${paragraph.id}-whole`,
+            orderIndex: 0,
+            text: paragraph.originalText,
+            translation: paragraph.translation,
+            page: paragraph.page,
+            searchText: paragraph.searchText,
+            audioPathEn: paragraph.audioPathEn,
+            audioPathZh: paragraph.audioPathZh,
+            ttsEnStatus: paragraph.ttsEnStatus,
+            ttsZhStatus: paragraph.ttsZhStatus,
+          },
+        };
+      }
+    }
+  }
+
+  return bestScore >= 55 ? best : undefined;
+}