feat: 搜索改为子串匹配，支持多关键词、排除词与分页加载

- 不再依赖 zhparser 分词：关键词按空格拆分，全部需在描述或语音转写中以子串出现；-词表示排除 - 英文/数字关键词要求词首对齐，避免 ai 命中 said - 按描述/转写命中次数打分，同分按发布时间倒序；总数随查询一并返回 - 返回结构化高亮片段（descParts / snippet），前端高亮描述与转写命中位置 - 前端显示描述/语音命中标记、真实结果总数，并支持加载更多 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-11-08 22:43:15 +08:00
parent 11d9d35002
commit 182ca9cf05
3 changed files with 489 additions and 257 deletions
@@ -0,0 +1,172 @@
+// 子串搜索的查询解析与摘要高亮工具。
+// 匹配本身在 Postgres 里用正则匹配 lower() 后的文本完成，这里负责：
+// - 把用户输入拆成关键词（空格分隔，全部需要命中；以 - 开头的词表示排除）
+// - 在原文里找命中位置，截取摘要片段并标出高亮
+
+export type SnippetPart = { text: string; hit: boolean };
+
+export type ParsedQuery = { terms: string[]; excludes: string[] };
+
+const MAX_TERMS = 10;
+const MAX_TERM_LENGTH = 50;
+
+export function parseSearchQuery(raw: string): ParsedQuery {
+  const terms: string[] = [];
+  const excludes: string[] = [];
+  const seen = new Set<string>();
+  for (const token of raw.trim().split(/\s+/)) {
+    if (!token) continue;
+    const isExclude = token.length > 1 && token.startsWith("-");
+    const word = (isExclude ? token.slice(1) : token)
+      .slice(0, MAX_TERM_LENGTH)
+      .toLowerCase();
+    const key = `${isExclude ? "-" : "+"}${word}`;
+    if (!word || seen.has(key)) continue;
+    seen.add(key);
+    (isExclude ? excludes : terms).push(word);
+    if (terms.length + excludes.length >= MAX_TERMS) break;
+  }
+  return { terms, excludes };
+}
+
+type Range = { start: number; end: number; term: string };
+
+function escapeRegExp(s: string) {
+  return s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+}
+
+// 纯英文/数字关键词要求「词首」对齐：前面不能紧挨字母数字。
+// 这样 "ai" 不会命中 "said"，但 "用AI做"、"AIGC" 仍能命中；中文关键词是纯子串匹配。
+const ASCII_WORD = /^[a-z0-9]/;
+
+/** 关键词对应的 Postgres 正则（ARE），用于匹配已 lower() 的文本。 */
+export function termToPgPattern(term: string) {
+  const escaped = escapeRegExp(term);
+  return ASCII_WORD.test(term) ? `(^|[^a-z0-9])${escaped}` : escaped;
+}
+
+function termToJsPattern(term: string) {
+  const escaped = escapeRegExp(term);
+  return ASCII_WORD.test(term) ? `(?<![a-z0-9])${escaped}` : escaped;
+}
+
+function findMatches(text: string, terms: string[]): Range[] {
+  if (!text || terms.length === 0) return [];
+  // 长词优先，避免 "老百姓" 被 "百姓" 抢先匹配成更短的高亮
+  const sorted = [...terms].sort((a, b) => b.length - a.length);
+  const re = new RegExp(sorted.map(termToJsPattern).join("|"), "giu");
+  const ranges: Range[] = [];
+  for (const m of text.matchAll(re)) {
+    const start = m.index ?? 0;
+    ranges.push({
+      start,
+      end: start + m[0].length,
+      term: m[0].toLowerCase(),
+    });
+  }
+  return ranges;
+}
+
+// 不要把 UTF-16 代理对（emoji 等）切成两半
+function safeStart(text: string, i: number) {
+  const c = text.charCodeAt(i);
+  return c >= 0xdc00 && c <= 0xdfff ? i - 1 : i;
+}
+function safeEnd(text: string, i: number) {
+  const c = text.charCodeAt(i);
+  return c >= 0xdc00 && c <= 0xdfff ? i + 1 : i;
+}
+
+function highlightRange(
+  text: string,
+  from: number,
+  to: number,
+  matches: Range[],
+): SnippetPart[] {
+  const parts: SnippetPart[] = [];
+  let cursor = from;
+  for (const m of matches) {
+    if (m.end <= from || m.start >= to) continue;
+    const s = Math.max(m.start, from);
+    const e = Math.min(m.end, to);
+    if (s < cursor) continue;
+    if (s > cursor) parts.push({ text: text.slice(cursor, s), hit: false });
+    parts.push({ text: text.slice(s, e), hit: true });
+    cursor = e;
+  }
+  if (cursor < to) parts.push({ text: text.slice(cursor, to), hit: false });
+  return parts;
+}
+
+function normalizeWhitespace(parts: SnippetPart[]): SnippetPart[] {
+  return parts
+    .map((p) => ({ ...p, text: p.text.replace(/\s*\n\s*/g, " ") }))
+    .filter((p) => p.text.length > 0);
+}
+
+/** 整段文字全部返回，只标出命中位置（用于描述）。 */
+export function highlightAll(text: string, terms: string[]): SnippetPart[] {
+  if (!text) return [];
+  return normalizeWhitespace(
+    highlightRange(text, 0, text.length, findMatches(text, terms)),
+  );
+}
+
+/**
+ * 截取命中位置附近的片段（用于语音转写这类长文本）。
+ * 尽量让不同片段覆盖不同的关键词；片段会对齐到换行（转写的句子边界）。
+ */
+export function buildSnippet(
+  text: string,
+  terms: string[],
+  { before = 24, after = 60, maxFragments = 2 } = {},
+): SnippetPart[] {
+  if (!text) return [];
+  const matches = findMatches(text, terms);
+  if (matches.length === 0) {
+    const end = safeEnd(text, Math.min(text.length, before + after));
+    const parts = normalizeWhitespace([
+      { text: text.slice(0, end), hit: false },
+    ]);
+    if (end < text.length) parts.push({ text: "…", hit: false });
+    return parts;
+  }
+
+  const windows: { start: number; end: number }[] = [];
+  const covered = new Set<string>();
+  const pickNext = () =>
+    matches.find(
+      (m) =>
+        !covered.has(m.term) &&
+        windows.every((w) => m.start >= w.end || m.end <= w.start),
+    ) ??
+    matches.find((m) =>
+      windows.every((w) => m.start >= w.end || m.end <= w.start),
+    );
+
+  while (windows.length < maxFragments) {
+    const m = pickNext();
+    if (!m) break;
+    let start = Math.max(0, m.start - before);
+    let end = Math.min(text.length, m.end + after);
+    const nlBefore = text.lastIndexOf("\n", m.start - 1);
+    if (nlBefore >= start) start = nlBefore + 1;
+    const nlAfter = text.indexOf("\n", m.end);
+    if (nlAfter !== -1 && nlAfter < end) end = nlAfter;
+    windows.push({ start: safeStart(text, start), end: safeEnd(text, end) });
+    for (const other of matches) {
+      if (other.start >= start && other.end <= end) covered.add(other.term);
+    }
+  }
+
+  windows.sort((a, b) => a.start - b.start);
+  const parts: SnippetPart[] = [];
+  windows.forEach((w, i) => {
+    if (i === 0 ? w.start > 0 : true) parts.push({ text: "…", hit: false });
+    parts.push(...highlightRange(text, w.start, w.end, matches));
+  });
+  if (windows[windows.length - 1].end < text.length) {
+    parts.push({ text: "…", hit: false });
+  }
+  return normalizeWhitespace(parts);
+}