perf: chunk trigger and paragraph split (#4893)

* perf: chunk trigger and paragraph split

* update max size computed

* perf: i18n

* remove table

packages/global/common/string/textSplitter.ts

@@ -7,6 +7,10 @@ export const CUSTOM_SPLIT_SIGN = '-----CUSTOM_SPLIT_SIGN-----';
 type SplitProps = {
   text: string;
   chunkSize: number;
+
+  paragraphChunkDeep?: number; // Paragraph deep
+  paragraphChunkMinSize?: number; // Paragraph min size, if too small, it will merge
+
   maxSize?: number;
   overlapRatio?: number;
   customReg?: string[];
@@ -108,6 +112,8 @@ const commonSplit = (props: SplitProps): SplitResponse => {
   let {
     text = '',
     chunkSize,
+    paragraphChunkDeep = 5,
+    paragraphChunkMinSize = 100,
     maxSize = defaultMaxChunkSize,
     overlapRatio = 0.15,
     customReg = []
@@ -123,7 +129,7 @@ const commonSplit = (props: SplitProps): SplitResponse => {
   text = text.replace(/(```[\s\S]*?```|~~~[\s\S]*?~~~)/g, function (match) {
     return match.replace(/\n/g, codeBlockMarker);
   });
-  // 2. 表格处理 - 单独提取表格出来，进行表头合并
+  // 2. Markdown 表格处理 - 单独提取表格出来，进行表头合并
   const tableReg =
     /(\n\|(?:(?:[^\n|]+\|){1,})\n\|(?:[:\-\s]+\|){1,}\n(?:\|(?:[^\n|]+\|)*\n?)*)(?:\n|$)/g;
   const tableDataList = text.match(tableReg);
@@ -143,25 +149,40 @@ const commonSplit = (props: SplitProps): SplitResponse => {
   text = text.replace(/(\r?\n|\r){3,}/g, '\n\n\n');
 
   // The larger maxLen is, the next sentence is less likely to trigger splitting
-  const markdownIndex = 4;
-  const forbidOverlapIndex = 8;
+  const customRegLen = customReg.length;
+  const markdownIndex = paragraphChunkDeep - 1;
+  const forbidOverlapIndex = customRegLen + markdownIndex + 4;
+
+  const markdownHeaderRules = ((deep?: number): { reg: RegExp; maxLen: number }[] => {
+    if (!deep || deep === 0) return [];
+
+    const maxDeep = Math.min(deep, 8); // Maximum 8 levels
+    const rules: { reg: RegExp; maxLen: number }[] = [];
+
+    for (let i = 1; i <= maxDeep; i++) {
+      const hashSymbols = '#'.repeat(i);
+      rules.push({
+        reg: new RegExp(`^(${hashSymbols}\\s[^\\n]+\\n)`, 'gm'),
+        maxLen: chunkSize
+      });
+    }
+
+    return rules;
+  })(paragraphChunkDeep);
 
   const stepReges: { reg: RegExp | string; maxLen: number }[] = [
     ...customReg.map((text) => ({
       reg: text.replaceAll('\\n', '\n'),
       maxLen: chunkSize
     })),
-    { reg: /^(#\s[^\n]+\n)/gm, maxLen: chunkSize },
-    { reg: /^(##\s[^\n]+\n)/gm, maxLen: chunkSize },
-    { reg: /^(###\s[^\n]+\n)/gm, maxLen: chunkSize },
-    { reg: /^(####\s[^\n]+\n)/gm, maxLen: chunkSize },
-    { reg: /^(#####\s[^\n]+\n)/gm, maxLen: chunkSize },
+    ...markdownHeaderRules,
 
     { reg: /([\n](```[\s\S]*?```|~~~[\s\S]*?~~~))/g, maxLen: maxSize }, // code block
+    // HTML Table tag 尽可能保障完整
     {
       reg: /(\n\|(?:(?:[^\n|]+\|){1,})\n\|(?:[:\-\s]+\|){1,}\n(?:\|(?:[^\n|]+\|)*\n)*)/g,
-      maxLen: Math.min(chunkSize * 1.5, maxSize)
-    }, // Table 尽可能保证完整性
+      maxLen: chunkSize
+    }, // Markdown Table 尽可能保证完整性
     { reg: /(\n{2,})/g, maxLen: chunkSize },
     { reg: /([\n])/g, maxLen: chunkSize },
     // ------ There's no overlap on the top
@@ -172,12 +193,10 @@ const commonSplit = (props: SplitProps): SplitResponse => {
     { reg: /([，]|,\s)/g, maxLen: chunkSize }
   ];
 
-  const customRegLen = customReg.length;
   const checkIsCustomStep = (step: number) => step < customRegLen;
   const checkIsMarkdownSplit = (step: number) =>
     step >= customRegLen && step <= markdownIndex + customRegLen;
-
-  const checkForbidOverlap = (step: number) => step <= forbidOverlapIndex + customRegLen;
+  const checkForbidOverlap = (step: number) => step <= forbidOverlapIndex;
 
   // if use markdown title split, Separate record title
   const getSplitTexts = ({ text, step }: { text: string; step: number }) => {
@@ -301,6 +320,7 @@ const commonSplit = (props: SplitProps): SplitResponse => {
     const splitTexts = getSplitTexts({ text, step });
 
     const chunks: string[] = [];
+
     for (let i = 0; i < splitTexts.length; i++) {
       const item = splitTexts[i];
 
@@ -443,7 +463,6 @@ const commonSplit = (props: SplitProps): SplitResponse => {
  */
 export const splitText2Chunks = (props: SplitProps): SplitResponse => {
   let { text = '' } = props;
-  const start = Date.now();
   const splitWithCustomSign = text.split(CUSTOM_SPLIT_SIGN);
 
   const splitResult = splitWithCustomSign.map((item) => {