feat: add code chunker utility

packages/llm/src/chunker.ts

@@ -0,0 +1,72 @@
+import type { FileNode } from "@codeboard/shared";
+
+const APPROX_CHARS_PER_TOKEN = 4;
+
+export function chunkCode(content: string, maxTokens: number): string[] {
+  const maxChars = maxTokens * APPROX_CHARS_PER_TOKEN;
+  if (content.length <= maxChars) return [content];
+
+  const lines = content.split("\n");
+  const chunks: string[] = [];
+  let current: string[] = [];
+  let currentLen = 0;
+
+  for (const line of lines) {
+    if (currentLen + line.length > maxChars && current.length > 0) {
+      chunks.push(current.join("\n"));
+      current = [];
+      currentLen = 0;
+    }
+    current.push(line);
+    currentLen += line.length + 1;
+  }
+
+  if (current.length > 0) {
+    chunks.push(current.join("\n"));
+  }
+
+  return chunks;
+}
+
+export function extractSignatures(fileNode: FileNode): string {
+  const parts: string[] = [];
+
+  parts.push(`File: ${fileNode.path} (${fileNode.language})`);
+
+  if (fileNode.imports.length > 0) {
+    parts.push("Imports:");
+    for (const imp of fileNode.imports) {
+      parts.push(`  from "${imp.source}" import {${imp.specifiers.join(", ")}}`);
+    }
+  }
+
+  if (fileNode.exports.length > 0) {
+    parts.push("Exports:");
+    for (const exp of fileNode.exports) {
+      parts.push(`  ${exp.isDefault ? "default " : ""}${exp.name}`);
+    }
+  }
+
+  for (const fn of fileNode.functions) {
+    const params = fn.params.join(", ");
+    const ret = fn.returnType ? `: ${fn.returnType}` : "";
+    const doc = fn.docstring ? ` — ${fn.docstring.slice(0, 100)}` : "";
+    parts.push(`function ${fn.name}(${params})${ret}${doc}`);
+  }
+
+  for (const cls of fileNode.classes) {
+    parts.push(`class ${cls.name}`);
+    for (const method of cls.methods) {
+      parts.push(`  method ${method.name}(${method.params.join(", ")})`);
+    }
+    for (const prop of cls.properties) {
+      parts.push(`  property ${prop.name}${prop.type ? `: ${prop.type}` : ""}`);
+    }
+  }
+
+  return parts.join("\n");
+}
+
+export function estimateTokens(text: string): number {
+  return Math.ceil(text.length / APPROX_CHARS_PER_TOKEN);
+}