feat(FN-4777): complete Step 2 — add tracking dedup helper module

Fusion-Task-Id: FN-4777
Fusion-Task-Lineage: ed00f639-c928-4c14-be1f-2b43db6022c7

packages/dashboard/src/github-tracking-dedup.ts

@@ -0,0 +1,129 @@
+import type { Task } from "@fusion/core";
+
+const FILE_SCOPE_HEADER = /^##\s+File\s+Scope\s*$/im;
+const FILE_SCOPE_BULLET = /^-\s+`?([^`\n]+?)`?\s*$/;
+const BACKTICK_IDENTIFIER_RE = /`([A-Za-z0-9_./-]{3,})`/g;
+const ERROR_NAME_RE = /\b([A-Z][A-Za-z0-9]*(?:Error|Exception))\b/g;
+const SYMBOL_TOKEN_RE = /\b([A-Za-z_][A-Za-z0-9_]{5,}|[a-z]+(?:[A-Z][A-Za-z0-9]+){2,})\b/g;
+
+const STOPWORDS = new Set([
+  "fusion",
+  "task",
+  "tasks",
+  "issue",
+  "github",
+  "tracking",
+  "bug",
+  "fix",
+  "error",
+  "failed",
+  "failure",
+  "create",
+  "update",
+  "description",
+  "scope",
+]);
+
+export const DEDUP_MATCH_THRESHOLD = 3;
+
+function stripTrailingGlob(path: string): string {
+  return path.replace(/\/+$/, "").replace(/\/(\*\*?|[^/]*[?*][^/]*)$/, "");
+}
+
+function quoteIfNeeded(value: string): string {
+  return /[/.\-]/.test(value) ? `"${value}"` : value;
+}
+
+function toSearchText(candidate: { title: string; body: string | null }): string {
+  return `${candidate.title}\n${candidate.body ?? ""}`.toLowerCase();
+}
+
+function escapeRegex(text: string): string {
+  return text.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+}
+
+export function extractFileScopePaths(task: Pick<Task, "description"> & { prompt?: string }): string[] {
+  const source = task.prompt ?? task.description ?? "";
+  const headerMatch = source.match(FILE_SCOPE_HEADER);
+  if (!headerMatch || headerMatch.index == null) {
+    return [];
+  }
+
+  const sectionStart = headerMatch.index + headerMatch[0].length;
+  const afterStart = source.slice(sectionStart);
+  const nextHeaderMatch = afterStart.match(/\n##\s+/);
+  const section = nextHeaderMatch ? afterStart.slice(0, nextHeaderMatch.index) : afterStart;
+
+  const paths: string[] = [];
+  const seen = new Set<string>();
+  for (const rawLine of section.split("\n")) {
+    const line = rawLine.trim();
+    if (!line.startsWith("- ")) continue;
+    const match = line.match(FILE_SCOPE_BULLET);
+    if (!match) continue;
+    const normalized = stripTrailingGlob(match[1].trim());
+    if (!normalized || seen.has(normalized)) continue;
+    seen.add(normalized);
+    paths.push(normalized);
+    if (paths.length >= 8) break;
+  }
+
+  return paths;
+}
+
+export function extractSymptomKeywords(task: Pick<Task, "title" | "description">, opts?: { max?: number }): string[] {
+  const max = Math.max(1, opts?.max ?? 6);
+  const source = `${task.title ?? ""}\n${task.description ?? ""}`;
+  const values: string[] = [];
+  const seen = new Set<string>();
+
+  for (const regex of [BACKTICK_IDENTIFIER_RE, ERROR_NAME_RE, SYMBOL_TOKEN_RE]) {
+    regex.lastIndex = 0;
+    let match: RegExpExecArray | null;
+    while ((match = regex.exec(source)) && values.length < max) {
+      const token = match[1].trim();
+      const normalized = token.toLowerCase();
+      if (token.length < 6) continue;
+      if (STOPWORDS.has(normalized)) continue;
+      if (seen.has(normalized)) continue;
+      seen.add(normalized);
+      values.push(token);
+    }
+    if (values.length >= max) break;
+  }
+
+  return values;
+}
+
+export function buildIssueSearchQueries(paths: string[], keywords: string[]): string[] {
+  const queries: string[] = [];
+  const topKeywords = keywords.slice(0, 3);
+  if (topKeywords.length > 0) {
+    queries.push(topKeywords.map((keyword) => quoteIfNeeded(keyword)).join(" "));
+  }
+
+  for (const path of paths.slice(0, 2)) {
+    queries.push(quoteIfNeeded(path));
+  }
+
+  return queries.slice(0, 3);
+}
+
+export function scoreCandidateIssue(
+  candidate: { title: string; body: string | null },
+  paths: string[],
+  keywords: string[],
+): { score: number; matchedPaths: string[]; matchedKeywords: string[] } {
+  const text = toSearchText(candidate);
+  const matchedPaths = paths.filter((path) => text.includes(path.toLowerCase()));
+  const matchedKeywords = keywords.filter((keyword) => {
+    const pattern = new RegExp(`\\b${escapeRegex(keyword)}\\b`, "i");
+    return pattern.test(`${candidate.title}\n${candidate.body ?? ""}`);
+  });
+
+  return {
+    score: (matchedPaths.length * 2) + matchedKeywords.length,
+    matchedPaths,
+    matchedKeywords,
+  };
+}