feat(core): add command, intent, and routing primitives

src/session/search.ts

@@ -0,0 +1,73 @@
+import type { SessionStore } from './store.js';
+import { tokenize } from './indexer.js';
+
+export interface HistorySearchResult {
+  sessionId: string;
+  messageId: number;
+  role: 'user' | 'assistant';
+  content: string;
+  score: number;
+  createdAt: number;
+}
+
+export interface HistorySearchConfig {
+  limit: number;
+  minScore: number;
+}
+
+export class SessionSearch {
+  private readonly store: SessionStore;
+  private readonly config: HistorySearchConfig;
+
+  constructor(store: SessionStore, config: HistorySearchConfig) {
+    this.store = store;
+    this.config = config;
+  }
+
+  search(query: string, opts?: { limit?: number; sessionId?: string }): HistorySearchResult[] {
+    const queryTokens = new Set(tokenize(query));
+    if (queryTokens.size === 0) {
+      return [];
+    }
+
+    const rows = opts?.sessionId
+      ? this.store.getMessagesWithMetadata(opts.sessionId)
+      : this.store.getAllMessagesWithMetadata();
+
+    const now = Math.floor(Date.now() / 1000);
+    const results: HistorySearchResult[] = [];
+
+    for (const row of rows) {
+      const keywords = row.metadata?.keywords ?? [];
+      if (keywords.length === 0) {
+        continue;
+      }
+
+      const overlapCount = keywords.filter(keyword => queryTokens.has(keyword)).length;
+      if (overlapCount === 0) {
+        continue;
+      }
+
+      const overlapScore = overlapCount / queryTokens.size;
+      const ageSeconds = Math.max(0, now - row.createdAt);
+      const recencyScore = Math.max(0, 1 - ageSeconds / (30 * 24 * 3600)) * 0.2;
+      const totalScore = overlapScore + recencyScore;
+
+      if (totalScore < this.config.minScore) {
+        continue;
+      }
+
+      results.push({
+        sessionId: row.sessionId,
+        messageId: row.id,
+        role: row.role,
+        content: row.content,
+        score: totalScore,
+        createdAt: row.createdAt,
+      });
+    }
+
+    results.sort((a, b) => b.score - a.score || b.createdAt - a.createdAt);
+    return results.slice(0, opts?.limit ?? this.config.limit);
+  }
+}