feat: scaffold realtime Korean voice assistant bot

src/services/conversation.ts

@@ -0,0 +1,77 @@
+export interface ConversationTurn {
+  role: "user" | "assistant";
+  text: string;
+  speakerId?: string;
+  speakerName?: string;
+  createdAt: number;
+}
+
+export interface UserUtterance {
+  speakerId: string;
+  speakerName: string;
+  text: string;
+}
+
+export class ConversationMemory {
+  private readonly turns: ConversationTurn[] = [];
+
+  constructor(private readonly maxTurns: number) {}
+
+  addUserTurn(utterance: UserUtterance): void {
+    this.turns.push({
+      role: "user",
+      text: utterance.text,
+      speakerId: utterance.speakerId,
+      speakerName: utterance.speakerName,
+      createdAt: Date.now(),
+    });
+    this.trim();
+  }
+
+  addAssistantTurn(text: string): void {
+    this.turns.push({
+      role: "assistant",
+      text,
+      createdAt: Date.now(),
+    });
+    this.trim();
+  }
+
+  clear(): void {
+    this.turns.splice(0, this.turns.length);
+  }
+
+  recentTurns(): ConversationTurn[] {
+    return [...this.turns];
+  }
+
+  buildPrompt(currentUtterance: UserUtterance): string {
+    const recent = this.turns
+      .slice(-this.maxTurns)
+      .map((turn) => {
+        if (turn.role === "assistant") {
+          return `[assistant]\n${turn.text}`;
+        }
+        return `[user speaker_id=${turn.speakerId ?? "unknown"} speaker_name=${turn.speakerName ?? "unknown"}]\n${turn.text}`;
+      })
+      .join("\n\n");
+
+    const historyBlock = recent.length > 0 ? recent : "(이전 대화 없음)";
+
+    return [
+      "최근 대화:",
+      historyBlock,
+      "",
+      "이번 발화:",
+      `[user speaker_id=${currentUtterance.speakerId} speaker_name=${currentUtterance.speakerName}]`,
+      currentUtterance.text,
+    ].join("\n");
+  }
+
+  private trim(): void {
+    const overflow = this.turns.length - this.maxTurns;
+    if (overflow > 0) {
+      this.turns.splice(0, overflow);
+    }
+  }
+}