AI Assistant

"use server";

import { getCurrentUserId } from "@/lib/get-current-user";
import { prisma } from "@/lib/prisma";
import { z } from "zod/v4";
import type { AiChatMessage } from "./ai.types";
import { HISTORY_LIMIT } from "./ai.constants";

// ─── getOrCreateConversation ──────────────────────────────────────────────────
// Finds or creates the single active conversation for the current user.
// Safe to call on every mount — idempotent.

export async function getOrCreateConversation(): Promise<{ id: string }> {
  const userId = await getCurrentUserId();

  const conversation = await prisma.aiConversation.upsert({
    where: { userId },
    create: { userId },
    update: {},
    select: { id: true },
  });

  return conversation;
}

// ─── getHistory ───────────────────────────────────────────────────────────────
// Fetches the most recent message history for a conversation, oldest-first.
// Verifies ownership — a user can only read their own conversation.

const conversationIdSchema = z.string().min(1);

export async function getHistory(
  conversationId: string,
): Promise<AiChatMessage[]> {
  const userId = await getCurrentUserId();

  const parsed = conversationIdSchema.safeParse(conversationId);
  if (!parsed.success) throw new Error("Invalid conversation ID");

  const conversation = await prisma.aiConversation.findUnique({
    where: { id: conversationId, userId },
    select: { id: true },
  });

  if (!conversation) throw new Error("Conversation not found");

  // Order descending + take, THEN reverse — take + ascending grabs the OLDEST
  // N messages, not the most recent N. This matters once a conversation grows
  // past HISTORY_LIMIT. Mirrors the same pattern in app/api/ai/route.ts.
  const recent = await prisma.aiMessage.findMany({
    where: { conversationId },
    orderBy: { createdAt: "desc" },
    take: HISTORY_LIMIT,
    select: {
      id: true,
      role: true,
      content: true,
      createdAt: true,
    },
  });

  return recent.reverse() as AiChatMessage[];
}