import express, { Request, Response } from "express";
import { prisma as db } from "@repo/db/client";
import { resolveAiProvider, getLlm } from "../ai/llm-factory";

const router = express.Router();

const FALLBACK_GREETINGS = [
  "How can I help you today?",
  "What can I do for you today?",
  "Ready when you are.",
  "What's on your mind today?",
  "Let's get started.",
];

let cachedGreeting: { text: string; date: string } | null = null;

function todayKey() {
  return new Date().toISOString().slice(0, 10);
}

router.get("/", async (_req: Request, res: Response): Promise<any> => {
  try {
    const today = todayKey();

    if (cachedGreeting && cachedGreeting.date === today) {
      return res.status(200).json({ greeting: cachedGreeting.text });
    }

    const aiSettings = await db.aiSettings.findFirst();
    const activeAi = aiSettings ? resolveAiProvider(aiSettings) : null;

    if (!activeAi) {
      const fallback = FALLBACK_GREETINGS[Math.floor(Math.random() * FALLBACK_GREETINGS.length)];
      return res.status(200).json({ greeting: fallback });
    }

    const llm = getLlm(activeAi.provider, activeAi.key, activeAi.model);
    const result = await llm.invoke([
      {
        role: "system",
        content: "Generate a single short AI greeting, similar to how ChatGPT or Claude greets users. Keep it to one short sentence. Examples of the style: 'How can I help you today?', 'What's on your mind?', 'Ready when you are.', 'What can I do for you today?'. Be warm but concise. Do not use emojis. Do not mention names. Vary each greeting.",
      },
      {
        role: "user",
        content: "Generate a short greeting.",
      },
    ]);

    const greeting = typeof result.content === "string"
      ? result.content.trim()
      : FALLBACK_GREETINGS[0]!;

    cachedGreeting = { text: greeting, date: today };
    return res.status(200).json({ greeting });
  } catch {
    const fallback = FALLBACK_GREETINGS[Math.floor(Math.random() * FALLBACK_GREETINGS.length)];
    return res.status(200).json({ greeting: fallback });
  }
});

export default router;