"use client";

import { useState } from "react";
import Link from "next/link";
import { useRouter } from "next/navigation";
import { api } from "@/lib/api";
import { useI18n } from "@/lib/i18n";
import { useToast } from "@/lib/toast";
import { mergeDestinationsIntoTrip } from "@/lib/tripActions";
import type { Destination } from "@/lib/types";
import RingNext from "@/components/RingNext";
import { useRingSteps } from "@/lib/rings";

const SUGGESTIONS = [
  "预算 6000，想找网速好的东南亚城市",
  "适合第一次远程办公的城市？",
  "清迈和巴厘岛怎么选？",
];

interface Props {
  destinations: Destination[];
}

export default function AiAssistantClient({ destinations }: Props) {
  const { t } = useI18n();
  const { toast } = useToast();
  const router = useRouter();
  const rings = useRingSteps();
  const [message, setMessage] = useState("");
  const [reply, setReply] = useState("");
  const [cities, setCities] = useState<{ slug: string; name: string; emoji: string }[]>([]);
  const [loading, setLoading] = useState(false);

  const ask = async (text?: string) => {
    const q = (text ?? message).trim();
    if (!q) {
      toast("先写一个问题", "info");
      return;
    }
    setMessage(q);
    setLoading(true);
    try {
      const res = await api.askAssistant(q);
      setReply(res.reply);
      setCities(res.cities || []);
    } catch {
      setReply(t.ai.fail);
      setCities([]);
    } finally {
      setLoading(false);
    }
  };

  const addToPlan = () => {
    const dests = cities
      .map((c) => destinations.find((d) => d.slug === c.slug))
      .filter((d): d is Destination => Boolean(d));
    if (dests.length === 0) {
      toast("推荐城市暂无完整数据，请从详情页加入计划", "info");
      router.push("/plan");
      return;
    }
    const { added, skipped } = mergeDestinationsIntoTrip(dests, 1);
    if (added === 0) {
      toast(skipped ? t.compare.alreadyInPlan : "未能写入计划", "info");
    } else {
      toast(`${t.compare.addedN} ${added} ${t.compare.citiesUnit}`);
    }
    router.push("/plan");
  };

  return (
    <div className="community-page">
      <div className="container">
        <nav className="detail-nav">
          <Link href="/">{t.common.backHome}</Link>
          <span> · </span>
          <Link href="/next-stop">{t.ai.nextStop}</Link>
        </nav>
        <div className="section-header reveal">
          <span className="section-tag">{t.ai.tag}</span>
          <h1>{t.ai.title}</h1>
          <p>{t.ai.subtitle}</p>
        </div>
        <div className="ai-suggestions reveal">
          {SUGGESTIONS.map((s) => (
            <button key={s} type="button" className="filter-btn" disabled={loading} onClick={() => void ask(s)}>
              {s}
            </button>
          ))}
        </div>
        <div className="community-compose reveal">
          <textarea
            rows={4}
            placeholder={t.ai.placeholder}
            value={message}
            onChange={(e) => setMessage(e.target.value)}
            onKeyDown={(e) => {
              if (e.key === "Enter" && (e.metaKey || e.ctrlKey)) void ask();
            }}
          />
          <button type="button" className="btn btn-primary" disabled={loading} onClick={() => void ask()}>
            {loading ? "思考中…" : t.ai.ask}
          </button>
          <p className="section-desc">Ctrl/⌘ + Enter 发送</p>
        </div>
        {reply && (
          <div className="ai-reply reveal">
            <p>{reply}</p>
            <div className="ai-cities">
              {cities.map((c) => (
                <Link key={c.slug} href={`/destinations/${c.slug}`} className="btn btn-sm">
                  {c.emoji} {c.name}
                </Link>
              ))}
              <Link href="/next-stop" className="btn btn-sm">
                {t.ai.nextStop}
              </Link>
              <Link href="/compare" className="btn btn-sm">
                城市对比
              </Link>
              {cities.length > 0 && (
                <button type="button" className="btn btn-sm btn-primary" onClick={addToPlan}>
                  写入计划
                </button>
              )}
            </div>
          </div>
        )}
        <RingNext steps={rings.afterDiscover} />
      </div>
    </div>
  );
}