"use client";

import { useEffect, useMemo, useState } from "react";
import Link from "next/link";
import type { Destination } from "@/lib/types";
import { useI18n } from "@/lib/i18n";
import { useToast } from "@/lib/toast";
import { mergeDestinationsIntoTrip } from "@/lib/tripActions";
import { meetupCityHref } from "@/lib/meetupLinks";

const STORAGE_KEY = "nomadro-runway";

interface Props {
  destinations: Destination[];
}

interface Saved {
  savings: number;
  monthly: number;
  income: number;
  slug: string;
}

export default function RunwayCalculator({ destinations }: Props) {
  const { t } = useI18n();
  const { toast } = useToast();
  const [savings, setSavings] = useState(80000);
  const [monthly, setMonthly] = useState(4500);
  const [income, setIncome] = useState(0);
  const [slug, setSlug] = useState("");
  const [ready, setReady] = useState(false);
  const [pulse, setPulse] = useState(false);

  useEffect(() => {
    try {
      const raw = localStorage.getItem(STORAGE_KEY);
      if (raw) {
        const s = JSON.parse(raw) as Saved;
        setSavings(s.savings ?? 80000);
        setMonthly(s.monthly ?? 4500);
        setIncome(s.income ?? 0);
        setSlug(s.slug ?? "");
      }
    } catch {
      /* ignore */
    }
    setReady(true);
  }, []);

  useEffect(() => {
    if (!ready) return;
    localStorage.setItem(STORAGE_KEY, JSON.stringify({ savings, monthly, income, slug }));
  }, [savings, monthly, income, slug, ready]);

  const selected = destinations.find((d) => d.slug === slug);

  const netBurn = Math.max(monthly - income, 0);
  const months = useMemo(() => {
    if (netBurn <= 0) return income > 0 ? 999 : 0;
    return Math.floor((savings / netBurn) * 10) / 10;
  }, [savings, netBurn, income]);

  const pct = Math.min((months / 18) * 100, 100);
  const level =
    months >= 12
      ? { label: "从容远航", color: "#4ECDC4", tip: "可以大胆规划长线旅居" }
      : months >= 6
        ? { label: "稳健起步", color: "#FFE66D", tip: "适合 1–2 站深度停留" }
        : months >= 3
          ? { label: "短途试水", color: "#F472B6", tip: "建议选低成本城市先验证" }
          : { label: "需要蓄力", color: "#FF6B6B", tip: "先攒启动金或提高远程收入" };

  const applyDest = (s: string) => {
    const d = destinations.find((x) => x.slug === s);
    if (!d) return;
    setSlug(s);
    setMonthly(d.cost);
    setPulse(true);
    setTimeout(() => setPulse(false), 500);
  };

  const addToPlan = () => {
    if (!selected) return;
    const stay = months >= 999 ? 6 : Math.max(1, Math.min(24, Math.round(months) || 1));
    const { added } = mergeDestinationsIntoTrip([selected], stay);
    toast(
      added ? `${selected.emoji} ${selected.name} ${t.plan.addedToPlan}` : t.common.alreadyInPlan,
      added ? "success" : "info",
      { href: "/plan", label: t.strip.openPlan }
    );
  };

  const milestones = [
    { m: 3, label: "试水期" },
    { m: 6, label: "半程" },
    { m: 12, label: "一年" },
    { m: 18, label: "长线" },
  ];

  return (
    <section className="section runway-section" id="runway">
      <div className="container">
        <div className="section-header reveal">
          <span className="section-tag">🚀 RUNWAY</span>
          <h2>旅居跑道计算器</h2>
          <p>用存款与月开销，算出你还能自由飞多久</p>
        </div>

        <div className={`runway-card reveal${pulse ? " runway-pulse" : ""}`}>
          <div className="runway-meter">
            <div
              className="runway-ring"
              style={{ background: `conic-gradient(${level.color} ${pct}%, rgba(255,255,255,0.08) 0)` }}
            >
              <div className="runway-ring-inner">
                <strong>{months >= 999 ? "∞" : months}</strong>
                <small>{months >= 999 ? "可持续" : "个月"}</small>
              </div>
            </div>
            <div className="runway-level" style={{ color: level.color }}>
              <span>{level.label}</span>
              <p>{level.tip}</p>
            </div>
          </div>

          <div className="runway-form">
            <label>
              <span>启动金 / 存款（¥）</span>
              <input
                type="number"
                min={0}
                step={1000}
                value={savings}
                onChange={(e) => setSavings(Math.max(0, +e.target.value || 0))}
              />
            </label>
            <label>
              <span>月开销（¥）</span>
              <input
                type="number"
                min={0}
                step={100}
                value={monthly}
                onChange={(e) => {
                  setMonthly(Math.max(0, +e.target.value || 0));
                  setSlug("");
                }}
              />
            </label>
            <label>
              <span>月远程收入（¥，可选）</span>
              <input
                type="number"
                min={0}
                step={100}
                value={income}
                onChange={(e) => setIncome(Math.max(0, +e.target.value || 0))}
              />
            </label>

            <div className="runway-dests">
              <small>一键套用目的地月均成本</small>
              <div className="runway-dest-list">
                {destinations.slice(0, 6).map((d) => (
                  <button
                    key={d.slug}
                    type="button"
                    className={`runway-dest${slug === d.slug ? " active" : ""}`}
                    onClick={() => applyDest(d.slug)}
                  >
                    <span>{d.emoji}</span>
                    <em>{d.name}</em>
                    <small>¥{d.cost.toLocaleString()}</small>
                  </button>
                ))}
              </div>
            </div>

            <div className="runway-summary">
              <div>
                <small>净月消耗</small>
                <strong>¥{netBurn.toLocaleString()}</strong>
              </div>
              <div>
                <small>预计支撑</small>
                <strong>{months >= 999 ? "收入覆盖开销" : `${months} 个月`}</strong>
              </div>
            </div>

            <div className="runway-milestones" aria-hidden>
              {milestones.map((m) => (
                <div key={m.m} className={`runway-ms${months >= m.m ? " on" : ""}`}>
                  <i />
                  <span>{m.label}</span>
                </div>
              ))}
            </div>

            {selected && (
              <div className="dating-empty-actions" style={{ marginTop: "1rem" }}>
                <button type="button" className="btn btn-primary btn-sm" onClick={addToPlan}>
                  🗓️ {t.nav.plan}
                </button>
                <Link href={`/destinations/${selected.slug}`} className="btn btn-sm">
                  {t.common.detail}
                </Link>
                <Link href={meetupCityHref(selected.name)} className="btn btn-sm btn-ghost">
                  {t.common.cityMeetups}
                </Link>
              </div>
            )}
          </div>
        </div>
      </div>
    </section>
  );
}