"use client";

import { useEffect, useMemo, useState } from "react";
import type { Destination } from "@/lib/types";

const TZ_OFFSETS: Record<string, number> = {
  bali: 8,
  lisbon: 0,
  chiangmai: 7,
  mexico: -6,
  barcelona: 1,
  tokyo: 9,
};

const HOME_TZ = 8; // China UTC+8
const WORK_START = 9;
const WORK_END = 18;

interface Props {
  destinations: Destination[];
}

function getLocalHour(utcOffset: number): number {
  const now = new Date();
  const utc = now.getUTCHours() + now.getUTCMinutes() / 60;
  return Math.floor((utc + utcOffset + 24) % 24);
}

function formatTime(hour: number, min: number): string {
  return `${String(hour).padStart(2, "0")}:${String(min).padStart(2, "0")}`;
}

function getOverlapHours(destOffset: number, homeStart: number, homeEnd: number): number {
  let overlap = 0;
  for (let h = homeStart; h < homeEnd; h++) {
    const destHour = (h - HOME_TZ + destOffset + 24) % 24;
    if (destHour >= 8 && destHour < 20) overlap++;
  }
  return overlap;
}

function overlapLabel(hours: number): { text: string; class: string } {
  if (hours >= 7) return { text: "极佳", class: "excellent" };
  if (hours >= 5) return { text: "良好", class: "good" };
  if (hours >= 3) return { text: "一般", class: "fair" };
  return { text: "困难", class: "poor" };
}

export default function TimezoneBoard({ destinations }: Props) {
  const [now, setNow] = useState(new Date());
  const [homeStart, setHomeStart] = useState(WORK_START);
  const [homeEnd, setHomeEnd] = useState(WORK_END);

  useEffect(() => {
    const timer = setInterval(() => setNow(new Date()), 1000);
    return () => clearInterval(timer);
  }, []);

  const cities = useMemo(() =>
    destinations
      .filter((d) => TZ_OFFSETS[d.slug] !== undefined)
      .map((d) => {
        const offset = TZ_OFFSETS[d.slug];
        const localHour = getLocalHour(offset);
        const overlap = getOverlapHours(offset, homeStart, homeEnd);
        const label = overlapLabel(overlap);
        const isWorkTime = localHour >= 9 && localHour < 18;
        return { ...d, offset, localHour, overlap, label, isWorkTime };
      })
      .sort((a, b) => b.overlap - a.overlap),
  [destinations, homeStart, homeEnd]);

  const homeTime = formatTime(now.getHours(), now.getMinutes());
  const homeSeconds = now.getSeconds();

  return (
    <section className="section timezone-section" id="timezone">
      <div className="container">
        <div className="section-header reveal">
          <span className="section-tag">🕐 TIMEZONE</span>
          <h2>时区工作看板</h2>
          <p>实时查看各城市当地时间，评估与国内团队的工作时间重叠</p>
        </div>

        <div className="tz-home-clock reveal">
          <div className="tz-home-time">
            <span className="tz-live-dot" />
            <span className="tz-home-label">🇨🇳 北京时间</span>
            <span className="tz-home-digits">
              {homeTime}<span className="tz-seconds">:{String(homeSeconds).padStart(2, "0")}</span>
            </span>
          </div>
          <div className="tz-work-slider">
            <label>⏰ 你的工作时间: {homeStart}:00 – {homeEnd}:00</label>
            <div className="tz-slider-row">
              <span>开始</span>
              <input type="range" min={6} max={12} value={homeStart}
                onChange={(e) => setHomeStart(Math.min(+e.target.value, homeEnd - 1))} />
              <span>{homeStart}:00</span>
            </div>
            <div className="tz-slider-row">
              <span>结束</span>
              <input type="range" min={13} max={22} value={homeEnd}
                onChange={(e) => setHomeEnd(Math.max(+e.target.value, homeStart + 1))} />
              <span>{homeEnd}:00</span>
            </div>
          </div>
        </div>

        <div className="tz-grid reveal">
          {cities.map((city) => {
            const localMin = now.getUTCMinutes();
            const localTime = formatTime(city.localHour, localMin);
            const angle = ((city.localHour % 12) + localMin / 60) * 30;
            return (
              <div key={city.slug} className={`tz-card${city.isWorkTime ? " working" : ""}`}>
                <div className="tz-card-header">
                  <span className="tz-card-emoji">{city.emoji}</span>
                  <div>
                    <strong>{city.name}</strong>
                    <span>UTC{city.offset >= 0 ? "+" : ""}{city.offset}</span>
                  </div>
                  <span className={`tz-overlap-badge ${city.label.class}`}>
                    {city.label.text}
                  </span>
                </div>

                <div className="tz-analog">
                  <svg viewBox="0 0 100 100">
                    <circle cx="50" cy="50" r="44" fill="none" stroke="rgba(255,255,255,0.06)" strokeWidth="2" />
                    {[0, 3, 6, 9].map((n) => (
                      <line key={n}
                        x1="50" y1="10" x2="50" y2="16"
                        stroke="rgba(255,255,255,0.15)" strokeWidth="1.5"
                        transform={`rotate(${n * 30} 50 50)`}
                      />
                    ))}
                    <line x1="50" y1="50" x2="50" y2="22"
                      stroke="url(#tzHand)" strokeWidth="2.5" strokeLinecap="round"
                      transform={`rotate(${angle} 50 50)`}
                    />
                    <circle cx="50" cy="50" r="3" fill="#4ECDC4" />
                  </svg>
                  <span className="tz-digital">{localTime}</span>
                </div>

                <div className="tz-overlap-bar">
                  <div className="tz-overlap-track">
                    <div
                      className={`tz-overlap-fill ${city.label.class}`}
                      style={{ width: `${(city.overlap / Math.max(homeEnd - homeStart, 1)) * 100}%` }}
                    />
                  </div>
                  <span>重叠 {city.overlap}h / {homeEnd - homeStart}h</span>
                </div>

                <div className="tz-status">
                  {city.isWorkTime ? "💼 当地工作时间" : "🌙 当地非工作时间"}
                </div>
              </div>
            );
          })}
        </div>

        <svg width="0" height="0">
          <defs>
            <linearGradient id="tzHand" x1="0%" y1="0%" x2="0%" y2="100%">
              <stop offset="0%" stopColor="#FF6B6B" />
              <stop offset="100%" stopColor="#4ECDC4" />
            </linearGradient>
          </defs>
        </svg>
      </div>
    </section>
  );
}