import { JSX } from "react";
import RefreshButton from "./RefreshButton";

// 1. Define explicit TypeScript interfaces for the Open-Meteo response
interface OpenMeteoResponse {
  current: {
    time: string;
    temperature_2m: number;
    relative_humidity_2m: number;
    wind_speed_10m: number;
    weather_code: number;
  };
  current_units: {
    temperature_2m: string;
    relative_humidity_2m: string;
    wind_speed_10m: string;
  };
}

// Map WMO Weather Interpretation Codes to friendly labels & badge styles
// https://emojipedia.org/ copy and paste!
function getWeatherInfo(code: number): { label: string; badgeClass: string } {
  if (code === 0) return { label: "Clear Sky ☀️", badgeClass: "badge-warning" };
  if (code >= 1 && code <= 3)
    return { label: "Partly Cloudy ⛅", badgeClass: "badge-info" };
  if (code >= 45 && code <= 48)
    return { label: "Foggy 🌫️", badgeClass: "badge-ghost" };
  if (code >= 51 && code <= 67)
    return { label: "Rain / Drizzle 🌧️", badgeClass: "badge-primary" };
  if (code >= 71 && code <= 77)
    return { label: "Snow ❄️", badgeClass: "badge-secondary" };
  return { label: "Stormy ⛈️", badgeClass: "badge-error" };
}

// 2. Async Server Component - direct data fetching on the server
export default async function WeatherPage(): Promise<JSX.Element> {
  // Fetching London forecast from Open-Meteo (No API key needed)
  const res = await fetch(
    "https://api.open-meteo.com/v1/forecast?latitude=51.5074&longitude=-0.1278&current=temperature_2m,relative_humidity_2m,wind_speed_10m,weather_code",
    {
      // Revalidate every 10 minutes (ISR - Incremental Static Regeneration)
      next: { revalidate: 600 }
      // next: {
      //   tags: ["weather-data"] // <--- Label this request with a tag
      // }
    }
  );

  // -------------------------------------------------------------
  // ⏳ SIMULATION DELAY
  // Slows down the revalidation so the STALE window stays open.
  // await new Promise((resolve) => setTimeout(resolve, 3000));
  // -------------------------------------------------------------

  if (!res.ok) {
    throw new Error("Failed to fetch weather data from Open-Meteo.");
  }

  const data: OpenMeteoResponse = await res.json();
  const weather = getWeatherInfo(data.current.weather_code);

  return (
    <main className="min-h-screen bg-base-200 p-8 flex justify-center items-center">
      {/* daisyUI Card Container */}
      <div className="card w-96 bg-base-100 shadow-xl border border-base-300">
        <div className="card-body">
          {/* Header section with Location & Condition Badge */}
          <div className="flex justify-between items-center">
            <h2 className="card-title text-2xl font-bold">London Weather</h2>
            <span
              className={`badge ${weather.badgeClass} gap-2 p-3 font-semibold`}
            >
              {weather.label}
            </span>
          </div>

          <p className="text-xs text-base-content/60">
            Last updated: {new Date(data.current.time).toLocaleTimeString()}
          </p>

          <div className="divider my-2"></div>

          {/* daisyUI Stats Grid */}
          <div className="stats stats-vertical shadow bg-base-200">
            {/* Temperature Stat */}
            <div className="stat">
              <div className="stat-title">Temperature</div>
              <div className="stat-value text-primary">
                {data.current.temperature_2m}
                <span className="text-2xl font-normal ml-1">
                  {data.current_units.temperature_2m}
                </span>
              </div>
              <div className="stat-desc">Real-time server reading</div>
            </div>

            {/* Humidity Stat */}
            <div className="stat">
              <div className="stat-title">Humidity</div>
              <div className="stat-value text-secondary">
                {data.current.relative_humidity_2m}
                <span className="text-xl font-normal ml-1">
                  {data.current_units.relative_humidity_2m}
                </span>
              </div>
              <div className="stat-desc">Relative humidity</div>
            </div>

            {/* Wind Speed Stat */}
            <div className="stat">
              <div className="stat-title">Wind Speed</div>
              <div className="stat-value text-accent">
                {data.current.wind_speed_10m}
                <span className="text-xl font-normal ml-1">
                  {data.current_units.wind_speed_10m}
                </span>
              </div>
              <div className="stat-desc">10m surface level</div>
            </div>
          </div>

          <div className="card-actions justify-end mt-4">
            <button className="btn btn-sm btn-outline btn-accent">
              Live Data (Server Fetched)
            </button>
          </div>
          <RefreshButton />
        </div>
      </div>
    </main>
  );
}