"use client";

import { useEffect, useRef, useState } from "react";
import { fetchProviders, fetchWeather } from "@/lib/client-api";
import { placeLabel, type Units } from "@/lib/display";
import { outlineButton, pixelLabel } from "@/lib/styles";
import type { Place, ProviderId, ProviderInfo, WeatherReport } from "@/lib/weather/types";
import type { ForecastView } from "./forecast/ForecastPanel";
import { HomeLanding } from "./HomeLanding";
import { SkyIcon } from "./PixelArt";
import { PlaceSearch } from "./PlaceSearch";
import { ProviderPicker } from "./ProviderPicker";
import { RadarPanel } from "./radar/RadarPanel";
import { SiteFooter } from "./SiteFooter";
import { Slot } from "./Slot";
import { WeatherView } from "./WeatherView";

/** Settings that survive a page reload (stored in this browser only). */
interface Settings {
  provider: ProviderId;
  units: Units;
  place: Place | null;
  recentPlaces: Place[];
  forecastView: ForecastView;
}

const STORAGE_KEY = "wayfarer:settings";
const MAX_RECENT_PLACES = 5;
const DEFAULT_SETTINGS: Settings = {
  provider: "openweather",
  units: "imperial",
  place: null,
  recentPlaces: [],
  forecastView: "hourly",
};

function samePlace(a: Place, b: Place): boolean {
  return Math.abs(a.lat - b.lat) < 0.01 && Math.abs(a.lon - b.lon) < 0.01;
}

function loadSettings(): Settings {
  try {
    const saved = localStorage.getItem(STORAGE_KEY);
    if (!saved) return DEFAULT_SETTINGS;
    const parsed = JSON.parse(saved) as Partial<Settings>;
    return {
      ...DEFAULT_SETTINGS,
      ...parsed,
      recentPlaces: Array.isArray(parsed.recentPlaces) ? parsed.recentPlaces.slice(0, MAX_RECENT_PLACES) : [],
    };
  } catch {
    return DEFAULT_SETTINGS; // private mode or blocked storage — just use defaults
  }
}

function saveSettings(settings: Settings) {
  try {
    localStorage.setItem(STORAGE_KEY, JSON.stringify(settings));
  } catch {
    /* not critical */
  }
}

type Status = "idle" | "loading" | "ready" | "error";

export default function WeatherApp() {
  const [settings, setSettings] = useState<Settings>(DEFAULT_SETTINGS);
  const [loaded, setLoaded] = useState(false);
  const [providers, setProviders] = useState<ProviderInfo[]>([]);
  const [report, setReport] = useState<WeatherReport | null>(null);
  const [status, setStatus] = useState<Status>("idle");
  const [error, setError] = useState<string | null>(null);
  const searchInputRef = useRef<HTMLInputElement>(null);

  const update = (changes: Partial<Settings>) => setSettings((prev) => ({ ...prev, ...changes }));

  function selectPlace(nextPlace: Place) {
    setSettings((prev) => {
      const filtered = prev.recentPlaces.filter((p) => !samePlace(p, nextPlace));
      return {
        ...prev,
        place: nextPlace,
        recentPlaces: [nextPlace, ...filtered].slice(0, MAX_RECENT_PLACES),
      };
    });
  }

  function removeRecentPlace(target: Place) {
    setSettings((prev) => ({
      ...prev,
      recentPlaces: prev.recentPlaces.filter((p) => !samePlace(p, target)),
    }));
  }

  function goHome() {
    setReport(null);
    setStatus("idle");
    setError(null);
    update({ place: null });
  }

  // 1. On first load: restore saved settings and find out which providers have keys.
  useEffect(() => {
    const saved = loadSettings();

    fetchProviders()
      .then((list) => {
        setProviders(list);
        // Prefer OpenWeather if its key was just added and user hasn't explicitly saved a choice;
        // otherwise keep saved provider if ready, or fall back to the first ready source.
        const savedIsReady = list.some((p) => p.id === saved.provider && p.ready);
        const fallback = list.find((p) => p.ready)?.id ?? saved.provider;
        setSettings({ ...saved, provider: savedIsReady ? saved.provider : fallback });
      })
      .catch(() => setSettings(saved))
      .finally(() => setLoaded(true));
  }, []);

  // 2. Remember settings whenever they change.
  useEffect(() => {
    if (loaded) saveSettings(settings);
  }, [settings, loaded]);

  // 3. Fetch weather whenever the place or provider changes.
  const { place, provider } = settings;
  useEffect(() => {
    if (!loaded || !place) return;

    const controller = new AbortController();
    setStatus("loading");
    setError(null);

    fetchWeather(provider, place, controller.signal)
      .then((data) => {
        setReport(data);
        setStatus("ready");
      })
      .catch((err: Error) => {
        if (controller.signal.aborted) return;
        setError(err.message);
        setStatus("error");
      });

    return () => controller.abort();
  }, [loaded, place, provider]);

  const activeProvider = providers.find((p) => p.id === settings.provider);
  const reportProvider = providers.find((p) => p.id === report?.provider);
  const hasOpenWeather = providers.some((p) => p.id === "openweather" && p.ready);

  return (
    <main
      className={[
        "mx-auto flex w-full max-w-[880px] flex-col gap-5",
        // --gutter is reused by the forecast strip to bleed to the screen edge
        "[--gutter:max(16px,env(safe-area-inset-left))] px-(--gutter)",
        "pt-[max(20px,env(safe-area-inset-top))] pb-[max(40px,env(safe-area-inset-bottom))]",
      ].join(" ")}
    >
      {/* Top station bar */}
      <header className="flex items-center justify-between gap-3 border-b border-gold-dim/50 pb-3.5">
        <div className="flex min-w-0 items-center gap-3.5">
          <div className="flex items-center gap-2.5">
            {place ? (
              <button
                type="button"
                onClick={goHome}
                title="Return to Wayfarer home"
                aria-label="Return to Wayfarer home"
                className="cursor-pointer"
              >
                <CompassStar />
              </button>
            ) : (
              <CompassStar />
            )}
            <div className="flex flex-col">
              {place ? (
                <button
                  type="button"
                  onClick={goHome}
                  title="Return to Wayfarer home"
                  className="cursor-pointer text-left font-display text-lg leading-none font-bold tracking-[0.28em] text-gold uppercase transition-colors hover:text-gold-bright sm:text-2xl"
                >
                  Wayfarer
                </button>
              ) : (
                <h1 className="font-display text-lg leading-none font-bold tracking-[0.28em] text-gold uppercase sm:text-2xl">
                  Wayfarer
                </h1>
              )}
              <a
                href="https://caydens.dev"
                target="_blank"
                rel="noopener"
                className="group/author mt-1 w-fit font-pixel text-[0.68rem] leading-none tracking-[0.04em] text-stone transition-colors hover:text-gold-bright"
              >
                by <span className="text-gold transition-colors group-hover/author:text-gold-bright">Cayden Codes</span>
              </a>
            </div>
          </div>
          <span className="hidden border-l border-gold-dim/60 pl-3.5 text-xs text-stone sm:inline">
            Weather for the road ahead
          </span>
        </div>

        <div className="flex items-center gap-2.5">
          {place && (
            <button
              type="button"
              onClick={goHome}
              className="min-h-9 cursor-pointer border border-gold-dim bg-panel/60 px-2.5 font-pixel text-[0.72rem] text-stone transition-colors hover:border-gold hover:text-gold-bright"
            >
              Home
            </button>
          )}
          <div className="flex divide-x divide-gold-dim border border-gold-dim bg-panel/60" role="group" aria-label="Temperature units">
            {(["imperial", "metric"] as const).map((u) => (
              <button
                key={u}
                type="button"
                aria-pressed={settings.units === u}
                onClick={() => update({ units: u })}
                className="min-h-9 min-w-11 cursor-pointer px-2.5 font-pixel text-[0.8rem] text-stone transition-colors hover:not-aria-pressed:text-ink aria-pressed:bg-gold aria-pressed:text-black"
              >
                {u === "imperial" ? "°F" : "°C"}
              </button>
            ))}
          </div>
        </div>
      </header>

      {/* Search & recent waypoints */}
      <div className="flex flex-col gap-2.5">
        <PlaceSearch inputRef={searchInputRef} onSelect={selectPlace} geocoderUsesOpenWeather={hasOpenWeather} />

        {settings.recentPlaces.length > 0 && (
          <div className="flex items-center gap-2 overflow-x-auto pb-0.5 [scrollbar-width:none]" aria-label="Recent waypoints">
            <span className={`${pixelLabel} flex-none`}>Recent</span>
            {settings.recentPlaces.map((item) => {
              const isCurrent = place ? samePlace(place, item) : false;
              return (
                <div
                  key={`${item.lat.toFixed(2)},${item.lon.toFixed(2)}`}
                  className={`flex flex-none items-center border text-xs transition-colors ${
                    isCurrent
                      ? "border-gold bg-gold/12 text-gold-bright"
                      : "border-gold-dim/70 bg-panel/60 text-stone hover:border-gold/60 hover:text-ink"
                  }`}
                >
                  <button
                    type="button"
                    onClick={() => selectPlace(item)}
                    className="min-h-7 cursor-pointer px-2.5 py-1 font-pixel text-[0.68rem]"
                  >
                    {placeLabel(item)}
                  </button>
                  <button
                    type="button"
                    aria-label={`Remove ${placeLabel(item)} from recent`}
                    onClick={() => removeRecentPlace(item)}
                    className="min-h-7 cursor-pointer pr-2 pl-1 font-pixel text-[0.68rem] opacity-60 hover:text-gold-bright hover:opacity-100"
                  >
                    ×
                  </button>
                </div>
              );
            })}
          </div>
        )}
      </div>

      {providers.length > 0 && (
        <ProviderPicker providers={providers} selected={settings.provider} onChange={(id) => update({ provider: id })} />
      )}

      {/* Homepage landing state when no place is selected */}
      {!place && (
        <HomeLanding
          onSelectPlace={selectPlace}
          onFocusSearch={() => searchInputRef.current?.focus()}
          activeProviderLabel={activeProvider?.label}
        />
      )}

      {status === "error" && error && (
        <Slot as="section" tone="danger" innerClassName="flex flex-wrap items-center justify-between gap-4 p-6">
          <p>{error}</p>
          <button type="button" className={outlineButton} onClick={() => update({ place: place ? { ...place } : null })}>
            Try again
          </button>
        </Slot>
      )}

      {/* Initial loading frame sits ABOVE radar so the radar doesn't jump down once forecast arrives */}
      {place && status === "loading" && !report && (
        <Slot as="section" className="[--cut:22px]" innerClassName="flex items-center gap-5 p-6 sm:px-8 sm:py-8">
          <SkyIcon condition="clear" size={56} className="flex-none animate-float motion-reduce:animate-none" />
          <div className="flex flex-col gap-1">
            <p className="font-display text-lg text-gold-bright">Reading the skies above {placeLabel(place)}…</p>
            <p className={pixelLabel}>Gathering current conditions, hourly horizon, and local alerts</p>
          </div>
        </Slot>
      )}

      {/* Keep the last report on screen while a new one loads, just dimmed */}
      {report && place && status !== "error" && (
        <div className={status === "loading" ? "opacity-50 transition-opacity" : undefined} aria-busy={status === "loading"}>
          <WeatherView
            report={report}
            place={place}
            units={settings.units}
            forecastView={settings.forecastView}
            onForecastViewChange={(view) => update({ forecastView: view })}
            providerLabel={reportProvider?.label ?? report.provider}
            maxDaysOnPlan={reportProvider?.forecastDays ?? report.daily.length}
          />
        </div>
      )}

      {/* The radar doesn't depend on the forecast, so it shows as soon as there's a place */}
      {place && <RadarPanel place={place} timeZone={report?.timeZone ?? null} hasOpenWeather={hasOpenWeather} />}

      <SiteFooter report={report} activeProvider={settings.provider} hasOpenWeather={hasOpenWeather} />
    </main>
  );
}

/** Four-point gold compass emblem in the station header. */
function CompassStar() {
  return (
    <svg width={20} height={20} viewBox="0 0 20 20" fill="none" aria-hidden="true" className="flex-none text-gold">
      <path d="M10 1L12.3 7.7L19 10L12.3 12.3L10 19L7.7 12.3L1 10L7.7 7.7L10 1Z" stroke="currentColor" strokeWidth="1.2" fill="var(--color-panel)" />
      <circle cx="10" cy="10" r="1.6" fill="var(--color-gold-bright)" />
    </svg>
  );
}