import { useCallback, useEffect, useMemo, useState } from 'react';
import { api } from '../api/api';
import { ApiError } from '../api/http';
import type { City, WorldEvent } from '../api/types';
import { useAuth } from '../auth/AuthContext';
import { useToast } from '../components/Toast';
import { formatMoney, riskLabel } from '../shared/format';

/** Sagoma stilizzata dell'Italia (coordinate 0-100, stesse di City.mapX/mapY). */
const ITALY_MAINLAND =
  'M12,18 L18,11 L30,9 L44,8 L50,13 L54,20 L60,28 L70,40 L82,46 L91,52 L88,57 L79,58 ' +
  'L71,63 L65,71 L63,79 L58,76 L57,67 L52,58 L45,46 L37,34 L25,27 L15,24 Z';
const ITALY_SICILY = 'M44,83 L54,81 L62,84 L58,91 L48,93 L43,88 Z';
const ITALY_SARDINIA = 'M13,55 L21,56 L22,66 L19,74 L12,72 L11,62 Z';

const RISK_COLORS: Record<string, string> = {
  basso: '#4caf6e',
  medio: '#d4a017',
  alto: '#d9534f',
};

export function TravelScreen() {
  const { player, setPlayer } = useAuth();
  const { toast } = useToast();
  const [cities, setCities] = useState<City[]>([]);
  const [events, setEvents] = useState<WorldEvent[]>([]);
  const [selected, setSelected] = useState<City | null>(null);
  const [busy, setBusy] = useState(false);

  const reload = useCallback(async () => {
    const [c, e] = await Promise.all([api.cities(), api.events()]);
    setCities(c.cities);
    setEvents(e.events);
  }, []);

  useEffect(() => {
    void reload();
  }, [reload]);

  const eventsByCity = useMemo(() => {
    const map = new Map<string, WorldEvent[]>();
    for (const event of events) {
      const key = event.city?.id ?? 'global';
      map.set(key, [...(map.get(key) ?? []), event]);
    }
    return map;
  }, [events]);

  const cityEvents = (cityId: string): WorldEvent[] => [
    ...(eventsByCity.get(cityId) ?? []),
    ...(eventsByCity.get('global') ?? []),
  ];

  async function travelTo(city: City) {
    setBusy(true);
    try {
      const res = await api.travel(city.id);
      setPlayer(res.player);
      toast(`Benvenuto a ${res.cityName} (−${formatMoney(res.cost)})`, 'success');
      setSelected(null);
    } catch (err) {
      toast(err instanceof ApiError ? err.message : 'Errore imprevisto', 'error');
    } finally {
      setBusy(false);
    }
  }

  return (
    <div className="screen">
      <h2 className="screen__title">Mappa</h2>

      <div className="map-card">
        <svg viewBox="0 0 100 100" className="map-svg" role="img" aria-label="Mappa delle città">
          <path d={ITALY_MAINLAND} className="map-land" />
          <path d={ITALY_SICILY} className="map-land" />
          <path d={ITALY_SARDINIA} className="map-land" />

          {cities.map((city) => {
            const isCurrent = player?.currentCityId === city.id;
            const hasEvent = (eventsByCity.get(city.id) ?? []).length > 0;
            const color = RISK_COLORS[riskLabel(city.riskLevel)] ?? '#d4a017';
            return (
              <g
                key={city.id}
                className="map-marker"
                onClick={() => setSelected(city)}
                transform={`translate(${city.mapX}, ${city.mapY})`}
              >
                {isCurrent && <circle r="4.5" className="map-marker__pulse" fill={color} />}
                <circle r="2.6" fill="#0f0f13" stroke={color} strokeWidth="0.8" />
                <circle r="1" fill={isCurrent ? '#e8e4da' : color} />
                {hasEvent && (
                  <text x="2.6" y="-2.2" fontSize="3.5">
                    ⚡
                  </text>
                )}
                <text x="0" y="6.8" textAnchor="middle" className="map-marker__label">
                  {city.name}
                </text>
              </g>
            );
          })}
        </svg>
        <p className="muted small map-legend">
          ● colore = rischio (verde basso, oro medio, rosso alto) · ⚡ evento in corso · tocca una
          città per viaggiare
        </p>
      </div>

      <ul className="list">
        {cities.map((city) => {
          const isCurrent = player?.currentCityId === city.id;
          return (
            <li
              key={city.id}
              className={`list__row list__row--clickable${isCurrent ? ' is-current' : ''}`}
              onClick={() => setSelected(city)}
            >
              <div>
                <strong>{city.name}</strong>
                {isCurrent && <span className="badge badge--small">sei qui</span>}
                {(eventsByCity.get(city.id) ?? []).length > 0 && <span> ⚡</span>}
              </div>
              <span className="muted small">
                {isCurrent ? '—' : formatMoney(city.travelCost)}
              </span>
            </li>
          );
        })}
      </ul>

      {selected && (
        <div className="modal-backdrop" onClick={() => setSelected(null)}>
          <div className="modal" onClick={(e) => e.stopPropagation()}>
            <h3>{selected.name}</h3>
            <p className="muted small">
              rischio {riskLabel(selected.riskLevel)} · economia ×{selected.economyModifier} ·
              polizia ×{selected.policePressure}
            </p>
            {cityEvents(selected.id).length > 0 && (
              <div className="banner">
                {cityEvents(selected.id).map((event) => (
                  <span key={event.id}>
                    ⚡ {event.title}
                    {!event.city && ' (globale)'}
                  </span>
                ))}
              </div>
            )}
            {player?.currentCityId === selected.id ? (
              <p className="muted">Ti trovi già in questa città.</p>
            ) : (
              <button
                type="button"
                className="btn btn--primary"
                disabled={busy || (player?.money ?? 0) < selected.travelCost}
                onClick={() => void travelTo(selected)}
              >
                Viaggia · {formatMoney(selected.travelCost)}
              </button>
            )}
          </div>
        </div>
      )}
    </div>
  );
}