import { useRef } from 'react';
import type { PeriodStats } from '../services/DataService';

interface StatsPanelProps {
  stats: PeriodStats | null;
  loading: boolean;
  periodDays: number;
  source: 'live' | 'mock';
}

const MEDALS = ['🥇', '🥈', '🥉'];

function StatCard({ label, value, sub, delta }: { label: string; value: string; sub?: string; delta?: 'up' | 'down' | null }) {
  return (
    <div className="bg-[#0f1016] border border-[#2e2f3a] rounded-xl p-4 space-y-1">
      <p className="text-[#4b5563] text-xs uppercase tracking-widest">{label}</p>
      <p className="text-[#d4a843] text-2xl font-bold tabular-nums">
        {value}
        {delta === 'up'   && <span className="text-emerald-400 text-sm ml-1.5">↑</span>}
        {delta === 'down' && <span className="text-red-400    text-sm ml-1.5">↓</span>}
      </p>
      {sub && <p className="text-[#6b7280] text-xs">{sub}</p>}
    </div>
  );
}

export function StatsPanel({ stats, loading, periodDays, source }: StatsPanelProps) {
  const periodLabel = periodDays === 1 ? '24 dernières heures' : `${periodDays} derniers jours`;
  const prevStats = useRef<PeriodStats | null>(null);

  // Calcule le delta d'une valeur par rapport au refresh précédent
  function delta(current: number, prevMap: Map<string, number>, key: string) {
    const prev = prevMap.get(key);
    if (prev === undefined) return null;
    if (current > prev) return <span className="text-emerald-400 text-xs ml-1">↑</span>;
    if (current < prev) return <span className="text-red-400 text-xs ml-1">↓</span>;
    return null;
  }

  // Construit une map volume précédent par ville
  const prevCityVolume = new Map(
    (prevStats.current?.topCities ?? []).map((c) => [c.name, c.volume])
  );
  const prevVolume   = prevStats.current?.totalVolume ?? null;
  const prevTxCount  = prevStats.current?.transactionCount ?? null;

  // Mémorise les stats après le rendu
  if (stats && !loading) prevStats.current = stats;
  const geoPct = stats && stats.transactionCount > 0
    ? Math.round((stats.geoCount / stats.transactionCount) * 100)
    : null;

  return (
    <aside className="w-72 shrink-0 flex flex-col gap-4 bg-[#0a0b0f]/95 backdrop-blur-sm border-r border-[#1e1f2a] p-5 overflow-y-auto">
      {/* Header */}
      <div className="flex items-center gap-2.5">
        <div className="w-8 h-8 rounded-full bg-[#d4a843] flex items-center justify-center text-[#0a0b0f] font-bold text-sm shadow-[0_0_16px_rgba(212,168,67,0.5)]">
          Ğ
        </div>
        <div>
          <h1 className="text-white font-bold text-lg leading-none">Ğ1Flux</h1>
          <p className="text-[#4b5563] text-xs">Monnaie libre · Flux géo</p>
        </div>
      </div>

      {/* Period label */}
      <p className="text-[#4b5563] text-xs border-t border-[#1e1f2a] pt-3">
        Période : <span className="text-[#6b7280]">{periodLabel}</span>
      </p>

      {/* Stats */}
      {loading ? (
        <div className="space-y-3">
          {[1, 2].map((i) => (
            <div key={i} className="bg-[#0f1016] border border-[#2e2f3a] rounded-xl p-4 h-20 animate-pulse" />
          ))}
        </div>
      ) : stats ? (
        <div className="space-y-3">
          <StatCard
            label="Volume total"
            value={`${stats.totalVolume.toLocaleString('fr-FR', { maximumFractionDigits: 2 })} Ğ1`}
            delta={prevVolume !== null ? (stats.totalVolume > prevVolume ? 'up' : stats.totalVolume < prevVolume ? 'down' : null) : null}
          />
          <StatCard
            label="Transactions"
            value={stats.transactionCount.toLocaleString('fr-FR')}
            sub={`≈ ${(stats.totalVolume / (stats.transactionCount || 1)).toFixed(2)} Ğ1 / tx`}
            delta={prevTxCount !== null ? (stats.transactionCount > prevTxCount ? 'up' : stats.transactionCount < prevTxCount ? 'down' : null) : null}
          />
          {/* Couverture géo — uniquement en mode live */}
          {source === 'live' && geoPct !== null && (
            <div className="bg-[#0f1016] border border-[#2e2f3a] rounded-xl p-3">
              <div className="flex justify-between items-center mb-1.5">
                <p className="text-[#4b5563] text-xs uppercase tracking-widest">Géolocalisées</p>
                <p className="text-[#6b7280] text-xs">{stats.geoCount} / {stats.transactionCount}</p>
              </div>
              <div className="w-full bg-[#1e1f2a] rounded-full h-1.5">
                <div
                  className="bg-[#d4a843] h-1.5 rounded-full transition-all duration-500"
                  style={{ width: `${geoPct}%` }}
                />
              </div>
              <p className="text-[#4b5563] text-xs mt-1 text-right">{geoPct}% via Cesium+</p>
            </div>
          )}
        </div>
      ) : null}

      {/* Top cities */}
      {!loading && stats && stats.topCities.length > 0 && (
        <div className="space-y-2">
          <p className="text-[#4b5563] text-xs uppercase tracking-widest border-t border-[#1e1f2a] pt-3">
            Top villes
          </p>
          {stats.topCities.map((city, i) => (
            <div
              key={city.name}
              className="bg-[#0f1016] border border-[#2e2f3a] rounded-lg px-3 py-2.5 flex gap-2.5"
            >
              <span className="text-base shrink-0 mt-0.5">{MEDALS[i]}</span>
              <div className="flex-1 min-w-0">
                <p className="text-white text-xs font-medium leading-snug">{city.name}</p>
                <div className="flex items-center justify-between mt-1">
                  <span className="flex items-center gap-1.5 text-[#6b7280] text-xs">
                    {city.countryCode && (
                      <span className="text-[10px] font-bold bg-[#1e1f2a] text-[#6b7280] rounded px-1 py-0.5 leading-none">
                        {city.countryCode}
                      </span>
                    )}
                    {city.count} tx
                  </span>
                  <span className="text-[#d4a843] text-xs font-mono flex items-center gap-1">
                    {city.volume.toLocaleString('fr-FR', { maximumFractionDigits: 0 })} Ğ1
                    {delta(city.volume, prevCityVolume, city.name)}
                  </span>
                </div>
              </div>
            </div>
          ))}
        </div>
      )}

      {/* Footer */}
      <div className="mt-auto pt-4 border-t border-[#1e1f2a]">
        <p className="text-[#2e2f3a] text-xs text-center">
          {source === 'live' ? 'Ğ1v2 · Subsquid + Cesium+' : 'Données simulées · mock'}
        </p>
      </div>
    </aside>
  );
}
