import {
  Users,
  Coins,
  TrendingUp,
  Gift,
  Loader2,
  AlertTriangle,
  CheckCircle,
  XCircle,
  Info,
  Clock,
  Wifi,
  Trophy,
  Crown,
  Gem,
  Wrench,
} from "lucide-react";
import { cn } from "../lib/utils";
import { useDashboard, type DashboardStats } from "../lib/useDashboard";

function formatNumber(n: number | string): string {
  const num = typeof n === "string" ? parseFloat(n) : n;
  if (num >= 1_000_000) return `${(num / 1_000_000).toFixed(1)}M`;
  if (num >= 1_000) return `${(num / 1_000).toFixed(1)}K`;
  return num.toLocaleString();
}

function formatUptime(ms: number): string {
  const hours = Math.floor(ms / 3_600_000);
  const minutes = Math.floor((ms % 3_600_000) / 60_000);
  if (hours >= 24) {
    const days = Math.floor(hours / 24);
    return `${days}d ${hours % 24}h`;
  }
  return `${hours}h ${minutes}m`;
}

function timeAgo(ts: string | Date): string {
  const diff = Date.now() - new Date(ts).getTime();
  const mins = Math.floor(diff / 60_000);
  if (mins < 1) return "just now";
  if (mins < 60) return `${mins}m ago`;
  const hours = Math.floor(mins / 60);
  if (hours < 24) return `${hours}h ago`;
  return `${Math.floor(hours / 24)}d ago`;
}

const eventIcons = {
  success: CheckCircle,
  error: XCircle,
  warn: AlertTriangle,
  info: Info,
} as const;

const eventColors = {
  success: "text-success",
  error: "text-destructive",
  warn: "text-warning",
  info: "text-info",
} as const;

function StatCard({
  icon: Icon,
  label,
  value,
  sub,
  accent = "border-primary",
}: {
  icon: React.ComponentType<{ className?: string }>;
  label: string;
  value: string;
  sub?: string;
  accent?: string;
}) {
  return (
    <div
      className={cn(
        "bg-gradient-to-br from-card to-surface rounded-lg border border-border p-6 border-l-4",
        accent
      )}
    >
      <div className="flex items-center gap-3 mb-3">
        <Icon className="w-5 h-5 text-primary" />
        <span className="text-[11px] font-semibold uppercase tracking-wider text-text-tertiary">
          {label}
        </span>
      </div>
      <div className="text-3xl font-bold font-display tracking-tight">{value}</div>
      {sub && <div className="text-sm text-text-tertiary mt-1">{sub}</div>}
    </div>
  );
}

function LeaderboardColumn({
  title,
  icon: Icon,
  entries,
  valueKey,
  valuePrefix,
}: {
  title: string;
  icon: React.ComponentType<{ className?: string }>;
  entries: Array<{ username: string; [k: string]: unknown }>;
  valueKey: string;
  valuePrefix?: string;
}) {
  return (
    <div className="bg-card rounded-lg border border-border">
      <div className="flex items-center gap-2 px-5 py-4 border-b border-border">
        <Icon className="w-4 h-4 text-primary" />
        <h3 className="text-sm font-semibold">{title}</h3>
      </div>
      <div className="divide-y divide-border">
        {entries.length === 0 && (
          <div className="px-5 py-4 text-sm text-text-tertiary">No data</div>
        )}
        {entries.slice(0, 10).map((entry, i) => (
          <div
            key={entry.username}
            className="flex items-center justify-between px-5 py-3 hover:bg-raised/40 transition-colors"
          >
            <div className="flex items-center gap-3">
              <span
                className={cn(
                  "w-6 text-xs font-mono font-medium text-right",
                  i === 0
                    ? "text-gold"
                    : i === 1
                    ? "text-text-secondary"
                    : i === 2
                    ? "text-warning"
                    : "text-text-tertiary"
                )}
              >
                #{i + 1}
              </span>
              <span className="text-sm">{entry.username}</span>
            </div>
            <span className="text-sm font-mono text-text-secondary">
              {valuePrefix}
              {formatNumber(entry[valueKey] as string | number)}
            </span>
          </div>
        ))}
      </div>
    </div>
  );
}

export default function Dashboard() {
  const { data, loading, error } = useDashboard();

  if (loading) {
    return (
      <div className="flex items-center justify-center py-32">
        <Loader2 className="w-6 h-6 animate-spin text-primary" />
      </div>
    );
  }

  if (error) {
    return (
      <div className="flex items-center justify-center py-32">
        <div className="text-center">
          <AlertTriangle className="w-8 h-8 text-warning mx-auto mb-3" />
          <p className="text-sm text-text-tertiary">{error}</p>
        </div>
      </div>
    );
  }

  if (!data) return null;

  return <DashboardContent data={data} />;
}

function DashboardContent({ data }: { data: DashboardStats }) {
  return (
    <div className="space-y-8">
      {/* Maintenance banner */}
      {data.maintenanceMode && (
        <div className="flex items-center gap-3 bg-warning/10 border border-warning/30 rounded-lg px-5 py-3">
          <Wrench className="w-4 h-4 text-warning shrink-0" />
          <span className="text-sm text-warning font-medium">
            Maintenance mode is active
          </span>
        </div>
      )}

      {/* Stat cards */}
      <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-4">
        <StatCard
          icon={Users}
          label="Total Users"
          value={formatNumber(data.users.total)}
          sub={`${formatNumber(data.users.active)} active`}
          accent="border-info"
        />
        <StatCard
          icon={Coins}
          label="Total Wealth"
          value={formatNumber(data.economy.totalWealth)}
          accent="border-gold"
        />
        <StatCard
          icon={TrendingUp}
          label="Avg Level"
          value={data.economy.avgLevel.toFixed(1)}
          sub={`Top streak: ${data.economy.topStreak}`}
          accent="border-success"
        />
        <StatCard
          icon={Gift}
          label="Active Lootdrops"
          value={String(data.activeLootdrops?.length ?? 0)}
          accent="border-primary"
        />
      </div>

      {/* Leaderboards */}
      {data.leaderboards && (
        <section>
          <h2 className="font-display text-lg font-semibold mb-4">Leaderboards</h2>
          <div className="grid grid-cols-1 md:grid-cols-3 gap-4">
            <LeaderboardColumn
              title="Top Levels"
              icon={Trophy}
              entries={data.leaderboards.topLevels}
              valueKey="level"
              valuePrefix="Lv. "
            />
            <LeaderboardColumn
              title="Top Wealth"
              icon={Crown}
              entries={data.leaderboards.topWealth}
              valueKey="balance"
            />
            <LeaderboardColumn
              title="Top Net Worth"
              icon={Gem}
              entries={data.leaderboards.topNetWorth}
              valueKey="netWorth"
            />
          </div>
        </section>
      )}

      {/* Recent Events */}
      {data.recentEvents.length > 0 && (
        <section>
          <h2 className="font-display text-lg font-semibold mb-4">Recent Events</h2>
          <div className="bg-card rounded-lg border border-border divide-y divide-border">
            {data.recentEvents.slice(0, 20).map((event, i) => {
              const Icon = eventIcons[event.type];
              return (
                <div
                  key={i}
                  className="flex items-start gap-3 px-5 py-3 hover:bg-raised/40 transition-colors"
                >
                  <Icon
                    className={cn("w-4 h-4 mt-0.5 shrink-0", eventColors[event.type])}
                  />
                  <span className="text-sm flex-1">
                    {event.icon && <span className="mr-1.5">{event.icon}</span>}
                    {event.message}
                  </span>
                  <span className="text-xs text-text-tertiary font-mono whitespace-nowrap">
                    {timeAgo(event.timestamp)}
                  </span>
                </div>
              );
            })}
          </div>
        </section>
      )}

      {/* Bot status footer */}
      <footer className="flex flex-wrap items-center gap-x-6 gap-y-2 text-xs text-text-tertiary border-t border-border pt-6">
        <span className="font-medium text-text-secondary">{data.bot.name}</span>
        <span className="flex items-center gap-1.5">
          <Wifi className="w-3 h-3" />
          {Math.round(data.ping.avg)}ms
        </span>
        <span className="flex items-center gap-1.5">
          <Clock className="w-3 h-3" />
          {formatUptime(data.uptime)}
        </span>
        {data.bot.status && (
          <span className="flex items-center gap-1.5">
            <span className="w-2 h-2 rounded-full bg-success" />
            {data.bot.status}
          </span>
        )}
      </footer>
    </div>
  );
}