import { useState } from "react";
import { useQuery } from "@tanstack/react-query";
import { useNavigate } from "react-router-dom";
import { Search, Users, Mail, Phone, DollarSign, Calendar, ChevronRight, Sparkles } from "lucide-react";
import { api } from "../lib/api";
import { PageHeader, Avatar, Spinner, EmptyState } from "../components/ui";
import { formatCurrency, formatDate, formatRelative } from "../lib/format";
import { CrmSyncPanel } from "../components/CrmSyncPanel";

export function ClientsPage() {
  const navigate = useNavigate();
  const [q, setQ] = useState("");
  const [debounced, setDebounced] = useState("");
  const [timer, setTimer] = useState<any>(null);

  const onChange = (v: string) => {
    setQ(v);
    if (timer) clearTimeout(timer);
    const t = setTimeout(() => setDebounced(v), 250);
    setTimer(t);
  };

  const { data, isFetching } = useQuery({
    queryKey: ["clients", debounced],
    queryFn: () => api.clients.list(debounced),
  });

  return (
    <div className="flex h-full flex-col">
      <PageHeader
        title="Clientes"
        subtitle="Busca, edita y revisa el historial de tus clientes."
      />

      <div className="px-5 pt-4 sm:px-7">
        <CrmSyncPanel />
      </div>

      <div className="px-5 pt-4 sm:px-7">
        <div className="relative max-w-md">
          <Search className="pointer-events-none absolute left-3 top-1/2 h-4 w-4 -translate-y-1/2 text-slate-400" />
          <input
            className="input pl-9"
            placeholder="Buscar por nombre, teléfono o correo…"
            value={q}
            onChange={(e) => onChange(e.target.value)}
          />
          {isFetching && <Spinner className="absolute right-3 top-1/2 -translate-y-1/2 text-slate-400" />}
        </div>
      </div>

      <div className="flex-1 px-5 py-5 sm:px-7">
        {isFetching && !data ? (
          <div className="flex h-40 items-center justify-center"><Spinner /></div>
        ) : !data?.clients.length ? (
          <EmptyState icon={Users} title="Sin clientes" description="Los clientes aparecerán aquí cuando agendes su primera cita." />
        ) : (
          <div className="card overflow-hidden">
            {/* Mobile card list */}
            <div className="divide-y divide-slate-50 sm:hidden">
              {data.clients.map((c) => (
                <button
                  key={c.id}
                  onClick={() => navigate(`/clients/${c.id}`)}
                  className="flex w-full items-center gap-3 px-4 py-3 text-left transition-colors hover:bg-slate-50/60"
                >
                  <Avatar name={c.name} color="#94a3b8" size={38} />
                  <div className="min-w-0 flex-1">
                    <div className="flex items-center gap-1.5">
                      <span className="truncate font-bold text-slate-900">{c.name}</span>
                      {c.tags?.split(",")[0] && (
                        <span className="chip bg-brand-50 text-brand-600">{c.tags.split(",")[0].trim()}</span>
                      )}
                    </div>
                    <div className="truncate text-[11px] text-slate-500">
                      {c.phone ?? c.email ?? "Sin contacto"}
                    </div>
                    <div className="mt-0.5 flex items-center gap-3 text-[11px]">
                      <span className="font-semibold text-slate-600">{c.stats?.visits ?? 0} visitas</span>
                      <span className="font-bold text-emerald-600">{formatCurrency(c.stats?.total_spent ?? 0)}</span>
                    </div>
                  </div>
                  <ChevronRight className="h-4 w-4 shrink-0 text-slate-300" />
                </button>
              ))}
            </div>
            {/* Desktop table */}
            <div className="hidden overflow-x-auto sm:block">
              <table className="w-full text-sm">
                <thead>
                  <tr className="border-b border-slate-100 text-left text-[11px] font-bold uppercase tracking-wider text-slate-400">
                    <th className="px-4 py-3">Cliente</th>
                    <th className="px-4 py-3">Contacto</th>
                    <th className="px-4 py-3 text-right">Visitas</th>
                    <th className="px-4 py-3 text-right">Gasto total</th>
                    <th className="px-4 py-3">Última visita</th>
                    <th className="px-4 py-3"></th>
                  </tr>
                </thead>
                <tbody>
                  {data.clients.map((c) => (
                    <tr
                      key={c.id}
                      onClick={() => navigate(`/clients/${c.id}`)}
                      className="group cursor-pointer border-b border-slate-50 transition-colors hover:bg-slate-50/60"
                    >
                      <td className="px-4 py-3">
                        <div className="flex items-center gap-2.5">
                          <Avatar name={c.name} color="#94a3b8" size={34} />
                          <div className="min-w-0">
                            <div className="flex items-center gap-1.5">
                              <span className="font-bold text-slate-900">{c.name}</span>
                              {c.tags?.split(",").map((t) => (
                                <span key={t} className="chip bg-brand-50 text-brand-600">{t.trim()}</span>
                              ))}
                            </div>
                            <span className="text-[11px] text-slate-400">Desde {formatDate(c.created_at)}</span>
                          </div>
                        </div>
                      </td>
                      <td className="px-4 py-3 text-slate-600">
                        <div className="flex flex-col gap-0.5 text-xs">
                          {c.phone && <span className="inline-flex items-center gap-1"><Phone className="h-3 w-3" /> {c.phone}</span>}
                          {c.email && <span className="inline-flex items-center gap-1"><Mail className="h-3 w-3" /> {c.email}</span>}
                        </div>
                      </td>
                      <td className="px-4 py-3 text-right">
                        <span className="inline-flex items-center gap-1 font-bold text-slate-800">
                          <Calendar className="h-3.5 w-3.5 text-slate-400" />
                          {c.stats?.visits ?? 0}
                        </span>
                      </td>
                      <td className="px-4 py-3 text-right">
                        <span className="inline-flex items-center gap-1 font-bold text-emerald-600">
                          <DollarSign className="h-3.5 w-3.5" />
                          {formatCurrency(c.stats?.total_spent ?? 0)}
                        </span>
                      </td>
                      <td className="px-4 py-3 text-xs text-slate-500">{formatRelative(c.stats?.last_visit ?? null)}</td>
                      <td className="px-4 py-3 text-right">
                        <ChevronRight className="h-4 w-4 text-slate-300 transition-transform group-hover:translate-x-0.5 group-hover:text-brand-500" />
                      </td>
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
            <div className="flex items-center justify-center gap-2 border-t border-slate-100 bg-slate-50/60 px-4 py-2.5 text-xs text-slate-500">
              <Sparkles className="h-3.5 w-3.5 text-brand-400" />
              Mostrando {data.clients.length} cliente{data.clients.length !== 1 ? "s" : ""}
            </div>
          </div>
        )}
      </div>
    </div>
  );
}