"use client";

import { useMemo } from "react";
import { iconArchive, iconBox, iconCart, iconDelivery, iconTag, iconUsersGroup } from "../_core/icons";
import { useOperatingDay } from "../_core/hooks/use-operating-day";
import { productsResource, shopCartsResource, usersResource, warehousesResource } from "../_core/services/entities";
import { QuickActionCard } from "./_components/quick-action-card";
import { StatCard } from "./_components/stat-card";

const ROLE_LABELS: Record<string, string> = { admin: "administrador", cashier: "cajero" };

function money(value: number) {
  return value.toLocaleString("es-AR", { style: "currency", currency: "USD" });
}

export default function AdminDashboardPage() {
  const { data: carts, isLoading: loadingCarts } = shopCartsResource.useList();
  const { data: products, isLoading: loadingProducts } = productsResource.useList();
  const { data: warehouses } = warehousesResource.useList();
  const { data: users, isLoading: loadingUsers } = usersResource.useList();
  const { start: operatingDayStart } = useOperatingDay();

  const salesToday = useMemo(() => {
    if (!carts) return null;
    return carts
      .filter((c) => c.status === "paid" && new Date(c.createdAt) >= operatingDayStart)
      .reduce((sum, c) => sum + Number(c.totalPrice), 0);
  }, [carts, operatingDayStart]);

  const stockByProduct = useMemo(() => {
    const map = new Map<number, number>();
    for (const w of warehouses ?? []) map.set(w.productId, (map.get(w.productId) ?? 0) + w.stock);
    return map;
  }, [warehouses]);

  const lowStockCount = useMemo(() => {
    if (!products) return null;
    return products.filter((p) => (stockByProduct.get(p.id) ?? 0) <= p.minStock).length;
  }, [products, stockByProduct]);

  const usersByRole = useMemo(() => {
    const counts: Record<string, number> = {};
    for (const u of users ?? []) counts[u.role] = (counts[u.role] ?? 0) + 1;
    return counts;
  }, [users]);

  const usersHint = Object.entries(usersByRole)
    .map(([role, count]) => `${count} ${ROLE_LABELS[role] ?? role}${count === 1 ? "" : "s"}`)
    .join(", ");

  return (
    <div className="flex flex-col gap-8">
      <div>
        <h1 className="text-xl font-semibold text-foreground">Resumen</h1>
        <p className="text-sm text-muted">Estado general del negocio.</p>
      </div>

      <div className="grid grid-cols-1 gap-4 sm:grid-cols-2 xl:grid-cols-4">
        <StatCard
          icon={iconCart}
          label="Ventas de hoy"
          value={loadingCarts || salesToday === null ? "—" : money(salesToday)}
          hint={salesToday ? "Total cobrado hoy" : "Sin ventas registradas aún"}
        />
        <StatCard
          icon={iconBox}
          label="Productos activos"
          value={loadingProducts || !products ? "—" : String(products.length)}
          hint={products && products.length > 0 ? "En el catálogo" : "Conectá el catálogo para ver el total"}
        />
        <StatCard
          icon={iconArchive}
          label="Alertas de stock"
          value={lowStockCount === null ? "—" : String(lowStockCount)}
          hint={lowStockCount ? "Productos bajo el mínimo" : "Sin datos de inventario aún"}
        />
        <StatCard
          icon={iconUsersGroup}
          label="Usuarios activos"
          value={loadingUsers || !users ? "—" : String(users.length)}
          hint={usersHint || "Sin usuarios"}
        />
      </div>

      <div>
        <h2 className="mb-3 text-sm font-semibold text-foreground">Accesos rápidos</h2>
        <div className="grid grid-cols-1 gap-3 sm:grid-cols-2 xl:grid-cols-3">
          <QuickActionCard href="/admin/inventario" icon={iconArchive} label="Almacenes" description="Stock, entradas y salidas" />
          <QuickActionCard href="/admin/inventario/productos" icon={iconBox} label="Productos" description="Catálogo y precios" />
          <QuickActionCard href="/admin/inventario/categorias" icon={iconTag} label="Categorías" description="Organizá el catálogo" />
          <QuickActionCard href="/admin/proveedores" icon={iconDelivery} label="Proveedores" description="Contactos y pedidos" />
          <QuickActionCard href="/admin/usuarios" icon={iconUsersGroup} label="Usuarios" description="Roles y accesos" />
        </div>
      </div>
    </div>
  );
}