import { useEffect, useState } from "react";
import { ChevronLeft, ChevronRight, Search, Loader2 } from "lucide-react";
import { cn } from "~/lib/utils";

/* ------------------------------ helpers ------------------------------ */

export const faNum = (n?: number | string | null) =>
  n === null || n === undefined || n === ""
    ? "—"
    : Number(n).toLocaleString("fa-IR");

export const faToman = (n?: number | null) =>
  n === null || n === undefined ? "—" : `${Math.round(n).toLocaleString("fa-IR")} تومان`;

export const faDate = (iso?: string | null) => {
  if (!iso) return "—";
  try {
    return new Date(iso).toLocaleDateString("fa-IR", {
      year: "numeric",
      month: "2-digit",
      day: "2-digit",
    });
  } catch {
    return "—";
  }
};

/** Debounce a rapidly-changing value (e.g. a search box). */
export function useDebouncedValue<T>(value: T, delay = 350): T {
  const [debounced, setDebounced] = useState(value);
  useEffect(() => {
    const t = setTimeout(() => setDebounced(value), delay);
    return () => clearTimeout(t);
  }, [value, delay]);
  return debounced;
}

/* ---------------------------- status badge --------------------------- */

type Tone = "green" | "red" | "yellow" | "blue" | "gray";

const TONE: Record<Tone, string> = {
  green: "bg-GREEN/10 text-GREEN",
  red: "bg-RED/10 text-RED",
  yellow: "bg-yellow-500/10 text-yellow-600",
  blue: "bg-VITROWN_BLUE/10 text-VITROWN_BLUE",
  gray: "bg-WHITE3 text-BLACK2",
};

export function StatusBadge({ label, tone }: { label: string; tone: Tone }) {
  return (
    <span
      className={cn(
        "inline-block px-2 py-0.5 rounded-full text-[11px] font-semibold whitespace-nowrap",
        TONE[tone]
      )}
    >
      {label}
    </span>
  );
}

/* ------------------------------- table ------------------------------- */

export interface Column<T> {
  header: string;
  render: (row: T) => React.ReactNode;
  className?: string;
}

export function AdminTable<T>({
  columns,
  rows,
  isLoading,
  getRowKey,
  emptyText = "موردی یافت نشد",
}: {
  columns: Column<T>[];
  rows: T[];
  isLoading?: boolean;
  getRowKey: (row: T) => string;
  emptyText?: string;
}) {
  return (
    <div className="rounded-2xl border border-WHITE3 bg-WHITE overflow-hidden">
      <div className="overflow-x-auto">
        <table className="w-full text-right border-collapse">
          <thead>
            <tr className="bg-WHITE2 text-GRAY text-[12px]">
              {columns.map((c, i) => (
                <th
                  key={i}
                  className={cn("px-3 py-3 font-bold whitespace-nowrap", c.className)}
                >
                  {c.header}
                </th>
              ))}
            </tr>
          </thead>
          <tbody>
            {isLoading ? (
              <tr>
                <td colSpan={columns.length} className="py-12 text-center">
                  <Loader2 className="inline h-6 w-6 animate-spin text-GRAY" />
                </td>
              </tr>
            ) : rows.length === 0 ? (
              <tr>
                <td
                  colSpan={columns.length}
                  className="py-12 text-center text-GRAY text-[13px]"
                >
                  {emptyText}
                </td>
              </tr>
            ) : (
              rows.map((row) => (
                <tr
                  key={getRowKey(row)}
                  className="border-t border-WHITE3 hover:bg-WHITE2/60 transition-colors text-[13px]"
                >
                  {columns.map((c, i) => (
                    <td
                      key={i}
                      className={cn("px-3 py-3 align-middle", c.className)}
                    >
                      {c.render(row)}
                    </td>
                  ))}
                </tr>
              ))
            )}
          </tbody>
        </table>
      </div>
    </div>
  );
}

/* ---------------------------- pagination ----------------------------- */

export function AdminPagination({
  page,
  pageSize,
  count,
  onPageChange,
}: {
  page: number;
  pageSize: number;
  count: number;
  onPageChange: (page: number) => void;
}) {
  const totalPages = Math.max(1, Math.ceil(count / pageSize));
  const from = count === 0 ? 0 : (page - 1) * pageSize + 1;
  const to = Math.min(count, page * pageSize);
  const btn =
    "h-8 w-8 grid place-items-center rounded-lg border border-WHITE3 text-BLACK2 disabled:opacity-40 hover:bg-WHITE2 transition-colors cursor-pointer disabled:cursor-default";

  return (
    <div className="flex items-center justify-between mt-3 text-[13px] text-GRAY">
      <span>
        {faNum(from)}–{faNum(to)} از {faNum(count)}
      </span>
      <div className="flex items-center gap-1.5">
        <button
          className={btn}
          disabled={page <= 1}
          onClick={() => onPageChange(page - 1)}
          aria-label="صفحه قبل"
        >
          <ChevronRight size={16} />
        </button>
        <span className="tabular-nums px-1">
          {faNum(page)} / {faNum(totalPages)}
        </span>
        <button
          className={btn}
          disabled={page >= totalPages}
          onClick={() => onPageChange(page + 1)}
          aria-label="صفحه بعد"
        >
          <ChevronLeft size={16} />
        </button>
      </div>
    </div>
  );
}

/* --------------------------- toolbar bits ---------------------------- */

export function AdminSearch({
  value,
  onChange,
  placeholder = "جستجو…",
}: {
  value: string;
  onChange: (v: string) => void;
  placeholder?: string;
}) {
  return (
    <div className="relative flex-1 min-w-[180px] max-w-[320px]">
      <Search
        size={16}
        className="absolute right-3 top-1/2 -translate-y-1/2 text-GRAY"
      />
      <input
        value={value}
        onChange={(e) => onChange(e.target.value)}
        placeholder={placeholder}
        className="w-full rounded-xl border border-WHITE3 bg-WHITE pr-9 pl-3 py-2 text-[13px] outline-none focus:border-VITROWN_BLUE"
      />
    </div>
  );
}

export function AdminSelect({
  value,
  onChange,
  options,
}: {
  value: string;
  onChange: (v: string) => void;
  options: { value: string; label: string }[];
}) {
  return (
    <select
      value={value}
      onChange={(e) => onChange(e.target.value)}
      className="rounded-xl border border-WHITE3 bg-WHITE px-3 py-2 text-[13px] outline-none focus:border-VITROWN_BLUE cursor-pointer"
    >
      {options.map((o) => (
        <option key={o.value} value={o.value}>
          {o.label}
        </option>
      ))}
    </select>
  );
}

export function AdminToolbar({ children }: { children: React.ReactNode }) {
  return <div className="flex flex-wrap items-center gap-2 mb-3">{children}</div>;
}

export function AdminPageTitle({ children }: { children: React.ReactNode }) {
  return (
    <h1 className="text-[22px] lg:text-[26px] font-extrabold mb-4">{children}</h1>
  );
}