import { useMemo, useState } from "react";
import { Link, useLocation, useSearchParams } from "react-router-dom";
import { useQuery } from "@tanstack/react-query";
import {
  fetchPurchaseRequests,
  type PurchaseRequestStatus,
  type PurchaseRequestSummary,
} from "../api/purchaseRequests";
import { PageHeader } from "../components/common/PageHeader";
import { StatusBadge } from "../components/common/StatusBadge";
import { PageScaffold } from "../components/patterns/PageScaffold";
import { Tabs, TabsList, TabsTrigger } from "../components/ui/tabs";
import { resolvePurchaseDisplayCode } from "../lib/approvalDisplay";
import { joinBusinessMeta } from "../lib/businessDisplay";
import { resolveErrorMessage } from "../lib/resolveErrorMessage";

const STATUS_TABS: Array<{ value: PurchaseRequestStatus; label: string }> = [
  { value: "draft", label: "草稿" },
  { value: "reviewing", label: "审批中" },
  { value: "approved", label: "已通过" },
  { value: "rejected", label: "已驳回" },
  { value: "cancelled", label: "已取消" },
];

function isPurchaseStatus(value: string | null): value is PurchaseRequestStatus {
  return ["draft", "reviewing", "approved", "rejected", "cancelled"].includes(value ?? "");
}

function formatCurrency(value: string | null | undefined, currencyCode = "CNY") {
  const amount = Number(value ?? 0);
  if (!Number.isFinite(amount)) {
    return "-";
  }
  return new Intl.NumberFormat("zh-CN", { style: "currency", currency: currencyCode }).format(amount);
}

function formatDate(value: string | null | undefined) {
  return value ? value.slice(0, 10) : "-";
}

function PurchaseRequestCard({
  item,
  currentMobileSource,
}: {
  item: PurchaseRequestSummary;
  currentMobileSource: string;
}) {
  const displayCode = resolvePurchaseDisplayCode(item);

  return (
    <Link
      className="mobile-list-card block"
      data-testid="mobile-purchase-request-card"
      state={{ from: currentMobileSource }}
      to={`/mobile/purchase-requests/${encodeURIComponent(item.id)}`}
    >
      <div className="flex items-start justify-between gap-3">
        <div className="min-w-0">
          <div className="truncate text-sm font-semibold text-zinc-900">{displayCode}</div>
          <div className="mt-1 truncate text-xs text-zinc-500">
            {joinBusinessMeta([
              item.title || null,
              item.applicant?.name ? `申请人：${item.applicant.name}` : null,
              item.updatedAt ? `更新：${formatDate(item.updatedAt)}` : null,
            ])}
          </div>
        </div>
        <StatusBadge className="shrink-0" status={item.status} />
      </div>
      <div className="mt-3 text-sm text-zinc-600">
        {joinBusinessMeta([
          `金额：${formatCurrency(item.totalAmount, item.currencyCode)}`,
          item.supplier?.name ? `供应商：${item.supplier.name}` : null,
          item.expectedDeliveryDate ? `到货：${formatDate(item.expectedDeliveryDate)}` : null,
        ])}
      </div>
    </Link>
  );
}

export function MobilePurchaseRequestsPage() {
  const location = useLocation();
  const [searchParams, setSearchParams] = useSearchParams();
  const [status, setStatus] = useState<PurchaseRequestStatus>(() => {
    const queryStatus = searchParams.get("status");
    return isPurchaseStatus(queryStatus) ? queryStatus : "draft";
  });

  const currentMobileSource = useMemo(() => {
    const params = new URLSearchParams(location.search);
    params.set("status", status);
    const query = params.toString();
    return `${location.pathname}${query ? `?${query}` : ""}`;
  }, [location.pathname, location.search, status]);

  const listQuery = useQuery({
    queryKey: ["mobile", "purchase-requests", status],
    queryFn: () => fetchPurchaseRequests({ mine: true, status, page: 1, pageSize: 20 }),
  });

  function handleStatusChange(value: string) {
    if (!isPurchaseStatus(value)) {
      return;
    }
    setStatus(value);
    const nextParams = new URLSearchParams(searchParams);
    nextParams.set("status", value);
    setSearchParams(nextParams, { replace: true });
  }

  const items = listQuery.data?.items ?? [];
  const totalAmount = useMemo(
    () => items.reduce((sum, item) => sum + Number(item.totalAmount ?? 0), 0),
    [items],
  );

  return (
    <PageScaffold className="space-y-4">
      <PageHeader title="采购" />

      <section className="mobile-card">
        <div className="mobile-info-grid">
          <div>
            <div className="text-xs text-zinc-500">当前列表</div>
            <div className="mt-1 text-2xl font-semibold text-zinc-900">{listQuery.data?.total ?? 0}</div>
          </div>
          <div>
            <div className="text-xs text-zinc-500">当前金额</div>
            <div className="mt-1 text-2xl font-semibold text-zinc-900">{formatCurrency(String(totalAmount))}</div>
          </div>
        </div>
      </section>

      <section className="mobile-card" data-testid="mobile-purchase-requests-list">
        <Tabs value={status} onValueChange={handleStatusChange}>
          <TabsList className="grid h-auto w-full grid-cols-3 gap-1 min-[390px]:grid-cols-5">
            {STATUS_TABS.map((item) => (
              <TabsTrigger key={item.value} value={item.value} data-testid={`mobile-purchase-tab-${item.value}`}>
                {item.label}
              </TabsTrigger>
            ))}
          </TabsList>
        </Tabs>

        <div className="mt-4 space-y-3">
          {listQuery.isLoading ? <div className="mobile-empty-state">加载中...</div> : null}
          {listQuery.isError ? (
            <div className="rounded-lg border border-red-200 bg-red-50 p-3 text-sm text-red-600">
              {resolveErrorMessage(listQuery.error)}
            </div>
          ) : null}
          {!listQuery.isLoading && !listQuery.isError && !items.length ? (
            <div className="mobile-empty-state">暂无采购申请</div>
          ) : null}
          {items.map((item) => (
            <PurchaseRequestCard currentMobileSource={currentMobileSource} item={item} key={item.id} />
          ))}
        </div>
      </section>
    </PageScaffold>
  );
}

export default MobilePurchaseRequestsPage;