import { useParams } from "react-router-dom";
import { useQuery } from "@tanstack/react-query";
import { fetchPurchaseRequestDetail } from "../api/purchaseRequests";
import { MobileDetailHeader } from "../components/mobile/MobileDetailHeader";
import { AttachmentGovernanceBadges } from "../components/common/AttachmentGovernanceBadges";
import { StatusBadge } from "../components/common/StatusBadge";
import { PageScaffold } from "../components/patterns/PageScaffold";
import {
  formatApprovalHistoryTime,
  resolvePurchaseDisplayCode,
  resolvePurchaseStatusHint,
  workflowActionLabel,
} from "../lib/approvalDisplay";
import { joinBusinessMeta } from "../lib/businessDisplay";
import { resolveErrorMessage } from "../lib/resolveErrorMessage";

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 formatBytes(value: number) {
  if (value < 1024) {
    return `${value} B`;
  }
  if (value < 1024 * 1024) {
    return `${(value / 1024).toFixed(1)} KB`;
  }
  return `${(value / 1024 / 1024).toFixed(1)} MB`;
}

function purchaseProgressFallback(status: string | undefined) {
  if (status === "draft") return "/mobile/approvals?progress=draft";
  if (status === "approved") return "/mobile/approvals?progress=approved";
  if (status === "rejected" || status === "cancelled") return "/mobile/approvals?progress=returned";
  return "/mobile/approvals?progress=reviewing";
}

export function MobilePurchaseRequestDetailPage() {
  const { purchaseRequestId = "" } = useParams();

  const detailQuery = useQuery({
    enabled: Boolean(purchaseRequestId),
    queryKey: ["mobile", "purchase-request", "detail", purchaseRequestId],
    queryFn: () => fetchPurchaseRequestDetail(purchaseRequestId),
  });

  const detail = detailQuery.data ?? null;
  const displayCode = detail ? resolvePurchaseDisplayCode(detail) : "采购详情";
  const nextStepText = detail
    ? detail.pendingWorkflow?.task?.stepName
      ? `当前在 ${detail.pendingWorkflow.task.stepName}，可从审批详情处理；本页用于核对采购依据。`
      : resolvePurchaseStatusHint(detail)
    : "";

  return (
    <PageScaffold className="space-y-3 pb-4">
      <MobileDetailHeader
        title={displayCode}
        subtitle="采购详情"
        status={detail ? <StatusBadge status={detail.status} /> : null}
        fallbackTo={purchaseProgressFallback(detail?.status)}
        testId="mobile-purchase-detail-header"
      />

      {!purchaseRequestId ? (
        <div className="mobile-card text-sm text-red-600">缺少采购申请 ID。</div>
      ) : null}

      {detailQuery.isLoading ? <div className="mobile-card text-sm text-zinc-500">加载中...</div> : null}

      {detailQuery.isError ? (
        <div className="mobile-card text-sm text-red-600">{resolveErrorMessage(detailQuery.error)}</div>
      ) : null}

      {detail ? (
        <>
          <section className="mobile-card mobile-focus-card mobile-page-stack" data-testid="mobile-purchase-detail-summary">
            <div className="flex items-start justify-between gap-3">
              <div className="min-w-0">
                <h2 className="truncate text-base font-semibold text-zinc-900">{displayCode}</h2>
                <p className="mt-1 text-sm text-zinc-500">{detail.title || "未命名采购申请"}</p>
              </div>
              <StatusBadge status={detail.status} />
            </div>
            <div className="mobile-info-grid mt-4 text-sm">
              <div>
                <div className="text-xs text-zinc-500">金额</div>
                <div className="mt-1 text-lg font-semibold text-zinc-900">
                  {formatCurrency(detail.totalAmount, detail.currencyCode)}
                </div>
              </div>
              <div>
                <div className="text-xs text-zinc-500">申请人</div>
                <div className="mt-1 truncate font-medium text-zinc-900">{detail.applicant?.name ?? "-"}</div>
              </div>
              <div>
                <div className="text-xs text-zinc-500">当前节点</div>
                <div className="mt-1 truncate font-medium text-zinc-900">{detail.pendingWorkflow?.task?.stepName ?? "-"}</div>
              </div>
            </div>
            <div className="mobile-subcard bg-white text-sm">
              <div className="text-xs font-semibold text-zinc-500">下一步</div>
              <div className="mt-1 leading-6 text-zinc-700">{nextStepText}</div>
            </div>
          </section>

          <section className="mobile-card" data-testid="mobile-purchase-detail-fields">
            <h3 className="text-base font-semibold text-zinc-900">业务信息</h3>
            <div className="mobile-field-list mt-3">
              <div className="mobile-field-row">
                <div className="mobile-field-label">供应商</div>
                <div className="mobile-field-value">{detail.supplier?.name ?? "-"}</div>
              </div>
              <div className="mobile-field-row">
                <div className="mobile-field-label">期望到货</div>
                <div className="mobile-field-value">{formatDate(detail.expectedDeliveryDate)}</div>
              </div>
              <div className="mobile-field-row">
                <div className="mobile-field-label">法体</div>
                <div className="mobile-field-value">{detail.legalEntity?.name ?? "-"}</div>
              </div>
              <div className="mobile-field-row">
                <div className="mobile-field-label">成本中心</div>
                <div className="mobile-field-value">{detail.costCenter?.name ?? "-"}</div>
              </div>
              <div className="mobile-field-row">
                <div className="mobile-field-label">预算池</div>
                <div className="mobile-field-value">{detail.budgetPool?.name ?? "未匹配"}</div>
              </div>
              <div className="mobile-field-row">
                <div className="mobile-field-label">当前节点</div>
                <div className="mobile-field-value">{detail.pendingWorkflow?.task?.stepName ?? "-"}</div>
              </div>
              {detail.reason ? (
                <div className="mobile-field-row">
                  <div className="mobile-field-label">申请说明</div>
                  <div className="mobile-field-value">{detail.reason}</div>
                </div>
              ) : null}
            </div>
          </section>

          <section className="mobile-card" data-testid="mobile-purchase-detail-items">
            <h3 className="text-base font-semibold text-zinc-900">采购明细</h3>
            <div className="mt-3 space-y-2">
              {detail.items.length ? detail.items.map((item) => (
                <article className="mobile-list-card text-sm" key={item.id}>
                  <div className="font-medium text-zinc-900">{item.description}</div>
                  <div className="mt-1 text-xs text-zinc-500">
                    {joinBusinessMeta([`数量：${item.quantity}`, `单价：${formatCurrency(item.unitPrice, detail.currencyCode)}`, `金额：${formatCurrency(item.lineAmount, detail.currencyCode)}`])}
                  </div>
                  {item.specification ? <div className="mt-1 text-xs text-zinc-500">{item.specification}</div> : null}
                </article>
              )) : <div className="mobile-empty-state">暂无采购明细</div>}
            </div>
          </section>

          <section className="mobile-card" data-testid="mobile-purchase-detail-attachments">
            <h3 className="text-base font-semibold text-zinc-900">附件</h3>
            <div className="mt-3 space-y-2">
              {detail.attachments.length ? detail.attachments.map((attachment) => (
                <article className="mobile-list-card text-sm" key={attachment.id}>
                  <div className="truncate font-medium text-zinc-900">{attachment.originalName}</div>
                  <div className="mt-1 text-xs text-zinc-500">
                    {joinBusinessMeta([formatBytes(attachment.fileSize), attachment.uploader?.name, formatDate(attachment.createdAt)])}
                  </div>
                  <AttachmentGovernanceBadges attachment={attachment} className="mt-2" />
                </article>
              )) : <div className="mobile-empty-state">暂无附件</div>}
            </div>
          </section>

          <section className="mobile-card" data-testid="mobile-purchase-detail-approval-history">
            <h3 className="text-base font-semibold text-zinc-900">审批记录</h3>
            <div className="mt-3 space-y-2">
              {detail.approvalHistory.length ? detail.approvalHistory.map((item) => (
                <article className="mobile-list-card text-sm" key={item.id}>
                  <div className="flex items-center justify-between gap-3">
                    <div className="font-medium text-zinc-900">{workflowActionLabel(item.action)}</div>
                    <span className="text-xs text-zinc-500">{formatApprovalHistoryTime(item.createdAt)}</span>
                  </div>
                  <div className="mt-1 text-xs text-zinc-500">{item.actorName ?? item.actorEmployeeNo ?? "-"}</div>
                  {item.comment ? <div className="mt-1 text-xs text-zinc-500">{item.comment}</div> : null}
                </article>
              )) : <div className="mobile-empty-state">暂无审批记录</div>}
            </div>
          </section>
        </>
      ) : null}
    </PageScaffold>
  );
}

export default MobilePurchaseRequestDetailPage;