import { useState } from "react";
import { Link, useParams } from "react-router-dom";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { isApiError } from "../api/types";
import { mapApiErrorMessage } from "../api/errorMessages";
import {
  fetchReimbursementDetail,
  payReimbursement,
  submitReimbursement,
  withdrawReimbursement,
} from "../api/reimbursements";
import { useAuth } from "../auth/AuthContext";
import { hasPermission } from "../auth/permissions";
import { PageHeader } from "../components/common/PageHeader";

export function ReimbursementDetailPage() {
  const { reimbursementId = "" } = useParams();
  const { permissions } = useAuth();
  const queryClient = useQueryClient();

  const [withdrawComment, setWithdrawComment] = useState("申请撤回并补充说明后重提");
  const [paymentVoucherNo, setPaymentVoucherNo] = useState("");
  const [paymentDate, setPaymentDate] = useState("2026-02-08");
  const [paymentChannel, setPaymentChannel] = useState<"bank" | "alipay" | "wechat" | "cash" | "other">(
    "bank",
  );
  const [actionError, setActionError] = useState("");

  const detailQuery = useQuery({
    enabled: Boolean(reimbursementId),
    queryKey: ["reimbursements", reimbursementId],
    queryFn: () => fetchReimbursementDetail(reimbursementId),
  });

  const mutation = useMutation({
    mutationFn: async (action: "submit" | "withdraw" | "pay") => {
      if (!reimbursementId) {
        throw new Error("missing reimbursementId");
      }

      if (action === "submit") {
        return submitReimbursement(reimbursementId);
      }

      if (action === "withdraw") {
        return withdrawReimbursement(reimbursementId, withdrawComment.trim());
      }

      return payReimbursement(reimbursementId, {
        paymentVoucherNo: paymentVoucherNo.trim() || undefined,
        paymentDate: paymentDate || undefined,
        paymentChannel,
      });
    },
    onSuccess: async () => {
      await Promise.all([
        queryClient.invalidateQueries({ queryKey: ["reimbursements"] }),
        queryClient.invalidateQueries({ queryKey: ["reimbursements", reimbursementId] }),
      ]);
      setActionError("");
    },
    onError: (error) => {
      if (isApiError(error)) {
        setActionError(
          `${error.code}: ${mapApiErrorMessage(error.code, error.details, error.message)}`,
        );
        return;
      }

      if (error instanceof Error) {
        setActionError(error.message);
        return;
      }

      setActionError("操作失败，请稍后重试");
    },
  });

  if (!reimbursementId) {
    return (
      <section className="card-std">
        <p className="text-sm text-red-600">缺少 reimbursementId 参数。</p>
      </section>
    );
  }

  if (detailQuery.isLoading) {
    return (
      <section className="card-std">
        <p className="text-sm text-slate-500">加载报销详情中...</p>
      </section>
    );
  }

  if (detailQuery.isError || !detailQuery.data) {
    const message = isApiError(detailQuery.error)
      ? `${detailQuery.error.code}: ${mapApiErrorMessage(
          detailQuery.error.code,
          detailQuery.error.details,
          detailQuery.error.message,
        )}`
      : "加载报销详情失败";

    return (
      <section className="card-std space-y-3">
        <p className="text-sm text-red-600">{message}</p>
        <Link className="btn-secondary" to="/reimbursements">
          返回报销列表
        </Link>
      </section>
    );
  }

  const detail = detailQuery.data;
  const canPay = hasPermission(permissions, "expense.finance.pay");

  return (
    <div className="space-y-6">
      <PageHeader
        title={`报销详情 ${detail.formNumber ?? detail.id}`}
        subtitle={`状态：${detail.status}`}
        actions={
          <Link className="btn-secondary" to="/reimbursements">
            返回列表
          </Link>
        }
      />

      <section className="card-std space-y-2 text-sm">
        <div>报销ID：{detail.id}</div>
        <div>报销日期：{detail.reimbursementDate ?? "-"}</div>
        <div>金额：{detail.totalAmount ?? "-"}</div>
        <div>提交人：{detail.submitter?.name ?? "-"}</div>
        <div>报销人：{detail.owner?.name ?? "-"}</div>
        <div>说明：{detail.description || "-"}</div>
      </section>

      <section className="card-std space-y-3">
        <h3 className="text-base font-semibold text-slate-900">可执行动作</h3>

        {actionError ? (
          <p className="rounded-lg border border-red-200 bg-red-50 px-3 py-2 text-sm text-red-600">
            {actionError}
          </p>
        ) : null}

        <div className="flex flex-wrap gap-2">
          <button
            className="btn-primary"
            disabled={mutation.isPending || detail.status !== "draft"}
            onClick={() => mutation.mutate("submit")}
            type="button"
          >
            提交报销
          </button>
        </div>

        <div className="space-y-2 rounded-lg border border-slate-200 p-3">
          <p className="text-sm font-medium text-slate-800">撤回报销</p>
          <textarea
            className="w-full rounded-lg border border-slate-300 px-3 py-2 text-sm"
            onChange={(event) => setWithdrawComment(event.target.value)}
            rows={2}
            value={withdrawComment}
          />
          <button
            className="btn-secondary"
            disabled={mutation.isPending || detail.status !== "reviewing" || withdrawComment.trim().length < 1}
            onClick={() => mutation.mutate("withdraw")}
            type="button"
          >
            撤回
          </button>
        </div>

        {canPay ? (
          <div className="space-y-2 rounded-lg border border-slate-200 p-3">
            <p className="text-sm font-medium text-slate-800">财务支付</p>
            <input
              className="w-full rounded-lg border border-slate-300 px-3 py-2 text-sm"
              onChange={(event) => setPaymentVoucherNo(event.target.value)}
              placeholder="付款凭证号"
              value={paymentVoucherNo}
            />
            <input
              className="w-full rounded-lg border border-slate-300 px-3 py-2 text-sm"
              onChange={(event) => setPaymentDate(event.target.value)}
              type="date"
              value={paymentDate}
            />
            <select
              className="w-full rounded-lg border border-slate-300 px-3 py-2 text-sm"
              onChange={(event) =>
                setPaymentChannel(event.target.value as "bank" | "alipay" | "wechat" | "cash" | "other")
              }
              value={paymentChannel}
            >
              <option value="bank">bank</option>
              <option value="alipay">alipay</option>
              <option value="wechat">wechat</option>
              <option value="cash">cash</option>
              <option value="other">other</option>
            </select>
            <button
              className="btn-secondary"
              disabled={mutation.isPending || !["approved", "paid"].includes(detail.status)}
              onClick={() => mutation.mutate("pay")}
              type="button"
            >
              执行支付
            </button>
          </div>
        ) : null}
      </section>

      <section className="card-std space-y-2">
        <h3 className="text-base font-semibold text-slate-900">关联票据</h3>
        {(detail.invoices ?? []).length ? (
          <div className="space-y-2 text-sm">
            {detail.invoices.map((item) => (
              <div className="rounded-lg border border-slate-200 px-3 py-2" key={item.id}>
                <div className="font-medium text-slate-900">{item.id}</div>
                <div className="text-slate-600">
                  状态 {item.status} / 发票 {item.invoiceCode || "-"}-{item.invoiceNumber || "-"}
                </div>
              </div>
            ))}
          </div>
        ) : (
          <p className="text-sm text-slate-500">暂无关联票据</p>
        )}
      </section>
    </div>
  );
}