import { Link, useSearchParams } from "react-router-dom";
import { useQuery } from "@tanstack/react-query";
import { isApiError } from "../api/types";
import { mapApiErrorMessage } from "../api/errorMessages";
import { fetchWorkflowTasks } from "../api/workflow";
import { PageHeader } from "../components/common/PageHeader";
import { Pagination } from "../components/common/Pagination";
import { StatusBadge } from "../components/common/StatusBadge";
import { TableSkeleton } from "../components/common/TableSkeleton";
import { Button } from "../components/ui/button";
import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "../components/ui/table";
import { Tabs, TabsList, TabsTrigger } from "../components/ui/tabs";

const PAGE_SIZE = 20;

function entityLabel(entityType: string | undefined) {
  if (entityType === "leave") {
    return "请假";
  }
  if (entityType === "reimbursement") {
    return "报销";
  }
  if (entityType === "purchase_request") {
    return "采购";
  }
  if (entityType === "travel_request") {
    return "差旅";
  }
  return entityType || "-";
}

export function WorkflowTasksPage() {
  const [searchParams, setSearchParams] = useSearchParams();

  const status =
    (searchParams.get("status") as
      | "pending"
      | "completed"
      | "rejected"
      | "cancelled"
      | "skipped"
      | null) ?? "pending";
  const page = Number(searchParams.get("page") ?? "1") || 1;

  const query = useQuery({
    queryKey: ["workflow", "tasks", status, page],
    queryFn: () => fetchWorkflowTasks({ status, page, pageSize: PAGE_SIZE }),
  });

  const totalPages = Math.max(1, Math.ceil((query.data?.total ?? 0) / PAGE_SIZE));

  return (
    <div className="space-y-6">
      <PageHeader title="待我处理" subtitle="审批待办列表，覆盖报销、请假、采购与差旅流程。" />

      <div className="card-std p-6 space-y-4">
        <Tabs
          data-testid="workflow-tasks-status-tabs"
          value={status}
          onValueChange={(value) => setSearchParams({ status: value, page: "1" })}
        >
          <TabsList className="flex w-full flex-wrap justify-start gap-1">
            {[
              { value: "pending", label: "待处理" },
              { value: "completed", label: "已通过" },
              { value: "rejected", label: "已驳回" },
              { value: "cancelled", label: "已取消" },
              { value: "skipped", label: "已跳过" },
            ].map((item) => (
              <TabsTrigger
                data-testid={`workflow-tasks-tab-${item.value}`}
                key={item.value}
                value={item.value}
              >
                {item.label}
              </TabsTrigger>
            ))}
          </TabsList>
        </Tabs>

        {query.isLoading ? <TableSkeleton columns={5} rows={5} /> : null}

        {query.isError ? (
          <p className="rounded-lg border border-red-200 bg-red-50 px-3 py-2 text-sm text-red-600">
            {isApiError(query.error)
              ? `${query.error.code}: ${mapApiErrorMessage(
                  query.error.code,
                  query.error.details,
                  query.error.message,
                )}`
              : "加载待办失败，请稍后重试"}
          </p>
        ) : null}

        {!query.isLoading && !query.isError ? (
          <div className="rounded-lg border border-zinc-200">
            <Table data-testid="workflow-tasks-table">
              <TableHeader>
                <tr>
                  <TableHead>任务</TableHead>
                  <TableHead>业务对象</TableHead>
                  <TableHead>状态</TableHead>
                  <TableHead>创建时间</TableHead>
                  <TableHead className="w-24">操作</TableHead>
                </tr>
              </TableHeader>
              <TableBody>
                {(query.data?.items ?? []).length ? (
                  query.data?.items.map((task) => (
                    <TableRow data-testid="workflow-task-row" key={task.id}>
                      <TableCell>
                        <div className="font-medium text-zinc-900">{task.stepName}</div>
                        <div className="text-xs text-zinc-500">{task.id}</div>
                      </TableCell>
                      <TableCell>
                        <div className="font-medium text-zinc-900">
                          {entityLabel(task.workflowInstance?.entityType)}
                        </div>
                        <div className="font-mono text-xs text-zinc-500">
                          {task.workflowInstance?.entityId ?? "-"}
                        </div>
                      </TableCell>
                      <TableCell><StatusBadge status={task.status} /></TableCell>
                      <TableCell>{new Date(task.createdAt).toLocaleString()}</TableCell>
                      <TableCell>
                        <Button
                          asChild
                          size="sm"
                          variant="secondary"
                          data-testid="workflow-task-detail-link"
                        >
                          <Link to={`/workflow/tasks/${task.id}`}>详情</Link>
                        </Button>
                      </TableCell>
                    </TableRow>
                  ))
                ) : (
                  <TableRow>
                    <TableCell className="py-3 text-zinc-500" colSpan={5}>
                      暂无数据
                    </TableCell>
                  </TableRow>
                )}
              </TableBody>
            </Table>
          </div>
        ) : null}

        <Pagination
          page={page}
          totalPages={totalPages}
          onPageChange={(p) => setSearchParams({ status, page: String(p) })}
          testIdPrefix="workflow-tasks"
        />
      </div>
    </div>
  );
}