import { useState } from "react";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { cancelTodo, completeTodo, createTodo, fetchTodos } from "../api/todos";
import { PageHeader } from "../components/common/PageHeader";
import { Button } from "../components/ui/button";
import { Input } from "../components/ui/input";
import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "../components/ui/table";
import { toast } from "sonner";
import { isApiError } from "../api/types";
import { mapApiErrorMessage } from "../api/errorMessages";

function errorMessage(error: unknown, fallback: string) {
  if (isApiError(error)) {
    return `${error.code}: ${mapApiErrorMessage(error.code, error.details, error.message)}`;
  }
  return error instanceof Error ? error.message : fallback;
}

export function TodosPage() {
  const queryClient = useQueryClient();
  const [title, setTitle] = useState("");
  const [description, setDescription] = useState("");
  const [statusFilter, setStatusFilter] = useState<"todo" | "doing" | "done" | "cancelled" | "">("");
  const todosQuery = useQuery({
    queryKey: ["todos", statusFilter],
    queryFn: () => fetchTodos({ status: statusFilter || undefined }),
  });

  const createMutation = useMutation({
    mutationFn: () => createTodo({ title, description: description || undefined }),
    onSuccess: async () => {
      setTitle("");
      setDescription("");
      await Promise.all([
        queryClient.invalidateQueries({ queryKey: ["todos"] }),
        queryClient.invalidateQueries({ queryKey: ["portal-home"] }),
      ]);
      toast.success("待办已创建");
    },
    onError: (error) => toast.error(errorMessage(error, "创建待办失败")),
  });

  const completeMutation = useMutation({
    mutationFn: (id: string) => completeTodo(id),
    onSuccess: async () => {
      await Promise.all([
        queryClient.invalidateQueries({ queryKey: ["todos"] }),
        queryClient.invalidateQueries({ queryKey: ["portal-home"] }),
      ]);
      toast.success("待办已完成");
    },
    onError: (error) => toast.error(errorMessage(error, "完成待办失败")),
  });

  const cancelMutation = useMutation({
    mutationFn: (id: string) => cancelTodo(id),
    onSuccess: async () => {
      await Promise.all([
        queryClient.invalidateQueries({ queryKey: ["todos"] }),
        queryClient.invalidateQueries({ queryKey: ["portal-home"] }),
      ]);
      toast.success("待办已取消");
    },
    onError: (error) => toast.error(errorMessage(error, "取消待办失败")),
  });

  return (
    <div className="space-y-6">
      <PageHeader title="待办" subtitle="员工维护个人待办，老板看高优先级和未完成项。" />

      <div className="card-std p-6 space-y-4">
        <div className="grid gap-3 md:grid-cols-3">
          <Input placeholder="待办标题" value={title} onChange={(event) => setTitle(event.target.value)} />
          <Input placeholder="补充说明（可选）" value={description} onChange={(event) => setDescription(event.target.value)} />
          <div className="flex gap-2">
            <select className="select-std" value={statusFilter} onChange={(event) => setStatusFilter(event.target.value as typeof statusFilter)}>
              <option value="">全部状态</option>
              <option value="todo">todo</option>
              <option value="doing">doing</option>
              <option value="done">done</option>
              <option value="cancelled">cancelled</option>
            </select>
            <Button type="button" onClick={() => createMutation.mutate()} disabled={createMutation.isPending || !title.trim()}>新建待办</Button>
          </div>
        </div>
      </div>

      <div className="card-std p-6">
        <Table>
          <TableHeader>
            <TableRow>
              <TableHead>标题</TableHead>
              <TableHead>负责人</TableHead>
              <TableHead>优先级</TableHead>
              <TableHead>状态</TableHead>
              <TableHead>操作</TableHead>
            </TableRow>
          </TableHeader>
          <TableBody>
            {(todosQuery.data?.items ?? []).map((item) => (
              <TableRow key={item.id}>
                <TableCell>
                  <div className="font-medium text-zinc-900">{item.title}</div>
                  <div className="text-xs text-zinc-500">{item.description ?? "-"}</div>
                </TableCell>
                <TableCell>{item.assignee?.name ?? "-"}</TableCell>
                <TableCell>{item.priority}</TableCell>
                <TableCell>{item.status}</TableCell>
                <TableCell>
                  <div className="flex gap-2">
                    <Button size="sm" type="button" disabled={completeMutation.isPending || item.status === "done"} onClick={() => completeMutation.mutate(item.id)}>完成</Button>
                    <Button size="sm" variant="secondary" type="button" disabled={cancelMutation.isPending || item.status === "cancelled"} onClick={() => cancelMutation.mutate(item.id)}>取消</Button>
                  </div>
                </TableCell>
              </TableRow>
            ))}
          </TableBody>
        </Table>
      </div>
    </div>
  );
}

export default TodosPage;