import { useEffect, useMemo, useState } from "react";
import { useNavigate } from "react-router-dom";
import { Button, Card, Form, Input, Tag, Select, InputNumber, Space, Popconfirm, Popover, Tooltip, TreeSelect } from "antd";
import { 
  PlusOutlined, EditOutlined, DeleteOutlined, AppstoreOutlined,
  CaretRightOutlined, CaretDownOutlined
} from "@ant-design/icons";
import ListTable from "../components/ListTable/ListTable";
import DetailDrawer from "../components/DetailDrawer/DetailDrawer";
import PageHeader from "../components/PageHeader/PageHeader";
import Toast from "../components/Toast/Toast";
import { api } from "../api";
import { clearTokens } from "../auth";
import { ICON_LIST, getIcon } from "../utils/icons";

interface PermItem {
  perm_id: number;
  parent_id: number | null;
  name: string;
  code: string;
  perm_type: string;
  level: number;
  path?: string | null;
  icon?: string | null;
  sort_order?: number;
  status?: number;
  children?: PermItem[];
}

type DrawerMode = "create" | "edit";

export default function PermissionTreePage() {
  const navigate = useNavigate();
  const [perms, setPerms] = useState<PermItem[]>([]);
  const [loading, setLoading] = useState(false);
  const [drawerOpen, setDrawerOpen] = useState(false);
  const [drawerMode, setDrawerMode] = useState<DrawerMode>("create");
  const [editing, setEditing] = useState<PermItem | null>(null);
  const [form] = Form.useForm();
  
  const [iconPopoverOpen, setIconPopoverOpen] = useState(false);
  const [selectedIcon, setSelectedIcon] = useState<string | null>(null);

  const load = async () => {
    try {
      setLoading(true);
      const res = await api.listPermissions();
      const tree = buildTree(res as any);
      setPerms(tree);
    } catch {
      clearTokens();
      navigate("/");
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    load();
  }, []);

  const openCreate = (parentId: number | null = null) => {
    setDrawerMode("create");
    setEditing(null);
    form.resetFields();
    setSelectedIcon(null);
    form.setFieldsValue({ parent_id: parentId, level: parentId ? 2 : 1, perm_type: parentId ? 'menu' : 'menu', status: 1 });
    setDrawerOpen(true);
  };

  const openEdit = (row: PermItem) => {
    setDrawerMode("edit");
    setEditing(row);
    setSelectedIcon(row.icon || null);
    form.setFieldsValue({
      parent_id: row.parent_id,
      name: row.name,
      code: row.code,
      perm_type: row.perm_type,
      level: row.level,
      path: row.path || "",
      icon: row.icon || "",
      sort_order: row.sort_order || 0,
      status: row.status || 1,
    });
    setDrawerOpen(true);
  };

  const notifyMenuRefresh = () => {
    window.dispatchEvent(new CustomEvent('menu-refresh'));
  };

  const submit = async () => {
    try {
      const values = await form.validateFields();
      if (drawerMode === "create") {
        await api.createPermission(values);
        Toast.success("已创建");
      } else if (editing) {
        await api.updatePermission(editing.perm_id, values);
        Toast.success("已更新");
      }
      setDrawerOpen(false);
      load();
      notifyMenuRefresh();
    } catch (e) {}
  };

  const remove = async (row: PermItem) => {
    await api.deletePermission(row.perm_id);
    Toast.success("已删除");
    load();
    notifyMenuRefresh();
  };

  const handleIconSelect = (iconName: string) => {
    form.setFieldsValue({ icon: iconName });
    setSelectedIcon(iconName);
    setIconPopoverOpen(false);
  };

  const iconContent = (
    <div style={{ 
      display: 'grid', 
      gridTemplateColumns: 'repeat(8, 1fr)', 
      gap: 4, 
      width: 320, 
      maxHeight: 240, 
      overflowY: 'auto',
      padding: '8px'
    }}>
      {ICON_LIST.map((item) => (
        <Tooltip key={item.name} title={item.name}>
          <div 
            onClick={() => handleIconSelect(item.name)}
            style={{ 
              cursor: 'pointer', 
              padding: '8px 0', 
              textAlign: 'center',
              borderRadius: 4,
              background: selectedIcon === item.name ? '#f0f7ff' : 'transparent',
              border: selectedIcon === item.name ? '1px solid #1890ff' : '1px solid transparent',
              fontSize: '18px',
              display: 'flex',
              alignItems: 'center',
              justifyContent: 'center',
              transition: 'all 0.2s'
            }}
            onMouseEnter={(e) => {
              if (selectedIcon !== item.name) {
                e.currentTarget.style.backgroundColor = '#f5f5f5';
              }
            }}
            onMouseLeave={(e) => {
              if (selectedIcon !== item.name) {
                e.currentTarget.style.backgroundColor = 'transparent';
              }
            }}
          >
            {item.icon}
          </div>
        </Tooltip>
      ))}
    </div>
  );

  const columns = useMemo(() => [
    { title: "名称", dataIndex: "name", key: "name" },
    { 
      title: "图标", 
      dataIndex: "icon", 
      key: "icon",
      width: 80,
      render: (v: string) => v ? <span style={{ fontSize: 18, color: '#1890ff' }}>{getIcon(v)}</span> : '-'
    },
    { title: "编码", dataIndex: "code", key: "code" },
    { 
      title: "类型", 
      dataIndex: "perm_type", 
      key: "perm_type",
      render: (v: string) => <Tag color={v === 'menu' ? 'blue' : 'orange'}>{v === 'menu' ? '菜单' : '按钮'}</Tag>
    },
    { title: "路径", dataIndex: "path", key: "path", render: (v: string | null) => v || "-" },
    {
      title: "操作",
      key: "action",
      width: 200,
      render: (_: any, record: PermItem) => (
        <Space size="middle">
          <Button type="link" size="small" icon={<EditOutlined />} onClick={() => openEdit(record)}>编辑</Button>
          {record.level < 3 && (
            <Button type="link" size="small" icon={<PlusOutlined />} onClick={() => openCreate(record.perm_id)}>子项</Button>
          )}
          <Popconfirm title="确定删除吗？" onConfirm={() => remove(record)}>
            <Button type="link" size="small" danger icon={<DeleteOutlined />}>删除</Button>
          </Popconfirm>
        </Space>
      )
    }
  ], [perms]);

  const treeData = useMemo(() => {
    const loop = (data: PermItem[], disabled = false): any[] =>
      data.map((item) => {
        const isDisabled = disabled || editing?.perm_id === item.perm_id;
        return {
          title: item.name,
          value: item.perm_id,
          key: item.perm_id,
          disabled: isDisabled,
          children: item.children ? loop(item.children, isDisabled) : [],
        };
      });
    return [
      { title: '无 (顶级菜单)', value: null, key: 'root', children: [] },
      ...loop(perms)
    ];
  }, [perms, editing]);

  return (
    <div className="page-wrapper" style={{ padding: 24 }}>
      <PageHeader 
        title="功能菜单" 
        description="管理系统功能权限结构，包括菜单和按钮"
        extra={
          <Button type="primary" icon={<PlusOutlined />} onClick={() => openCreate()}>
            新增权限
          </Button>
        }
      />

      <div className="shadow-card" style={{ marginTop: 24, background: '#fff', padding: 24, borderRadius: 8 }}>
        <ListTable<PermItem>
          columns={columns}
          dataSource={perms}
          rowKey="perm_id"
          loading={loading}
          pagination={false}
          scroll={{ x: 1000 }}
          expandable={{
            expandIcon: ({ expanded, onExpand, record }) => {
              if (record.children && record.children.length > 0) {
                return expanded ? (
                  <CaretDownOutlined 
                    onClick={e => onExpand(record, e)} 
                    style={{ marginRight: 8, cursor: 'pointer', color: '#666', fontSize: '12px' }} 
                  />
                ) : (
                  <CaretRightOutlined 
                    onClick={e => onExpand(record, e)} 
                    style={{ marginRight: 8, cursor: 'pointer', color: '#666', fontSize: '12px' }} 
                  />
                );
              }
              return <span style={{ marginRight: 8, display: 'inline-block', width: 14 }} />;
            }
          }}
        />
      </div>

      <DetailDrawer
        visible={drawerOpen}
        onClose={() => setDrawerOpen(false)}
        title={{ text: drawerMode === "create" ? "新增权限" : "编辑权限" }}
        headerActions={[
          { key: "cancel", label: "取消", onClick: () => setDrawerOpen(false) },
          { key: "submit", label: "保存", type: "primary", onClick: submit },
        ]}
        width={450}
      >
        <Form form={form} layout="vertical" style={{ padding: 24 }}>
          <Form.Item label="上级菜单" name="parent_id">
            <TreeSelect
              style={{ width: '100%' }}
              dropdownStyle={{ maxHeight: 400, overflow: 'auto' }}
              treeData={treeData}
              placeholder="请选择上级菜单"
              treeDefaultExpandAll
              allowClear
            />
          </Form.Item>
          <Form.Item label="权限名称" name="name" rules={[{ required: true, message: '请输入名称' }]}>
            <Input placeholder="例如: 用户管理" />
          </Form.Item>
          <Form.Item label="权限编码" name="code" rules={[{ required: true, message: '请输入编码' }]}>
            <Input placeholder="例如: system:user" />
          </Form.Item>
          <Form.Item label="类型" name="perm_type" initialValue="menu">
            <Select>
              <Select.Option value="menu">菜单</Select.Option>
              <Select.Option value="button">按钮</Select.Option>
            </Select>
          </Form.Item>
          
          <Form.Item label="图标" name="icon">
            <Popover 
              content={iconContent} 
              title="选择图标" 
              trigger="click" 
              open={iconPopoverOpen} 
              onOpenChange={setIconPopoverOpen}
              placement="bottom"
              overlayStyle={{ zIndex: 2000 }}
            >
              <div style={{ position: 'relative' }}>
                <Input 
                  placeholder="点击选择图标" 
                  readOnly 
                  prefix={selectedIcon ? getIcon(selectedIcon) : <AppstoreOutlined style={{ opacity: 0.3 }} />} 
                  style={{ cursor: 'pointer' }}
                />
                {selectedIcon && (
                  <span 
                    style={{ 
                      position: 'absolute', 
                      right: 10, 
                      top: '50%', 
                      transform: 'translateY(-50%)', 
                      cursor: 'pointer', 
                      opacity: 0.5,
                      zIndex: 1
                    }} 
                    onClick={(e) => {
                      e.stopPropagation();
                      handleIconSelect('');
                    }}
                  >
                    ×
                  </span>
                )}
              </div>
            </Popover>
          </Form.Item>

          <Form.Item label="层级" name="level">
            <InputNumber min={1} max={3} style={{ width: '100%' }} />
          </Form.Item>
          <Form.Item label="访问路径" name="path">
            <Input placeholder="例如: /system/users" />
          </Form.Item>
          <Form.Item label="排序" name="sort_order" initialValue={0}>
            <InputNumber style={{ width: '100%' }} />
          </Form.Item>
        </Form>
      </DetailDrawer>
    </div>
  );
}

function buildTree(items: any[]): PermItem[] {
  const map = new Map<number, PermItem>();
  const roots: PermItem[] = [];
  
  const rawItems = items.map(it => ({...it, children: []}));
  rawItems.forEach((it) => map.set(it.perm_id, it));
  
  rawItems.forEach((it) => {
    if (it.parent_id) {
      const parent = map.get(it.parent_id);
      if (parent) {
        if (!parent.children) parent.children = [];
        parent.children.push(it);
      } else {
        roots.push(it);
      }
    } else {
      roots.push(it);
    }
  });
  
  // Sort children by sort_order
  const sortFunc = (a: any, b: any) => (a.sort_order || 0) - (b.sort_order || 0);
  rawItems.forEach(it => {
    if (it.children && it.children.length > 0) {
      it.children.sort(sortFunc);
    }
  });
  roots.sort(sortFunc);
  
  return roots;
}