import { useState, useCallback, useEffect, useRef } from 'react';
import {
  Tree,
  Button,
  Space,
  Form,
  Input,
  InputNumber,
  Table,
  Popconfirm,
  Empty,
  Tag,
} from 'antd';
import {
  PlusOutlined,
  DeleteOutlined,
  EditOutlined,
  ApartmentOutlined,
} from '@ant-design/icons';
import type { DataNode } from 'antd/es/tree';
import { useThemeMode } from '../hooks/useThemeMode';
import { DrawerForm } from '../components/DrawerForm';
import { useCrudDrawer } from '../hooks/useCrudDrawer';
import { useApiRequest } from '../hooks/useApiRequest';
import {
  listOrgTree,
  createOrg,
  updateOrg,
  deleteOrg,
  listDeptTree,
  createDept,
  deleteDept,
  listPositions,
  createPosition,
  deletePosition,
  type OrganizationInfo,
  type DepartmentInfo,
  type PositionInfo,
} from '../api/orgs';

export default function Organizations() {
  const isDark = useThemeMode();
  const { execute } = useApiRequest();

  const cardStyle = {
    background: isDark ? '#111827' : '#FFFFFF',
    borderRadius: 12,
    border: `1px solid ${isDark ? '#0f172a' : '#f8fafc'}`,
  };

  // --- Org tree state ---
  const [orgTree, setOrgTree] = useState<OrganizationInfo[]>([]);
  const [selectedOrg, setSelectedOrg] = useState<OrganizationInfo | null>(null);

  // --- Department tree state ---
  const [deptTree, setDeptTree] = useState<DepartmentInfo[]>([]);
  const [selectedDept, setSelectedDept] = useState<DepartmentInfo | null>(null);

  // --- Position list state ---
  const [positions, setPositions] = useState<PositionInfo[]>([]);

  // --- Ref for drawer onSuccess callback (avoids before-declaration issue) ---
  const refreshOrgTreeRef = useRef<() => void>(() => {});

  // --- Fetch org tree ---
  const fetchOrgTree = useCallback(async () => {
    try {
      const tree = await listOrgTree();
      setOrgTree(tree);
      if (selectedOrg) {
        const stillExists = findOrgInTree(tree, selectedOrg.id);
        if (!stillExists) { setSelectedOrg(null); setDeptTree([]); setPositions([]); }
      }
    } catch { /* silent */ }
  }, [selectedOrg]);

  refreshOrgTreeRef.current = () => { fetchOrgTree(); };

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

  // --- Dept Drawer ---
  const [deptDrawerOpen, setDeptDrawerOpen] = useState(false);

  // --- Position Drawer ---
  const [positionDrawerOpen, setPositionDrawerOpen] = useState(false);

  // --- Org Drawer (uses ref to avoid before-declaration) ---
  const orgDrawer = useCrudDrawer<OrganizationInfo>({
    getId: (r) => r.id,
    onCreate: async (values) => {
      await createOrg({ ...(values as { name: string; code?: string; sort_order?: number }), parent_id: selectedOrg?.id });
    },
    onUpdate: async (id, values) => {
      await updateOrg(id, values as { name: string; code?: string; sort_order?: number; version: number });
    },
    onSuccess: () => { refreshOrgTreeRef.current(); },
  });

  // --- Fetch dept tree ---
  const fetchDeptTree = useCallback(async () => {
    if (!selectedOrg) return;
    try {
      const tree = await listDeptTree(selectedOrg.id);
      setDeptTree(tree);
      if (selectedDept) {
        const stillExists = findDeptInTree(tree, selectedDept.id);
        if (!stillExists) { setSelectedDept(null); setPositions([]); }
      }
    } catch { /* silent */ }
  }, [selectedOrg, selectedDept]);

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

  // --- Fetch positions ---
  const fetchPositions = useCallback(async () => {
    if (!selectedDept) return;
    try {
      setPositions(await listPositions(selectedDept.id));
    } catch { /* silent */ }
  }, [selectedDept]);

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

  // --- Org handlers ---
  const handleDeleteOrg = async (id: string) => {
    await execute(() => deleteOrg(id), '组织已删除');
    setSelectedOrg(null); setDeptTree([]); setPositions([]);
    fetchOrgTree();
  };

  // --- Dept handlers ---
  const handleCreateDept = async (values: Record<string, unknown>) => {
    if (!selectedOrg) return;
    await execute(() => createDept(selectedOrg.id, {
      name: values.name as string, code: values.code as string | undefined,
      parent_id: selectedDept?.id, sort_order: values.sort_order as number | undefined,
    }), '部门创建成功');
    setDeptDrawerOpen(false);
    fetchDeptTree();
  };

  const handleDeleteDept = async (id: string) => {
    await execute(() => deleteDept(id), '部门已删除');
    setSelectedDept(null); setPositions([]);
    fetchDeptTree();
  };

  // --- Position handlers ---
  const handleCreatePosition = async (values: Record<string, unknown>) => {
    if (!selectedDept) return;
    await execute(() => createPosition(selectedDept.id, {
      name: values.name as string, code: values.code as string | undefined,
      level: values.level as number | undefined, sort_order: values.sort_order as number | undefined,
    }), '岗位创建成功');
    setPositionDrawerOpen(false);
    fetchPositions();
  };

  const handleDeletePosition = async (id: string) => {
    await execute(() => deletePosition(id), '岗位已删除');
    fetchPositions();
  };

  // --- Tree node converters ---
  const convertOrgTree = (items: OrganizationInfo[]): DataNode[] =>
    items.map((item) => ({
      key: item.id,
      title: <span>{item.name} {item.code && <Tag style={{ marginLeft: 4, background: isDark ? '#0f172a' : '#eff6ff', border: 'none', color: '#2563eb', fontSize: 11 }}>{item.code}</Tag>}</span>,
      children: convertOrgTree(item.children),
    }));

  const convertDeptTree = (items: DepartmentInfo[]): DataNode[] =>
    items.map((item) => ({
      key: item.id,
      title: <span>{item.name} {item.code && <Tag style={{ marginLeft: 4, background: isDark ? '#0f172a' : '#ECFDF5', border: 'none', color: '#059669', fontSize: 11 }}>{item.code}</Tag>}</span>,
      children: convertDeptTree(item.children),
    }));

  const onSelectOrg = (selectedKeys: React.Key[]) => {
    if (selectedKeys.length === 0) { setSelectedOrg(null); setDeptTree([]); setSelectedDept(null); setPositions([]); return; }
    setSelectedOrg(findOrgInTree(orgTree, selectedKeys[0] as string));
    setSelectedDept(null); setPositions([]);
  };

  const onSelectDept = (selectedKeys: React.Key[]) => {
    if (selectedKeys.length === 0) { setSelectedDept(null); setPositions([]); return; }
    setSelectedDept(findDeptInTree(deptTree, selectedKeys[0] as string));
  };

  const positionColumns = [
    { title: '岗位名称', dataIndex: 'name', key: 'name' },
    { title: '编码', dataIndex: 'code', key: 'code', render: (v?: string) => v || '-' },
    { title: '级别', dataIndex: 'level', key: 'level' },
    { title: '排序', dataIndex: 'sort_order', key: 'sort_order' },
    {
      title: '操作', key: 'actions',
      render: (_: unknown, record: PositionInfo) => (
        <Popconfirm title="确定删除此岗位？" onConfirm={() => handleDeletePosition(record.id)}>
          <Button size="small" type="text" danger icon={<DeleteOutlined />}>删除</Button>
        </Popconfirm>
      ),
    },
  ];

  return (
    <div>
      <div className="erp-page-header">
        <div>
          <h4><ApartmentOutlined style={{ marginRight: 8, color: '#2563eb' }} />组织架构管理</h4>
          <div className="erp-page-subtitle">管理组织、部门和岗位的层级结构</div>
        </div>
      </div>

      <div style={{ display: 'flex', gap: 16, minHeight: 500 }}>
        {/* 左栏：组织树 */}
        <div style={{ width: 300, flexShrink: 0, ...cardStyle, overflow: 'hidden' }}>
          <div style={{
            padding: '14px 20px', borderBottom: `1px solid ${isDark ? '#0f172a' : '#f8fafc'}`,
            display: 'flex', alignItems: 'center', justifyContent: 'space-between',
          }}>
            <span style={{ fontWeight: 600, fontSize: 14 }}>组织</span>
            <Space size={4}>
              <Button size="small" type="text" icon={<PlusOutlined />} onClick={() => orgDrawer.openCreate()} />
              {selectedOrg && (
                <>
                  <Button size="small" type="text" icon={<EditOutlined />} onClick={() => orgDrawer.openEdit(selectedOrg, (r) => ({
                    name: r.name, code: r.code, sort_order: r.sort_order,
                  }))} />
                  <Popconfirm title="确定删除此组织？" onConfirm={() => handleDeleteOrg(selectedOrg.id)}>
                    <Button size="small" type="text" danger icon={<DeleteOutlined />} />
                  </Popconfirm>
                </>
              )}
            </Space>
          </div>
          <div style={{ padding: 12 }}>
            {orgTree.length > 0 ? (
              <Tree showLine defaultExpandAll treeData={convertOrgTree(orgTree)} onSelect={onSelectOrg} selectedKeys={selectedOrg ? [selectedOrg.id] : []} />
            ) : <Empty description="暂无组织" />}
          </div>
        </div>

        {/* 中栏：部门树 */}
        <div style={{ width: 300, flexShrink: 0, ...cardStyle, overflow: 'hidden' }}>
          <div style={{
            padding: '14px 20px', borderBottom: `1px solid ${isDark ? '#0f172a' : '#f8fafc'}`,
            display: 'flex', alignItems: 'center', justifyContent: 'space-between',
          }}>
            <span style={{ fontWeight: 600, fontSize: 14 }}>{selectedOrg ? `${selectedOrg.name} · 部门` : '部门'}</span>
            {selectedOrg && (
              <Space size={4}>
                <Button size="small" type="text" icon={<PlusOutlined />} onClick={() => setDeptDrawerOpen(true)} />
                {selectedDept && (
                  <Popconfirm title="确定删除此部门？" onConfirm={() => handleDeleteDept(selectedDept.id)}>
                    <Button size="small" type="text" danger icon={<DeleteOutlined />} />
                  </Popconfirm>
                )}
              </Space>
            )}
          </div>
          <div style={{ padding: 12 }}>
            {selectedOrg ? (
              deptTree.length > 0 ? (
                <Tree showLine defaultExpandAll treeData={convertDeptTree(deptTree)} onSelect={onSelectDept} selectedKeys={selectedDept ? [selectedDept.id] : []} />
              ) : <Empty description="暂无部门" />
            ) : <Empty description="请先选择组织" />}
          </div>
        </div>

        {/* 右栏：岗位表 */}
        <div style={{ flex: 1, ...cardStyle, overflow: 'hidden' }}>
          <div style={{
            padding: '14px 20px', borderBottom: `1px solid ${isDark ? '#0f172a' : '#f8fafc'}`,
            display: 'flex', alignItems: 'center', justifyContent: 'space-between',
          }}>
            <span style={{ fontWeight: 600, fontSize: 14 }}>{selectedDept ? `${selectedDept.name} · 岗位` : '岗位'}</span>
            {selectedDept && (
              <Button size="small" type="text" icon={<PlusOutlined />} onClick={() => setPositionDrawerOpen(true)}>新建岗位</Button>
            )}
          </div>
          <div style={{ padding: '0 4px' }}>
            {selectedDept ? (
              <Table columns={positionColumns} dataSource={positions} rowKey="id" size="small" pagination={false} />
            ) : <div style={{ padding: 24 }}><Empty description="请先选择部门" /></div>}
          </div>
        </div>
      </div>

      {/* Org Drawer */}
      <DrawerForm
        title={orgDrawer.editingRecord ? '编辑组织' : selectedOrg ? `在 ${selectedOrg.name} 下新建子组织` : '新建根组织'}
        open={orgDrawer.open}
        onClose={orgDrawer.close}
        onSubmit={orgDrawer.handleSubmit}
        initialValues={orgDrawer.initialValues}
        loading={orgDrawer.loading}
        width={480}
        columns={1}
      >
        <Form.Item name="name" label="名称" rules={[{ required: true, message: '请输入组织名称' }]}>
          <Input />
        </Form.Item>
        <Form.Item name="code" label="编码"><Input /></Form.Item>
        <Form.Item name="sort_order" label="排序" initialValue={0}>
          <InputNumber min={0} style={{ width: '100%' }} />
        </Form.Item>
      </DrawerForm>

      {/* Dept Drawer */}
      <DrawerForm
        title={selectedDept ? `在 ${selectedDept.name} 下新建子部门` : `在 ${selectedOrg?.name} 下新建部门`}
        open={deptDrawerOpen}
        onClose={() => setDeptDrawerOpen(false)}
        onSubmit={handleCreateDept}
        initialValues={{ sort_order: 0 }}
        loading={false}
        width={480}
        columns={1}
      >
        <Form.Item name="name" label="名称" rules={[{ required: true, message: '请输入部门名称' }]}>
          <Input />
        </Form.Item>
        <Form.Item name="code" label="编码"><Input /></Form.Item>
        <Form.Item name="sort_order" label="排序" initialValue={0}>
          <InputNumber min={0} style={{ width: '100%' }} />
        </Form.Item>
      </DrawerForm>

      {/* Position Drawer */}
      <DrawerForm
        title={`在 ${selectedDept?.name} 下新建岗位`}
        open={positionDrawerOpen}
        onClose={() => setPositionDrawerOpen(false)}
        onSubmit={handleCreatePosition}
        initialValues={{ level: 1, sort_order: 0 }}
        loading={false}
        width={480}
        columns={1}
      >
        <Form.Item name="name" label="岗位名称" rules={[{ required: true, message: '请输入岗位名称' }]}>
          <Input />
        </Form.Item>
        <Form.Item name="code" label="编码"><Input /></Form.Item>
        <Form.Item name="level" label="级别" initialValue={1}>
          <InputNumber min={1} style={{ width: '100%' }} />
        </Form.Item>
        <Form.Item name="sort_order" label="排序" initialValue={0}>
          <InputNumber min={0} style={{ width: '100%' }} />
        </Form.Item>
      </DrawerForm>
    </div>
  );
}

function findOrgInTree(tree: OrganizationInfo[], id: string): OrganizationInfo | null {
  for (const item of tree) {
    if (item.id === id) return item;
    const found = findOrgInTree(item.children, id);
    if (found) return found;
  }
  return null;
}

function findDeptInTree(tree: DepartmentInfo[], id: string): DepartmentInfo | null {
  for (const item of tree) {
    if (item.id === id) return item;
    const found = findDeptInTree(item.children, id);
    if (found) return found;
  }
  return null;
}