import { useEffect, useMemo, useState } from 'react'
import type { ReactNode } from 'react'
import { Outlet, useLocation, useNavigate } from 'react-router-dom'
import {
  Layout,
  Dropdown,
  Form,
  Input,
  Modal,
  Space,
  Typography,
  Avatar,
  Tag,
  Button,
  message,
  Tooltip,
} from 'antd'
import {
  ApiOutlined,
  AppstoreOutlined,
  CodeOutlined,
  DashboardOutlined,
  DownOutlined,
  FileTextOutlined,
  KeyOutlined,
  LogoutOutlined,
  MenuOutlined,
  OrderedListOutlined,
  ShopOutlined,
  TeamOutlined,
  UserOutlined,
  WalletOutlined,
} from '@ant-design/icons'
import { useAuth } from '../store/auth'
import { authApi } from '../api'
import type { MenuProps } from 'antd'

const { Header, Sider, Content } = Layout

interface SidebarChild {
  key: string
  label: string
  path?: string
  disabled?: boolean
  permission?: string
  feature?: string
}

interface SidebarSection {
  key: string
  label: string
  icon: ReactNode
  path?: string
  disabled?: boolean
  children?: SidebarChild[]
}

const adminSections: SidebarSection[] = [
  {
    key: 'dashboard',
    label: '工作台',
    icon: <DashboardOutlined />,
    path: '/',
  },
  {
    key: 'products',
    label: '商品管理',
    icon: <AppstoreOutlined />,
    children: [
      { key: 'merchant-products', label: '商品列表', path: '/merchant-products' },
      { key: 'platform-products', label: '渠道与路由配置', path: '/platform-products' },
    ],
  },
  {
    key: 'shops',
    label: '商户管理',
    icon: <ShopOutlined />,
    children: [{ key: 'shop-list', label: '平台商户', path: '/platform-merchants' }],
  },
  {
    key: 'accounts',
    label: '账号管理',
    icon: <UserOutlined />,
    children: [{ key: 'platform-users', label: '平台账号', path: '/platform-users' }],
  },
  {
    key: 'orders',
    label: '订单管理',
    icon: <OrderedListOutlined />,
    children: [{ key: 'fulfillment-orders', label: '发货订单', path: '/merchant-orders' }],
  },
  {
    key: 'staff',
    label: '员工管理',
    icon: <TeamOutlined />,
    children: [{ key: 'merchant-members', label: '成员管理', path: '/merchant-members' }],
  },
  {
    key: 'funds',
    label: '积分管理',
    icon: <WalletOutlined />,
    children: [
      { key: 'merchant-wallet', label: '积分明细', path: '/merchant-wallet' },
      { key: 'merchant-recharge', label: '积分充值', path: '/merchant-recharge' },
      { key: 'merchant-alert-settings', label: '余额告警', path: '/merchant-alert-settings' },
    ],
  },
  {
    key: 'open-api',
    label: '开放 API',
    icon: <ApiOutlined />,
    children: [
      { key: 'api-keys', label: 'API 密钥', path: '/merchant-api-keys' },
      { key: 'api-callbacks', label: '回调订阅', path: '/merchant-callbacks' },
      { key: 'api-docs', label: '对接文档', path: '/open-api' },
      { key: 'api-debug', label: '调用调试', path: '/api-debug' },
    ],
  },
]

const merchantSections: SidebarSection[] = [
  {
    key: 'dashboard',
    label: '工作台',
    icon: <DashboardOutlined />,
    path: '/',
  },
  {
    key: 'products',
    label: '商品管理',
    icon: <AppstoreOutlined />,
    children: [{ key: 'merchant-products', label: '商品列表', path: '/merchant-products', permission: 'products:manage', feature: 'products' }],
  },
  {
    key: 'orders',
    label: '订单管理',
    icon: <OrderedListOutlined />,
    children: [{ key: 'fulfillment-orders', label: '发货订单', path: '/merchant-orders', permission: 'orders:manage', feature: 'orders' }],
  },
  {
    key: 'funds',
    label: '积分管理',
    icon: <WalletOutlined />,
    children: [
      { key: 'merchant-wallet', label: '积分明细', path: '/merchant-wallet', permission: 'wallet:ledger', feature: 'wallet' },
      { key: 'merchant-recharge', label: '积分充值', path: '/merchant-recharge', permission: 'wallet:view', feature: 'wallet' },
      { key: 'merchant-alert-settings', label: '余额告警', path: '/merchant-alert-settings', permission: 'recharge:manage', feature: 'wallet' },
    ],
  },
  {
    key: 'staff',
    label: '员工管理',
    icon: <TeamOutlined />,
    children: [{ key: 'merchant-members', label: '成员管理', path: '/merchant-members', permission: 'members:manage' }],
  },
  {
    key: 'open-api',
    label: '开放 API',
    icon: <ApiOutlined />,
    children: [
      { key: 'api-keys', label: 'API 密钥', path: '/merchant-api-keys', permission: 'api:manage', feature: 'api' },
      { key: 'api-callbacks', label: '回调订阅', path: '/merchant-callbacks', permission: 'callbacks:manage', feature: 'callbacks' },
      { key: 'api-docs', label: '对接文档', path: '/open-api', permission: 'api:manage', feature: 'api' },
    ],
  },
]

function getSelectedKey(pathname: string, search: string) {
  if (pathname === '/') return 'dashboard'
  if (pathname.startsWith('/merchant-products')) return 'merchant-products'
  if (pathname.startsWith('/merchant-orders')) return 'fulfillment-orders'
  if (pathname.startsWith('/merchant-wallet')) return 'merchant-wallet'
  if (pathname.startsWith('/merchant-recharge')) return 'merchant-recharge'
  if (pathname.startsWith('/merchant-alert-settings')) return 'merchant-alert-settings'
  if (pathname.startsWith('/merchant-members')) return 'merchant-members'
  if (pathname.startsWith('/merchant-callbacks')) return 'api-callbacks'
  if (pathname.startsWith('/merchant-api-keys')) return 'api-keys'
  if (pathname.startsWith('/merchant-center')) {
    const tab = new URLSearchParams(search).get('tab')
    const tabKeys: Record<string, string> = {
      products: 'merchant-products',
      orders: 'fulfillment-orders',
      wallet: 'merchant-wallet',
      members: 'merchant-members',
      callbacks: 'api-callbacks',
    }
    return tab ? tabKeys[tab] || 'merchant-products' : 'merchant-products'
  }
  if (pathname.startsWith('/open-api')) return 'api-docs'
  if (pathname.startsWith('/api-debug')) return 'api-debug'
  if (pathname.startsWith('/platform-merchants')) return 'shop-list'
  if (pathname.startsWith('/platform-users')) return 'platform-users'
  return 'dashboard'
}

function getInitialOpenKeys(sections: SidebarSection[], selectedKey: string) {
  return sections
    .filter((section) => section.children?.some((child) => child.key === selectedKey))
    .map((section) => section.key)
}

const SIDEBAR_OPEN_KEYS_KEY = 'sidebar_open_keys'
const SIDEBAR_COLLAPSED_KEY = 'sidebar_collapsed'

function loadStoredOpenKeys(sections: SidebarSection[], selectedKey: string): string[] {
  const initial = getInitialOpenKeys(sections, selectedKey)
  try {
    const raw = localStorage.getItem(SIDEBAR_OPEN_KEYS_KEY)
    if (raw) {
      const parsed = JSON.parse(raw)
      if (Array.isArray(parsed)) {
        return Array.from(new Set([...parsed, ...initial]))
      }
    }
  } catch (e) {
    // ignore
  }
  return initial
}

export default function MainLayout() {
  const [collapsed, setCollapsed] = useState<boolean>(() => {
    return localStorage.getItem(SIDEBAR_COLLAPSED_KEY) === 'true'
  })
  const { user, logout, refreshProfile, isAdmin, merchant, merchantPermissions } = useAuth()
  const [passwordOpen, setPasswordOpen] = useState(false)
  const [passwordSaving, setPasswordSaving] = useState(false)
  const [passwordForm] = Form.useForm()
  const navigate = useNavigate()
  const location = useLocation()
  const isDocsPage = location.pathname.startsWith('/open-api')

  const sections = useMemo(() => {
    if (isAdmin) return adminSections
    const features = new Set((merchant?.features || '').split(/[\s,]+/).filter(Boolean))
    return merchantSections.flatMap((section) => {
      if (!section.children) return [section]
      const children = section.children.filter((child) => (
        (!child.permission || merchantPermissions.includes(child.permission))
        && (!child.feature || features.has(child.feature))
      ))
      return children.length > 0 ? [{ ...section, children }] : []
    })
  }, [isAdmin, merchant?.features, merchantPermissions])
  const selectedKey = getSelectedKey(location.pathname, location.search)
  const [openKeys, setOpenKeys] = useState<string[]>(() => loadStoredOpenKeys(sections, selectedKey))

  useEffect(() => {
    const nextOpenKeys = getInitialOpenKeys(sections, selectedKey)
    setOpenKeys((current) => {
      const merged = Array.from(new Set([...current, ...nextOpenKeys]))
      localStorage.setItem(SIDEBAR_OPEN_KEYS_KEY, JSON.stringify(merged))
      return merged
    })
  }, [sections, selectedKey])

  const toggleSection = (section: SidebarSection) => {
    if (section.disabled) return
    if (section.path) {
      navigate(section.path)
      return
    }
    if (collapsed) {
      const firstEnabledChild = section.children?.find((child) => child.path && !child.disabled)
      if (firstEnabledChild?.path) navigate(firstEnabledChild.path)
      return
    }
    setOpenKeys((current) => {
      const next = current.includes(section.key)
        ? current.filter((key) => key !== section.key)
        : [...current, section.key]
      localStorage.setItem(SIDEBAR_OPEN_KEYS_KEY, JSON.stringify(next))
      return next
    })
  }

  const handleToggleCollapse = (next: boolean) => {
    setCollapsed(next)
    localStorage.setItem(SIDEBAR_COLLAPSED_KEY, String(next))
  }

  const handleChildClick = (child: SidebarChild) => {
    if (!child.path || child.disabled) return
    navigate(child.path)
  }

  const submitAccountUpdate = async () => {
    try {
      const values = await passwordForm.validateFields()
      setPasswordSaving(true)
      await authApi.updateCurrentAccount({
        current_password: values.current_password,
        username: values.username,
        nickname: values.nickname || '',
        new_password: values.new_password || undefined,
      })
      await refreshProfile()
      setPasswordOpen(false)
      passwordForm.resetFields()
      message.success('账户设置已保存')
    } catch (e) {
      message.error(e instanceof Error ? e.message : '保存失败')
    } finally {
      setPasswordSaving(false)
    }
  }

  const userMenu: MenuProps['items'] = [
    {
      key: 'user-info',
      disabled: true,
      label: (
        <div style={{ padding: '4px 0' }}>
          <div style={{ fontWeight: 600, color: '#0f172a' }}>{user?.nickname || user?.username}</div>
          <div style={{ fontSize: 12, color: '#64748b' }}>角色：{isAdmin ? '平台超级管理员' : '商户成员'}</div>
        </div>
      ),
    },
    { type: 'divider' },
    {
      key: 'account-settings',
      icon: <KeyOutlined />,
      label: '账户设置',
      onClick: () => {
        passwordForm.setFieldsValue({ username: user?.username || '', nickname: user?.nickname || '' })
        setPasswordOpen(true)
      },
    },
    {
      key: 'logout',
      icon: <LogoutOutlined style={{ color: '#dc2626' }} />,
      label: <span style={{ color: '#dc2626' }}>退出登录</span>,
      onClick: () => {
        logout()
        navigate('/login')
      },
    },
  ]

  return (
    <Layout className="app-shell">
      <Sider
        className={`app-sidebar${collapsed ? ' app-sidebar--collapsed' : ''}`}
        trigger={null}
        collapsible
        collapsed={collapsed}
        width={240}
        collapsedWidth={74}
        style={{
          position: 'sticky',
          top: 0,
          height: '100vh',
          left: 0,
          zIndex: 100,
        }}
      >
        <div className="app-sidebar__brand">
          <span className="app-sidebar__brand-mark">S</span>
          {!collapsed ? <span className="app-sidebar__brand-text">Skin Hub</span> : null}
        </div>
        <nav className="app-sidebar__nav">
          {sections.map((section) => {
            const isOpen = openKeys.includes(section.key)
            const isSelected = selectedKey === section.key
            const hasSelectedChild = section.children?.some((child) => child.key === selectedKey)
            const isParentActive = hasSelectedChild
            const isSingleActive = isSelected && !section.children?.length
            return (
              <div className="app-sidebar__group" key={section.key}>
                <button
                  className={`app-sidebar__item${isSingleActive ? ' app-sidebar__item--active' : ''}${isParentActive ? ' app-sidebar__item--parent-active' : ''}${section.disabled ? ' app-sidebar__item--disabled' : ''}`}
                  type="button"
                  onClick={() => toggleSection(section)}
                  title={collapsed ? section.label : undefined}
                >
                  <span className="app-sidebar__icon">{section.icon}</span>
                  {!collapsed ? <span className="app-sidebar__label">{section.label}</span> : null}
                  {!collapsed && section.children?.length ? (
                    <DownOutlined className={`app-sidebar__arrow${isOpen ? ' app-sidebar__arrow--open' : ''}`} />
                  ) : null}
                </button>
                {!collapsed && section.children?.length && isOpen ? (
                  <div className="app-sidebar__children">
                    {section.children.map((child) => (
                      <button
                        className={`app-sidebar__child${selectedKey === child.key ? ' app-sidebar__child--active' : ''}${child.disabled ? ' app-sidebar__child--disabled' : ''}`}
                        key={child.key}
                        type="button"
                        onClick={() => handleChildClick(child)}
                        disabled={child.disabled}
                      >
                        {child.label}
                      </button>
                    ))}
                  </div>
                ) : null}
              </div>
            )
          })}
        </nav>
      </Sider>
      <Layout className={`app-main${isDocsPage ? ' app-main--flush' : ''}`}>
        <Header className="app-header">
          <div className="app-header__left">
            <button
              className="app-header__collapse"
              type="button"
              onClick={() => handleToggleCollapse(!collapsed)}
              aria-label={collapsed ? '展开侧边栏' : '收起侧边栏'}
              title={collapsed ? '展开侧边栏' : '收起侧边栏'}
            >
              <MenuOutlined />
            </button>
          </div>
          <div className="app-header__right">
            {isAdmin && (
              <Space size="small">
                <Tooltip title="开放 API 接口文档">
                  <Button
                    type="text"
                    size="small"
                    icon={<FileTextOutlined />}
                    onClick={() => navigate('/open-api')}
                  >
                    API文档
                  </Button>
                </Tooltip>
                <Tooltip title="API 签名与请求在线调试器">
                  <Button
                    type="text"
                    size="small"
                    icon={<CodeOutlined />}
                    onClick={() => navigate('/api-debug')}
                  >
                    接口调试
                  </Button>
                </Tooltip>
              </Space>
            )}
            <Dropdown menu={{ items: userMenu }} placement="bottomRight">
              <div className="app-header__user">
                <Avatar className="app-header__user-avatar" size="small" icon={<UserOutlined />} />
                <Typography.Text style={{ fontWeight: 600, fontSize: 13.5, color: '#1e293b' }}>
                  {user?.nickname || user?.username}
                </Typography.Text>
                {isAdmin ? (
                  <Tag color="blue" bordered={false} style={{ margin: 0, fontSize: 11, fontWeight: 600 }}>
                    管理员
                  </Tag>
                ) : (
                  <Tag color="cyan" bordered={false} style={{ margin: 0, fontSize: 11, fontWeight: 600 }}>
                    商户
                  </Tag>
                )}
              </div>
            </Dropdown>
          </div>
        </Header>
        <Content className="app-content">
          <div className="app-content__body">
            <Outlet />
          </div>
        </Content>
        <Modal
          title="账户设置"
          open={passwordOpen}
          confirmLoading={passwordSaving}
          onOk={submitAccountUpdate}
          onCancel={() => {
            setPasswordOpen(false)
            passwordForm.resetFields()
          }}
          destroyOnClose
        >
          <Form form={passwordForm} layout="vertical" style={{ marginTop: 16 }}>
            <Form.Item name="username" label="用户名" rules={[{ required: true, message: '请输入用户名' }, { min: 3, message: '用户名至少 3 位' }, { max: 64, message: '用户名不能超过 64 位' }]}>
              <Input autoComplete="username" />
            </Form.Item>
            <Form.Item name="nickname" label="昵称" rules={[{ max: 64, message: '昵称不能超过 64 位' }]}>
              <Input autoComplete="off" />
            </Form.Item>
            <Form.Item name="current_password" label="当前密码" rules={[{ required: true, message: '请输入当前密码' }]}>
              <Input.Password autoComplete="current-password" />
            </Form.Item>
            <Form.Item name="new_password" label="新密码" rules={[{ min: 8, message: '新密码至少 8 位' }]} extra="留空表示不修改密码">
              <Input.Password autoComplete="new-password" />
            </Form.Item>
            <Form.Item name="confirm_password" label="确认新密码" dependencies={['new_password']} rules={[
              ({ getFieldValue }) => ({ validator: (_, value) => !value || getFieldValue('new_password') === value ? Promise.resolve() : Promise.reject(new Error('两次输入的密码不一致')) }),
            ]}>
              <Input.Password autoComplete="new-password" />
            </Form.Item>
          </Form>
        </Modal>
      </Layout>
    </Layout>
  )
}