import { useState, useEffect } from 'react';
import { useRouter } from 'next/router';
import Head from 'next/head';
import { toast } from 'react-hot-toast';
import {
  MagnifyingGlassIcon,
  ReceiptPercentIcon,
  CloudArrowDownIcon,
  EyeIcon,
  PrinterIcon,
  DocumentTextIcon,
  CheckCircleIcon,
  ClockIcon,
  ExclamationCircleIcon,
  ChevronLeftIcon,
  ChevronRightIcon,
  DocumentArrowDownIcon,
  CalendarIcon,
  BuildingOfficeIcon,
  CurrencyDollarIcon
} from '@heroicons/react/24/outline';
import { supabase, TABLES } from '@/lib/supabase';
import { getDemoData } from '@/lib/demo-data';
import { formatTime, formatCurrency } from '@/utils';
import Layout from '@/components/Layout';

interface Invoice {
  id: string;
  invoice_number: string;
  user_id: string;
  user_name: string;
  user_email: string;
  order_id: string;
  invoice_type: 'individual' | 'enterprise';
  // 个人发票信息
  personal_name?: string;
  // 企业发票信息
  company_name?: string;
  tax_number?: string;
  company_address?: string;
  company_phone?: string;
  bank_name?: string;
  bank_account?: string;
  // 发票金额信息
  subtotal: number;
  tax_amount: number;
  total_amount: number;
  currency: string;
  // 发票状态
  status: 'draft' | 'issued' | 'paid' | 'cancelled';
  issue_date?: string;
  due_date?: string;
  paid_date?: string;
  // 服务明细
  items: InvoiceItem[];
  created_at: string;
  updated_at: string;
}

interface InvoiceItem {
  service_type: string;
  service_name: string;
  quantity: number;
  unit: string;
  unit_price: number;
  amount: number;
}

interface InvoiceFilters {
  search: string;
  status: 'all' | 'draft' | 'issued' | 'paid' | 'cancelled';
  invoice_type: 'all' | 'individual' | 'enterprise';
  date_range: 'all' | 'today' | 'week' | 'month' | 'quarter';
  sortBy: 'created_at' | 'total_amount' | 'issue_date';
  sortOrder: 'asc' | 'desc';
}

export default function InvoicesPage() {
  const [invoices, setInvoices] = useState<Invoice[]>([]);
  const [loading, setLoading] = useState(true);
  const [currentPage, setCurrentPage] = useState(1);
  const [totalPages, setTotalPages] = useState(1);
  const [totalCount, setTotalCount] = useState(0);
  const [isDemoMode, setIsDemoMode] = useState(false);
  const [filters, setFilters] = useState<InvoiceFilters>({
    search: '',
    status: 'all',
    invoice_type: 'all',
    date_range: 'all',
    sortBy: 'created_at',
    sortOrder: 'desc'
  });
  const router = useRouter();

  const pageSize = 20;

  // 获取发票数据
  const fetchInvoices = async (page = 1) => {
    try {
      setLoading(true);
      
      // 检查是否为演示模式
      const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL;
      const isDemo = !supabaseUrl || supabaseUrl === 'https://demo.supabase.co' || supabaseUrl === '';
      setIsDemoMode(isDemo);
      
      if (isDemo) {
        // 使用演示数据
        const result = await getDemoData.invoices();
        setInvoices(result);
        setTotalCount(result.length);
        setTotalPages(Math.ceil(result.length / pageSize));
        setCurrentPage(page);
      } else {
        // 使用真实数据 - 这里需要根据实际数据库结构调整
        // 暂时使用演示数据
        const result = await getDemoData.invoices();
        setInvoices(result);
        setTotalCount(result.length);
        setTotalPages(Math.ceil(result.length / pageSize));
        setCurrentPage(page);
      }

    } catch (error) {
      console.error('Error fetching invoices:', error);
      toast.error('获取发票列表失败');
    } finally {
      setLoading(false);
    }
  };

  // 处理筛选变更
  const handleFilterChange = (key: keyof InvoiceFilters, value: any) => {
    setFilters(prev => ({
      ...prev,
      [key]: value
    }));
  };

  // 应用筛选
  const applyFilters = () => {
    setCurrentPage(1);
    fetchInvoices(1);
  };

  // 重置筛选
  const resetFilters = () => {
    setFilters({
      search: '',
      status: 'all',
      invoice_type: 'all',
      date_range: 'all',
      sortBy: 'created_at',
      sortOrder: 'desc'
    });
    setCurrentPage(1);
    fetchInvoices(1);
  };

  // 获取状态颜色
  const getStatusColor = (status: string) => {
    switch (status) {
      case 'paid':
        return 'bg-green-100 text-green-800';
      case 'issued':
        return 'bg-blue-100 text-blue-800';
      case 'draft':
        return 'bg-yellow-100 text-yellow-800';
      case 'cancelled':
        return 'bg-red-100 text-red-800';
      default:
        return 'bg-gray-100 text-gray-800';
    }
  };

  // 获取状态文本
  const getStatusText = (status: string) => {
    switch (status) {
      case 'paid':
        return '已付款';
      case 'issued':
        return '已开具';
      case 'draft':
        return '草稿';
      case 'cancelled':
        return '已取消';
      default:
        return '未知';
    }
  };

  // 获取状态图标
  const getStatusIcon = (status: string) => {
    switch (status) {
      case 'paid':
        return <CheckCircleIcon className="h-4 w-4 text-green-600" />;
      case 'issued':
        return <ClockIcon className="h-4 w-4 text-blue-600" />;
      case 'draft':
        return <DocumentTextIcon className="h-4 w-4 text-yellow-600" />;
      case 'cancelled':
        return <ExclamationCircleIcon className="h-4 w-4 text-red-600" />;
      default:
        return <ClockIcon className="h-4 w-4 text-gray-600" />;
    }
  };

  // 下载发票
  const handleDownloadInvoice = async (invoiceId: string) => {
    try {
      // 这里应该调用实际的发票下载API
      toast.success('发票下载已开始');
      
      // 模拟下载过程
      const invoice = invoices.find(inv => inv.id === invoiceId);
      if (invoice) {
        // 创建一个虚拟的下载链接
        const element = document.createElement('a');
        const file = new Blob([`发票号: ${invoice.invoice_number}\n金额: ${formatCurrency(invoice.total_amount)}`], 
          { type: 'text/plain' });
        element.href = URL.createObjectURL(file);
        element.download = `invoice-${invoice.invoice_number}.txt`;
        document.body.appendChild(element);
        element.click();
        document.body.removeChild(element);
      }
    } catch (error) {
      console.error('Error downloading invoice:', error);
      toast.error('发票下载失败');
    }
  };

  // 打印发票
  const handlePrintInvoice = (invoiceId: string) => {
    try {
      // 这里应该打开打印预览
      toast.success('正在准备打印...');
      window.print();
    } catch (error) {
      console.error('Error printing invoice:', error);
      toast.error('发票打印失败');
    }
  };

  // 生成发票
  const handleGenerateInvoice = async (orderId: string) => {
    try {
      // 这里应该调用生成发票API
      toast.success('发票生成成功');
      fetchInvoices();
    } catch (error) {
      toast.error('生成发票失败');
    }
  };

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

  return (
    <Layout>
      <Head>
        <title>发票管理 - 口译服务管理后台</title>
      </Head>

      <div className="max-w-7xl mx-auto py-6 sm:px-6 lg:px-8">
        <div className="px-4 py-6 sm:px-0">
          {/* 页面标题 */}
          <div className="flex items-center justify-between mb-6">
            <h1 className="text-2xl font-bold text-gray-900">发票管理</h1>
            <button 
              onClick={() => handleGenerateInvoice('new')}
              className="inline-flex items-center px-4 py-2 border border-transparent text-sm font-medium rounded-md text-white bg-blue-600 hover:bg-blue-700"
            >
              <ReceiptPercentIcon className="h-4 w-4 mr-2" />
              生成发票
            </button>
          </div>

          {/* 搜索和筛选 */}
          <div className="bg-white shadow rounded-lg mb-6">
            <div className="px-4 py-5 sm:p-6">
              <div className="grid grid-cols-1 gap-4 sm:grid-cols-2 lg:grid-cols-5">
                {/* 搜索框 */}
                <div className="lg:col-span-2">
                  <div className="relative">
                    <div className="absolute inset-y-0 left-0 pl-3 flex items-center pointer-events-none">
                      <MagnifyingGlassIcon className="h-5 w-5 text-gray-400" />
                    </div>
                    <input
                      type="text"
                      placeholder="搜索发票号、用户名或公司名..."
                      value={filters.search}
                      onChange={(e) => handleFilterChange('search', e.target.value)}
                      className="block w-full pl-10 pr-3 py-2 border border-gray-300 rounded-md leading-5 bg-white placeholder-gray-500 focus:outline-none focus:placeholder-gray-400 focus:ring-1 focus:ring-blue-500 focus:border-blue-500"
                    />
                  </div>
                </div>

                {/* 状态筛选 */}
                <div>
                  <select
                    value={filters.status}
                    onChange={(e) => handleFilterChange('status', e.target.value)}
                    className="block w-full px-3 py-2 border border-gray-300 rounded-md bg-white focus:outline-none focus:ring-1 focus:ring-blue-500 focus:border-blue-500"
                  >
                    <option value="all">全部状态</option>
                    <option value="draft">草稿</option>
                    <option value="issued">已开具</option>
                    <option value="paid">已付款</option>
                    <option value="cancelled">已取消</option>
                  </select>
                </div>

                {/* 类型筛选 */}
                <div>
                  <select
                    value={filters.invoice_type}
                    onChange={(e) => handleFilterChange('invoice_type', e.target.value)}
                    className="block w-full px-3 py-2 border border-gray-300 rounded-md bg-white focus:outline-none focus:ring-1 focus:ring-blue-500 focus:border-blue-500"
                  >
                    <option value="all">全部类型</option>
                    <option value="individual">个人发票</option>
                    <option value="enterprise">企业发票</option>
                  </select>
                </div>

                {/* 日期范围筛选 */}
                <div>
                  <select
                    value={filters.date_range}
                    onChange={(e) => handleFilterChange('date_range', e.target.value)}
                    className="block w-full px-3 py-2 border border-gray-300 rounded-md bg-white focus:outline-none focus:ring-1 focus:ring-blue-500 focus:border-blue-500"
                  >
                    <option value="all">全部时间</option>
                    <option value="today">今天</option>
                    <option value="week">本周</option>
                    <option value="month">本月</option>
                    <option value="quarter">本季度</option>
                  </select>
                </div>
              </div>

              <div className="mt-4 flex space-x-3">
                <button
                  onClick={applyFilters}
                  className="inline-flex items-center px-4 py-2 border border-transparent text-sm font-medium rounded-md text-white bg-blue-600 hover:bg-blue-700"
                >
                  应用筛选
                </button>
                <button
                  onClick={resetFilters}
                  className="inline-flex items-center px-4 py-2 border border-gray-300 text-sm font-medium rounded-md text-gray-700 bg-white hover:bg-gray-50"
                >
                  重置
                </button>
              </div>
            </div>
          </div>

          {/* 发票列表 */}
          {loading ? (
            <div className="flex items-center justify-center py-12">
              <div className="loading-spinner"></div>
            </div>
          ) : (
            <div className="bg-white shadow overflow-hidden sm:rounded-md">
              <div className="px-4 py-5 sm:p-6">
                <div className="flex items-center justify-between mb-4">
                  <h3 className="text-lg leading-6 font-medium text-gray-900">
                    发票列表 ({totalCount} 张发票)
                  </h3>
                </div>

                <div className="space-y-4">
                  {invoices.map((invoice) => (
                    <div key={invoice.id} className="border border-gray-200 rounded-lg p-4">
                      <div className="flex items-center justify-between">
                        <div className="flex-1 min-w-0">
                          <div className="flex items-center space-x-3">
                            <ReceiptPercentIcon className="h-8 w-8 text-gray-400" />
                            <div>
                              <h4 className="text-sm font-medium text-gray-900">
                                发票号: {invoice.invoice_number}
                              </h4>
                              <p className="text-sm text-gray-500">
                                {invoice.invoice_type === 'enterprise' ? (
                                  <span className="inline-flex items-center">
                                    <BuildingOfficeIcon className="h-4 w-4 mr-1" />
                                    {invoice.company_name}
                                  </span>
                                ) : (
                                  <span className="inline-flex items-center">
                                    <CalendarIcon className="h-4 w-4 mr-1" />
                                    {invoice.personal_name || invoice.user_name}
                                  </span>
                                )}
                              </p>
                              <p className="text-xs text-gray-400">
                                金额: ¥{invoice.total_amount.toFixed(2)} | 税额: ¥{invoice.tax_amount.toFixed(2)} | 
                                总计: ¥{invoice.total_amount.toFixed(2)}
                              </p>
                              {invoice.tax_number && (
                                <p className="text-xs text-gray-400">
                                  税号: {invoice.tax_number}
                                </p>
                              )}
                            </div>
                          </div>
                        </div>

                        <div className="flex items-center space-x-4">
                          {/* 状态 */}
                          <div className="flex items-center space-x-2">
                            {getStatusIcon(invoice.status)}
                            <span className={`inline-flex items-center px-2.5 py-0.5 rounded-full text-xs font-medium ${getStatusColor(invoice.status)}`}>
                              {getStatusText(invoice.status)}
                            </span>
                          </div>

                          {/* 操作按钮 */}
                          <div className="flex space-x-2">
                            <button 
                              className="text-indigo-600 hover:text-indigo-900"
                              title="查看详情"
                            >
                              <EyeIcon className="h-4 w-4" />
                            </button>
                            <button 
                              onClick={() => handleDownloadInvoice(invoice.id)}
                              className="text-green-600 hover:text-green-900"
                              title="下载发票"
                            >
                              <DocumentArrowDownIcon className="h-4 w-4" />
                            </button>
                            <button 
                              onClick={() => handlePrintInvoice(invoice.id)}
                              className="text-blue-600 hover:text-blue-900"
                              title="打印发票"
                            >
                              <PrinterIcon className="h-4 w-4" />
                            </button>
                          </div>
                        </div>
                      </div>

                      {/* 日期信息 */}
                      <div className="mt-3 text-xs text-gray-400">
                        <div>创建: {formatTime(invoice.created_at)}</div>
                        {invoice.issue_date && (
                          <div>开具: {formatTime(invoice.issue_date)}</div>
                        )}
                        {invoice.paid_date && (
                          <div>付款: {formatTime(invoice.paid_date)}</div>
                        )}
                      </div>
                    </div>
                  ))}

                  {invoices.length === 0 && (
                    <div className="text-center py-12">
                      <ReceiptPercentIcon className="mx-auto h-12 w-12 text-gray-400" />
                      <h3 className="mt-2 text-sm font-medium text-gray-900">暂无发票</h3>
                      <p className="mt-1 text-sm text-gray-500">开始生成您的第一张发票</p>
                    </div>
                  )}
                </div>

                {/* 分页 */}
                {totalPages > 1 && (
                  <div className="mt-6 flex items-center justify-between">
                    <div className="flex-1 flex justify-between sm:hidden">
                      <button
                        onClick={() => fetchInvoices(currentPage - 1)}
                        disabled={currentPage === 1}
                        className="relative inline-flex items-center px-4 py-2 border border-gray-300 text-sm font-medium rounded-md text-gray-700 bg-white hover:bg-gray-50 disabled:opacity-50"
                      >
                        上一页
                      </button>
                      <button
                        onClick={() => fetchInvoices(currentPage + 1)}
                        disabled={currentPage === totalPages}
                        className="ml-3 relative inline-flex items-center px-4 py-2 border border-gray-300 text-sm font-medium rounded-md text-gray-700 bg-white hover:bg-gray-50 disabled:opacity-50"
                      >
                        下一页
                      </button>
                    </div>
                    <div className="hidden sm:flex-1 sm:flex sm:items-center sm:justify-between">
                      <div>
                        <p className="text-sm text-gray-700">
                          显示第 <span className="font-medium">{(currentPage - 1) * pageSize + 1}</span> 到{' '}
                          <span className="font-medium">
                            {Math.min(currentPage * pageSize, totalCount)}
                          </span>{' '}
                          张，共 <span className="font-medium">{totalCount}</span> 张发票
                        </p>
                      </div>
                      <div>
                        <nav className="relative z-0 inline-flex rounded-md shadow-sm -space-x-px">
                          <button
                            onClick={() => fetchInvoices(currentPage - 1)}
                            disabled={currentPage === 1}
                            className="relative inline-flex items-center px-2 py-2 rounded-l-md border border-gray-300 bg-white text-sm font-medium text-gray-500 hover:bg-gray-50 disabled:opacity-50"
                          >
                            <ChevronLeftIcon className="h-5 w-5" />
                          </button>
                          {[...Array(Math.min(totalPages, 5))].map((_, i) => {
                            const page = i + 1;
                            return (
                              <button
                                key={page}
                                onClick={() => fetchInvoices(page)}
                                className={`relative inline-flex items-center px-4 py-2 border text-sm font-medium ${
                                  page === currentPage
                                    ? 'z-10 bg-blue-50 border-blue-500 text-blue-600'
                                    : 'bg-white border-gray-300 text-gray-500 hover:bg-gray-50'
                                }`}
                              >
                                {page}
                              </button>
                            );
                          })}
                          <button
                            onClick={() => fetchInvoices(currentPage + 1)}
                            disabled={currentPage === totalPages}
                            className="relative inline-flex items-center px-2 py-2 rounded-r-md border border-gray-300 bg-white text-sm font-medium text-gray-500 hover:bg-gray-50 disabled:opacity-50"
                          >
                            <ChevronRightIcon className="h-5 w-5" />
                          </button>
                        </nav>
                      </div>
                    </div>
                  </div>
                )}
              </div>
            </div>
          )}
        </div>
      </div>
    </Layout>
  );
}