import { useState, useEffect, useRef } from 'react';
import { motion } from 'framer-motion';
import {
  Upload,
  FileSpreadsheet,
  Database,
  History,
  CheckCircle,
  AlertCircle,
  X,
  Download,
  Calendar,
  Settings
} from 'lucide-react';
import { adminApi, createSyncTaskWebSocket } from '@/services/adminApi';

interface ImportTask {
  id: string;
  type: 'stock' | 'sector' | 'trade' | 'kline';
  name: string;
  fileName: string;
  status: 'pending' | 'processing' | 'completed' | 'error';
  progress: number;
  totalRecords: number;
  importedRecords: number;
  errorMessage?: string;
  createdAt: string;
}

const importTemplates = [
  { type: 'stock', name: '股票基础数据', format: 'CSV/Excel', fields: ['code', 'name', 'industry', 'market_cap'] },
  { type: 'sector', name: '版块数据', format: 'CSV/Excel', fields: ['code', 'name', 'parent_code'] },
  { type: 'trade', name: '交易数据', format: 'CSV/Excel', fields: ['code', 'date', 'open', 'high', 'low', 'close', 'volume'] },
  { type: 'kline', name: 'K线数据', format: 'CSV/Excel', fields: ['code', 'date', 'open', 'high', 'low', 'close', 'volume'] },
];

export default function DataImport() {
  const [tasks, setTasks] = useState<ImportTask[]>([]);
  const [loading, setLoading] = useState(true);
  const [dragActive, setDragActive] = useState(false);
  const [selectedType, setSelectedType] = useState<string>('stock');
  const [showTemplateModal, setShowTemplateModal] = useState(false);
  const [uploading, setUploading] = useState(false);
  const fileInputRef = useRef<HTMLInputElement>(null);
  const wsRef = useRef<WebSocket | null>(null);

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

  useEffect(() => {
    return () => {
      if (wsRef.current) {
        wsRef.current.close();
      }
    };
  }, []);

  const fetchTasks = async () => {
    setLoading(true);
    try {
      const data = await adminApi.getImportTasks();
      setTasks(data.map(t => ({
        id: t.id,
        type: 'stock' as const,
        name: t.name,
        fileName: t.fileName,
        status: t.status as ImportTask['status'],
        progress: t.progress,
        totalRecords: t.totalRecords,
        importedRecords: t.importedRecords,
        createdAt: t.createdAt,
      })));
    } catch (error) {
      console.error('Failed to fetch tasks:', error);
    } finally {
      setLoading(false);
    }
  };

  const handleDrag = (e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    if (e.type === 'dragenter' || e.type === 'dragover') {
      setDragActive(true);
    } else if (e.type === 'dragleave') {
      setDragActive(false);
    }
  };

  const handleDrop = (e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setDragActive(false);

    if (e.dataTransfer.files && e.dataTransfer.files[0]) {
      handleFile(e.dataTransfer.files[0]);
    }
  };

  const handleFile = async (file: File) => {
    setUploading(true);
    
    try {
      const result = await adminApi.uploadImportFile(file, selectedType);
      
      // 添加新任务到列表
      const newTask: ImportTask = {
        id: result.taskId,
        type: selectedType as ImportTask['type'],
        name: importTemplates.find(t => t.type === selectedType)?.name || '数据导入',
        fileName: file.name,
        status: 'pending',
        progress: 0,
        totalRecords: 0,
        importedRecords: 0,
        createdAt: new Date().toLocaleString('zh-CN'),
      };

      setTasks(prev => [newTask, ...prev]);
      
      // 连接 WebSocket 获取进度
      connectWebSocket(result.taskId, newTask.id);
    } catch (error: any) {
      alert('上传失败: ' + error.message);
    } finally {
      setUploading(false);
    }
  };

  const connectWebSocket = (serverTaskId: string, localTaskId: string) => {
    if (wsRef.current) {
      wsRef.current.close();
    }

    const ws = createSyncTaskWebSocket(serverTaskId);
    
    ws.onmessage = (event) => {
      const data = JSON.parse(event.data);
      
      setTasks(prev => prev.map(t => 
        t.id === localTaskId ? {
          ...t,
          status: data.status,
          progress: data.progress,
          totalRecords: data.totalRecords || t.totalRecords,
          importedRecords: data.processedRecords || t.importedRecords,
          errorMessage: data.error,
        } : t
      ));

      if (data.status === 'completed' || data.status === 'failed') {
        ws.close();
      }
    };

    ws.onerror = (error) => {
      console.error('WebSocket error:', error);
    };

    wsRef.current = ws;
  };

  const handleDeleteTask = (taskId: string) => {
    setTasks(prev => prev.filter(t => t.id !== taskId));
  };

  const getStatusIcon = (status: ImportTask['status']) => {
    switch (status) {
      case 'completed':
        return <CheckCircle className="w-5 h-5 text-green-400" />;
      case 'error':
        return <AlertCircle className="w-5 h-5 text-red-400" />;
      case 'processing':
        return <div className="w-5 h-5 border-2 border-[#ff6b35] border-t-transparent rounded-full animate-spin" />;
      default:
        return <div className="w-5 h-5 rounded-full border-2 border-[#666]" />;
    }
  };

  const downloadTemplate = (type: string) => {
    const template = importTemplates.find(t => t.type === type);
    if (!template) return;

    const headers = template.fields.join(',');
    const sample = template.fields.map(() => '示例数据').join(',');
    const content = `${headers}\n${sample}`;
    
    const blob = new Blob([content], { type: 'text/csv;charset=utf-8;' });
    const link = document.createElement('a');
    link.href = URL.createObjectURL(blob);
    link.download = `${type}_template.csv`;
    link.click();
  };

  return (
    <div className="space-y-6">
      {/* Header */}
      <div className="flex flex-col sm:flex-row sm:items-center sm:justify-between gap-4">
        <div>
          <h1 className="text-2xl font-bold text-white">数据导入</h1>
          <p className="text-[#b0b0b0] mt-1">批量导入股票、交易历史等数据</p>
        </div>
        <button
          onClick={() => setShowTemplateModal(true)}
          className="flex items-center gap-2 px-4 py-2 bg-[#2a2a2a] text-white rounded-lg hover:bg-[#333] transition-colors"
        >
          <Download className="w-4 h-4" />
          下载模板
        </button>
      </div>

      {/* Upload Area */}
      <motion.div
        initial={{ opacity: 0, y: 20 }}
        animate={{ opacity: 1, y: 0 }}
        className={`bg-[#111111] border-2 border-dashed rounded-xl p-8 text-center transition-colors ${
          dragActive ? 'border-[#ff6b35] bg-[#ff6b35]/5' : 'border-[#2a2a2a]'
        }`}
        onDragEnter={handleDrag}
        onDragLeave={handleDrag}
        onDragOver={handleDrag}
        onDrop={handleDrop}
      >
        <input
          ref={fileInputRef}
          type="file"
          accept=".csv,.xlsx,.xls"
          onChange={(e) => e.target.files?.[0] && handleFile(e.target.files[0])}
          className="hidden"
        />

        <div className="w-16 h-16 bg-[#ff6b35]/20 rounded-full flex items-center justify-center mx-auto mb-4">
          {uploading ? (
            <div className="w-8 h-8 border-2 border-[#ff6b35] border-t-transparent rounded-full animate-spin" />
          ) : (
            <Upload className="w-8 h-8 text-[#ff6b35]" />
          )}
        </div>

        <p className="text-white text-lg mb-2">
          {uploading ? '上传中...' : '拖拽文件到此处上传'}
        </p>
        <p className="text-[#666] text-sm mb-4">支持 CSV、Excel 格式文件</p>

        {/* Data Type Selector */}
        <div className="flex flex-wrap justify-center gap-2 mb-4">
          {importTemplates.map(template => (
            <button
              key={template.type}
              onClick={() => setSelectedType(template.type)}
              disabled={uploading}
              className={`px-4 py-2 rounded-lg text-sm transition-colors disabled:opacity-50 ${
                selectedType === template.type
                  ? 'bg-[#ff6b35] text-white'
                  : 'bg-[#2a2a2a] text-[#b0b0b0] hover:bg-[#333]'
              }`}
            >
              {template.name}
            </button>
          ))}
        </div>

        <button
          onClick={() => fileInputRef.current?.click()}
          disabled={uploading}
          className="px-6 py-2 bg-[#ff6b35] text-white rounded-lg hover:bg-[#ff6b35]/90 transition-colors disabled:opacity-50"
        >
          选择文件
        </button>
      </motion.div>

      {/* Import Tasks */}
      <motion.div
        initial={{ opacity: 0, y: 20 }}
        animate={{ opacity: 1, y: 0 }}
        className="bg-[#111111] border border-[#2a2a2a] rounded-xl overflow-hidden"
      >
        <div className="px-5 py-4 border-b border-[#2a2a2a] flex items-center justify-between">
          <div className="flex items-center gap-3">
            <History className="w-5 h-5 text-[#ff6b35]" />
            <h2 className="text-white font-semibold">导入记录</h2>
          </div>
          <div className="flex gap-2">
            <button
              onClick={fetchTasks}
              disabled={loading}
              className="p-2 hover:bg-[#2a2a2a] rounded-lg transition-colors disabled:opacity-50"
            >
              <RefreshCw className={`w-4 h-4 text-[#666] ${loading ? 'animate-spin' : ''}`} />
            </button>
            <button
              onClick={() => setTasks([])}
              className="text-sm text-[#666] hover:text-white transition-colors"
            >
              清空记录
            </button>
          </div>
        </div>

        <div className="divide-y divide-[#2a2a2a]">
          {loading ? (
            <div className="p-8 text-center text-[#b0b0b0]">
              <RefreshCw className="w-6 h-6 animate-spin mx-auto mb-2" />
              加载中...
            </div>
          ) : tasks.length === 0 ? (
            <div className="p-8 text-center text-[#666]">
              暂无导入记录
            </div>
          ) : (
            tasks.map((task) => (
              <div key={task.id} className="p-5 hover:bg-[#1a1a1a] transition-colors">
                <div className="flex items-start justify-between">
                  <div className="flex items-start gap-4">
                    {getStatusIcon(task.status)}
                    <div>
                      <h3 className="text-white font-medium">{task.name}</h3>
                      <p className="text-sm text-[#666] mt-1">{task.fileName}</p>
                      <div className="flex items-center gap-4 mt-2 text-xs text-[#666]">
                        <span>{task.createdAt}</span>
                        <span>类型: {task.type}</span>
                        {task.status !== 'pending' && task.totalRecords > 0 && (
                          <span>
                            记录: {task.importedRecords.toLocaleString()} / {task.totalRecords.toLocaleString()}
                          </span>
                        )}
                      </div>
                      {task.errorMessage && (
                        <p className="text-sm text-red-400 mt-2">{task.errorMessage}</p>
                      )}
                    </div>
                  </div>
                  <button
                    onClick={() => handleDeleteTask(task.id)}
                    className="p-2 hover:bg-[#2a2a2a] rounded-lg transition-colors"
                  >
                    <X className="w-4 h-4 text-[#666]" />
                  </button>
                </div>

                {task.status === 'processing' && (
                  <div className="mt-4">
                    <div className="flex items-center justify-between text-sm mb-2">
                      <span className="text-[#b0b0b0]">导入进度</span>
                      <span className="text-[#ff6b35]">{task.progress.toFixed(0)}%</span>
                    </div>
                    <div className="h-2 bg-[#2a2a2a] rounded-full overflow-hidden">
                      <motion.div
                        className="h-full bg-gradient-to-r from-[#ff6b35] to-[#ff9f43]"
                        initial={{ width: 0 }}
                        animate={{ width: `${task.progress}%` }}
                        transition={{ duration: 0.3 }}
                      />
                    </div>
                  </div>
                )}

                {task.status === 'completed' && (
                  <div className="mt-4 flex items-center gap-2 text-green-400 text-sm">
                    <CheckCircle className="w-4 h-4" />
                    导入成功
                  </div>
                )}
              </div>
            ))
          )}
        </div>
      </motion.div>

      {/* Import Guide */}
      <motion.div
        initial={{ opacity: 0, y: 20 }}
        animate={{ opacity: 1, y: 0 }}
        transition={{ delay: 0.2 }}
        className="bg-[#111111] border border-[#2a2a2a] rounded-xl p-5"
      >
        <h2 className="text-white font-semibold mb-4">导入说明</h2>
        <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
          <div className="flex items-start gap-3">
            <div className="w-8 h-8 bg-blue-500/20 rounded-lg flex items-center justify-center flex-shrink-0">
              <FileSpreadsheet className="w-4 h-4 text-blue-400" />
            </div>
            <div>
              <h3 className="text-white font-medium">文件格式</h3>
              <p className="text-sm text-[#666] mt-1">
                支持 CSV (.csv) 和 Excel (.xlsx, .xls) 格式，文件大小不超过 100MB
              </p>
            </div>
          </div>
          <div className="flex items-start gap-3">
            <div className="w-8 h-8 bg-green-500/20 rounded-lg flex items-center justify-center flex-shrink-0">
              <Database className="w-4 h-4 text-green-400" />
            </div>
            <div>
              <h3 className="text-white font-medium">数据验证</h3>
              <p className="text-sm text-[#666] mt-1">
                系统会自动验证数据格式，错误数据将被跳过并生成报告
              </p>
            </div>
          </div>
          <div className="flex items-start gap-3">
            <div className="w-8 h-8 bg-purple-500/20 rounded-lg flex items-center justify-center flex-shrink-0">
              <Calendar className="w-4 h-4 text-purple-400" />
            </div>
            <div>
              <h3 className="text-white font-medium">数据去重</h3>
              <p className="text-sm text-[#666] mt-1">
                已存在的记录将被更新，新记录将被插入，不会重复导入
              </p>
            </div>
          </div>
          <div className="flex items-start gap-3">
            <div className="w-8 h-8 bg-orange-500/20 rounded-lg flex items-center justify-center flex-shrink-0">
              <Settings className="w-4 h-4 text-orange-400" />
            </div>
            <div>
              <h3 className="text-white font-medium">自动计算</h3>
              <p className="text-sm text-[#666] mt-1">
                导入交易数据后，系统会自动重新计算动量指标和排名
              </p>
            </div>
          </div>
        </div>
      </motion.div>

      {/* Template Modal */}
      {showTemplateModal && (
        <motion.div
          initial={{ opacity: 0 }}
          animate={{ opacity: 1 }}
          exit={{ opacity: 0 }}
          className="fixed inset-0 z-[100] flex items-center justify-center p-4 bg-black/70 backdrop-blur-sm"
          onClick={() => setShowTemplateModal(false)}
        >
          <motion.div
            initial={{ opacity: 0, scale: 0.95 }}
            animate={{ opacity: 1, scale: 1 }}
            exit={{ opacity: 0, scale: 0.95 }}
            className="bg-[#1a1a1a] border border-[#2a2a2a] rounded-xl w-full max-w-lg"
            onClick={e => e.stopPropagation()}
          >
            <div className="p-5 border-b border-[#2a2a2a] flex items-center justify-between">
              <h2 className="text-white font-semibold">下载导入模板</h2>
              <button
                onClick={() => setShowTemplateModal(false)}
                className="p-2 hover:bg-[#2a2a2a] rounded-lg transition-colors"
              >
                <X className="w-5 h-5 text-[#666]" />
              </button>
            </div>
            <div className="p-5 space-y-3">
              {importTemplates.map(template => (
                <div
                  key={template.type}
                  className="flex items-center justify-between p-4 bg-[#0a0a0a] rounded-lg"
                >
                  <div>
                    <h3 className="text-white font-medium">{template.name}</h3>
                    <p className="text-sm text-[#666] mt-1">
                      字段: {template.fields.join(', ')}
                    </p>
                  </div>
                  <button
                    onClick={() => downloadTemplate(template.type)}
                    className="px-4 py-2 bg-[#ff6b35] text-white rounded-lg hover:bg-[#ff6b35]/90 transition-colors"
                  >
                    下载
                  </button>
                </div>
              ))}
            </div>
          </motion.div>
        </motion.div>
      )}
    </div>
  );
}