import React, { useState, useEffect } from 'react';
import { Table, TableHeader, TableBody, TableHead, TableRow, TableCell, TableCaption } from './ui/table';
import { Button } from './ui/button';

const DataTable = () => {
  const [data, setData] = useState([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);
  const [sortConfig, setSortConfig] = useState({ key: null, direction: 'asc' });

  // Mock data for demonstration - replace with actual MongoDB data
  const mockData = [
    { id: 1, name: 'John Doe', email: 'john@example.com', role: 'Developer' },
    { id: 2, name: 'Jane Smith', email: 'jane@example.com', role: 'Designer' },
    { id: 3, name: 'Bob Johnson', email: 'bob@example.com', role: 'Manager' },
    { id: 4, name: 'Alice Brown', email: 'alice@example.com', role: 'Developer' },
    { id: 5, name: 'Charlie Wilson', email: 'charlie@example.com', role: 'Designer' },
  ];

  useEffect(() => {
    // Simulate loading data
    setTimeout(() => {
      setData(mockData);
      setLoading(false);
    }, 1000);
  }, []);

  // Sorting function
  const sortData = (key) => {
    let direction = 'asc';
    
    // Three-state sorting: asc → desc → none
    if (sortConfig.key === key) {
      if (sortConfig.direction === 'asc') {
        direction = 'desc';
      } else if (sortConfig.direction === 'desc') {
        // Reset to no sorting
        setSortConfig({ key: null, direction: 'none' });
        return;
      }
    }
    
    setSortConfig({ key, direction });
  };

  // Get sorted data
  const getSortedData = () => {
    if (!sortConfig.key || sortConfig.direction === 'none') return data;

    return [...data].sort((a, b) => {
      let aValue = a[sortConfig.key];
      let bValue = b[sortConfig.key];

      // Handle string comparison (case-insensitive)
      if (typeof aValue === 'string') {
        aValue = aValue.toLowerCase();
        bValue = bValue.toLowerCase();
      }

      if (aValue < bValue) {
        return sortConfig.direction === 'asc' ? -1 : 1;
      }
      if (aValue > bValue) {
        return sortConfig.direction === 'asc' ? 1 : -1;
      }
      return 0;
    });
  };

  // Get sort indicator for column headers
  const getSortIndicator = (key) => {
    if (sortConfig.key !== key) return '⇵';
    if (sortConfig.direction === 'asc') return '↑';
    if (sortConfig.direction === 'desc') return '↓';
    return '⇵';
  };

  const fetchFromMongoDB = async () => {
    try {
      setLoading(true);
      // Replace this with your actual MongoDB connection logic
      // const response = await fetch('/api/data');
      // const result = await response.json();
      // setData(result);
      
      // For now, using mock data
      setData(mockData);
    } catch (err) {
      setError('Failed to fetch data');
    } finally {
      setLoading(false);
    }
  };

  if (loading) {
    return (
      <div className="flex items-center justify-center p-8">
        <div className="text-lg text-muted-foreground">Loading...</div>
      </div>
    );
  }

  if (error) {
    return (
      <div className="flex items-center justify-center p-8">
        <div className="text-red-500">{error}</div>
      </div>
    );
  }

  const sortedData = getSortedData();

  return (
    <div className="w-full mx-auto p-6">
      <div className="flex justify-between items-center mb-6">
        <h2 className="text-2xl font-bold text-foreground">Interesting Mock Data</h2>
        <Button onClick={fetchFromMongoDB}>
          Refresh Data
        </Button>
      </div>
      
      <div className="border rounded-lg bg-card">
        <Table>
          <TableCaption>A list of users from the database.</TableCaption>
          <TableHeader>
            <TableRow>
              <TableHead 
                className="cursor-pointer hover:bg-muted/50 transition-colors"
                onClick={() => sortData('id')}
              >
                ID {getSortIndicator('id')}
              </TableHead>
              <TableHead 
                className="cursor-pointer hover:bg-muted/50 transition-colors"
                onClick={() => sortData('name')}
              >
                Name {getSortIndicator('name')}
              </TableHead>
              <TableHead 
                className="cursor-pointer hover:bg-muted/50 transition-colors"
                onClick={() => sortData('email')}
              >
                Email {getSortIndicator('email')}
              </TableHead>
              <TableHead 
                className="cursor-pointer hover:bg-muted/50 transition-colors"
                onClick={() => sortData('role')}
              >
                Role {getSortIndicator('role')}
              </TableHead>
            </TableRow>
          </TableHeader>
          <TableBody>
            {sortedData.map((user) => (
              <TableRow key={user.id}>
                <TableCell className="font-medium">{user.id}</TableCell>
                <TableCell>{user.name}</TableCell>
                <TableCell>{user.email}</TableCell>
                <TableCell>{user.role}</TableCell>
              </TableRow>
            ))}
          </TableBody>
        </Table>
      </div>
    </div>
  );
};

export default DataTable;