'use client'

import { useState, useMemo } from 'react'
import { Search, ChevronDown, ChevronUp, AlertTriangle, CheckCircle } from 'lucide-react'

interface Transaction {
  id: number
  amount: number
  merchant: string
  category: string
  is_fraud: number
  prediction: string
  final_score: number
  classical_score: number
  quantum_score: number
}

interface TransactionTableProps {
  transactions: Transaction[]
  compact?: boolean
}

export default function TransactionTable({ transactions, compact = false }: TransactionTableProps) {
  const [search, setSearch] = useState('')
  const [sortField, setSortField] = useState<keyof Transaction>('id')
  const [sortDirection, setSortDirection] = useState<'asc' | 'desc'>('desc')
  const [filterPrediction, setFilterPrediction] = useState<'all' | 'Fraud' | 'Safe'>('all')
  const [page, setPage] = useState(0)
  const pageSize = compact ? 10 : 20

  const filteredTransactions = useMemo(() => {
    let result = [...transactions]
    
    // Filter by search
    if (search) {
      const searchLower = search.toLowerCase()
      result = result.filter(t => 
        t.merchant?.toLowerCase().includes(searchLower) ||
        t.category?.toLowerCase().includes(searchLower) ||
        t.id.toString().includes(searchLower)
      )
    }
    
    // Filter by prediction
    if (filterPrediction !== 'all') {
      result = result.filter(t => t.prediction === filterPrediction)
    }
    
    // Sort
    result.sort((a, b) => {
      const aVal = a[sortField]
      const bVal = b[sortField]
      
      if (typeof aVal === 'number' && typeof bVal === 'number') {
        return sortDirection === 'asc' ? aVal - bVal : bVal - aVal
      }
      
      const aStr = String(aVal).toLowerCase()
      const bStr = String(bVal).toLowerCase()
      return sortDirection === 'asc' 
        ? aStr.localeCompare(bStr) 
        : bStr.localeCompare(aStr)
    })
    
    return result
  }, [transactions, search, sortField, sortDirection, filterPrediction])

  const paginatedTransactions = useMemo(() => {
    const start = page * pageSize
    return filteredTransactions.slice(start, start + pageSize)
  }, [filteredTransactions, page, pageSize])

  const totalPages = Math.ceil(filteredTransactions.length / pageSize)

  const handleSort = (field: keyof Transaction) => {
    if (sortField === field) {
      setSortDirection(prev => prev === 'asc' ? 'desc' : 'asc')
    } else {
      setSortField(field)
      setSortDirection('desc')
    }
  }

  const SortIcon = ({ field }: { field: keyof Transaction }) => {
    if (sortField !== field) return null
    return sortDirection === 'asc' 
      ? <ChevronUp className="w-4 h-4" />
      : <ChevronDown className="w-4 h-4" />
  }

  if (transactions.length === 0) {
    return (
      <div className="text-center py-8 text-dark-400">
        <p>No transactions to display</p>
      </div>
    )
  }

  return (
    <div className="space-y-4">
      {/* Filters - only show if not compact */}
      {!compact && (
        <div className="flex flex-wrap gap-4">
          {/* Search */}
          <div className="relative flex-1 min-w-[200px]">
            <Search className="absolute left-3 top-1/2 transform -translate-y-1/2 w-4 h-4 text-dark-400" />
            <input
              type="text"
              placeholder="Search merchant, category, ID..."
              value={search}
              onChange={(e) => setSearch(e.target.value)}
              className="w-full bg-dark-700 border border-dark-600 rounded-lg pl-10 pr-4 py-2 text-sm focus:border-primary-500 focus:outline-none"
            />
          </div>
          
          {/* Filter dropdown */}
          <select
            value={filterPrediction}
            onChange={(e) => setFilterPrediction(e.target.value as any)}
            className="bg-dark-700 border border-dark-600 rounded-lg px-4 py-2 text-sm focus:border-primary-500 focus:outline-none"
          >
            <option value="all">All Predictions</option>
            <option value="Fraud">Fraud Only</option>
            <option value="Safe">Safe Only</option>
          </select>
        </div>
      )}
      
      {/* Table */}
      <div className="overflow-x-auto">
        <table className="w-full text-sm">
          <thead>
            <tr className="border-b border-dark-700">
              <th 
                className="text-left py-3 px-4 text-dark-300 font-medium cursor-pointer hover:text-white"
                onClick={() => handleSort('id')}
              >
                <div className="flex items-center gap-1">
                  ID <SortIcon field="id" />
                </div>
              </th>
              <th 
                className="text-left py-3 px-4 text-dark-300 font-medium cursor-pointer hover:text-white"
                onClick={() => handleSort('amount')}
              >
                <div className="flex items-center gap-1">
                  Amount <SortIcon field="amount" />
                </div>
              </th>
              {!compact && (
                <>
                  <th className="text-left py-3 px-4 text-dark-300 font-medium">Merchant</th>
                  <th className="text-left py-3 px-4 text-dark-300 font-medium">Category</th>
                </>
              )}
              <th 
                className="text-left py-3 px-4 text-dark-300 font-medium cursor-pointer hover:text-white"
                onClick={() => handleSort('final_score')}
              >
                <div className="flex items-center gap-1">
                  Risk Score <SortIcon field="final_score" />
                </div>
              </th>
              <th className="text-left py-3 px-4 text-dark-300 font-medium">Status</th>
              <th className="text-left py-3 px-4 text-dark-300 font-medium">Actual</th>
            </tr>
          </thead>
          <tbody>
            {paginatedTransactions.map((t) => (
              <tr 
                key={t.id} 
                className={`
                  border-b border-dark-800 hover:bg-dark-800/50 transition-colors
                  ${t.prediction === 'Fraud' ? 'bg-red-500/5' : ''}
                `}
              >
                <td className="py-3 px-4 font-mono text-dark-300">#{t.id}</td>
                <td className="py-3 px-4 font-semibold">${t.amount.toFixed(2)}</td>
                {!compact && (
                  <>
                    <td className="py-3 px-4 text-dark-300 truncate max-w-[150px]">{t.merchant}</td>
                    <td className="py-3 px-4 text-dark-400">{t.category}</td>
                  </>
                )}
                <td className="py-3 px-4">
                  <div className="flex items-center gap-2">
                    <div className="w-20 h-2 bg-dark-700 rounded-full overflow-hidden">
                      <div 
                        className={`h-full rounded-full ${
                          t.final_score > 0.7 ? 'bg-red-500' : 
                          t.final_score > 0.4 ? 'bg-yellow-500' : 'bg-green-500'
                        }`}
                        style={{ width: `${t.final_score * 100}%` }}
                      />
                    </div>
                    <span className="text-xs text-dark-400">
                      {(t.final_score * 100).toFixed(0)}%
                    </span>
                  </div>
                </td>
                <td className="py-3 px-4">
                  {t.prediction === 'Fraud' ? (
                    <span className="badge-fraud flex items-center gap-1 w-fit">
                      <AlertTriangle className="w-3 h-3" /> Fraud
                    </span>
                  ) : (
                    <span className="badge-safe flex items-center gap-1 w-fit">
                      <CheckCircle className="w-3 h-3" /> Safe
                    </span>
                  )}
                </td>
                <td className="py-3 px-4">
                  <span className={t.is_fraud ? 'text-red-400' : 'text-green-400'}>
                    {t.is_fraud ? '⚠️ Fraud' : '✓ Safe'}
                  </span>
                </td>
              </tr>
            ))}
          </tbody>
        </table>
      </div>
      
      {/* Pagination - only show if not compact and multiple pages */}
      {!compact && totalPages > 1 && (
        <div className="flex items-center justify-between pt-4">
          <p className="text-sm text-dark-400">
            Showing {page * pageSize + 1} - {Math.min((page + 1) * pageSize, filteredTransactions.length)} of {filteredTransactions.length}
          </p>
          <div className="flex items-center gap-2">
            <button
              onClick={() => setPage(Math.max(0, page - 1))}
              disabled={page === 0}
              className="btn-secondary text-sm py-1 px-3 disabled:opacity-50"
            >
              Previous
            </button>
            <span className="text-sm text-dark-400">
              Page {page + 1} of {totalPages}
            </span>
            <button
              onClick={() => setPage(Math.min(totalPages - 1, page + 1))}
              disabled={page >= totalPages - 1}
              className="btn-secondary text-sm py-1 px-3 disabled:opacity-50"
            >
              Next
            </button>
          </div>
        </div>
      )}
    </div>
  )
}