import React, { memo, useMemo } from 'react';
import {
  StyleSheet,
  Text,
  View,
} from 'react-native';
import Ionicons from '@react-native-vector-icons/ionicons';

import type { TransactionRecord } from '../../types/app';
import { useTheme } from '../../theme';
import { formatCurrency, formatDate } from '../../utils/formatters';

interface TransactionItemProps {
  item: TransactionRecord;
}

type RiskLevel = 'safe' | 'medium' | 'high';

const TransactionItemComponent = ({ item }: TransactionItemProps) => {
  const theme = useTheme();
  const isCredit = item.direction === 'credit';

  const riskLevel = useMemo<RiskLevel>(() => {
    const sum = item.id.split('').reduce((acc, char) => acc + char.charCodeAt(0), 0);
    if (sum % 10 < 7) return 'safe';
    if (sum % 10 < 9) return 'medium';
    return 'high';
  }, [item.id]);

  const riskConfig = {
    safe: { color: theme.colors.success, label: 'SECURE', icon: 'shield-checkmark' as const },
    medium: { color: theme.colors.warning, label: 'FLAGGED', icon: 'warning' as const },
    high: { color: theme.colors.danger, label: 'HIGH RISK', icon: 'alert-circle' as const },
  }[riskLevel];

  return (
    <View
      style={[
        styles.wrapper,
        {
          borderBottomColor: 'rgba(255, 255, 255, 0.05)',
        },
      ]}
    >
      <View style={styles.leading}>
        <View
          style={[
            styles.icon,
            {
              backgroundColor: isCredit
                ? `${theme.colors.success}10`
                : 'rgba(255, 255, 255, 0.05)',
              borderColor: isCredit ? `${theme.colors.success}30` : 'rgba(255, 255, 255, 0.1)',
            },
          ]}
        >
          <Ionicons 
            name={isCredit ? 'chevron-down' : 'chevron-up'} 
            size={18} 
            color={isCredit ? theme.colors.success : theme.colors.white} 
          />
        </View>
        <View style={styles.copy}>
          <View style={styles.titleRow}>
            <Text style={[styles.title, { color: theme.colors.white }]}>{item.title}</Text>
          </View>
          <View style={styles.subtitleRow}>
            <Text style={[styles.subtitle, { color: 'rgba(255, 255, 255, 0.5)' }]}>
              {item.counterparty}
            </Text>
            <View style={styles.dot} />
            <Text style={[styles.subtitle, { color: 'rgba(255, 255, 255, 0.5)' }]}>
              {formatDate(item.occurredAt)}
            </Text>
          </View>
        </View>
      </View>
      
      <View style={styles.trailing}>
        <Text
          style={[
            styles.amount,
            { color: isCredit ? theme.colors.success : theme.colors.white },
          ]}
        >
          {isCredit ? '+' : '-'}
          {formatCurrency(item.amount)}
        </Text>
        <View style={[styles.riskBadge, { backgroundColor: `${riskConfig.color}10`, borderColor: `${riskConfig.color}20` }]}>
          <Text style={[styles.riskText, { color: riskConfig.color }]}>{riskConfig.label}</Text>
        </View>
      </View>
    </View>
  );
};

const styles = StyleSheet.create({
  wrapper: {
    flexDirection: 'row',
    alignItems: 'center',
    justifyContent: 'space-between',
    paddingVertical: 18,
    borderBottomWidth: 1,
  },
  leading: {
    flexDirection: 'row',
    alignItems: 'center',
    gap: 16,
    flex: 1,
  },
  icon: {
    width: 46,
    height: 46,
    borderRadius: 23,
    alignItems: 'center',
    justifyContent: 'center',
    borderWidth: 1,
  },
  copy: {
    gap: 4,
    flex: 1,
  },
  titleRow: {
    flexDirection: 'row',
    alignItems: 'center',
  },
  title: {
    fontSize: 16,
    fontWeight: '800',
    letterSpacing: -0.3,
  },
  subtitleRow: {
    flexDirection: 'row',
    alignItems: 'center',
    gap: 6,
  },
  dot: {
    width: 3,
    height: 3,
    borderRadius: 1.5,
    backgroundColor: 'rgba(255, 255, 255, 0.2)',
  },
  subtitle: {
    fontSize: 12,
    fontWeight: '500',
  },
  trailing: {
    alignItems: 'flex-end',
    gap: 4,
  },
  amount: {
    fontSize: 16,
    fontWeight: '800',
    letterSpacing: -0.2,
  },
  riskBadge: {
    paddingHorizontal: 6,
    paddingVertical: 2,
    borderRadius: 6,
    borderWidth: 1,
  },
  riskText: {
    fontSize: 8,
    fontWeight: '900',
    letterSpacing: 0.5,
  },
});


export const TransactionItem = memo(TransactionItemComponent);