/**
 * 통화 금액 입력 필드
 * 천단위 콤마 포맷, 통화 기호 prefix 지원
 *
 * properties: { currency, precision, showSymbol, allowNegative }
 * 저장값: number (포맷 없이)
 */

'use client';

import { useState, useCallback } from 'react';
import { Input } from '@/components/ui/input';
import { Label } from '@/components/ui/label';
import type { DynamicFieldRendererProps, CurrencyConfig } from '../types';

const CURRENCY_SYMBOLS: Record<string, string> = {
  KRW: '\u20A9',
  USD: '$',
  EUR: '\u20AC',
  JPY: '\u00A5',
  CNY: '\u00A5',
  GBP: '\u00A3',
};

function formatCurrency(num: number, precision: number): string {
  const fixed = num.toFixed(precision);
  const [intPart, decPart] = fixed.split('.');
  const formatted = intPart.replace(/\B(?=(\d{3})+(?!\d))/g, ',');
  return decPart !== undefined ? `${formatted}.${decPart}` : formatted;
}

function parseCurrency(str: string): number {
  const cleaned = str.replace(/[^0-9.\-]/g, '');
  const num = parseFloat(cleaned);
  return isNaN(num) ? 0 : num;
}

export function CurrencyField({
  field,
  value,
  onChange,
  error,
  disabled,
}: DynamicFieldRendererProps) {
  const fieldKey = field.field_key || `field_${field.id}`;
  const config = (field.properties || {}) as CurrencyConfig;
  const currency = config.currency || 'KRW';
  const precision = config.precision ?? 0;
  const showSymbol = config.showSymbol !== false;
  const allowNegative = config.allowNegative === true;

  const symbol = CURRENCY_SYMBOLS[currency] || currency;

  const numericValue = value !== null && value !== undefined ? Number(value) : null;

  const [isFocused, setIsFocused] = useState(false);
  const [inputValue, setInputValue] = useState(
    numericValue !== null ? String(numericValue) : ''
  );

  const handleFocus = useCallback(() => {
    setIsFocused(true);
    setInputValue(numericValue !== null ? String(numericValue) : '');
  }, [numericValue]);

  const handleBlur = useCallback(() => {
    setIsFocused(false);
    if (inputValue === '' || inputValue === '-') {
      onChange(null);
      return;
    }
    const parsed = parseCurrency(inputValue);
    const final = allowNegative ? parsed : Math.abs(parsed);
    onChange(final);
  }, [inputValue, onChange, allowNegative]);

  const handleChange = useCallback((e: React.ChangeEvent<HTMLInputElement>) => {
    const raw = e.target.value;
    // 숫자, 점, 마이너스만 허용
    const pattern = allowNegative ? /[^0-9.\-]/g : /[^0-9.]/g;
    const cleaned = raw.replace(pattern, '');
    setInputValue(cleaned);
  }, [allowNegative]);

  const displayValue = isFocused
    ? inputValue
    : numericValue !== null
      ? formatCurrency(numericValue, precision)
      : '';

  return (
    <div>
      <Label htmlFor={fieldKey}>
        {field.field_name}
        {field.is_required && <span className="text-red-500"> *</span>}
      </Label>
      <div className="relative">
        {showSymbol && (
          <span className="absolute left-3 top-1/2 -translate-y-1/2 text-sm text-muted-foreground pointer-events-none">
            {symbol}
          </span>
        )}
        <Input
          id={fieldKey}
          type="text"
          inputMode="decimal"
          placeholder={field.placeholder || '0'}
          value={displayValue}
          onChange={handleChange}
          onFocus={handleFocus}
          onBlur={handleBlur}
          disabled={disabled}
          className={`${showSymbol ? 'pl-8' : ''} text-right ${error ? 'border-red-500' : ''}`}
        />
      </div>
      {error && (
        <p className="text-xs text-red-500 mt-1">{error}</p>
      )}
      {!error && field.description && (
        <p className="text-xs text-muted-foreground mt-1">
          * {field.description}
        </p>
      )}
    </div>
  );
}