monisuo/flutter_monisuo/lib/ui/pages/trade/components/amount_input.dart

import 'package:flutter/material.dart';
import '../../../../core/theme/app_color_scheme.dart';
import '../../../../core/theme/app_spacing.dart';
import '../../../../core/theme/app_theme.dart';

/// 金額輸入框組件（含超額提示）
///
/// 設計稿：bg-tertiary，圓角md，高48。
/// 輸入金額超過可用 USDT 餘額時顯示警告提示。
class AmountInput extends StatefulWidget {
  final TextEditingController amountController;
  final String maxAmount;
  final bool isBuy;
  final Color actionColor;
  final VoidCallback onChanged;

  const AmountInput({
    super.key,
    required this.amountController,
    required this.maxAmount,
    required this.isBuy,
    required this.actionColor,
    required this.onChanged,
  });

  @override
  State<AmountInput> createState() => _AmountInputState();
}

class _AmountInputState extends State<AmountInput> {
  bool _isExceeded = false;

  void _checkLimit() {
    final input = double.tryParse(widget.amountController.text) ?? 0;
    final max = double.tryParse(widget.maxAmount) ?? 0;
    final exceeded = widget.isBuy && input > max && max > 0 && input > 0;
    if (exceeded != _isExceeded) {
      setState(() => _isExceeded = exceeded);
    }
    widget.onChanged();
  }

  @override
  void initState() {
    super.initState();
    widget.amountController.addListener(_checkLimit);
  }

  @override
  void dispose() {
    widget.amountController.removeListener(_checkLimit);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final colorScheme = Theme.of(context).colorScheme;
    final warningColor = AppColorScheme.warning;

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Container(
          height: 48,
          decoration: BoxDecoration(
            color: colorScheme.surfaceContainerHighest.withOpacity(0.5), // 調整透明度
            borderRadius: BorderRadius.circular(AppRadius.md),
          ),
          child: TextField(
            controller: widget.amountController,
            keyboardType: const TextInputType.numberWithOptions(decimal: true),
            onChanged: (_) => _checkLimit(),
            style: AppTextStyles.numberMedium(context).copyWith(
              fontWeight: FontWeight.w400,
            ),
            decoration: InputDecoration(
              hintText: '請輸入金額',
              hintStyle: AppTextStyles.numberMedium(context).copyWith(
                fontWeight: FontWeight.w400,
                color: colorScheme.onSurfaceVariant.withOpacity(0.5),
              ),
              border: InputBorder.none,
              contentPadding: const EdgeInsets.symmetric(
                horizontal: AppSpacing.md,
              ),
            ),
          ),
        ),
        if (_isExceeded)
          Padding(
            padding: EdgeInsets.only(top: AppSpacing.xs),
            child: Row(
              children: [
                Icon(Icons.error_outline, size: 13, color: warningColor),
                SizedBox(width: AppSpacing.xs),
                Text(
                  '超出可用USDT餘額',
                  style: AppTextStyles.bodySmall(context).copyWith(
                    color: warningColor,
                  ),
                ),
              ],
            ),
          ),
      ],
    );
  }
}