import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:provider/provider.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart';
import '../../../core/theme/app_theme.dart';
import '../../../core/theme/app_spacing.dart';
import '../../../providers/asset_provider.dart';
import '../../../data/models/account_models.dart';
import '../../components/material_input.dart';

/// 划转页面
class TransferPage extends StatefulWidget {
  const TransferPage({super.key});

  @override
  State<TransferPage> createState() => _TransferPageState();
}

class _TransferPageState extends State<TransferPage> {
  final _amountController = TextEditingController();
  final _focusNode = FocusNode();
  int _direction = 1; // 1: 资金→交易, 2: 交易→资金
  bool _isLoading = false;

  @override
  void initState() {
    super.initState();
    _amountController.addListener(() => setState(() {}));
    WidgetsBinding.instance.addPostFrameCallback((_) {
      context.read<AssetProvider>().refreshAll(force: true);
    });
  }

  @override
  void dispose() {
    _amountController.dispose();
    _focusNode.dispose();
    super.dispose();
  }

  // ============================================
  // 数据访问
  // ============================================

  String get _fundBalance {
    try {
      final provider = context.read<AssetProvider>();
      final balance = provider.fundAccount?.balance ??
          provider.overview?.fundBalance ??
          '0.00';
      return _formatBalance(balance);
    } catch (e) {
      return '0.00';
    }
  }

  String get _tradeUsdtBalance {
    try {
      final provider = context.read<AssetProvider>();
      if (provider.tradeAccounts.isEmpty) return '0.00';
      final usdtHolding = provider.tradeAccounts.firstWhere(
        (t) => t.coinCode.toUpperCase() == 'USDT',
        orElse: () => AccountTrade(
          id: 0,
          userId: 0,
          coinCode: 'USDT',
          quantity: '0',
          avgPrice: '1',
          totalCost: '0',
          currentValue: '0',
          profit: '0',
          profitRate: 0,
        ),
      );
      return _formatBalance(usdtHolding.quantity);
    } catch (e) {
      return '0.00';
    }
  }

  String get _availableBalance =>
      _direction == 1 ? _fundBalance : _tradeUsdtBalance;

  String get _fromLabel => _direction == 1 ? '資金賬戶' : '交易賬戶';
  String get _toLabel => _direction == 1 ? '交易賬戶' : '資金賬戶';
  String get _fromBalance => _direction == 1 ? _fundBalance : _tradeUsdtBalance;
  String get _toBalance => _direction == 1 ? _tradeUsdtBalance : _fundBalance;

  // ============================================
  // 业务逻辑
  // ============================================

  Future<void> _doTransfer() async {
    final amount = _amountController.text;
    final available = double.tryParse(_availableBalance) ?? 0;
    final transferAmount = double.tryParse(amount) ?? 0;

    if (transferAmount <= 0) {
      _showSnackBar('請輸入有效的劃轉金額');
      return;
    }

    if (transferAmount > available) {
      _showSnackBar('餘額不足');
      return;
    }

    setState(() => _isLoading = true);

    try {
      final response = await context.read<AssetProvider>().transfer(
            direction: _direction,
            amount: amount,
          );

      if (mounted) {
        if (response.success) {
          _amountController.clear();
          _showSnackBar('劃轉成功');
          await Future.delayed(const Duration(milliseconds: 500));
          if (mounted) Navigator.of(context).pop(true);
        } else {
          _showSnackBar(response.message ?? '劃轉失敗');
        }
      }
    } finally {
      if (mounted) setState(() => _isLoading = false);
    }
  }

  void _showSnackBar(String message) {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(
        content: Text(message),
        behavior: SnackBarBehavior.floating,
        shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(12)),
      ),
    );
  }

  void _setQuickAmount(double percent) {
    final available = double.tryParse(_availableBalance) ?? 0;
    final amount = available * percent;
    // 向下截斷到2位小數，避免四捨五入超出餘額
    _amountController.text =
        ((amount * 100).truncateToDouble() / 100).toStringAsFixed(2);

    // Trigger haptic feedback
    HapticFeedback.selectionClick();
  }

  void _toggleDirection() {
    HapticFeedback.mediumImpact();
    setState(() => _direction = _direction == 1 ? 2 : 1);
  }

  // ============================================
  // 构建 UI
  // ============================================

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

    return Scaffold(
      backgroundColor: colorScheme.surface,
      appBar: AppBar(
        backgroundColor: Colors.transparent,
        elevation: 0,
        scrolledUnderElevation: 0,
        leading: IconButton(
          icon: Icon(LucideIcons.arrowLeft,
              color: colorScheme.onSurface, size: 20),
          onPressed: () => Navigator.of(context).pop(),
        ),
        title: Text(
          '賬戶劃轉',
          style: AppTextStyles.headlineLarge(context).copyWith(
            fontWeight: FontWeight.w600,
          ),
        ),
        centerTitle: true,
      ),
      body: Consumer<AssetProvider>(
        builder: (context, provider, _) {
          return SingleChildScrollView(
            padding: const EdgeInsets.fromLTRB(
                AppSpacing.md, AppSpacing.xs, AppSpacing.md, AppSpacing.xl),
            child: Column(
              children: [
                _buildTransferCard(colorScheme),
                const SizedBox(height: AppSpacing.md),
                _buildAmountSection(colorScheme),
                const SizedBox(height: AppSpacing.md),
                _buildTips(colorScheme),
                const SizedBox(height: AppSpacing.xl),
                _buildConfirmButton(colorScheme),
                const SizedBox(height: AppSpacing.lg),
              ],
            ),
          );
        },
      ),
    );
  }

  // ============================================
  // 划转方向卡片
  // ============================================

  Widget _buildTransferCard(ColorScheme colorScheme) {
    return Container(
      width: double.infinity,
      decoration: BoxDecoration(
        color: colorScheme.surface,
        borderRadius: BorderRadius.circular(20),
        border: Border.all(
          color: colorScheme.outlineVariant.withValues(alpha: 0.5),
          width: 1,
        ),
      ),
      child: Stack(
        clipBehavior: Clip.none,
        children: [
          Column(
            children: [
              // From
              Padding(
                padding:
                    const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    Row(
                      children: [
                        Text(
                          '从',
                          style: AppTextStyles.bodySmall(context).copyWith(
                            color: colorScheme.onSurfaceVariant,
                          ),
                        ),
                        const SizedBox(width: 8),
                        Text(
                          _fromLabel,
                          style:
                              AppTextStyles.bodyLarge(context).copyWith(
                            fontWeight: FontWeight.w500,
                          ),
                        ),
                      ],
                    ),
                    Text(
                      _fromBalance,
                      style: AppTextStyles.bodyLarge(context).copyWith(
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                  ],
                ),
              ),
              Divider(
                height: 1,
                thickness: 1,
                color: colorScheme.outlineVariant.withValues(alpha: 0.5),
              ),
              // To
              Padding(
                padding:
                    const EdgeInsets.symmetric(horizontal: 16, vertical: 14),
                child: Row(
                  mainAxisAlignment: MainAxisAlignment.spaceBetween,
                  children: [
                    Row(
                      children: [
                        Text(
                          '到',
                          style: AppTextStyles.bodySmall(context).copyWith(
                            color: colorScheme.onSurfaceVariant,
                          ),
                        ),
                        const SizedBox(width: 8),
                        Text(
                          _toLabel,
                          style:
                              AppTextStyles.bodyLarge(context).copyWith(
                            fontWeight: FontWeight.w500,
                          ),
                        ),
                      ],
                    ),
                    Text(
                      _toBalance,
                      style: AppTextStyles.bodyLarge(context).copyWith(
                        fontWeight: FontWeight.w600,
                      ),
                    ),
                  ],
                ),
              ),
            ],
          ),
          // 交换按钮 - 右側居中分割線
          Positioned(
            right: 12,
            top: 20,
            bottom: 20,
            child: Center(
              child: GestureDetector(
                onTap: _toggleDirection,
                child: Container(
                  width: 28,
                  height: 28,
                  decoration: BoxDecoration(
                    color: colorScheme.surface,
                    shape: BoxShape.circle,
                    border: Border.all(
                      color: colorScheme.outlineVariant,
                      width: 1,
                    ),
                  ),
                  child: Icon(
                    LucideIcons.repeat2,
                    size: 13,
                    color: colorScheme.onSurfaceVariant,
                  ),
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }

  // ============================================
  // 金额输入区域
  // ============================================

  Widget _buildAmountSection(ColorScheme colorScheme) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        // 标题行
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Text(
              '劃轉金額',
              style: AppTextStyles.bodyMedium(context).copyWith(
                color: colorScheme.onSurfaceVariant,
                fontWeight: FontWeight.w500,
              ),
            ),
            GestureDetector(
              onTap: () => _setQuickAmount(1.0),
              child: Text(
                '全部',
                style: AppTextStyles.bodyMedium(context).copyWith(
                  color: colorScheme.secondary,
                  fontWeight: FontWeight.w500,
                ),
              ),
            ),
          ],
        ),
        const SizedBox(height: 12),

        // 金额输入框
        MaterialInput(
          controller: _amountController,
          focusNode: _focusNode,
          hintText: '0.00',
          keyboardType: const TextInputType.numberWithOptions(decimal: true),
          inputFormatters: [
            FilteringTextInputFormatter.allow(RegExp(r'^\d*\.?\d{0,8}')),
          ],
          onChanged: (_) => setState(() {}),
          suffixIcon: Padding(
            padding: const EdgeInsets.only(right: AppSpacing.md),
            child: Text(
              'USDT',
              style: AppTextStyles.bodyMedium(context).copyWith(
                color: colorScheme.onSurfaceVariant,
                fontWeight: FontWeight.w500,
              ),
            ),
          ),
        ),
        const SizedBox(height: 10),

        // 可用余额
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Text(
              '可用餘額',
              style: AppTextStyles.bodySmall(context).copyWith(
                color: colorScheme.onSurfaceVariant,
              ),
            ),
            Text(
              '$_availableBalance USDT',
              style: AppTextStyles.bodySmall(context).copyWith(
                color: colorScheme.onSurfaceVariant,
                fontWeight: FontWeight.w500,
              ),
            ),
          ],
        ),
        const SizedBox(height: 12),

        // 百分比按钮
        Row(
          children: [
            _buildPercentButton('25%', 0.25, colorScheme),
            const SizedBox(width: 8),
            _buildPercentButton('50%', 0.50, colorScheme),
            const SizedBox(width: 8),
            _buildPercentButton('75%', 0.75, colorScheme),
            const SizedBox(width: 8),
            _buildPercentButton('100%', 1.0, colorScheme),
          ],
        ),
      ],
    );
  }

  Widget _buildPercentButton(
      String label, double percent, ColorScheme colorScheme) {
    return Expanded(
      child: GestureDetector(
        onTap: () => _setQuickAmount(percent),
        child: Container(
          height: 34,
          decoration: BoxDecoration(
            color: colorScheme.surfaceContainerHighest.withValues(alpha: 0.5),
            borderRadius: BorderRadius.circular(8),
          ),
          child: Center(
            child: Text(
              label,
              style: AppTextStyles.bodySmall(context).copyWith(
                color: colorScheme.onSurfaceVariant,
                fontWeight: FontWeight.w500,
              ),
            ),
          ),
        ),
      ),
    );
  }

  // ============================================
  // 提示文字
  // ============================================

  Widget _buildTips(ColorScheme colorScheme) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 4),
      child: Row(
        children: [
          Icon(LucideIcons.info,
              size: 13, color: colorScheme.onSurfaceVariant),
          const SizedBox(width: 6),
          Text(
            '劃轉即時到賬，無需手續費',
            style: AppTextStyles.bodySmall(context).copyWith(
              color: colorScheme.onSurfaceVariant,
            ),
          ),
        ],
      ),
    );
  }

  // ============================================
  // 确认按钮
  // ============================================

  Widget _buildConfirmButton(ColorScheme colorScheme) {
    final hasAmount = _amountController.text.isNotEmpty &&
        double.tryParse(_amountController.text) != null &&
        double.parse(_amountController.text) > 0;

    return SizedBox(
      width: double.infinity,
      height: 48,
      child: ElevatedButton(
        onPressed: _isLoading ? null : _doTransfer,
        style: ElevatedButton.styleFrom(
          backgroundColor: hasAmount
              ? colorScheme.onSurface
              : colorScheme.surfaceContainerHighest,
          foregroundColor: hasAmount
              ? colorScheme.surface
              : colorScheme.onSurfaceVariant,
          disabledBackgroundColor: colorScheme.surfaceContainerHighest,
          disabledForegroundColor: colorScheme.onSurfaceVariant,
          elevation: 0,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(14),
          ),
        ),
        child: _isLoading
            ? SizedBox(
                width: 20,
                height: 20,
                child: CircularProgressIndicator(
                  strokeWidth: 2,
                  valueColor: AlwaysStoppedAnimation<Color>(
                    colorScheme.onSurfaceVariant,
                  ),
                ),
              )
            : Text(
                '確認劃轉',
                style: TextStyle(
                  fontSize: 15,
                  fontWeight: FontWeight.w600,
                ),
              ),
      ),
    );
  }

  // ============================================
  // Helpers
  // ============================================

  String _formatBalance(String balance) {
    final val = double.tryParse(balance);
    if (val == null) return '0.00';
    return val.toStringAsFixed(2);
  }
}