import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:provider/provider.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart';
import '../../../core/theme/app_spacing.dart';
import '../../../providers/asset_provider.dart';
import '../../../data/models/account_models.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();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      context.read<AssetProvider>().refreshAll(force: true);
    });
  }

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

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

  /// 获取资金账户余额
  String get _fundBalance {
    final provider = context.read<AssetProvider>();
    return provider.fundAccount?.balance ?? provider.overview?.fundBalance ?? '0.00';
  }

  /// 获取交易账户 USDT 余额
  String get _tradeUsdtBalance {
    final provider = context.read<AssetProvider>();
    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 usdtHolding.quantity;
  }

  /// 获取当前可用余额（根据方向）
  String get _availableBalance => _direction == 1 ? _fundBalance : _tradeUsdtBalance;

  /// 从账户名
  String get _fromLabel => _direction == 1 ? '资金账户' : '交易账户';
  String get _toLabel => _direction == 1 ? '交易账户' : '资金账户';
  String get _fromBalance => _direction == 1 ? _fundBalance : _tradeUsdtBalance;
  String get _toBalance => _direction == 1 ? _tradeUsdtBalance : _fundBalance;

  // ============================================
  // 主题辅助
  // ============================================

  bool get _isDark => Theme.of(context).brightness == Brightness.dark;

  /// 一次性获取所有主题感知颜色
  _TransferColors get _colors => _TransferColors(_isDark);

  TextStyle _inter({
    required double fontSize,
    required FontWeight fontWeight,
    required Color color,
  }) {
    return GoogleFonts.inter(fontSize: fontSize, fontWeight: fontWeight, color: color);
  }

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

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

    if (transferAmount <= 0) {
      _showSnackBar('请输入有效的划转金额');
      return;
    }

    if (transferAmount > available) {
      _showSnackBar('余额不足');
      return;
    }

    setState(() => _isLoading = true);

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

      if (mounted) {
        if (response.success) {
          _amountController.clear();
          _showSnackBar('划转成功');
          Navigator.of(context).pop(true);
        } else {
          _showSnackBar(response.message ?? '划转失败');
        }
      }
    } finally {
      if (mounted) {
        setState(() => _isLoading = false);
      }
    }
  }

  void _showSnackBar(String message) {
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text(message)),
    );
  }

  /// 设置快捷百分比金额
  void _setQuickAmount(double percent) {
    final available = double.tryParse(_availableBalance) ?? 0;
    final amount = available * percent;
    _amountController.text = amount.toStringAsFixed(8).replaceAll(RegExp(r'\.?0+$'), '');
  }

  /// 切换方向
  void _toggleDirection() {
    setState(() {
      _direction = _direction == 1 ? 2 : 1;
    });
  }

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

  @override
  Widget build(BuildContext context) {
    final c = _colors;

    return Scaffold(
      backgroundColor: c.bgSecondary,
      appBar: AppBar(
        backgroundColor: c.surfaceCard,
        elevation: 0,
        scrolledUnderElevation: 0,
        leading: IconButton(
          icon: Icon(LucideIcons.arrowLeft, color: c.textPrimary, size: 20),
          onPressed: () => Navigator.of(context).pop(),
        ),
        title: Text(
          '账户划转',
          style: _inter(fontSize: 16, fontWeight: FontWeight.w600, color: c.textPrimary),
        ),
        centerTitle: true,
      ),
      body: Consumer<AssetProvider>(
        builder: (context, provider, _) {
          return SingleChildScrollView(
            padding: const EdgeInsets.fromLTRB(16, 16, 16, 32),
            child: Column(
              children: [
                _buildTransferDirectionCard(c),
                const SizedBox(height: 24),
                _buildAmountSection(c),
                const SizedBox(height: 24),
                _buildTipsCard(c),
                const SizedBox(height: 24),
                _buildConfirmButton(c),
              ],
            ),
          );
        },
      ),
    );
  }

  // ============================================
  // Transfer direction card
  // ============================================

  Widget _buildTransferDirectionCard(_TransferColors c) {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.all(20),
      decoration: BoxDecoration(
        color: c.surfaceCard,
        borderRadius: BorderRadius.circular(AppRadius.xl),
        border: Border.all(color: c.borderDefault.withValues(alpha: 0.6)),
      ),
      child: Column(
        children: [
          // Source account
          _animatedSwitcher(
            key: 'src-$_direction',
            beginOffset: const Offset(0, -1),
            child: _buildAccountRow(
              label: '从',
              accountName: _fromLabel,
              balance: _fromBalance,
              c: c,
            ),
          ),

          // Swap button
          GestureDetector(
            onTap: _toggleDirection,
            child: Container(
              width: 36,
              height: 36,
              margin: const EdgeInsets.symmetric(vertical: 16),
              decoration: BoxDecoration(
                color: c.accentPrimary,
                shape: BoxShape.circle,
              ),
              child: Center(
                child: Icon(LucideIcons.arrowUpDown, size: 18, color: c.textInverse),
              ),
            ),
          ),

          // Destination account
          _animatedSwitcher(
            key: 'dst-$_direction',
            beginOffset: const Offset(0, 1),
            child: _buildAccountRow(
              label: '到',
              accountName: _toLabel,
              balance: _toBalance,
              c: c,
            ),
          ),
        ],
      ),
    );
  }

  /// 统一的 AnimatedSwitcher 构造
  Widget _animatedSwitcher({
    required String key,
    required Offset beginOffset,
    required Widget child,
  }) {
    return AnimatedSwitcher(
      duration: const Duration(milliseconds: 300),
      switchInCurve: Curves.easeInOut,
      switchOutCurve: Curves.easeInOut,
      transitionBuilder: (widget, animation) {
        return SlideTransition(
          position: Tween<Offset>(begin: beginOffset, end: Offset.zero).animate(animation),
          child: FadeTransition(opacity: animation, child: widget),
        );
      },
      child: KeyedSubtree(key: ValueKey(key), child: child),
    );
  }

  /// Single account row inside the direction card
  Widget _buildAccountRow({
    required String label,
    required String accountName,
    required String balance,
    required _TransferColors c,
  }) {
    return SizedBox(
      width: double.infinity,
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(label, style: _inter(fontSize: 11, fontWeight: FontWeight.normal, color: c.textMuted)),
          const SizedBox(height: 8),
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Row(
                children: [
                  Icon(
                    label == '从' ? LucideIcons.wallet : LucideIcons.repeat,
                    size: 18,
                    color: c.textSecondary,
                  ),
                  const SizedBox(width: 10),
                  Text(accountName, style: _inter(fontSize: 14, fontWeight: FontWeight.w600, color: c.textPrimary)),
                ],
              ),
              Text(
                '\u00A5 ${_formatBalance(balance)}',
                style: _inter(fontSize: 14, fontWeight: FontWeight.w600, color: c.textPrimary),
              ),
            ],
          ),
        ],
      ),
    );
  }

  // ============================================
  // Amount input section
  // ============================================

  Widget _buildAmountSection(_TransferColors c) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        // Label row: "划转金额" + "全部划转"
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Text('划转金额', style: _inter(fontSize: 14, fontWeight: FontWeight.w500, color: c.textSecondary)),
            GestureDetector(
              onTap: () => _setQuickAmount(1.0),
              child: Text('全部划转', style: _inter(fontSize: 12, fontWeight: FontWeight.w600, color: c.goldAccent)),
            ),
          ],
        ),
        const SizedBox(height: 12),

        // Amount input field
        GestureDetector(
          onTap: () => _focusNode.requestFocus(),
          child: Container(
            width: double.infinity,
            height: 56,
            padding: const EdgeInsets.symmetric(horizontal: 16),
            decoration: BoxDecoration(
              color: c.bgTertiary,
              borderRadius: BorderRadius.circular(AppRadius.lg),
            ),
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              children: [
                Expanded(
                  child: TextField(
                    controller: _amountController,
                    focusNode: _focusNode,
                    keyboardType: const TextInputType.numberWithOptions(decimal: true),
                    inputFormatters: [
                      FilteringTextInputFormatter.allow(RegExp(r'^\d*\.?\d{0,8}')),
                    ],
                    style: _inter(fontSize: 28, fontWeight: FontWeight.w700, color: c.textPrimary),
                    decoration: InputDecoration(
                      hintText: '0.00',
                      hintStyle: _inter(fontSize: 28, fontWeight: FontWeight.w700, color: c.textMuted),
                      border: InputBorder.none,
                      contentPadding: EdgeInsets.zero,
                      isDense: true,
                    ),
                  ),
                ),
                Padding(
                  padding: const EdgeInsets.only(left: 8),
                  child: Text('USDT', style: _inter(fontSize: 14, fontWeight: FontWeight.normal, color: c.textMuted)),
                ),
              ],
            ),
          ),
        ),
        const SizedBox(height: 12),

        // Percent buttons
        Row(
          children: [0.25, 0.50, 0.75, 1.0].asMap().entries.map((entry) {
            final index = entry.key;
            final percent = entry.value;
            final label = '${(percent * 100).toInt()}%';
            return Padding(
              padding: EdgeInsets.only(left: index > 0 ? 8 : 0),
              child: _buildPercentButton(label, percent, c),
            );
          }).toList(),
        ),
      ],
    );
  }

  Widget _buildPercentButton(String label, double percent, _TransferColors c) {
    return Expanded(
      child: GestureDetector(
        onTap: () => _setQuickAmount(percent),
        child: Container(
          height: 36,
          decoration: BoxDecoration(
            color: c.bgTertiary,
            borderRadius: BorderRadius.circular(AppRadius.sm),
          ),
          child: Center(
            child: Text(label, style: _inter(fontSize: 13, fontWeight: FontWeight.w500, color: c.textSecondary)),
          ),
        ),
      ),
    );
  }

  // ============================================
  // Tips card & Confirm button
  // ============================================

  Widget _buildTipsCard(_TransferColors c) {
    return Container(
      width: double.infinity,
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
      decoration: BoxDecoration(
        color: c.profitGreenBg,
        borderRadius: BorderRadius.circular(AppRadius.lg),
      ),
      child: Row(
        children: [
          Icon(LucideIcons.info, size: 16, color: c.profitGreen),
          const SizedBox(width: 8),
          Expanded(
            child: Text(
              '划转即时到账，无需手续费',
              style: _inter(fontSize: 12, fontWeight: FontWeight.normal, color: c.profitGreen),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildConfirmButton(_TransferColors c) {
    return SizedBox(
      width: double.infinity,
      height: 52,
      child: GestureDetector(
        onTap: _isLoading ? null : _doTransfer,
        child: Container(
          decoration: BoxDecoration(
            color: c.accentPrimary,
            borderRadius: BorderRadius.circular(AppRadius.lg),
          ),
          child: Center(
            child: _isLoading
                ? SizedBox(
                    width: 20,
                    height: 20,
                    child: CircularProgressIndicator(
                      strokeWidth: 2,
                      valueColor: AlwaysStoppedAnimation<Color>(c.textInverse),
                    ),
                  )
                : Text(
                    '确认划转',
                    style: _inter(fontSize: 16, fontWeight: FontWeight.w700, color: c.textInverse),
                  ),
          ),
        ),
      ),
    );
  }

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

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

/// 主题感知颜色集合，避免在 build() 中重复定义大量局部变量
class _TransferColors {
  final Color bgSecondary;
  final Color surfaceCard;
  final Color bgTertiary;
  final Color borderDefault;
  final Color textPrimary;
  final Color textSecondary;
  final Color textMuted;
  final Color textInverse;
  final Color accentPrimary;
  final Color goldAccent;
  final Color profitGreen;
  final Color profitGreenBg;

  _TransferColors(bool isDark)
      : bgSecondary = isDark ? const Color(0xFF0B1120) : const Color(0xFFF8FAFC),
        surfaceCard = isDark ? const Color(0xFF0F172A) : const Color(0xFFFFFFFF),
        bgTertiary = isDark ? const Color(0xFF1E293B) : const Color(0xFFF1F5F9),
        borderDefault = isDark ? const Color(0xFF334155) : const Color(0xFFE2E8F0),
        textPrimary = isDark ? const Color(0xFFF8FAFC) : const Color(0xFF0F172A),
        textSecondary = isDark ? const Color(0xFF94A3B8) : const Color(0xFF475569),
        textMuted = isDark ? const Color(0xFF64748B) : const Color(0xFF94A3B8),
        textInverse = isDark ? const Color(0xFF0F172A) : const Color(0xFFFFFFFF),
        accentPrimary = isDark ? const Color(0xFFD4AF37) : const Color(0xFF1F2937),
        goldAccent = isDark ? const Color(0xFFD4AF37) : const Color(0xFFF59E0B),
        profitGreen = isDark ? const Color(0xFF4ADE80) : const Color(0xFF16A34A),
        profitGreenBg = isDark ? const Color(0xFF052E16) : const Color(0xFFF0FDF4);
}