import 'package:flutter/material.dart';
import 'package:shadcn_ui/shadcn_ui.dart';
import 'package:provider/provider.dart';
import '../../../data/models/coin.dart';
import '../../../providers/market_provider.dart';
import '../../../providers/asset_provider.dart';

/// 交易页面 - 使用 shadcn_ui 现代化设计
class TradePage extends StatefulWidget {
  const TradePage({super.key});

  @override
  State<TradePage> createState() => _TradePageState();
}

class _TradePageState extends State<TradePage> with AutomaticKeepAliveClientMixin {
  @override
  bool get wantKeepAlive => true;

  int _tradeType = 0; // 0=买入, 1=卖出
  Coin? _selectedCoin;
  final _formKey = GlobalKey<ShadFormState>();
  final _priceController = TextEditingController();
  final _quantityController = TextEditingController();

  // 颜色常量
  static const upColor = Color(0xFF00C853);
  static const downColor = Color(0xFFFF5252);

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _loadData();
    });
  }

  void _loadData() {
    context.read<MarketProvider>().loadCoins();
    context.read<AssetProvider>().loadOverview();
  }

  @override
  void dispose() {
    _priceController.dispose();
    _quantityController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    super.build(context);
    final theme = ShadTheme.of(context);

    return Scaffold(
      backgroundColor: theme.colorScheme.background,
      body: Consumer2<MarketProvider, AssetProvider>(
        builder: (context, market, asset, _) {
          return SingleChildScrollView(
            padding: const EdgeInsets.all(16),
            child: ShadForm(
              key: _formKey,
              child: Column(
                children: [
                  _buildCoinSelector(market),
                  const SizedBox(height: 16),
                  _buildPriceCard(),
                  const SizedBox(height: 16),
                  _buildTradeForm(asset),
                  const SizedBox(height: 16),
                  _buildTradeButton(),
                ],
              ),
            ),
          );
        },
      ),
    );
  }

  Widget _buildCoinSelector(MarketProvider market) {
    final theme = ShadTheme.of(context);
    final coins = market.allCoins;

    if (_selectedCoin == null && coins.isNotEmpty) {
      _selectedCoin = coins.first;
      _priceController.text = _selectedCoin!.formattedPrice;
    }

    return ShadCard(
      padding: const EdgeInsets.all(16),
      child: Row(
        children: [
          CircleAvatar(
            radius: 22,
            backgroundColor: theme.colorScheme.primary.withValues(alpha: 0.1),
            child: Text(
              _selectedCoin?.displayIcon ?? '?',
              style: TextStyle(
                fontSize: 20,
                color: theme.colorScheme.primary,
              ),
            ),
          ),
          const SizedBox(width: 12),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  _selectedCoin != null ? '${_selectedCoin!.code}/USDT' : '选择币种',
                  style: theme.textTheme.large.copyWith(
                    fontWeight: FontWeight.bold,
                  ),
                ),
                const SizedBox(height: 4),
                Text(
                  _selectedCoin != null ? _selectedCoin!.name : '点击选择交易对',
                  style: theme.textTheme.muted,
                ),
              ],
            ),
          ),
          Icon(
            LucideIcons.chevronRight,
            color: theme.colorScheme.mutedForeground,
          ),
        ],
      ),
    );
  }

  Widget _buildPriceCard() {
    final theme = ShadTheme.of(context);

    if (_selectedCoin == null) {
      return const SizedBox.shrink();
    }

    final coin = _selectedCoin!;

    return ShadCard(
      padding: const EdgeInsets.all(16),
      child: Row(
        mainAxisAlignment: MainAxisAlignment.spaceBetween,
        children: [
          Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                '最新价',
                style: theme.textTheme.muted,
              ),
              const SizedBox(height: 4),
              Text(
                '\$${coin.formattedPrice}',
                style: theme.textTheme.h2.copyWith(
                  fontWeight: FontWeight.bold,
                ),
              ),
            ],
          ),
          Container(
            padding: const EdgeInsets.symmetric(horizontal: 12, vertical: 6),
            decoration: BoxDecoration(
              color: coin.isUp ? upColor.withValues(alpha: 0.2) : downColor.withValues(alpha: 0.2),
              borderRadius: BorderRadius.circular(8),
            ),
            child: Text(
              coin.formattedChange,
              style: TextStyle(
                fontSize: 16,
                color: coin.isUp ? upColor : downColor,
                fontWeight: FontWeight.w600,
              ),
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildTradeForm(AssetProvider asset) {
    final theme = ShadTheme.of(context);

    return ShadCard(
      padding: const EdgeInsets.all(16),
      child: Column(
        children: [
          // 买入/卖出切换
          Row(
            children: [
              Expanded(
                child: GestureDetector(
                  onTap: () => setState(() => _tradeType = 0),
                  child: Container(
                    padding: const EdgeInsets.symmetric(vertical: 12),
                    decoration: BoxDecoration(
                      color: _tradeType == 0 ? upColor : Colors.transparent,
                      borderRadius: BorderRadius.circular(8),
                      border: _tradeType != 0 ? Border.all(color: upColor) : null,
                    ),
                    child: Center(
                      child: Text(
                        '买入',
                        style: TextStyle(
                          color: _tradeType == 0 ? Colors.white : upColor,
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                    ),
                  ),
                ),
              ),
              const SizedBox(width: 16),
              Expanded(
                child: GestureDetector(
                  onTap: () => setState(() => _tradeType = 1),
                  child: Container(
                    padding: const EdgeInsets.symmetric(vertical: 12),
                    decoration: BoxDecoration(
                      color: _tradeType == 1 ? downColor : Colors.transparent,
                      borderRadius: BorderRadius.circular(8),
                      border: _tradeType != 1 ? Border.all(color: downColor) : null,
                    ),
                    child: Center(
                      child: Text(
                        '卖出',
                        style: TextStyle(
                          color: _tradeType == 1 ? Colors.white : downColor,
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                    ),
                  ),
                ),
              ),
            ],
          ),
          const SizedBox(height: 20),
          // 价格输入
          ShadInputFormField(
            id: 'price',
            label: const Text('价格(USDT)'),
            controller: _priceController,
            keyboardType: const TextInputType.numberWithOptions(decimal: true),
            placeholder: const Text('输入价格'),
            trailing: const Padding(
              padding: EdgeInsets.only(right: 8),
              child: Text('USDT'),
            ),
            validator: (value) {
              if (value == null || value.isEmpty) {
                return '请输入价格';
              }
              final price = double.tryParse(value);
              if (price == null || price <= 0) {
                return '请输入有效价格';
              }
              return null;
            },
          ),
          const SizedBox(height: 12),
          // 数量输入
          ShadInputFormField(
            id: 'quantity',
            label: const Text('数量'),
            controller: _quantityController,
            keyboardType: const TextInputType.numberWithOptions(decimal: true),
            placeholder: const Text('输入数量'),
            trailing: Padding(
              padding: const EdgeInsets.only(right: 8),
              child: Text(_selectedCoin?.code ?? ''),
            ),
            validator: (value) {
              if (value == null || value.isEmpty) {
                return '请输入数量';
              }
              final quantity = double.tryParse(value);
              if (quantity == null || quantity <= 0) {
                return '请输入有效数量';
              }
              return null;
            },
          ),
          const SizedBox(height: 16),
          // 交易金额
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Text(
                '交易金额',
                style: theme.textTheme.muted,
              ),
              Text(
                '${_calculateAmount()} USDT',
                style: theme.textTheme.small.copyWith(
                  fontWeight: FontWeight.w600,
                ),
              ),
            ],
          ),
          const SizedBox(height: 8),
          // 可用余额
          Row(
            mainAxisAlignment: MainAxisAlignment.spaceBetween,
            children: [
              Text(
                '可用',
                style: theme.textTheme.muted,
              ),
              Text(
                '${asset.overview?.tradeBalance ?? '0.00'} USDT',
                style: theme.textTheme.muted,
              ),
            ],
          ),
        ],
      ),
    );
  }

  String _calculateAmount() {
    final price = double.tryParse(_priceController.text) ?? 0;
    final quantity = double.tryParse(_quantityController.text) ?? 0;
    return (price * quantity).toStringAsFixed(2);
  }

  Widget _buildTradeButton() {
    final isBuy = _tradeType == 0;
    final color = isBuy ? upColor : downColor;

    return SizedBox(
      width: double.infinity,
      height: 48,
      child: ShadButton(
        backgroundColor: color,
        onPressed: () {
          if (_formKey.currentState!.saveAndValidate()) {
            _executeTrade();
          }
        },
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            Icon(
              isBuy ? LucideIcons.arrowDownToLine : LucideIcons.arrowUpFromLine,
              size: 18,
              color: Colors.white,
            ),
            const SizedBox(width: 8),
            Text(
              '${isBuy ? '买入' : '卖出'} ${_selectedCoin?.code ?? ''}',
              style: const TextStyle(
                color: Colors.white,
                fontSize: 16,
                fontWeight: FontWeight.w600,
              ),
            ),
          ],
        ),
      ),
    );
  }

  void _executeTrade() {
    final price = _priceController.text;
    final quantity = _quantityController.text;

    showShadDialog(
      context: context,
      builder: (context) => ShadDialog.alert(
        title: Text(_tradeType == 0 ? '确认买入' : '确认卖出'),
        description: Text(
          '${_tradeType == 0 ? '买入' : '卖出'} $quantity ${_selectedCoin?.code ?? ''} @ $price USDT',
        ),
        actions: [
          ShadButton.outline(
            child: const Text('取消'),
            onPressed: () => Navigator.of(context).pop(),
          ),
          ShadButton(
            child: const Text('确认'),
            onPressed: () {
              Navigator.of(context).pop();
              _showTradeResult();
            },
          ),
        ],
      ),
    );
  }

  void _showTradeResult() {
    final theme = ShadTheme.of(context);

    showShadDialog(
      context: context,
      builder: (context) => ShadDialog.alert(
        title: Row(
          children: [
            Icon(
              LucideIcons.circleCheck,
              color: theme.colorScheme.primary,
              size: 24,
            ),
            const SizedBox(width: 8),
            const Text('交易成功'),
          ],
        ),
        description: Text(
          '已${_tradeType == 0 ? '买入' : '卖出'} ${_quantityController.text} ${_selectedCoin?.code ?? ''}',
        ),
        actions: [
          ShadButton(
            child: const Text('确定'),
            onPressed: () {
              Navigator.of(context).pop();
              _quantityController.clear();
            },
          ),
        ],
      ),
    );
  }
}