import 'package:flutter/material.dart';
import 'package:shadcn_ui/shadcn_ui.dart';
import '../../../core/theme/app_color_scheme.dart';
import '../../../core/theme/app_spacing.dart';
import '../../../core/theme/app_theme.dart';
import '../../../core/theme/app_theme_extension.dart';
import '../../../core/storage/local_storage.dart';

/// 引導頁數據模型
class _OnboardingItem {
  final String title;
  final String description;
  final IconData? icon;          // 圖標（二選一）
  final String? imagePath;       // 圖片路徑（二選一）
  final List<Color> gradientColors;

  const _OnboardingItem({
    required this.title,
    required this.description,
    this.icon,
    this.imagePath,
    required this.gradientColors,
  });
}

/// 首次啟動引導頁
class OnboardingPage extends StatefulWidget {
  final VoidCallback onComplete;

  const OnboardingPage({super.key, required this.onComplete});

  @override
  State<OnboardingPage> createState() => _OnboardingPageState();
}

class _OnboardingPageState extends State<OnboardingPage> {
  final PageController _pageController = PageController();
  int _currentPage = 0;

  final _items = const [
    _OnboardingItem(
      title: '實時行情',
      description: '全球市場行情實時更新，把握每一個投資機會',
      imagePath: 'assets/images/onboarding_1.png',  // 替換為你的圖片
      gradientColors: [AppColorScheme.darkPrimary, AppColorScheme.darkPrimaryContainer],
    ),
    _OnboardingItem(
      title: '模擬交易',
      description: '零風險體驗真實交易，學習投資策略',
      imagePath: 'assets/images/onboarding_2.png',  // 替換為你的圖片
      gradientColors: [AppColorScheme.darkTertiary, AppColorScheme.darkTertiaryContainer],
    ),
    _OnboardingItem(
      title: '資產管理',
      description: '清晰的資產概覽，輕鬆管理你的投資組合',
      imagePath: 'assets/images/onboarding_3.png',  // 替換為你的圖片
      gradientColors: [AppColorScheme.darkSecondary, AppColorScheme.darkSecondaryFixed],
    ),
    _OnboardingItem(
      title: '安全可靠',
      description: '數據加密存儲，保護你的隱私安全',
      imagePath: 'assets/images/onboarding_4.png',  // 替換為你的圖片
      gradientColors: [AppColorScheme.darkPrimaryFixed, AppColorScheme.darkPrimaryFixedDim],
    ),
  ];

  @override
  void dispose() {
    _pageController.dispose();
    super.dispose();
  }

  void _nextPage() {
    if (_currentPage < _items.length - 1) {
      _pageController.nextPage(
        duration: const Duration(milliseconds: 400),
        curve: Curves.easeInOut,
      );
    } else {
      _completeOnboarding();
    }
  }

  void _skip() {
    _completeOnboarding();
  }

  Future<void> _completeOnboarding() async {
    await LocalStorage.setBool('onboarding_completed', true);
    widget.onComplete();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: context.colors.surface,
      body: SafeArea(
        child: Column(
          children: [
            // 頂部跳過按鈕
            Padding(
              padding: const EdgeInsets.symmetric(
                horizontal: AppSpacing.lg,
                vertical: AppSpacing.md,
              ),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.end,
                children: [
                  TextButton(
                    onPressed: _skip,
                    child: Text(
                      '跳過',
                      style: AppTextStyles.headlineMedium(context).copyWith(
                        color: context.colors.onSurfaceVariant,
                      ),
                    ),
                  ),
                ],
              ),
            ),
            // 頁面內容
            Expanded(
              child: PageView.builder(
                controller: _pageController,
                onPageChanged: (index) {
                  setState(() {
                    _currentPage = index;
                  });
                },
                itemCount: _items.length,
                itemBuilder: (context, index) {
                  return _buildPage(_items[index]);
                },
              ),
            ),
            // 底部指示器和按鈕
            Padding(
              padding: const EdgeInsets.fromLTRB(
                AppSpacing.lg,
                AppSpacing.md,
                AppSpacing.lg,
                AppSpacing.xl,
              ),
              child: Column(
                children: [
                  // 頁面指示器
                  Row(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: List.generate(
                      _items.length,
                      (index) => _buildIndicator(index),
                    ),
                  ),
                  const SizedBox(height: AppSpacing.xl),
                  // 下一步/開始按鈕
                  SizedBox(
                    width: double.infinity,
                    height: 56,
                    child: ElevatedButton(
                      onPressed: _nextPage,
                      style: ElevatedButton.styleFrom(
                        backgroundColor: context.colors.primary,
                        foregroundColor: context.colors.onPrimary,
                        shape: RoundedRectangleBorder(
                          borderRadius: BorderRadius.circular(AppRadius.lg),
                        ),
                        elevation: 0,
                      ),
                      child: Text(
                        _currentPage == _items.length - 1 ? '開始使用' : '下一步',
                        style: AppTextStyles.headlineLarge(context).copyWith(
                          fontWeight: FontWeight.w600,
                        ),
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildPage(_OnboardingItem item) {
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: AppSpacing.xl),
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          // 圖標/圖片容器
          Container(
            width: 200,
            height: 200,
            decoration: BoxDecoration(
              gradient: LinearGradient(
                begin: Alignment.topLeft,
                end: Alignment.bottomRight,
                colors: item.gradientColors,
              ),
              shape: BoxShape.circle,
              boxShadow: [
                BoxShadow(
                  color: item.gradientColors.first.withValues(alpha: 0.4),
                  blurRadius: 40,
                  offset: const Offset(0, 20),
                ),
              ],
            ),
            child: Center(
              child: item.imagePath != null
                  ? ClipOval(
                      child: Image.asset(
                        item.imagePath!,
                        width: 180,
                        height: 180,
                        fit: BoxFit.cover,
                        errorBuilder: (context, error, stackTrace) {
                          // 圖片加載失敗時顯示圖標
                          return Icon(
                            item.icon ?? LucideIcons.image,
                            size: 72,
                            color: context.colors.onPrimary,
                          );
                        },
                      ),
                    )
                  : Icon(
                      item.icon ?? LucideIcons.star,
                      size: 72,
                      color: context.colors.onPrimary,
                    ),
            ),
          ),
          const SizedBox(height: AppSpacing.xxl + AppSpacing.lg),
          // 標題
          Text(
            item.title,
            style: AppTextStyles.displaySmall(context).copyWith(
              fontWeight: FontWeight.bold,
              color: context.colors.onSurface,
              letterSpacing: -0.5,
            ),
          ),
          const SizedBox(height: AppSpacing.md),
          // 描述
          Text(
            item.description,
            textAlign: TextAlign.center,
            style: AppTextStyles.headlineMedium(context).copyWith(
              color: context.colors.onSurfaceVariant,
              height: 1.6,
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildIndicator(int index) {
    final isActive = index == _currentPage;

    return AnimatedContainer(
      duration: const Duration(milliseconds: 300),
      margin: const EdgeInsets.symmetric(horizontal: AppSpacing.xs),
      width: isActive ? 24 : 8,
      height: 8,
      decoration: BoxDecoration(
        color: isActive ? context.colors.primary : context.colors.outlineVariant,
        borderRadius: BorderRadius.circular(AppRadius.sm),
      ),
    );
  }
}