import 'package:flutter/material.dart';
import 'package:fluwx/fluwx.dart';
import '../../../../app/theme/app_colors.dart';
import '../../../../app/theme/app_typography.dart';
import '../../../../app/theme/app_spacing.dart';
import '../../../../shared/widgets/genex_button.dart';
import '../../../../app/i18n/app_localizations.dart';
import '../../../../core/services/auth_service.dart';

/// A1. 欢迎页 - 品牌展示 + 注册/登录入口
///
/// 品牌Logo、Slogan、手机号注册、邮箱注册、社交登录入口（WeChat/Google/Apple）
class WelcomePage extends StatefulWidget {
  const WelcomePage({super.key});

  @override
  State<WelcomePage> createState() => _WelcomePageState();
}

class _WelcomePageState extends State<WelcomePage> {
  bool _wechatLoading = false;

  @override
  void initState() {
    super.initState();
    // 监听微信授权回调（用户授权后，微信 App 返回 code）
    weChatResponseEventHandler.distinct().listen((res) {
      if (res is WXAuthResp && mounted) {
        _handleWechatAuthResp(res);
      }
    });
  }

  Future<void> _onWechatTap() async {
    final installed = await isWeChatInstalled;
    if (!installed) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(context.t('welcome.wechatNotInstalled'))),
        );
      }
      return;
    }
    setState(() => _wechatLoading = true);
    // 发起微信授权，scope = snsapi_userinfo 可获取用户信息（昵称、头像）
    await sendWeChatAuth(scope: 'snsapi_userinfo', state: 'genex_login');
    // 授权结果通过 weChatResponseEventHandler 异步回调
  }

  Future<void> _handleWechatAuthResp(WXAuthResp resp) async {
    setState(() => _wechatLoading = false);
    if (resp.errCode != 0 || resp.code == null) {
      // 用户取消授权或授权失败，不做任何处理
      return;
    }
    try {
      await AuthService.instance.loginByWechat(code: resp.code!);
      if (mounted) {
        Navigator.pushReplacementNamed(context, '/main');
      }
    } catch (e) {
      if (mounted) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(content: Text(context.t('welcome.wechatLoginFailed'))),
        );
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 24),
          child: Column(
            children: [
              const Spacer(flex: 2),

              // Brand Logo
              ClipRRect(
                borderRadius: AppSpacing.borderRadiusXl,
                child: Image.asset(
                  'assets/images/logo_icon.png',
                  width: 80,
                  height: 80,
                ),
              ),
              const SizedBox(height: 12),

              // Brand Name — 遵循 lockup 设计: "GEN" 深色 + "EX" 渐变
              Row(
                mainAxisSize: MainAxisSize.min,
                children: [
                  Text(
                    'GEN',
                    style: AppTypography.displayLarge.copyWith(
                      color: const Color(0xFF1A103A),
                      fontWeight: FontWeight.w800,
                      letterSpacing: -0.3,
                    ),
                  ),
                  ShaderMask(
                    shaderCallback: (bounds) => const LinearGradient(
                      colors: [Color(0xFF9B8FFF), Color(0xFFB8ADFF)],
                    ).createShader(bounds),
                    child: Text(
                      'EX',
                      style: AppTypography.displayLarge.copyWith(
                        color: Colors.white,
                        fontWeight: FontWeight.w800,
                        letterSpacing: -0.3,
                      ),
                    ),
                  ),
                ],
              ),
              const SizedBox(height: 6),

              // Slogan
              Text(
                context.t('welcome.slogan'),
                style: AppTypography.bodyLarge.copyWith(
                  color: AppColors.textSecondary,
                ),
              ),

              const Spacer(flex: 3),

              // Phone Register
              GenexButton(
                label: context.t('welcome.phoneRegister'),
                icon: Icons.phone_android_rounded,
                onPressed: () {
                  Navigator.pushNamed(context, '/register');
                },
              ),
              const SizedBox(height: 12),

              // Email Register
              GenexButton(
                label: context.t('welcome.emailRegister'),
                icon: Icons.email_outlined,
                variant: GenexButtonVariant.outline,
                onPressed: () {
                  Navigator.pushNamed(context, '/register', arguments: {'isEmail': true});
                },
              ),
              const SizedBox(height: 24),

              // Social Login Divider
              Row(
                children: [
                  const Expanded(child: Divider(color: AppColors.border)),
                  Padding(
                    padding: const EdgeInsets.symmetric(horizontal: 16),
                    child: Text(context.t('welcome.otherLogin'), style: AppTypography.caption),
                  ),
                  const Expanded(child: Divider(color: AppColors.border)),
                ],
              ),
              const SizedBox(height: 16),

              // Social Login Buttons — WeChat + Google + Apple
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  _SocialLoginButton(
                    icon: Icons.wechat,
                    label: context.t('welcome.wechat'),
                    color: const Color(0xFF07C160),
                    loading: _wechatLoading,
                    onTap: _onWechatTap,
                  ),
                  const SizedBox(width: 24),
                  _SocialLoginButton(
                    icon: Icons.g_mobiledata_rounded,
                    label: 'Google',
                    onTap: () {
                      Navigator.pushReplacementNamed(context, '/main');
                    },
                  ),
                  const SizedBox(width: 24),
                  _SocialLoginButton(
                    icon: Icons.apple_rounded,
                    label: 'Apple',
                    onTap: () {
                      Navigator.pushReplacementNamed(context, '/main');
                    },
                  ),
                ],
              ),
              const SizedBox(height: 32),

              // Already have account
              Row(
                mainAxisAlignment: MainAxisAlignment.center,
                children: [
                  Text(context.t('welcome.hasAccount'), style: AppTypography.bodyMedium.copyWith(
                    color: AppColors.textSecondary,
                  )),
                  GestureDetector(
                    onTap: () {
                      Navigator.pushNamed(context, '/login');
                    },
                    child: Text(context.t('welcome.login'), style: AppTypography.labelMedium.copyWith(
                      color: AppColors.primary,
                    )),
                  ),
                ],
              ),
              const SizedBox(height: 16),

              // Terms
              Text(
                context.t('welcome.agreement'),
                style: AppTypography.caption.copyWith(fontSize: 10),
                textAlign: TextAlign.center,
              ),
              const SizedBox(height: 16),
            ],
          ),
        ),
      ),
    );
  }
}

class _SocialLoginButton extends StatelessWidget {
  final IconData icon;
  final String label;
  final Color? color;
  final VoidCallback onTap;
  final bool loading;

  const _SocialLoginButton({
    required this.icon,
    required this.label,
    required this.onTap,
    this.color,
    this.loading = false,
  });

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: loading ? null : onTap,
      child: Column(
        children: [
          Container(
            width: 52,
            height: 52,
            decoration: BoxDecoration(
              color: color != null ? color!.withValues(alpha: 0.1) : AppColors.gray50,
              shape: BoxShape.circle,
              border: Border.all(color: color?.withValues(alpha: 0.3) ?? AppColors.border),
            ),
            child: loading
                ? Padding(
                    padding: const EdgeInsets.all(14),
                    child: CircularProgressIndicator(
                      strokeWidth: 2,
                      color: color ?? AppColors.textPrimary,
                    ),
                  )
                : Icon(icon, size: 28, color: color ?? AppColors.textPrimary),
          ),
          const SizedBox(height: 6),
          Text(label, style: AppTypography.caption),
        ],
      ),
    );
  }
}