slogan/app/lib/shared/widgets/avatar_viewer.dart

import 'dart:async';

import 'package:flutter/material.dart';

import '../../core/config/app_config.dart';

/// 3D 化身查看组件
///
/// 服务端预渲染帧序列（36 帧绕 Y 轴旋转 PNG）轮播模拟 3D；
/// framesUrl 为空时降级为静态占位。
class AvatarViewer extends StatefulWidget {
  final String? glbUrl;
  final String? framesUrl;
  final String title;
  final String subtitle;
  final double height;

  const AvatarViewer({
    super.key,
    this.glbUrl,
    this.framesUrl,
    required this.title,
    required this.subtitle,
    this.height = 360,
  });

  @override
  State<AvatarViewer> createState() => _AvatarViewerState();
}

class _AvatarViewerState extends State<AvatarViewer> {
  static const int _frameCount = 36;

  Timer? _timer;
  int _frame = 0;

  @override
  void initState() {
    super.initState();
    if (widget.framesUrl != null && widget.framesUrl!.isNotEmpty) {
      _timer = Timer.periodic(const Duration(milliseconds: 120), (_) {
        setState(() => _frame = (_frame + 1) % _frameCount);
      });
    }
  }

  @override
  void dispose() {
    _timer?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final framesUrl = widget.framesUrl;
    if (framesUrl != null && framesUrl.isNotEmpty) {
      final frameUrl = AppConfig.resolveUrl(
          '$framesUrl/frame_${_frame.toString().padLeft(3, '0')}.png');
      final scheme = Theme.of(context).colorScheme;
      return Container(
        height: widget.height,
        width: double.infinity,
        clipBehavior: Clip.antiAlias,
        decoration: BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.topCenter,
            end: Alignment.bottomCenter,
            colors: [
              scheme.primaryContainer,
              scheme.primary.withValues(alpha: 0.3),
            ],
          ),
          borderRadius: BorderRadius.circular(16),
        ),
        child: Stack(
          alignment: Alignment.bottomCenter,
          children: [
            Positioned.fill(
              child: Image.network(
                frameUrl,
                fit: BoxFit.contain,
                errorBuilder: (_, _, _) => _placeholder(context),
              ),
            ),
            Padding(
              padding: const EdgeInsets.only(bottom: 10),
              child: Text(
                widget.subtitle,
                style: const TextStyle(
                    color: Colors.white, fontSize: 12, shadows: [
                  Shadow(color: Colors.black45, blurRadius: 4),
                ]),
              ),
            ),
          ],
        ),
      );
    }
    return _placeholder(context);
  }

  Widget _placeholder(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    return Container(
      height: widget.height,
      width: double.infinity,
      decoration: BoxDecoration(
        gradient: LinearGradient(
          begin: Alignment.topCenter,
          end: Alignment.bottomCenter,
          colors: [
            scheme.primaryContainer,
            scheme.primary.withValues(alpha: 0.3),
          ],
        ),
        borderRadius: BorderRadius.circular(16),
      ),
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Icon(Icons.accessibility_new, size: 72, color: scheme.primary),
          const SizedBox(height: 12),
          Text(widget.title,
              style: const TextStyle(
                  fontSize: 16, fontWeight: FontWeight.bold)),
          const SizedBox(height: 4),
          Padding(
            padding: const EdgeInsets.symmetric(horizontal: 24),
            child: Text(
              widget.subtitle.isEmpty ? '3D 渲染服务未就绪' : widget.subtitle,
              textAlign: TextAlign.center,
              style: const TextStyle(color: Colors.grey, fontSize: 12),
            ),
          ),
        ],
      ),
    );
  }
}