import 'package:flutter/material.dart';
import 'package:sysfarma_mobile/src/core/theme/app_tokens.dart';

/// Loader estandar de la app — reemplazo directo de
/// `Center(child: CircularProgressIndicator())`. Entra con un fade suave en
/// vez de aparecer de golpe, y usa el color de marca en vez del color por
/// defecto del tema.
class AppLoader extends StatefulWidget {
  const AppLoader({super.key, this.size = 36});

  final double size;

  @override
  State<AppLoader> createState() => _AppLoaderState();
}

class _AppLoaderState extends State<AppLoader> {
  bool _visible = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      if (mounted) setState(() => _visible = true);
    });
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: AnimatedOpacity(
        opacity: _visible ? 1 : 0,
        duration: const Duration(milliseconds: 300),
        curve: Curves.easeOut,
        child: SizedBox(
          width: widget.size,
          height: widget.size,
          child: const CircularProgressIndicator(
            strokeWidth: 2.6,
            valueColor: AlwaysStoppedAnimation<Color>(AppTokens.primary),
          ),
        ),
      ),
    );
  }
}