// widgets/ds/ds_toast.dart — 原型 .toast（atoms.css）1:1：
// fixed bottom:26 水平居中 / --toast-bg 底 + 白字 fs-body / pad 11 18 / r-md /
// **内容自适应宽**（不定宽、不贯穿）/ .25s 淡入+上滑 / 2.2s 自动消失。
// 单例复用：新消息顶替旧消息（对齐原型同一 #toast 节点 + 计时器重置），
// 天然避免多条提示叠罗汉。语义底色（成功/失败）由调用点传 [bg] 覆盖。
import 'dart:async';

import 'package:flutter/material.dart';

import '../../core/theme/app_dims.g.dart';
import '../../core/theme/context_tokens.dart';

OverlayEntry? _entry;
Timer? _timer;

void showDsToast(
  BuildContext context,
  String message, {
  Color? bg,
  Duration duration = const Duration(milliseconds: 2200),
}) {
  final overlay = Overlay.maybeOf(context, rootOverlay: true);
  if (overlay == null) return;
  final color = bg ?? context.tokens.toastBg;

  _timer?.cancel();
  if (_entry?.mounted ?? false) _entry!.remove();
  _entry = null;
  final entry = OverlayEntry(
    builder: (_) => _DsToast(message: message, bg: color),
  );
  _entry = entry;
  overlay.insert(entry);
  _timer = Timer(duration, () {
    if (_entry == entry) {
      if (entry.mounted) entry.remove();
      _entry = null;
    }
  });
}

class _DsToast extends StatelessWidget {
  final String message;
  final Color bg;
  const _DsToast({required this.message, required this.bg});

  @override
  Widget build(BuildContext context) {
    return Positioned(
      left: 0,
      right: 0,
      bottom: 26,
      child: IgnorePointer(
        child: Row(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            TweenAnimationBuilder<double>(
              tween: Tween(begin: 0, end: 1),
              duration: const Duration(milliseconds: 250),
              curve: Curves.easeOut,
              builder: (_, v, child) => Opacity(
                opacity: v,
                child: Transform.translate(
                    offset: Offset(0, 20 * (1 - v)), child: child),
              ),
              child: Material(
                color: Colors.transparent,
                child: Container(
                  constraints: const BoxConstraints(maxWidth: 560),
                  padding:
                      const EdgeInsets.symmetric(horizontal: 18, vertical: 11),
                  decoration: BoxDecoration(
                    color: bg,
                    borderRadius: BorderRadius.circular(AppDims.rMd),
                  ),
                  child: Text(
                    message,
                    style: const TextStyle(
                      fontSize: AppDims.fsBody,
                      color: Colors
                          .white, // ds-ignore: toast 白字固定（承 toast-bg/语义色底）
                    ),
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }
}