import 'dart:async';

import 'package:flutter/material.dart';

import '../theme/app_theme.dart';

/// Slide-in toast for cross-session incoming messages.
class ToastOverlay extends StatefulWidget {
  final String sessionName;
  final String preview;
  final VoidCallback onTap;
  final VoidCallback onDismiss;

  const ToastOverlay({
    super.key,
    required this.sessionName,
    required this.preview,
    required this.onTap,
    required this.onDismiss,
  });

  @override
  State<ToastOverlay> createState() => _ToastOverlayState();
}

class _ToastOverlayState extends State<ToastOverlay>
    with SingleTickerProviderStateMixin {
  late final AnimationController _controller;
  late final Animation<Offset> _slideAnimation;
  Timer? _autoDismiss;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      vsync: this,
      duration: const Duration(milliseconds: 300),
    );
    _slideAnimation = Tween<Offset>(
      begin: const Offset(0, -1),
      end: Offset.zero,
    ).animate(CurvedAnimation(parent: _controller, curve: Curves.easeOutCubic));

    _controller.forward();
    _autoDismiss = Timer(const Duration(seconds: 4), _dismiss);
  }

  void _dismiss() {
    _autoDismiss?.cancel();
    _controller.reverse().then((_) {
      widget.onDismiss();
    });
  }

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

  @override
  Widget build(BuildContext context) {
    return SlideTransition(
      position: _slideAnimation,
      child: SafeArea(
        bottom: false,
        child: GestureDetector(
          onTap: () {
            _autoDismiss?.cancel();
            widget.onTap();
          },
          onVerticalDragEnd: (details) {
            if (details.primaryVelocity != null &&
                details.primaryVelocity! < -100) {
              _dismiss();
            }
          },
          child: Container(
            margin: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
            padding: const EdgeInsets.all(12),
            decoration: BoxDecoration(
              color: AppColors.darkSurface,
              borderRadius: BorderRadius.circular(12),
              boxShadow: [
                BoxShadow(
                  color: Colors.black.withAlpha(80),
                  blurRadius: 12,
                  offset: const Offset(0, 4),
                ),
              ],
            ),
            child: Row(
              children: [
                Container(
                  width: 36,
                  height: 36,
                  decoration: const BoxDecoration(
                    color: AppColors.accent,
                    shape: BoxShape.circle,
                  ),
                  child: const Icon(
                    Icons.chat_bubble_outline,
                    color: Colors.white,
                    size: 18,
                  ),
                ),
                const SizedBox(width: 12),
                Expanded(
                  child: Column(
                    crossAxisAlignment: CrossAxisAlignment.start,
                    mainAxisSize: MainAxisSize.min,
                    children: [
                      Text(
                        widget.sessionName,
                        style: const TextStyle(
                          color: Colors.white,
                          fontWeight: FontWeight.w600,
                          fontSize: 13,
                        ),
                      ),
                      const SizedBox(height: 2),
                      Text(
                        widget.preview,
                        style: const TextStyle(
                          color: AppColors.darkTextSecondary,
                          fontSize: 12,
                        ),
                        maxLines: 2,
                        overflow: TextOverflow.ellipsis,
                      ),
                    ],
                  ),
                ),
              ],
            ),
          ),
        ),
      ),
    );
  }
}

/// Global toast manager for showing cross-session notifications.
class ToastManager {
  ToastManager._();

  static OverlayEntry? _currentEntry;

  static void show(
    BuildContext context, {
    required String sessionName,
    required String preview,
    required VoidCallback onTap,
  }) {
    dismiss();

    _currentEntry = OverlayEntry(
      builder: (ctx) => Positioned(
        top: 0,
        left: 0,
        right: 0,
        child: Material(
          color: Colors.transparent,
          child: ToastOverlay(
            sessionName: sessionName,
            preview: preview,
            onTap: () {
              dismiss();
              onTap();
            },
            onDismiss: dismiss,
          ),
        ),
      ),
    );

    Overlay.of(context).insert(_currentEntry!);
  }

  static void dismiss() {
    _currentEntry?.remove();
    _currentEntry = null;
  }
}