import 'package:flutter/material.dart';
import 'package:shadcn_ui/shadcn_ui.dart';

/// A short in-app explanation displayed immediately before the system prompt.
class NotificationPermissionTip extends StatelessWidget {
  const NotificationPermissionTip({super.key});

  @override
  Widget build(BuildContext context) {
    final colors = ShadTheme.of(context).colorScheme;
    return IgnorePointer(
      child: Align(
        alignment: Alignment.topCenter,
        child: Material(
          type: MaterialType.transparency,
          child: SafeArea(
            bottom: false,
            child: Padding(
              padding: const EdgeInsets.fromLTRB(16, 12, 16, 0),
              child: Container(
                padding: const EdgeInsets.fromLTRB(16, 14, 12, 14),
                decoration: BoxDecoration(
                  color: colors.foreground,
                  borderRadius: BorderRadius.circular(16),
                  boxShadow: const [
                    BoxShadow(
                      color: Color(0x33000000),
                      blurRadius: 16,
                      offset: Offset(0, 6),
                    ),
                  ],
                ),
                child: Row(
                  children: [
                    Icon(
                      Icons.notifications_outlined,
                      size: 20,
                      color: colors.background,
                    ),
                    const SizedBox(width: 12),
                    Expanded(
                      child: Column(
                        mainAxisSize: MainAxisSize.min,
                        crossAxisAlignment: CrossAxisAlignment.start,
                        children: [
                          Text(
                            '通知权限使用说明',
                            style: TextStyle(
                              fontSize: 14,
                              fontWeight: FontWeight.w600,
                              color: colors.background,
                            ),
                          ),
                          const SizedBox(height: 2),
                          Text(
                            '用于向你传递重要服务提醒。',
                            style: TextStyle(
                              fontSize: 12,
                              color: colors.background,
                            ),
                          ),
                        ],
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ),
        ),
      ),
    );
  }
}

/// Keeps the explanation visible while Android's system permission dialog is
/// presented. Call [remove] after the permission request completes.
NotificationPermissionTipHandle showNotificationPermissionTip(
  BuildContext context,
) {
  final overlay = Overlay.of(context, rootOverlay: true);
  final entry = OverlayEntry(builder: (_) => const NotificationPermissionTip());
  overlay.insert(entry);
  return NotificationPermissionTipHandle._(entry);
}

class NotificationPermissionTipHandle {
  NotificationPermissionTipHandle._(this._entry);

  final OverlayEntry _entry;
  bool _isRemoved = false;

  void remove() {
    if (_isRemoved) return;
    _isRemoved = true;
    _entry.remove();
  }
}