import 'dart:io';
import 'package:flutter/material.dart';
import 'package:permission_handler/permission_handler.dart';
import 'package:send_message/send_message.dart' show sendSMS;
import 'package:simcards/sim_card.dart';
import 'package:simcards/simcards.dart';

// This enum provides detailed status back to the UI layer.
enum PermissionStatusResult { granted, denied, permanentlyDenied, restricted }

class SmsService {
  final Simcards _simcards = Simcards();

  /// Handles the requesting of SMS and Phone permissions.
  /// Returns a detailed status: granted, denied, or permanentlyDenied.
  Future<PermissionStatusResult> handleSmsPermission() async {
    var smsStatus = await Permission.sms.status;
    var phoneStatus = await Permission.phone.status;

    // Check initial status
    if (smsStatus.isGranted && phoneStatus.isGranted) {
      return PermissionStatusResult.granted;
    }
    if (smsStatus.isPermanentlyDenied || phoneStatus.isPermanentlyDenied) {
      return PermissionStatusResult.permanentlyDenied;
    }
    if (smsStatus.isRestricted || phoneStatus.isRestricted) {
      return PermissionStatusResult.restricted;
    }

    // Request permissions if not granted
    print("Requesting SMS and Phone permissions...");
    await [Permission.phone, Permission.sms].request();

    // Re-check status after request
    smsStatus = await Permission.sms.status;
    phoneStatus = await Permission.phone.status;

    if (smsStatus.isGranted && phoneStatus.isGranted) {
      return PermissionStatusResult.granted;
    }
    if (smsStatus.isPermanentlyDenied || phoneStatus.isPermanentlyDenied) {
      return PermissionStatusResult.permanentlyDenied;
    }
    if (smsStatus.isRestricted || phoneStatus.isRestricted) {
      return PermissionStatusResult.restricted;
    }

    // If none of the above, it's denied
    return PermissionStatusResult.denied;
  }

  /// Tries to send a single verification SMS.
  /// This should only be called AFTER permissions have been granted.
  Future<bool> sendVerificationSms({
    required BuildContext context,
    required String destinationNumber,
    required String message,
  }) async {
    try {
      List<SimCard> simCardList = await _simcards.getSimCards();
      if (simCardList.isEmpty) {
        print("No SIM card detected.");
        return false;
      }
      return await _sendSms(destinationNumber, message, simCardList.first);
    } catch (e) {
      print("An error occurred in the SMS process: $e");
      return false;
    }
  }

  /// Private function to perform the SMS sending action.
  Future<bool> _sendSms(
      String destinationNumber, String message, SimCard selectedSim) async {
    if (Platform.isAndroid) {
      try {
        String smsMessage = message;
        String result = await sendSMS(
          message: smsMessage,
          recipients: [destinationNumber],
          sendDirect: true,
        );
        print("Background SMS send attempt result: $result");

        if (result.toLowerCase().contains('sent')) {
          print("Success: SMS appears to have been sent.");
          return true;
        } else {
          print("Failure: SMS was not sent. Result: $result");
          return false;
        }
      } catch (e) {
        print("Error attempting to send SMS directly: $e");
        return false;
      }
    } else {
      print("SMS sending is only supported on Android.");
      return false;
    }
  }
}