using static Microsoft.Maui.ApplicationModel.Permissions;

namespace InTheHand.Permissions
{
    /// <summary>
    ///	BluetoothPermissions (.NET MAUI on Android).
    /// </summary>
    /// <remarks>The Android implementation is based on (https://gist.github.com/salarcode/da8ad2b993e67c602db88a62259d0456).</remarks>
    public partial class BluetoothPermissions : BasePlatformPermission
    {
        private readonly bool _connect;
        private readonly bool _scan;
        private readonly bool _location;
        private readonly bool _advertise;
        
        public BluetoothPermissions()
            : this(connect:true, scan:false, location:false, advertise:false)
        {
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="connect">Needed only if your app communicates with already-paired Bluetooth devices.</param>
        /// <param name="scan">Needed only if your app looks for Bluetooth devices.
        /// If your app doesn't use Bluetooth scan results to derive physical location, you can make a strong assertion that your app never uses the Bluetooth permissions to derive physical location. 
        /// Add the `android:usesPermissionFlags` attribute to your BLUETOOTH_SCAN permission declaration, and set this attribute's value to `neverForLocation`.
        /// </param>
        /// <param name="location">Needed only if your app uses Bluetooth scan results to derive physical location.</param>
        /// <param name="advertise">Needed only if your app makes the device discoverable to Bluetooth devices.</param>
        /// <remarks>
        ///  https://developer.android.com/guide/topics/connectivity/bluetooth/permissions
        /// </remarks>
        public BluetoothPermissions(bool connect = true, bool scan = true, bool location = true, bool advertise = true)
        {
            _connect = connect;
            _scan = scan;
            _location = location;
            _advertise = advertise;
        }

        private (string androidPermission, bool isRuntime)[] _requiredPermissions;

        public override (string androidPermission, bool isRuntime)[] RequiredPermissions
        {
            get
            {
                if (_requiredPermissions != null)
                    return _requiredPermissions;

                var result = new List<(string androidPermission, bool isRuntime)>();

                var sdk = (int)Android.OS.Build.VERSION.SdkInt;
                if (sdk >= 31)
                {
                    // If your app targets Android 12 (API level 31) or higher, declare the following permissions in your app's manifest file:

                    if (_connect)
                        result.Add((global::Android.Manifest.Permission.BluetoothConnect, true));

                    if (_scan)
                        result.Add((global::Android.Manifest.Permission.BluetoothScan, true));

                    if (_location)
                        result.Add((global::Android.Manifest.Permission.AccessFineLocation, true));

                    if (_advertise)
                        result.Add((global::Android.Manifest.Permission.BluetoothAdvertise, true));  
                }
                else
                {
                    // If your app targets Android 11 (API level 30) or lower, declare the following permissions in your app's manifest file:

                    result.Add((global::Android.Manifest.Permission.Bluetooth, true));

                    if (sdk >= 29)
                    {
                        result.Add((global::Android.Manifest.Permission.AccessFineLocation, true));
                    }
                    else
                    {
                        // If your app targets Android 9 (API level 28) or lower, you can declare the ACCESS_COARSE_LOCATION permission instead of the ACCESS_FINE_LOCATION permission.

                        result.Add((global::Android.Manifest.Permission.AccessCoarseLocation, true));
                    }

                    if (_scan || _advertise)
                    {
                        result.Add((global::Android.Manifest.Permission.BluetoothAdmin, true));

                        if (sdk >= 29)
                        {
                            // If your app supports a service and can run on Android 10 (API level 29) or Android 11, you must also declare the ACCESS_BACKGROUND_LOCATION permission to discover Bluetooth devices. 

                            result.Add((global::Android.Manifest.Permission.AccessBackgroundLocation, true));
                        }
                    }
                }

                _requiredPermissions = result.ToArray();

                return _requiredPermissions;
            }
        }
    }
}