From ceba79e911449d7ab29aa234d749962befbc9d16 Mon Sep 17 00:00:00 2001
From: Dante P <dantejpuglisi@gmail.com>
Date: Mon, 16 May 2022 16:03:46 -0300
Subject: [PATCH] Make WriteCharacteristic fail if types mismatch

---
 Bluejay/Bluejay/Error.swift               | 10 ++++++++--
 Bluejay/Bluejay/WriteCharacteristic.swift |  6 ++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/Bluejay/Bluejay/Error.swift b/Bluejay/Bluejay/Error.swift
index 87155d9..d77ce18 100644
--- a/Bluejay/Bluejay/Error.swift
+++ b/Bluejay/Bluejay/Error.swift
@@ -7,6 +7,7 @@
 //
 
 import Foundation
+import CoreBluetooth
 
 /// Errors specific to Bluejay.
 public enum BluejayError {
@@ -26,6 +27,8 @@ public enum BluejayError {
     case missingService(ServiceIdentifier)
     /// A Bluetooth characteristic is not found.
     case missingCharacteristic(CharacteristicIdentifier)
+    /// A Bluetooth characteristic doesn't have the requested property
+    case missingCharacteristicProperty(CBCharacteristicProperties)
     /// A Bluetooth operation is cancelled.
     case cancelled
     /// Bluejay disconnect is called.
@@ -89,6 +92,8 @@ extension BluejayError: LocalizedError {
             return "Service not found: \(service.uuid)"
         case let .missingCharacteristic(characteristic):
             return "Characteristic not found: \(characteristic.uuid)"
+        case let .missingCharacteristicProperty(property):
+            return "Write type (\(property)) on characteristic was not found"
         case .cancelled:
             return "Cancelled"
         case .explicitDisconnect:
@@ -140,11 +145,11 @@ extension BluejayError: LocalizedError {
 }
 
 extension BluejayError: CustomNSError {
-
+    
     public static var errorDomain: String {
         return "Bluejay"
     }
-
+    
     public var errorCode: Int {
         switch self {
         case .bluetoothUnavailable: return 1
@@ -176,6 +181,7 @@ extension BluejayError: CustomNSError {
         case .multipleListenTrapped: return 27
         case .multipleListenReplaced: return 28
         case .tooMuchData: return 29
+        case .missingCharacteristicProperty: return 30
         }
     }
 
diff --git a/Bluejay/Bluejay/WriteCharacteristic.swift b/Bluejay/Bluejay/WriteCharacteristic.swift
index bae77da..1de2615 100644
--- a/Bluejay/Bluejay/WriteCharacteristic.swift
+++ b/Bluejay/Bluejay/WriteCharacteristic.swift
@@ -52,6 +52,12 @@ class WriteCharacteristic<T: Sendable>: Operation {
             return
         }
 
+        let property: CBCharacteristicProperties = type == .withoutResponse ? .writeWithoutResponse : .write
+        guard characteristic.properties.contains(property) else {
+            fail(BluejayError.missingCharacteristicProperty(property))
+            return
+        }
+        
         state = .running
 
         peripheral.writeValue(value.toBluetoothData(), for: characteristic, type: type)