[IOS] Add method to retrieve untouched resource

(IN TESTING) Add method to retrieve original photo/video instead of altered one. getTitleAsync now returns original filename instead of 'FullsizeRender'.

ios/Classes/core/PHAsset+PM_COMMON.h

@@ -29,6 +29,7 @@ NS_ASSUME_NONNULL_BEGIN
 - (nullable NSString*)mimeType;
 - (BOOL)isAdjust;
 - (PHAssetResource *)getAdjustResource;
+- (PHAssetResource *)getUntouchedResource;
 - (void)requestAdjustedData:(void (^)(NSData *_Nullable result))block;
 - (PHAssetResource *)getLivePhotosResource;
 

ios/Classes/core/PHAsset+PM_COMMON.m

@@ -68,7 +68,7 @@ - (NSString *)originalFilenameWithSubtype:(int)subtype {
             return [self getLivePhotosResource].originalFilename;
         }
     }
-    PHAssetResource *resource = [self getAdjustResource];
+    PHAssetResource *resource = [self getUntouchedResource];
     if (resource) {
         return resource.originalFilename;
     }
@@ -120,6 +120,31 @@ - (BOOL)videoIsAdjust:(NSArray<PHAssetResource *> *)resources {
     return NO;
 }
 
+- (PHAssetResource *)getUntouchedResource {
+    NSArray<PHAssetResource *> *resources = [PHAssetResource assetResourcesForAsset:self];
+    if (resources.count == 0) {
+        return nil;
+    }
+
+    if (resources.count == 1) {
+        return resources[0];
+    }
+
+    for (PHAssetResource *res in resources) {
+        if (self.mediaType == PHAssetMediaTypeImage
+            && res.type == PHAssetResourceTypePhoto) {
+            return res;
+        }
+
+        if (self.mediaType == PHAssetMediaTypeVideo
+            && res.type == PHAssetResourceTypeVideo) {
+            return res;
+        }
+    }
+
+    return nil;
+}
+
 - (PHAssetResource *)getAdjustResource {
     NSArray<PHAssetResource *> *resources = [PHAssetResource assetResourcesForAsset:self];
     if (resources.count == 0) {