From c65803845b2ef3c6a8285ad8a7f2d44f58142265 Mon Sep 17 00:00:00 2001
From: James Magahern <james@magahern.com>
Date: Sun, 7 Jan 2024 18:11:59 -0800
Subject: [PATCH] FetchAttachment: need to check for some edge cases wrt
 preview generation

---
 .../Operations/MBIMFetchAttachmentOperation.m | 34 +++++++++++++------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/kordophone/Bridge/Operations/MBIMFetchAttachmentOperation.m b/kordophone/Bridge/Operations/MBIMFetchAttachmentOperation.m
index 1822d70..be39d9f 100644
--- a/kordophone/Bridge/Operations/MBIMFetchAttachmentOperation.m
+++ b/kordophone/Bridge/Operations/MBIMFetchAttachmentOperation.m
@@ -52,20 +52,34 @@
         NSURL *localURL = [transfer localURL];
         NSString *extension = [[localURL pathExtension] lowercaseString];
         if (preview) {
+            IMPreviewConstraints constraints = IMPreviewConstraintsZero();
+
+            // Fetch preview constraints from transfer
+            NSDictionary *previewConstraintsDict = [[transfer attributionInfo] objectForKey:@"pgenszc"];
+            if (previewConstraintsDict) {
+                constraints = IMPreviewConstraintsFromDictionary(previewConstraintsDict);
+            } else {
+                // Or, make a guess. 
+                constraints.maxPxWidth = 500.0;
+                constraints.scale = 1.0;
+            }
+
             NSURL *previewURL = IMAttachmentPreviewFileURL(localURL, extension, YES);
+            if (!previewURL) {
+                // I'm not sure why this sometimes returns nil... 
+                MBIMLogInfo(@"Unable to generate attachment preview cache URL for %@, making one up.", localURL);
+
+                NSURL *temporaryAttachmentCache = [[[NSFileManager defaultManager] temporaryDirectory] URLByAppendingPathComponent:@"kordophone_attachment_cache"];
+                temporaryAttachmentCache = [temporaryAttachmentCache URLByAppendingPathComponent:guid];
+
+                [[NSFileManager defaultManager] createDirectoryAtURL:temporaryAttachmentCache withIntermediateDirectories:YES attributes:nil error:nil];
+
+                previewURL = [temporaryAttachmentCache URLByAppendingPathComponent:[localURL lastPathComponent]];
+            }
+
             if (![[NSFileManager defaultManager] fileExistsAtPath:[previewURL path]]) {
                 MBIMLogInfo(@"Generating preview image for guid: %@ at %@", guid, [previewURL path]);
                 
-                // Fetch preview constraints from transfer
-                NSDictionary *previewConstraintsDict = [[transfer attributionInfo] objectForKey:@"pgenszc"];
-                if (!previewConstraintsDict) {
-                    MBIMLogInfo(@"No preview constraints for attachment guid: %@", guid);
-                    response = [[HTTPErrorResponse alloc] initWithErrorCode:500];
-                    break;
-                }
-                
-                IMPreviewConstraints constraints = IMPreviewConstraintsFromDictionary(previewConstraintsDict);
-                
                 // Generate preview using preview generator manager
                 NSError *error = nil;
                 IMPreviewGeneratorManager *generator = [IMPreviewGeneratorManager sharedInstance];