private IEnumerator PerformBatchWrite()

in firestore/testapp/Assets/Firebase/Sample/Firestore/UIHandler.cs [305:397]
84 lines of code
12 McCabe index (conditional complexity)

    private IEnumerator PerformBatchWrite() {
      DocumentReference doc1 = db.Collection("col2").Document("batch_doc1");
      DocumentReference doc2 = db.Collection("col2").Document("batch_doc2");
      DocumentReference doc3 = db.Collection("col2").Document("batch_doc3");

      // Initialize doc1 and doc2 with some data.
      var initialData = new Dictionary<string, object>{
        {"field", "value"},
      };
      yield return new WaitForTaskCompletion(this, doc1.SetAsync(initialData));
      yield return new WaitForTaskCompletion(this, doc2.SetAsync(initialData));

      // Perform batch that deletes doc1, updates doc2, and overwrites doc3.
      DebugLog("INFO: Going to perform the following three operations in a batch:");
      DebugLog("\tDelete col2/batch_doc1");
      DebugLog("\tUpdate col2/batch_doc2");
      DebugLog("\tOverwrite col2/batch_doc3");
      yield return new WaitForTaskCompletion(this, doc1.Firestore.StartBatch()
          .Delete(doc1)
          .Update(doc2, new Dictionary<string, object> { { "field2", "value2" } })
          .Update(doc2, new Dictionary<FieldPath, object> { { new FieldPath("field3"), "value3" } })
          .Update(doc2, "field4", "value4")
          .Set(doc3, initialData)
          .CommitAsync());

      DebugLog("INFO: Batch operation completed.");

      DebugLog("INFO: Checking the resulting documents.");

      Task<DocumentSnapshot> get1 = doc1.GetSnapshotAsync();
      yield return new WaitForTaskCompletion(this, get1);
      if (get1.IsCanceled) {
        DebugLog("INFO: Read operation for batch_doc1 was cancelled.");
      } else if (get1.IsFaulted) {
        DebugLog("ERROR: An error occurred while retrieving col2/batch_doc1.");
        DebugLog("ERROR: " + get1.Exception.ToString());
      } else {
        DocumentSnapshot snap = get1.Result;
        if(snap.Exists) {
          DebugLog("ERROR: col2/batch_doc1 should have been deleted.");
        } else {
          DebugLog("Success: col2/batch_doc1 does not exist.");
        }
      }

      Task<DocumentSnapshot> get2 = doc2.GetSnapshotAsync();
      yield return new WaitForTaskCompletion(this, get2);
      if (get2.IsCanceled) {
        DebugLog("INFO: Read operation for batch_doc2 was cancelled.");
      } else if (get2.IsFaulted) {
        DebugLog("ERROR: An error occurred while retrieving col2/batch_doc2.");
        DebugLog("ERROR: " + get2.Exception.ToString());
      } else {
        DocumentSnapshot snap = get2.Result;
        if(snap.Exists) {
          bool deepEquals = ObjectDeepEquals(snap.ToDictionary(),
          new Dictionary<string, object> {
            { "field", "value" },
            { "field2", "value2" },
            { "field3", "value3" },
            { "field4", "value4" },
          });
          if(deepEquals) {
            DebugLog("Success: col2/batch_doc2 content is as expected.");
          } else {
            DebugLog("ERROR: col2/batch_doc2 has incorrect content.");
          }
        } else {
          DebugLog("ERROR: col2/batch_doc2 does not exist.");
        }
      }

      Task<DocumentSnapshot> get3 = doc3.GetSnapshotAsync();
      yield return new WaitForTaskCompletion(this, get3);
      if (get3.IsCanceled) {
        DebugLog("INFO: Read operation for batch_doc3 was cancelled.");
      } else if (get3.IsFaulted) {
        DebugLog("ERROR: An error occurred while retrieving col2/batch_doc3.");
        DebugLog("ERROR: " + get3.Exception.ToString());
      } else {
        DocumentSnapshot snap = get3.Result;
        if(snap.Exists) {
          bool deepEquals = ObjectDeepEquals(snap.ToDictionary(), initialData);
          if(deepEquals) {
            DebugLog("Success: col2/batch_doc3 content is as expected.");
          } else {
            DebugLog("ERROR: col2/batch_doc3 has incorrect content.");
          }
        } else {
          DebugLog("ERROR: col2/batch_doc3 does not exist.");
        }
      }
    }