From 239085f1fc0c297a96b35678114ae18861dedd4e Mon Sep 17 00:00:00 2001
From: abraunegg <alex.braunegg@gmail.com>
Date: Thu, 23 May 2019 05:38:32 +1000
Subject: [PATCH] Check timestamp to ensure that latest timestamp is used when
 comparing OneDrive changes (Issue #505) (#506)

* If OneDrive presents a change to download and the file already exists, check the local modified timestamp to ensure that the local file is not technically newer than the file we are going to download
---
 src/sync.d | 61 ++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 48 insertions(+), 13 deletions(-)

diff --git a/src/sync.d b/src/sync.d
index 92bfffd3..408f7d58 100644
--- a/src/sync.d
+++ b/src/sync.d
@@ -919,14 +919,31 @@ final class SyncEngine
 				oldPath = itemdb.computePath(item.driveId, item.id);
 				if (!isItemSynced(oldItem, oldPath)) {
 					if (exists(oldPath)) {
-						auto ext = extension(oldPath);
-						auto newPath = path.chomp(ext) ~ "-" ~ deviceName ~ ext;
-						log.vlog("The local item is unsynced, renaming: ", oldPath, " -> ", newPath);
-						if (!dryRun) {
-							safeRename(oldPath);
+						// Is the local file technically 'newer' based on UTC timestamp?
+						SysTime localModifiedTime = timeLastModified(oldPath).toUTC();
+						localModifiedTime.fracSecs = Duration.zero;
+						item.mtime.fracSecs = Duration.zero;
+						
+						if (localModifiedTime > item.mtime) {
+							// local file is newer than item on OneDrive
+							// no local rename
+							// no download needed
+							log.vlog("Local item modified time is newer based on UTC time conversion - keeping local item");
+							log.vdebug("Skipping OneDrive change as this is determined to be unwanted due to local item modified time being newer than OneDrive item");
+							skippedItems ~= item.id;
+							return;
 						} else {
-							log.vdebug("DRY-RUN: Skipping local file rename");
-							// Expectation here is that there is a new file locally (newPath) however as we don't create this, the "new file" will not be uploaded as it does not exist
+							// remote file is newer than local item
+							log.vlog("Remote item modified time is newer based on UTC time conversion");
+							auto ext = extension(oldPath);
+							auto newPath = path.chomp(ext) ~ "-" ~ deviceName ~ ext;
+							log.vlog("The local item is out-of-sync with OneDrive, renaming to preserve existing file: ", oldPath, " -> ", newPath);
+							if (!dryRun) {
+								safeRename(oldPath);
+							} else {
+								// Expectation here is that there is a new file locally (newPath) however as we don't create this, the "new file" will not be uploaded as it does not exist
+								log.vdebug("DRY-RUN: Skipping local file rename");
+							}
 						}
 					}
 					cached = false;
@@ -968,13 +985,31 @@ final class SyncEngine
 				return;
 			} else {
 				// TODO: force remote sync by deleting local item
-				auto ext = extension(path);
-				auto newPath = path.chomp(ext) ~ "-" ~ deviceName ~ ext;
-				log.vlog("The local item is out of sync, renaming: ", path, " -> ", newPath);
-				if (!dryRun) {
-					safeRename(path);
+				
+				// Is the local file technically 'newer' based on UTC timestamp?
+				SysTime localModifiedTime = timeLastModified(path).toUTC();
+				localModifiedTime.fracSecs = Duration.zero;
+				item.mtime.fracSecs = Duration.zero;
+				
+				if (localModifiedTime > item.mtime) {
+					// local file is newer than item on OneDrive
+					// no local rename
+					// no download needed
+					log.vlog("Local item modified time is newer based on UTC time conversion - keeping local item");
+					log.vdebug("Skipping OneDrive change as this is determined to be unwanted due to local item modified time being newer than OneDrive item");
+					return;
 				} else {
-					log.vdebug("DRY-RUN: Skipping local file rename");
+					// remote file is newer than local item
+					log.vlog("Remote item modified time is newer based on UTC time conversion");
+					auto ext = extension(path);
+					auto newPath = path.chomp(ext) ~ "-" ~ deviceName ~ ext;
+					log.vlog("The local item is out-of-sync with OneDrive, renaming to preserve existing file: ", path, " -> ", newPath);
+					if (!dryRun) {
+						safeRename(path);
+					} else {
+						// Expectation here is that there is a new file locally (newPath) however as we don't create this, the "new file" will not be uploaded as it does not exist
+						log.vdebug("DRY-RUN: Skipping local file rename");
+					}
 				}
 			}
 		}