From c05243444fde4da979d476eea8c018d5eacc6c2e Mon Sep 17 00:00:00 2001
From: abraunegg <alex.braunegg@gmail.com>
Date: Sun, 26 Apr 2020 06:52:29 +1000
Subject: [PATCH] Update progress bar to be more accurate when downloading
 large files (#888)

* Change from round to floor, so % bar increases when downloaded data is at X% not potentially under, thus leading to under reporting
* Add debug output when each % increase when downloading a file to assist with validating progress
* Start displaying ETA starting at 5% rather than 10%
---
 src/log.d      |  2 +-
 src/onedrive.d | 28 ++++++++++++++++++++++------
 src/progress.d |  6 +++---
 src/upload.d   |  2 +-
 4 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/src/log.d b/src/log.d
index fcbcf1f3..c868fd50 100644
--- a/src/log.d
+++ b/src/log.d
@@ -100,7 +100,7 @@ void vdebug(T...)(T args)
 	}
 }
 
-void vdebugUpload(T...)(T args)
+void vdebugNewLine(T...)(T args)
 {
 	if (verbose >= 2) {
 		writeln("\n[DEBUG] ", args);
diff --git a/src/onedrive.d b/src/onedrive.d
index 0a3ee6ef..de4f2a88 100644
--- a/src/onedrive.d
+++ b/src/onedrive.d
@@ -567,18 +567,34 @@ final class OneDriveApi
 			Progress p = new Progress(iteration);
 			p.title = "Downloading";
 			writeln();
-	
+			bool barInit = false;
 			real previousDLPercent = -1.0;
 			real percentCheck = 5.0;
 			// Setup progress bar to display
 			http.onProgress = delegate int(size_t dltotal, size_t dlnow, size_t ultotal, size_t ulnow)
 			{
 				// For each onProgress, what is the % of dlnow to dltotal
-				real currentDLPercent = round(double(dlnow)/dltotal*100);
-				// If matching 5% of download, increment progress bar
-				if ((isIdentical(fmod(currentDLPercent, percentCheck), 0.0)) && (previousDLPercent != currentDLPercent)) {
-					p.next();
-					previousDLPercent = currentDLPercent;
+				// floor - rounds down to nearest whole number
+				real currentDLPercent = floor(double(dlnow)/dltotal*100);
+				if (currentDLPercent > 0){
+					// We have started downloading
+					// If matching 5% of download, increment progress bar
+					if ((isIdentical(fmod(currentDLPercent, percentCheck), 0.0)) && (previousDLPercent != currentDLPercent)) {
+						// What have we downloaded thus far
+						log.vdebugNewLine("Data Received  = ", dlnow);
+						log.vdebug("Expected Total = ", dltotal);
+						log.vdebug("Percent Complete = ", currentDLPercent);
+						// Increment counter & show bar update
+						p.next();
+						previousDLPercent = currentDLPercent;
+					}
+				} else {
+					if ((currentDLPercent == 0) && (!barInit)) {
+						// Initialise the download bar at 0%
+						// Downloading   0% |                                        |   ETA   --:--:--:^C
+						p.next();
+						barInit = true;
+					}
 				}
 				return 0;
 			};
diff --git a/src/progress.d b/src/progress.d
index d8b33e04..c07a43d0 100644
--- a/src/progress.d
+++ b/src/progress.d
@@ -82,7 +82,7 @@ class Progress
 
       header.formattedWrite("%s %3d%% |", caption, cast(int)(ratio * 100));
 
-      if(counter <= 1 || ratio == 0.0) {
+      if(counter <= 0 || ratio == 0.0) {
         footer.formattedWrite("|   ETA   --:--:--:");
       } else {
         int h, m, s;
@@ -114,7 +114,7 @@ class Progress
     this(size_t iterations) {
       if(iterations <= 0) iterations = 1;
 
-      counter = 0;
+      counter = -1;
       this.iterations = iterations;
       start_time = Clock.currTime.toUnixTime;
     }
@@ -140,7 +140,7 @@ class Progress
     }
 
     void reset() {
-      counter = 0;
+      counter = -1;
       start_time = Clock.currTime.toUnixTime;
     }
 
diff --git a/src/upload.d b/src/upload.d
index 275ac46a..d868dc4a 100644
--- a/src/upload.d
+++ b/src/upload.d
@@ -176,7 +176,7 @@ struct UploadSession
 			
 			while (true) {
 				fragmentCount++;
-				log.vdebugUpload("Fragment: ", fragmentCount, " of ", iteration);
+				log.vdebugNewLine("Fragment: ", fragmentCount, " of ", iteration);
 				p.next();
 				long fragSize = fragmentSize < fileSize - offset ? fragmentSize : fileSize - offset;
 				// If the resume upload fails, we need to check for a return code here