Show time of next update

README.md

@@ -39,7 +39,7 @@ ToDo
 	- [ ] Show statistics
 		- [x] How often gets the feed updated (min, max, avg)
 		- [ ] Automatically choose best interval?
-		- [ ] Show time of next update
+		- [x] Show time of next update
 	- [ ] Feeds with authentication
 
 

baRSS/FeedDownload.h

@@ -26,6 +26,7 @@
 @class Feed;
 
 @interface FeedDownload : NSObject
+@property (class, readonly) NSDate *dateScheduled;
 @property (class, readonly) BOOL allowNetworkConnection;
 @property (class, readonly) BOOL isUpdating;
 @property (class, setter=setPaused:) BOOL isPaused;

baRSS/FeedDownload.m

@@ -29,6 +29,7 @@
 
 #import <SystemConfiguration/SystemConfiguration.h>
 
+static NSTimer *_timer;
 static SCNetworkReachabilityRef _reachability = NULL;
 static BOOL _isReachable = NO;
 static BOOL _isUpdating = NO;
@@ -41,6 +42,9 @@ static BOOL _nextUpdateIsForced = NO;
 
 #pragma mark - User Interaction -
 
+/// @return Date when background update will fire. If updates are paused, date is @c distantFuture.
++ (NSDate *)dateScheduled { return _timer.fireDate; }
+
 /// @return @c YES if current network state is reachable and updates are not paused by user.
 + (BOOL)allowNetworkConnection { return (_isReachable && !_updatePaused); }
 
@@ -80,9 +84,8 @@ static BOOL _nextUpdateIsForced = NO;
 + (void)scheduleUpdateForUpcomingFeeds {
 	if (![self allowNetworkConnection]) // timer will restart once connection exists
 		return;
-	NSDate *nextTime = [StoreCoordinator nextScheduledUpdate];
+	NSDate *nextTime = [StoreCoordinator nextScheduledUpdate]; // if nextTime = nil, then no feeds to update
-	if (!nextTime) return; // no timer means no feeds to update
+	if (nextTime && [nextTime timeIntervalSinceNow] < 1) { // mostly, if app was closed for a long time
-	if ([nextTime timeIntervalSinceNow] < 1) { // mostly, if app was closed for a long time
 		nextTime = [NSDate dateWithTimeIntervalSinceNow:1];
 	}
 	[self scheduleTimer:nextTime];
@@ -104,16 +107,16 @@ static BOOL _nextUpdateIsForced = NO;
  @param nextTime If @c nil timer will be disabled with a @c .fireDate very far in the future.
  */
 + (void)scheduleTimer:(NSDate*)nextTime {
-	static NSTimer *timer;
+	static dispatch_once_t onceToken;
-	if (!timer) {
+	dispatch_once(&onceToken, ^{
-		timer = [NSTimer timerWithTimeInterval:NSTimeIntervalSince1970 target:[self class] selector:@selector(updateTimerCallback) userInfo:nil repeats:YES];
+		_timer = [NSTimer timerWithTimeInterval:NSTimeIntervalSince1970 target:[self class] selector:@selector(updateTimerCallback) userInfo:nil repeats:YES];
-		[[NSRunLoop mainRunLoop] addTimer:timer forMode:NSRunLoopCommonModes];
+		[[NSRunLoop mainRunLoop] addTimer:_timer forMode:NSRunLoopCommonModes];
-	}
+	});
 	if (!nextTime)
-		nextTime = [NSDate dateWithTimeIntervalSinceNow:NSTimeIntervalSince1970];
+		nextTime = [NSDate distantFuture];
 	NSTimeInterval tolerance = [nextTime timeIntervalSinceNow] * 0.15;
-	timer.tolerance = (tolerance < 1 ? 1 : tolerance); // at least 1 sec
+	_timer.tolerance = (tolerance < 1 ? 1 : tolerance); // at least 1 sec
-	timer.fireDate = nextTime;
+	_timer.fireDate = nextTime;
 }
 
 /**

baRSS/Preferences/Feeds Tab/SettingsFeeds.m

@@ -37,6 +37,9 @@
 
 @property (strong) NSArray<NSTreeNode*> *currentlyDraggedNodes;
 @property (strong) NSUndoManager *undoManager;
+
+@property (strong) NSTimer *timerStatusInfo;
+@property (strong) NSDateComponentsFormatter *intervalFormatter;
 @end
 
 @implementation SettingsFeeds
@@ -47,7 +50,6 @@ static NSString *dragNodeType = @"baRSS-feed-drag";
 
 - (void)viewDidLoad {
     [super viewDidLoad];
-	[self activateSpinner:([FeedDownload isUpdating] ? -1 : 0)]; // start spinner if update is in progress when preferences open
 	[self.outlineView registerForDraggedTypes:[NSArray arrayWithObject:dragNodeType]];
 	[self.dataStore setSortDescriptors:[NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"sortIndex" ascending:YES]]];
 	
@@ -69,6 +71,64 @@ static NSString *dragNodeType = @"baRSS-feed-drag";
 }
 
 
+#pragma mark - Activity Spinner & Status Info
+
+
+/// Initialize status info timer
+- (void)viewWillAppear {
+	self.intervalFormatter = [[NSDateComponentsFormatter alloc] init];
+	self.intervalFormatter.unitsStyle = NSDateComponentsFormatterUnitsStyleShort; // e.g., '30 min'
+	self.intervalFormatter.maximumUnitCount = 1;
+	self.timerStatusInfo = [NSTimer timerWithTimeInterval:NSTimeIntervalSince1970 target:self selector:@selector(keepTimerRunning) userInfo:nil repeats:YES];
+	[[NSRunLoop mainRunLoop] addTimer:self.timerStatusInfo forMode:NSRunLoopCommonModes];
+	// start spinner if update is in progress when preferences open
+	[self activateSpinner:([FeedDownload isUpdating] ? -1 : 0)];
+}
+
+/// Timer cleanup
+- (void)viewWillDisappear {
+	// in viewWillDisappear otherwise dealloc will not be called
+	[self.timerStatusInfo invalidate];
+	self.timerStatusInfo = nil;
+	self.intervalFormatter = nil;
+}
+
+/// Callback method to update status info. Will be called more often when interval is getting shorter.
+- (void)keepTimerRunning {
+	NSDate *date = [FeedDownload dateScheduled];
+	if (date) {
+		double nextFire = fabs(date.timeIntervalSinceNow);
+		if (nextFire > 60) { // update 1/min
+			nextFire = fmod(nextFire, 60); // next update will align with minute
+		} else {
+			nextFire = 1; // update 1/sec
+		}
+		NSString *str = [self.intervalFormatter stringFromTimeInterval: date.timeIntervalSinceNow];
+		self.spinnerLabel.stringValue = [NSString stringWithFormat:NSLocalizedString(@"Next update in %@", nil), str];
+		[self.timerStatusInfo setFireDate:[NSDate dateWithTimeIntervalSinceNow: nextFire]];
+	}
+}
+
+/// Start ( @c c @c > @c 0 ) or stop ( @c c @c = @c 0 ) activity spinner. Also, sets status info.
+- (void)activateSpinner:(NSInteger)c {
+	if (c == 0) {
+		[self.spinner stopAnimation:nil];
+		self.spinnerLabel.stringValue = @"";
+		[self.timerStatusInfo fire];
+	} else {
+		[self.timerStatusInfo setFireDate:[NSDate distantFuture]];
+		[self.spinner startAnimation:nil];
+		if (c == 1) { // exactly one feed
+			self.spinnerLabel.stringValue = NSLocalizedString(@"Updating 1 feed …", nil);
+		} else if (c < 0) { // unknown number of feeds
+			self.spinnerLabel.stringValue = NSLocalizedString(@"Updating feeds …", nil);
+		} else {
+			self.spinnerLabel.stringValue = [NSString stringWithFormat:NSLocalizedString(@"Updating %lu feeds …", nil), c];
+		}
+	}
+}
+
+
 #pragma mark - Notification callback methods
 
 
@@ -89,25 +149,6 @@ static NSString *dragNodeType = @"baRSS-feed-drag";
 	[self activateSpinner:[notify.object integerValue]];
 }
 
-/// Start or stop activity spinner (will run on main thread). If @c c @c == @c 0 stop spinner.
-- (void)activateSpinner:(NSInteger)c {
-	dispatch_async(dispatch_get_main_queue(), ^{
-		if (c == 0) {
-			[self.spinner stopAnimation:nil];
-			self.spinnerLabel.stringValue = @"";
-		} else {
-			[self.spinner startAnimation:nil];
-			if (c < 0) { // unknown number of feeds
-				self.spinnerLabel.stringValue = NSLocalizedString(@"Updating feeds …", nil);
-			} else if (c == 1) {
-				self.spinnerLabel.stringValue = NSLocalizedString(@"Updating 1 feed …", nil);
-			} else {
-				self.spinnerLabel.stringValue = [NSString stringWithFormat:NSLocalizedString(@"Updating %lu feeds …", nil), c];
-			}
-		}
-	});
-}
-
 
 #pragma mark - Persist state
 
@@ -133,6 +174,8 @@ static NSString *dragNodeType = @"baRSS-feed-drag";
 	[self.undoManager endUndoGrouping];
 	if (!flag && self.dataStore.managedObjectContext.hasChanges) {
 		[StoreCoordinator saveContext:self.dataStore.managedObjectContext andParent:YES];
+		[FeedDownload scheduleUpdateForUpcomingFeeds];
+		[self.timerStatusInfo fire];
 		return YES;
 	}
 	[self.undoManager disableUndoRegistration];

baRSS/Preferences/Feeds Tab/SettingsFeeds.xib

@@ -221,19 +221,19 @@ CA
                         <action selector="shareMenu:" target="-2" id="JJq-7D-Bti"/>
                     </connections>
                 </button>
-                <progressIndicator wantsLayer="YES" horizontalHuggingPriority="750" verticalHuggingPriority="750" fixedFrame="YES" maxValue="100" displayedWhenStopped="NO" bezeled="NO" indeterminate="YES" controlSize="small" style="spinning" translatesAutoresizingMaskIntoConstraints="NO" id="fos-vP-s2s">
-                    <rect key="frame" x="168" y="3" width="16" height="16"/>
-                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
-                </progressIndicator>
                 <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="44U-lx-hnq">
-                    <rect key="frame" x="190" y="4" width="112" height="14"/>
+                    <rect key="frame" x="166" y="4" width="141" height="14"/>
                     <autoresizingMask key="autoresizingMask" widthSizable="YES" flexibleMaxY="YES"/>
-                    <textFieldCell key="cell" lineBreakMode="clipping" title="&lt;string&gt;" id="yyA-K6-M3v">
+                    <textFieldCell key="cell" lineBreakMode="clipping" alignment="center" title="&lt;string&gt;" id="yyA-K6-M3v">
                         <font key="font" metaFont="smallSystem"/>
                         <color key="textColor" name="systemGrayColor" catalog="System" colorSpace="catalog"/>
                         <color key="backgroundColor" name="textBackgroundColor" catalog="System" colorSpace="catalog"/>
                     </textFieldCell>
                 </textField>
+                <progressIndicator wantsLayer="YES" horizontalHuggingPriority="750" verticalHuggingPriority="750" fixedFrame="YES" maxValue="100" displayedWhenStopped="NO" bezeled="NO" indeterminate="YES" controlSize="small" style="spinning" translatesAutoresizingMaskIntoConstraints="NO" id="fos-vP-s2s">
+                    <rect key="frame" x="301" y="3" width="16" height="16"/>
+                    <autoresizingMask key="autoresizingMask" flexibleMinX="YES" flexibleMaxY="YES"/>
+                </progressIndicator>
             </subviews>
             <point key="canvasLocation" x="27" y="882.5"/>
         </customView>