Merge pull request #57 from rizumita/fix-schedule

Showing current session block when startup and schedule tab re-tapped

Author: NatashaTheRobot

trySwift/ScheduleViewController.swift

@@ -30,6 +30,8 @@ class ScheduleViewController: ButtonBarPagerTabStripViewController {
         buttonBarView.backgroundColor = .white
         settings.style.selectedBarBackgroundColor = .white
         buttonBarView.selectedBar.backgroundColor = .trySwiftAccentColor()
+        
+        tabBarController?.delegate = self
     }
 
     override func viewDidAppear(_ animated: Bool) {
@@ -59,14 +61,35 @@ class ScheduleViewController: ButtonBarPagerTabStripViewController {
 
 private extension ScheduleViewController {
 
-  func moveToCorrectDate() {
-    if days.count > 1 {
-      let calendar = NSCalendar.current
-      if let todaysIndex = days.enumerated()
-        .first(where:{ calendar.isDateInToday($0.element.date) })
-        .map({$0.offset}) {
-        moveToViewController(at: todaysIndex, animated: false)
-      }
+    @discardableResult
+    func moveToCorrectDate(animated: Bool = false) -> Int? {
+        if days.count > 1 {
+            let calendar = Calendar.current
+            if let todaysIndex = days.enumerated()
+                .first(where:{ calendar.isDateInToday($0.element.date) })
+                .map({$0.offset}) {
+                moveToViewController(at: todaysIndex, animated: animated)
+                return todaysIndex
+            }
+        }
+        
+        return .none
+    }
+}
+
+extension ScheduleViewController: UITabBarControllerDelegate {
+    func tabBarController(_ tabBarController: UITabBarController, shouldSelect viewController: UIViewController) -> Bool {
+        guard
+            tabBarController.selectedViewController === viewController,
+            navigationController?.viewControllers.last === self
+            else { return true }
+
+        guard
+            let index = moveToCorrectDate(animated: true),
+            let controller = viewControllers[index] as? SessionsTableViewController
+            else { return true }
+        controller.scrollToCurrentSession(animated: true)
+
+        return true
     }
-  }
 }

trySwift/SessionsTableViewController.swift

@@ -11,7 +11,8 @@ import XLPagerTabStrip
 import TrySwiftData
 
 class SessionsTableViewController: UITableViewController {
-    
+    private lazy var needsToScrollToCurrentSession = Calendar.current.isDateInToday(conferenceDay.date)
+
     var conferenceDay: ConferenceDay
     weak var scheduleViewController: ScheduleViewController?
 
@@ -40,7 +41,12 @@ class SessionsTableViewController: UITableViewController {
 
     override func viewDidAppear(_ animated: Bool) {
         super.viewDidAppear(animated)
-        
+    
+        if needsToScrollToCurrentSession {
+            needsToScrollToCurrentSession = false
+            scrollToCurrentSession(animated: false)
+        }
+
         guard
             let firstSelectableSession = conferenceDay.sessionBlocks
                 .flatMap({ $0.sessions })
@@ -216,3 +222,17 @@ private extension SessionsTableViewController {
         return workshopDetailVC
     }
 }
+
+extension SessionsTableViewController {
+    
+    func scrollToCurrentSession(animated: Bool) {
+        let secondsFromGMT = TimeZone.current.secondsFromGMT()
+        guard
+            let date = Date().changed(second: secondsFromGMT),
+            let section = conferenceDay.sessionBlocks.index(where: { date < $0.endTime }),
+            !conferenceDay.sessionBlocks[section].sessions.isEmpty
+            else { return }
+        
+        tableView.scrollToRow(at: IndexPath(row: 0, section: section), at: .top, animated: animated)
+    }
+}