fix issue with two votes on the same date

fix issue with header not showing correct vote date
split logic for Persistence into different files
create class that deals with voting time, existing votes, and what should be shown based on that

Shared/Persisence/PersistenceADD.swift

@@ -0,0 +1,63 @@
+//
+//  PersistenceADD.swift
+//  Feels
+//
+//  Created by Trey Tartt on 2/17/22.
+//
+
+import CoreData
+
+extension PersistenceController {
+    public func add(mood: Mood, forDate date: Date, entryType: EntryType) {
+        if let existingEntry = getEntry(byDate: date) {
+            viewContext.delete(existingEntry)
+            try? viewContext.save()
+        }
+        
+        let newItem = MoodEntry(context: viewContext)
+        newItem.timestamp = Date()
+        newItem.moodValue = Int16(mood.rawValue)
+        newItem.forDate = date
+        newItem.weekDay = Int16(Calendar.current.component(.weekday, from: date))
+        newItem.canEdit = true
+        newItem.canDelete = true
+        newItem.entryType = Int16(entryType.rawValue)
+        
+        do {
+            try viewContext.save()
+        } catch {
+            let nsError = error as NSError
+            fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
+        }
+    }
+    
+    func fillInMissingDates() {
+        let endDate = ShowBasedOnVoteLogics.getLastDateVoteShouldExist()
+        
+        let fetchRequest = NSFetchRequest<MoodEntry>(entityName: "MoodEntry")
+        fetchRequest.sortDescriptors = [NSSortDescriptor(key: "forDate", ascending: false)]
+        let entries = try! viewContext.fetch(fetchRequest)
+        
+        if let firstEntry = entries.last?.forDate {
+            let allDates: [Date] = Date.dates(from: firstEntry, to: endDate).map({
+                let zeroDate = Calendar.current.date(bySettingHour: 0, minute: 0, second: 0, of: $0)!
+                return zeroDate
+            })
+                    
+            let existingEntries: [Date] = entries.compactMap({
+                if let date = $0.forDate {
+                    let zeroDate = Calendar.current.date(bySettingHour: 0, minute: 0, second: 0, of: date)!
+                    return zeroDate
+                }
+                return nil
+            })
+            
+            let allDatesSet = Set(allDates)
+            let existingEntriesSet = Set(existingEntries)
+            let missing = Array(allDatesSet.subtracting(existingEntriesSet)).sorted(by: >)
+            for date in missing {
+                add(mood: .missing, forDate: date, entryType: .listView)
+            }
+        }
+    }
+}