Update Import and Export to account for missing year

- Add custom ics tag Constants.MISSING_YEAR that would be set to 1 if an event has the Constants.MISSING_YEAR_FLAG
- While Importing, check for the presence of the custom tag. If it is present and set to 1, add the Constants.MISSING_YEAR_FLAG to the event

app/src/main/kotlin/com/simplemobiletools/calendar/pro/activities/MainActivity.kt

@@ -628,7 +628,7 @@ class MainActivity : SimpleActivity(), RefreshRecyclerViewListener {
                     val flags = if(format in yearDateFormats){
                         FLAG_ALL_DAY
                     }else {
-                        FLAG_ALL_DAY or FLAG_MISSING_YEAR_EVENT
+                        FLAG_ALL_DAY or FLAG_MISSING_YEAR
                     }
 
                     val timestamp = date.time / 1000L

app/src/main/kotlin/com/simplemobiletools/calendar/pro/helpers/Constants.kt

@@ -93,7 +93,7 @@ const val REPEAT_ORDER_WEEKDAY = 4                      // i.e. every 4th sunday
 // special event flags
 const val FLAG_ALL_DAY = 1
 const val FLAG_IS_PAST_EVENT = 2
-const val FLAG_MISSING_YEAR_EVENT = 4
+const val FLAG_MISSING_YEAR = 4
 
 // constants related to ICS file exporting / importing
 const val BEGIN_CALENDAR = "BEGIN:VCALENDAR"
@@ -130,6 +130,7 @@ const val SEQUENCE = "SEQUENCE"
 // this tag isn't a standard ICS tag, but there's no official way of adding a category color in an ics file
 const val CATEGORY_COLOR = "X-SMT-CATEGORY-COLOR:"
 const val CATEGORY_COLOR_LEGACY = "CATEGORY_COLOR:"
+const val MISSING_YEAR = "X-SMT-MISSING-YEAR:"
 
 const val DISPLAY = "DISPLAY"
 const val EMAIL = "EMAIL"

app/src/main/kotlin/com/simplemobiletools/calendar/pro/helpers/EventsHelper.kt

@@ -307,7 +307,7 @@ class EventsHelper(val context: Context) {
                 (anniversaryEventId != -1L && it.eventType == anniversaryEventId)){
                 val eventStartDate = Formatter.getDateFromTS(it.startTS)
                 val originalEventStartDate = Formatter.getDateFromTS(originalEvent.startTS)
-                if(it.flags and FLAG_MISSING_YEAR_EVENT == 0){
+                if(it.hasMissingYear().not()){
                     val years = (eventStartDate.year - originalEventStartDate.year).coerceAtLeast(0)
                     if(years > 0){
                         it.title = "${it.title} ($years)"

app/src/main/kotlin/com/simplemobiletools/calendar/pro/helpers/IcsExporter.kt

@@ -58,6 +58,7 @@ class IcsExporter {
                         event.startTS.let { out.writeLn("$DTSTART:${Formatter.getExportedTime(it * 1000L)}") }
                         event.endTS.let { out.writeLn("$DTEND:${Formatter.getExportedTime(it * 1000L)}") }
                     }
+                    event.hasMissingYear().let { out.writeLn("$MISSING_YEAR${if(it) 1 else 0}") }
 
                     out.writeLn("$DTSTAMP$exportTime")
                     out.writeLn("$STATUS$CONFIRMED")

app/src/main/kotlin/com/simplemobiletools/calendar/pro/helpers/IcsImporter.kt

@@ -128,6 +128,10 @@ class IcsImporter(val activity: SimpleActivity) {
                         if (color.trimStart('-').areDigitsOnly()) {
                             curCategoryColor = Integer.parseInt(color)
                         }
+                    } else if (line.startsWith(MISSING_YEAR)) {
+                        if (line.substring(MISSING_YEAR.length) == "1") {
+                            curFlags = curFlags or FLAG_MISSING_YEAR
+                        }
                     } else if (line.startsWith(CATEGORIES) && !overrideFileEventTypes) {
                         val categories = line.substring(CATEGORIES.length)
                         tryAddCategories(categories)

app/src/main/kotlin/com/simplemobiletools/calendar/pro/models/Event.kt

@@ -138,6 +138,7 @@ data class Event(
     }
 
     fun getIsAllDay() = flags and FLAG_ALL_DAY != 0
+    fun hasMissingYear() = flags and FLAG_MISSING_YEAR != 0
 
     fun getReminders() = setOf(
         Reminder(reminder1Minutes, reminder1Type),