Display day change messages

Similar to weechat.look.day_change.

Author: jspricke

app/src/main/java/com/ubergeek42/WeechatAndroid/relay/Lines.kt

@@ -8,6 +8,12 @@ import com.ubergeek42.WeechatAndroid.utils.Linkify
 import com.ubergeek42.WeechatAndroid.utils.Utils
 import com.ubergeek42.WeechatAndroid.utils.invalidatableLazy
 import com.ubergeek42.weechat.Color
+import java.time.Instant
+import java.time.LocalDateTime
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
+import java.time.temporal.ChronoUnit
 import java.util.*
 import kotlin.properties.Delegates.observable
 
@@ -93,12 +99,46 @@ class Lines {
         filtered.clear()
     }
 
+    private fun addDateLine(array: ArrayDeque<Line>, newTimestamp: Long) {
+        var oldDate = LocalDateTime.MIN
+        if (!array.isEmpty()) {
+            oldDate = Instant.ofEpochSecond(array.getLast().timestamp / 1000)
+                      .atZone(ZoneId.systemDefault())
+                      .toLocalDateTime()
+        }
+        val newDate = Instant.ofEpochSecond(newTimestamp / 1000)
+                      .atZone(ZoneId.systemDefault())
+                      .toLocalDateTime()
+        if (newDate.getHour() < oldDate.getHour() ||
+            newDate.getDayOfYear() > oldDate.getDayOfYear() ||
+            newDate.getYear() > oldDate.getYear()) {
+            val midnight = newDate.truncatedTo(ChronoUnit.DAYS)
+            val tstamp = midnight.atZone(ZoneId.systemDefault()).toEpochSecond() * 1000
+            var msg = midnight.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM)) + " --"
+            if (newDate.getDayOfYear() > oldDate.getDayOfYear() + 1 ||
+                newDate.getYear() > oldDate.getYear()) {
+                val oldMidnight = oldDate.truncatedTo(ChronoUnit.DAYS)
+                msg = midnight.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM)) +
+                      " (" +
+                      oldMidnight.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM)) +
+                      ") --"
+            }
+            val dateLine = Line(++fakePointerCounter, LineSpec.Type.Other, tstamp, "-- ", msg,
+                           nick = null, isVisible = true, isHighlighted = false,
+                           LineSpec.DisplayAs.Unspecified, LineSpec.NotifyLevel.Low)
+            array.addLast(dateLine)
+        }
+    }
+
     fun addLast(line: Line) {
         if (shouldAddSquiggleOnNewLine) {
             shouldAddSquiggleOnNewLine = false
             if (status == Status.Init && unfiltered.size > 0) addLast(SquiggleLine())   // invisible
         }
 
+        addDateLine(unfiltered, line.timestamp)
+        if (line.isVisible) addDateLine(filtered, line.timestamp)
+
         if (shouldAddSquiggleOnNewVisibleLine && line.isVisible) {
             shouldAddSquiggleOnNewVisibleLine = false
             if (status == Status.Init && filtered.size > 0) {