From 40329424b8d47c6261ce93d9b53af555c52a6db7 Mon Sep 17 00:00:00 2001
From: Jochen Sprickerhof <git@jochen.sprickerhof.de>
Date: Sun, 13 Jun 2021 12:23:36 +0200
Subject: [PATCH] Display day change messages

Similar to weechat.look.day_change.
---
 .../ubergeek42/WeechatAndroid/relay/Lines.kt  | 49 +++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/app/src/main/java/com/ubergeek42/WeechatAndroid/relay/Lines.kt b/app/src/main/java/com/ubergeek42/WeechatAndroid/relay/Lines.kt
index 8b5ab65b..87bae21f 100644
--- a/app/src/main/java/com/ubergeek42/WeechatAndroid/relay/Lines.kt
+++ b/app/src/main/java/com/ubergeek42/WeechatAndroid/relay/Lines.kt
@@ -8,6 +8,11 @@ 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.LocalDate
+import java.time.ZoneId
+import java.time.format.DateTimeFormatter
+import java.time.format.FormatStyle
 import java.util.*
 import kotlin.properties.Delegates.observable
 
@@ -46,6 +51,13 @@ class Lines {
     var maxUnfilteredSize = P.lineIncrement
         private set
 
+    private var unfilteredDate: LocalDate? = null
+    private var filteredDate: LocalDate? = null
+
+    private var lastOldDate: LocalDate? = null
+    private lateinit var lastNewDate: LocalDate
+    private lateinit var lastDateLine: Line
+
     // after reconnecting, in *full sync mode*, we are receiving and adding new lines to buffers.
     // there can be inconsistencies; if some lines were added while we were offline,
     // we can't display them, but can display what's on top and what's on bottom.
@@ -91,17 +103,54 @@ class Lines {
         if (status != Status.Fetching) return
         unfiltered.clear()
         filtered.clear()
+        unfilteredDate = null
+        filteredDate = null
+
         for (line in lines) {
             addLast(line)
         }
     }
 
+    private fun getDateChangeLine(oldDate: LocalDate?, newDate: LocalDate) : Line {
+        if (lastOldDate == null || oldDate == null ||
+            lastOldDate != oldDate || lastNewDate != newDate) {
+            val tstamp = newDate.atStartOfDay(ZoneId.systemDefault()).toEpochSecond() * 1000
+            var msg = newDate.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM))
+            if (oldDate != null && oldDate.plusDays(1) != newDate) {
+                msg += " (" +
+                       oldDate.format(DateTimeFormatter.ofLocalizedDate(FormatStyle.MEDIUM)) +
+                       ")"
+            }
+            msg += " --"
+            lastDateLine = Line(++fakePointerCounter, LineSpec.Type.Other, tstamp, "--", msg,
+                                nick = null, isVisible = true, isHighlighted = false,
+                                LineSpec.DisplayAs.Unspecified, LineSpec.NotifyLevel.Low)
+            lastOldDate = oldDate
+            lastNewDate = newDate
+        }
+        return lastDateLine
+    }
+
     fun addLast(line: Line) {
         if (shouldAddSquiggleOnNewLine) {
             shouldAddSquiggleOnNewLine = false
             if (status == Status.Init && unfiltered.size > 0) addLast(SquiggleLine())   // invisible
         }
 
+        val newDate = Instant.ofEpochSecond(line.timestamp / 1000)
+                      .atZone(ZoneId.systemDefault())
+                      .toLocalDate()
+
+        if (unfilteredDate == null || unfilteredDate != newDate) {
+            unfiltered.addLast(getDateChangeLine(unfilteredDate, newDate))
+            unfilteredDate = newDate
+        }
+
+        if (line.isVisible && (filteredDate == null || filteredDate != newDate)) {
+            filtered.addLast(getDateChangeLine(filteredDate, newDate))
+            filteredDate = newDate
+        }
+
         if (shouldAddSquiggleOnNewVisibleLine && line.isVisible) {
             shouldAddSquiggleOnNewVisibleLine = false
             if (status == Status.Init && filtered.size > 0) {