Listing account calendars on the shell, some visual state updates and reacting to calendar setting changes properly.

Wino.Core/Extensions/GoogleIntegratorExtensions.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Web;
+using CommunityToolkit.Diagnostics;
 using Google.Apis.Calendar.v3.Data;
 using Google.Apis.Gmail.v1.Data;
 using MimeKit;
@@ -9,6 +10,7 @@ using Wino.Core.Domain;
 using Wino.Core.Domain.Entities.Calendar;
 using Wino.Core.Domain.Entities.Mail;
 using Wino.Core.Domain.Enums;
+using Wino.Core.Misc;
 using Wino.Services;
 using Wino.Services.Extensions;
 
@@ -170,7 +172,7 @@ namespace Wino.Core.Extensions
 
         public static AccountCalendar AsCalendar(this CalendarListEntry calendarListEntry, Guid accountId)
         {
-            return new AccountCalendar()
+            var calendar = new AccountCalendar()
             {
                 RemoteCalendarId = calendarListEntry.Id,
                 AccountId = accountId,
@@ -179,6 +181,25 @@ namespace Wino.Core.Extensions
                 TimeZone = calendarListEntry.TimeZone,
                 IsPrimary = calendarListEntry.Primary.GetValueOrDefault(),
             };
+
+            // Optional background color.
+            if (calendarListEntry.BackgroundColor != null) calendar.BackgroundColorHex = calendarListEntry.BackgroundColor;
+
+            if (!string.IsNullOrEmpty(calendarListEntry.ForegroundColor))
+            {
+                calendar.TextColorHex = calendarListEntry.ForegroundColor;
+            }
+            else
+            {
+                // Calendars must have text color assigned.
+                // Generate one if not provided.
+
+                var randomColor = RandomFlatColorGenerator.Generate();
+
+                calendar.TextColorHex = randomColor.ToHexString();
+            }
+
+            return calendar;
         }
 
         /// <summary>

Wino.Core/Misc/RandomFlatColorGenerator.cs

@@ -0,0 +1,44 @@
+using System;
+using System.Drawing;
+
+namespace Wino.Core.Misc
+{
+    public static class RandomFlatColorGenerator
+    {
+        public static Color Generate()
+        {
+            Random random = new();
+            int hue = random.Next(0, 360);      // Full hue range
+            int saturation = 70 + random.Next(30); // High saturation (70-100%)
+            int lightness = 50 + random.Next(20);  // Bright colors (50-70%)
+
+            return FromHsl(hue, saturation, lightness);
+        }
+
+        private static Color FromHsl(int h, int s, int l)
+        {
+            double hue = h / 360.0;
+            double saturation = s / 100.0;
+            double lightness = l / 100.0;
+
+            // Conversion from HSL to RGB
+            var chroma = (1 - Math.Abs(2 * lightness - 1)) * saturation;
+            var x = chroma * (1 - Math.Abs((hue * 6) % 2 - 1));
+            var m = lightness - chroma / 2;
+
+            double r = 0, g = 0, b = 0;
+
+            if (hue < 1.0 / 6.0) { r = chroma; g = x; b = 0; }
+            else if (hue < 2.0 / 6.0) { r = x; g = chroma; b = 0; }
+            else if (hue < 3.0 / 6.0) { r = 0; g = chroma; b = x; }
+            else if (hue < 4.0 / 6.0) { r = 0; g = x; b = chroma; }
+            else if (hue < 5.0 / 6.0) { r = x; g = 0; b = chroma; }
+            else { r = chroma; g = 0; b = x; }
+
+            return Color.FromArgb(
+                (int)((r + m) * 255),
+                (int)((g + m) * 255),
+                (int)((b + m) * 255));
+        }
+    }
+}