From 6b73e32cdae2efa9a7c919863ba27b168b3db329 Mon Sep 17 00:00:00 2001
From: Sven van Heugten <sven@memcmp.org>
Date: Sat, 17 Jan 2026 18:01:14 +0100
Subject: [PATCH] Implement fading alarm

---
 NightLight.Core/Models.fs                 |  7 ++++++-
 NightLight.Core/NightLightStateMachine.fs |  6 +++++-
 NightLight.Core/PartsOfDay.fs             | 20 +++++++++++++++-----
 3 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/NightLight.Core/Models.fs b/NightLight.Core/Models.fs
index 10fe7f8..18e4ef3 100644
--- a/NightLight.Core/Models.fs
+++ b/NightLight.Core/Models.fs
@@ -79,7 +79,12 @@ type internal State =
     | On
     | Off
 
-type internal Brightness = Brightness of int
+type internal Brightness =
+    | Brightness of int
+
+    member this.Scale(b: float) =
+        match this with
+        | Brightness brightness -> Brightness <| int (float brightness * b)
 
 type internal Color =
     | ColorByCoordinates of float * float
diff --git a/NightLight.Core/NightLightStateMachine.fs b/NightLight.Core/NightLightStateMachine.fs
index a91b4be..f68d66d 100644
--- a/NightLight.Core/NightLightStateMachine.fs
+++ b/NightLight.Core/NightLightStateMachine.fs
@@ -48,7 +48,11 @@ let internal createOrUpdateNightLightState
 
             light,
             { Color = color
-              Brightness = brightness
+              Brightness =
+                if alarm && light.ControlledWithRemote <> NonRemote then
+                    brightness.Scale(getAlarmWeight time)
+                else
+                    brightness
               State = if alarm then On else previousState })
         |> Map.ofSeq
 
diff --git a/NightLight.Core/PartsOfDay.fs b/NightLight.Core/PartsOfDay.fs
index ac430f4..621ae14 100644
--- a/NightLight.Core/PartsOfDay.fs
+++ b/NightLight.Core/PartsOfDay.fs
@@ -6,11 +6,21 @@ type PartOfDay =
     | Day
     | Night
 
+let private startOfDay = TimeSpan.FromHours 6
+let private endOfDay = TimeSpan.FromHours 20.5
+
 let getPartOfDay (dateTime: DateTime) =
     match dateTime with
-    | _ when
-        dateTime.TimeOfDay >= TimeSpan.FromHours 6
-        && dateTime.TimeOfDay < TimeSpan.FromHours 20.5
-        ->
-        Day
+    | _ when dateTime.TimeOfDay >= startOfDay && dateTime.TimeOfDay < endOfDay -> Day
     | _ -> Night
+
+let getAlarmWeight (dateTime: DateTime) =
+    let currentTime = dateTime.TimeOfDay
+    let alarmEnd = startOfDay + TimeSpan(0, 15, 0)
+    let totalSeconds = (alarmEnd - startOfDay).TotalSeconds
+
+    if startOfDay <= currentTime && currentTime <= alarmEnd then
+        let elapsedSeconds = (currentTime - startOfDay).TotalSeconds
+        elapsedSeconds / totalSeconds
+    else
+        1.0