From ef64bc598f28818d56c86629dad98b468af9c071 Mon Sep 17 00:00:00 2001
From: Robert Helgesson <robert@rycee.net>
Date: Wed, 2 Oct 2019 22:00:58 +0200
Subject: [PATCH] redshift: add assertion on latitude and longitude

These two options must be set if the provider is set to "manual".

Closes #841

(cherry picked from commit 8bddc1adab0f7a51476f819fa2197353e8e1d136)
---
 modules/services/redshift.nix | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/modules/services/redshift.nix b/modules/services/redshift.nix
index b1351dfb..5d8431ad 100644
--- a/modules/services/redshift.nix
+++ b/modules/services/redshift.nix
@@ -123,6 +123,18 @@ in
   };
 
   config = mkIf cfg.enable {
+    assertions = [
+      {
+        assertion =
+          cfg.provider == "manual"
+          -> cfg.latitude != null && cfg.longitude != null;
+        message =
+          "Must provide services.redshift.latitude and"
+          + " services.redshift.latitude when"
+          + " services.redshift.provider is set to \"manual\".";
+      }
+    ];
+
     systemd.user.services.redshift = {
       Unit = {
         Description = "Redshift colour temperature adjuster";