discord: add option for different config locations

Different discord branches use different config locations, but home-manager
uses `${configDir}/discord` unconditionally. This adds an option that changes
that to `${configDir}/${configName}`.

modules/programs/discord.nix

@@ -16,6 +16,15 @@ in
   options.programs.discord = {
     enable = lib.mkEnableOption "Discord, the chat platform";
     package = lib.mkPackageOption pkgs "discord" { nullable = true; };
+    configName = lib.mkOption {
+      type = lib.types.str;
+      default = "discord";
+      example = "discordptb";
+      description = ''
+        Name of the subdirectory where {file}`settings.json` is linked under.
+        For example discord-canary uses `discordcanary`.
+      '';
+    };
     settings = lib.mkOption {
       description = ''
         Configuration for Discord.
@@ -62,7 +71,7 @@ in
     in
     {
       home.packages = lib.mkIf (cfg.package != null) [ cfg.package ];
-      home.file."${configDir}/discord/settings.json".source =
+      home.file."${configDir}/${cfg.configName}/settings.json".source =
         jsonFormat.generate "discord-settings" cfg.settings;
     }
   );

tests/modules/programs/discord/default.nix

@@ -1,3 +1,4 @@
 {
   discord-basic-configuration = ./basic-configuration.nix;
+  discord-non-default-config-dir = ./non-default-config-dir.nix;
 }

tests/modules/programs/discord/non-default-config-dir.nix

@@ -0,0 +1,24 @@
+{ pkgs, ... }:
+{
+  config = {
+    programs.discord = {
+      enable = true;
+      configName = "discordcanary";
+      settings.DANGEROUS_ENABLE_DEVTOOLS_ONLY_ENABLE_IF_YOU_KNOW_WHAT_YOURE_DOING = true;
+    };
+
+    nmt.script =
+      let
+        configDir =
+          if pkgs.stdenv.hostPlatform.isLinux then
+            "home-files/.config/discordcanary"
+          else
+            "home-files/Library/Application Support/discordcanary";
+      in
+      ''
+        assertFileExists "${configDir}/settings.json"
+        assertFileContent "${configDir}/settings.json" \
+          ${./basic-settings.json}
+      '';
+  };
+}