From 68445b2146ca8a7c153bfaa3d14d9564e912e755 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nikodem=20Rabuli=C5=84ski?= <nikodem@rabulinski.com>
Date: Sat, 4 Jan 2025 20:46:16 +0100
Subject: [PATCH] modules/flake/services: init

---
 README.md                  |  1 +
 flake.nix                  |  1 +
 hosts/default.nix          | 10 +++-
 modules/flake/default.nix  |  1 +
 modules/flake/services.nix | 95 ++++++++++++++++++++++++++++++++++++++
 services/default.nix       |  5 ++
 6 files changed, 111 insertions(+), 2 deletions(-)
 create mode 100644 modules/flake/services.nix
 create mode 100644 services/default.nix

diff --git a/README.md b/README.md
index f7b1f12..c4e3545 100644
--- a/README.md
+++ b/README.md
@@ -24,6 +24,7 @@ Collection of my personal Nix configurations and opinionated NixOS, nix-darwin,
   - system - my opinionated nixos/nix-darwin modules
   - home - my opinionated home-manager modules
   - flake - flake-parts modules
+- services - configs for services I self-host
 - secrets - agenix secrets
 - wrappers - nix packages wrapped with my configs (see: [wrapper-manager](https://github.com/viperML/wrapper-manager))
 - assets - miscellaneous values reused throughout my config
diff --git a/flake.nix b/flake.nix
index 8186624..9fc332d 100644
--- a/flake.nix
+++ b/flake.nix
@@ -16,6 +16,7 @@
         ./modules
         ./wrappers
         ./pkgs
+        ./services
       ];
 
       perSystem =
diff --git a/hosts/default.nix b/hosts/default.nix
index d2e1d5a..3c334c3 100644
--- a/hosts/default.nix
+++ b/hosts/default.nix
@@ -62,7 +62,10 @@
       nixos =
         name: module:
         baseNixos.extendModules {
-          modules = [ module ];
+          modules = [
+            module
+            config.__extraHostConfigs.${name} or { }
+          ];
           specialArgs.configurationName = name;
         };
 
@@ -70,7 +73,10 @@
         name: module:
         let
           eval = baseDarwin._module.args.extendModules {
-            modules = [ module ];
+            modules = [
+              module
+              config.__extraHostConfigs.${name} or { }
+            ];
             specialArgs.configurationName = name;
           };
         in
diff --git a/modules/flake/default.nix b/modules/flake/default.nix
index 2d83b08..78bb73d 100644
--- a/modules/flake/default.nix
+++ b/modules/flake/default.nix
@@ -8,5 +8,6 @@
 
   imports = [
     (import ./configurations.nix { inherit nixpkgs darwin home-manager; })
+    ./services.nix
   ];
 }
diff --git a/modules/flake/services.nix b/modules/flake/services.nix
new file mode 100644
index 0000000..f2f07d4
--- /dev/null
+++ b/modules/flake/services.nix
@@ -0,0 +1,95 @@
+# List of features I want this module to eventually have
+# TODO: Automatic port allocation
+# TODO: Making it possible to conveniently isolate services (running them in NixOS containers)
+# TODO: Handling specializations
+# TODO: Convenient http handling
+# TODO: Automatic backup
+{ config, lib, ... }:
+let
+  serviceModule =
+    { config, ... }:
+    {
+      options = {
+        host = lib.mkOption {
+          type = lib.types.str;
+        };
+        ports = lib.mkOption {
+          type = with lib.types; listOf port;
+          default = [ ];
+        };
+        hosts = lib.mkOption {
+          type = with lib.types; listOf str;
+          default = [ config.host ];
+        };
+        config = lib.mkOption {
+          type = lib.types.deferredModule;
+          default = { };
+        };
+        hostConfig = lib.mkOption {
+          type = with lib.types; attrsOf deferredModule;
+          default = { };
+        };
+      };
+    };
+
+  moduleToHostConfigs =
+    cfg:
+    lib.genAttrs cfg.hosts (host: {
+      imports = [
+        cfg.config
+        (cfg.hostConfig.${host} or { })
+      ];
+    });
+
+  maybeGetPreviousConfigs = acc: host: (acc.${host} or { imports = [ ]; }).imports;
+in
+{
+  _file = ./services.nix;
+
+  options = {
+    services = lib.mkOption {
+      type = with lib.types; attrsOf (submodule serviceModule);
+      default = { };
+    };
+
+    __extraHostConfigs = lib.mkOption {
+      type = with lib.types; attrsOf deferredModule;
+      readOnly = true;
+    };
+  };
+
+  config.__extraHostConfigs =
+    let
+      duplicatePorts = lib.pipe config.services [
+        lib.attrValues
+        (map (cfg: cfg.ports))
+        lib.flatten
+        (lib.groupBy' (cnt: _: cnt + 1) 0 toString)
+        (lib.filterAttrs (_: cnt: cnt > 1))
+        lib.attrNames
+      ];
+      assertMsg =
+        let
+          plural = lib.length duplicatePorts > 1;
+        in
+        "\nBad service config:\nThe following port${if plural then "s" else ""} ${
+          if plural then "were" else "was"
+        } declared multiple times: ${lib.concatStringsSep ", " duplicatePorts}";
+      # Here I collect all the services.<name>.config into a flat
+      # __extraHostConfigs.<host>.imports = [
+      #   ...
+      # ]
+      # so that I can easily import them in hosts/default.nix
+      hostConfigs = lib.pipe config.services [
+        lib.attrValues
+        (lib.foldl' (
+          acc: cfg:
+          acc
+          // lib.mapAttrs (host: c: {
+            imports = c.imports ++ (maybeGetPreviousConfigs acc host);
+          }) (moduleToHostConfigs cfg)
+        ) { })
+      ];
+    in
+    if duplicatePorts != [ ] then throw assertMsg else hostConfigs;
+}
diff --git a/services/default.nix b/services/default.nix
new file mode 100644
index 0000000..1f0f2c2
--- /dev/null
+++ b/services/default.nix
@@ -0,0 +1,5 @@
+{
+  imports = [
+
+  ];
+}