From 37d4634ee0a7d9d6fca45a9ea6035fa50ae8fea3 Mon Sep 17 00:00:00 2001
From: Sean Buckley <sean.bck@gmail.com>
Date: Thu, 28 Oct 2021 15:01:50 -0400
Subject: [PATCH] restructure hosts directory

---
 hosts/cube/default.nix                        |  4 --
 hosts/hp/default.nix                          |  4 --
 hosts/nixdev/default.nix                      |  4 --
 hosts/slate/default.nix                       |  4 --
 .../cube/default.nix}                         |  0
 .../hp/default.nix}                           |  0
 .../nixdev/default.nix}                       |  0
 .../slate/default.nix}                        |  0
 lib/hosts.nix                                 | 42 ++++++++++++-------
 9 files changed, 28 insertions(+), 30 deletions(-)
 delete mode 100644 hosts/cube/default.nix
 delete mode 100644 hosts/hp/default.nix
 delete mode 100644 hosts/nixdev/default.nix
 delete mode 100644 hosts/slate/default.nix
 rename hosts/{cube/configuration.nix => x86_64-linux/cube/default.nix} (100%)
 rename hosts/{hp/configuration.nix => x86_64-linux/hp/default.nix} (100%)
 rename hosts/{nixdev/configuration.nix => x86_64-linux/nixdev/default.nix} (100%)
 rename hosts/{slate/configuration.nix => x86_64-linux/slate/default.nix} (100%)

diff --git a/hosts/cube/default.nix b/hosts/cube/default.nix
deleted file mode 100644
index cb764cd..0000000
--- a/hosts/cube/default.nix
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  system = "x86_64-linux";
-  module = ./configuration.nix;
-}
diff --git a/hosts/hp/default.nix b/hosts/hp/default.nix
deleted file mode 100644
index cb764cd..0000000
--- a/hosts/hp/default.nix
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  system = "x86_64-linux";
-  module = ./configuration.nix;
-}
diff --git a/hosts/nixdev/default.nix b/hosts/nixdev/default.nix
deleted file mode 100644
index cb764cd..0000000
--- a/hosts/nixdev/default.nix
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  system = "x86_64-linux";
-  module = ./configuration.nix;
-}
diff --git a/hosts/slate/default.nix b/hosts/slate/default.nix
deleted file mode 100644
index cb764cd..0000000
--- a/hosts/slate/default.nix
+++ /dev/null
@@ -1,4 +0,0 @@
-{
-  system = "x86_64-linux";
-  module = ./configuration.nix;
-}
diff --git a/hosts/cube/configuration.nix b/hosts/x86_64-linux/cube/default.nix
similarity index 100%
rename from hosts/cube/configuration.nix
rename to hosts/x86_64-linux/cube/default.nix
diff --git a/hosts/hp/configuration.nix b/hosts/x86_64-linux/hp/default.nix
similarity index 100%
rename from hosts/hp/configuration.nix
rename to hosts/x86_64-linux/hp/default.nix
diff --git a/hosts/nixdev/configuration.nix b/hosts/x86_64-linux/nixdev/default.nix
similarity index 100%
rename from hosts/nixdev/configuration.nix
rename to hosts/x86_64-linux/nixdev/default.nix
diff --git a/hosts/slate/configuration.nix b/hosts/x86_64-linux/slate/default.nix
similarity index 100%
rename from hosts/slate/configuration.nix
rename to hosts/x86_64-linux/slate/default.nix
diff --git a/lib/hosts.nix b/lib/hosts.nix
index 96cb1a3..2db90eb 100644
--- a/lib/hosts.nix
+++ b/lib/hosts.nix
@@ -1,20 +1,34 @@
 { path, nixpkgs, nixosModule }:
 let
 
-  hostMetadata = builtins.mapAttrs
-    (name: _: import (path + "/${name}"))
-    (builtins.readDir path);
+  inherit (builtins) mapAttrs attrValues attrNames readDir foldl' listToAttrs;
 
-  getHostConfig = hostName: hostMeta:
-    nixpkgs.lib.nixosSystem
-      {
-        inherit (hostMeta) system;
-        modules = [
-          (nixosModule)
-          (hostMeta.module)
-          (_: { networking.hostName = hostName; })
-        ];
-      };
+  # grab a list of systems, with associated hostnames
+  # { x86_64-linux = [ "host1" "host2" ]; }
+  sysToHosts = mapAttrs
+    (system: _: attrNames (readDir "${path}/${system}"))
+    (readDir path);
+
+  # invert the attrset, from {sys=[name]} to {name=sys}
+  # { host1 = "x86_64-linux"; host2 = "x86_64-linux"; }
+  hostToSys = foldl' (a: b: a // b) { }
+    (attrValues
+      (mapAttrs
+        (system: hosts: listToAttrs (map (name: { inherit name; value = system; }) hosts))
+        sysToHosts));
+
+  # build system configurations
+  # { host1 = <nixosConfiguration>; host2 = <nixosConfiguration>; }
+  hostToConfig = mapAttrs
+    (hostName: system: nixpkgs.lib.nixosSystem {
+      inherit system;
+      modules = [
+        (nixosModule)
+        ("${path}/${system}/${hostName}")
+        (_: { networking.hostName = hostName; })
+      ];
+    })
+    hostToSys;
 
 in
-builtins.mapAttrs getHostConfig hostMetadata
+hostToConfig