docs/infrastructure: embed host config json

dev/docs.nix

@@ -1,3 +1,4 @@
+{ self, ... }:
 {
   perSystem =
     { config, pkgs, ... }:
@@ -20,7 +21,8 @@
               };
             }
             ''
-              cd $files
+              cp --no-preserve=mode -r $files/* .
+              cp --no-preserve=mode ${config.packages.docs-json}/*.json docs
               mkdocs build --strict --site-dir $out
             '';
         docs-linkcheck = pkgs.testers.lycheeLinkCheck rec {
@@ -33,6 +35,30 @@
           };
           site = config.packages.docs;
         };
+        docs-json =
+          pkgs.runCommand "docs-json"
+            {
+              buildInputs = [ pkgs.jq ];
+              hosts = pkgs.writeText "hosts.json" (
+                builtins.toJSON (
+                  pkgs.lib.mapAttrs (_: x: {
+                    experimental-features = x.config.nix.settings.experimental-features or [ ];
+                    extra-platforms = x.config.nix.settings.extra-platforms or [ ];
+                    system-features = x.config.nix.settings.system-features or [ ];
+                    inherit (x.config.nixpkgs.hostPlatform) system;
+                    inherit (x.config.nix.settings) sandbox;
+                  }) (self.darwinConfigurations // self.nixosConfigurations)
+                )
+              );
+            }
+            ''
+              mkdir -p $out
+              for host in $(jq -r 'keys[]' $hosts); do
+                jq --arg host "$host" \
+                  '.[$host] | walk(if type == "array" then sort else . end)' \
+                  --sort-keys < $hosts > $out/$host.json
+              done
+            '';
       };
     };
 }