revert bd3861c580

revert Merge pull request 'Remove clanModules/*' (#4202) from remove-modules into main

Reviewed-on: https://git.clan.lol/clan/clan-core/pulls/4202

See: https://git.clan.lol/clan/clan-core/issues/4365

Not all modules are migrated.
If they are not migrated, we need to write migration docs and please display the link to the migration docs

clanModules/static-hosts/default.nix

@@ -0,0 +1,63 @@
+{ lib, config, ... }:
+{
+  options.clan.static-hosts = {
+    excludeHosts = lib.mkOption {
+      type = lib.types.listOf lib.types.str;
+      default =
+        if config.clan.static-hosts.topLevelDomain != "" then
+          [ ]
+        else
+          [ config.clan.core.settings.machine.name ];
+      defaultText = lib.literalExpression ''
+        if config.clan.static-hosts.topLevelDomain != "" then
+          [ ]
+        else
+          [ config.clan.core.settings.machine.name ];
+      '';
+      description = "Hosts that should be excluded";
+    };
+    topLevelDomain = lib.mkOption {
+      type = lib.types.str;
+      default = "";
+      description = "Top level domain to reach hosts";
+    };
+  };
+
+  config.networking.hosts =
+    let
+      dir = config.clan.core.settings.directory;
+      machineDir = "${dir}/vars/per-machine";
+      zerotierIpMachinePath = machine: "${machineDir}/${machine}/zerotier/zerotier-ip/value";
+      machinesFileSet = builtins.readDir machineDir;
+      machines = lib.mapAttrsToList (name: _: name) machinesFileSet;
+      networkIpsUnchecked = builtins.map (
+        machine:
+        let
+          fullPath = zerotierIpMachinePath machine;
+        in
+        if builtins.pathExists fullPath then machine else null
+      ) machines;
+      networkIps = lib.filter (machine: machine != null) networkIpsUnchecked;
+      machinesWithIp = lib.filterAttrs (name: _: (lib.elem name networkIps)) machinesFileSet;
+      filteredMachines = lib.filterAttrs (
+        name: _: !(lib.elem name config.clan.static-hosts.excludeHosts)
+      ) machinesWithIp;
+    in
+    lib.filterAttrs (_: value: value != null) (
+      lib.mapAttrs' (
+        machine: _:
+        let
+          path = zerotierIpMachinePath machine;
+        in
+        if builtins.pathExists path then
+          lib.nameValuePair (builtins.readFile path) (
+            if (config.clan.static-hosts.topLevelDomain == "") then
+              [ machine ]
+            else
+              [ "${machine}.${config.clan.static-hosts.topLevelDomain}" ]
+          )
+        else
+          { }
+      ) filteredMachines
+    );
+}