lsp: use nvim-metals instead of lsp-config for scala

config/lsp/default.nix

@@ -3,5 +3,6 @@
     ./lsp.nix
     ./lsp-format.nix
     ./lspkind.nix
+    ./nvim-metals.nix
   ];
 }

config/lsp/lsp.nix

@@ -1,4 +1,4 @@
-{ ... }:
+{ helpers, ... }:
 
 {
   plugins.lsp = {
@@ -16,9 +16,6 @@
       nixd = {
         enable = true;
       };
-      metals = {
-        enable = true;
-      };
     };
     inlayHints = true;
     keymaps = {
@@ -73,4 +70,19 @@
       };
     };
   };
+
+  keymaps = [
+    {
+      mode = [ "n" ];
+      key = "<leader>th";
+      action = helpers.mkRaw ''
+        function()
+          vim.lsp.inlay_hint.enable(not vim.lsp.inlay_hint.is_enabled())
+        end
+      '';
+      options = {
+        desc = "Toggle inlay hints";
+      };
+    }
+  ];
 }

config/lsp/nvim-metals.nix

@@ -0,0 +1,41 @@
+{ pkgs, helpers, ... }:
+
+{
+  extraPlugins = [
+    pkgs.vimPlugins.nvim-metals
+    pkgs.vimPlugins.plenary-nvim
+  ];
+
+  extraPackages = [
+    pkgs.metals
+  ];
+
+  autoGroups.nvim_metals_group = {
+    clear = true;
+  };
+
+  autoCmd = [
+    {
+      event = "FileType";
+      group = "nvim_metals_group";
+      desc = "Initialize nvim-metals";
+      callback = helpers.mkRaw ''
+        function()
+          metals_config = require("metals").bare_config()
+          metals_config.init_options.statusBarProvider = "off"
+          metals_config.settings = {
+            showInferredType = true,
+            showImplicitArguments = false,
+            showImplicitConversionsAndClasses = false,
+            metalsBinaryPath = "${pkgs.lib.getExe pkgs.metals}",
+            useGlobalExecutable = true
+          }
+          vim.lsp.inlay_hint.enable(true)
+          require("metals").initialize_or_attach(metals_config)
+        end
+      '';
+    }
+  ];
+
+  plugins.fidget.enable = true;
+}