plugins/nvim-jdtls: init + tests (#298)

plugins/default.nix

@@ -27,6 +27,7 @@
     ./languages/ledger.nix
     ./languages/markdown-preview.nix
     ./languages/nix.nix
+    ./languages/nvim-jdtls.nix
     ./languages/plantuml-syntax.nix
     ./languages/rust.nix
     ./languages/sniprun.nix

plugins/languages/nvim-jdtls.nix

@@ -0,0 +1,81 @@
+{
+  pkgs,
+  config,
+  lib,
+  ...
+}:
+with lib; let
+  cfg = config.plugins.nvim-jdtls;
+  helpers = import ../helpers.nix {inherit lib;};
+in {
+  options.plugins.nvim-jdtls =
+    helpers.extraOptionsOptions
+    // {
+      enable = mkEnableOption "nvim-jdtls";
+
+      package = helpers.mkPackageOption "nvim-jdtls" pkgs.vimPlugins.nvim-jdtls;
+
+      cmd = mkOption {
+        type = types.listOf types.str;
+        description = "The command that starts the language server";
+        default = ["${pkgs.jdt-language-server}/bin/jdt-language-server"];
+      };
+
+      rootDir =
+        helpers.defaultNullOpts.mkNullable
+        (types.either types.str helpers.rawType)
+        ''{ __raw = "require('jdtls.setup').find_root({'.git', 'mvnw', 'gradlew'})"; }''
+        ''
+          This is the default if not provided, you can remove it. Or adjust as needed.
+          One dedicated LSP server & client will be started per unique root_dir
+        '';
+
+      settings =
+        helpers.mkNullOrOption (types.attrs)
+        ''
+          Here you can configure eclipse.jdt.ls specific settings
+          See https://github.com/eclipse/eclipse.jdt.ls/wiki/Running-the-JAVA-LS-server-from-the-command-line#initialize-request
+          for a list of options.
+        '';
+
+      initOptions =
+        helpers.mkNullOrOption (types.attrs)
+        ''
+          Language server `initializationOptions`
+          You need to extend the `bundles` with paths to jar files if you want to use additional
+          eclipse.jdt.ls plugins.
+
+          See https://github.com/mfussenegger/nvim-jdtls#java-debug-installation
+
+          If you don't plan on using the debugger or other eclipse.jdt.ls plugins, ignore this option
+        '';
+    };
+
+  config = let
+    options =
+      {
+        inherit (cfg) cmd;
+        root_dir = cfg.rootDir;
+        inherit (cfg) settings;
+        init_options = cfg.initOptions;
+      }
+      // cfg.extraOptions;
+  in
+    mkIf cfg.enable {
+      extraPlugins = [cfg.package];
+
+      extraPackages = [pkgs.jdt-language-server];
+
+      autoCmd = [
+        {
+          event = "FileType";
+          pattern = "java";
+          callback.__raw = ''
+            function ()
+              require('jdtls').start_or_attach(${helpers.toLuaObject options})
+            end
+          '';
+        }
+      ];
+    };
+}