implement java module

modules/plugins/languages/java.nix

@@ -8,11 +8,60 @@
   inherit (lib.modules) mkIf mkMerge;
   inherit (lib.meta) getExe;
   inherit (lib.lists) isList;
-  inherit (lib.types) either listOf package str;
+  inherit (builtins) attrNames;
+  inherit (lib.types) either listOf package str enum;
   inherit (lib.nvim.types) mkGrammarOption;
   inherit (lib.nvim.lua) expToLua;
+  inherit (lib.nvim.attrsets) mapListToAttrs;
+  inherit (lib.nvim.dag) entryBefore;
+  inherit (lib.generators) mkLuaInline;
 
   cfg = config.vim.languages.java;
+
+  defaultServers = ["jdtls"];
+  servers = {
+    jdtls = {
+      enable = true;
+      cmd =
+        mkLuaInline
+        /*
+        lua
+        */
+        ''
+          {
+            '${getExe pkgs.jdt-language-server}',
+            '-configuration',
+            get_jdtls_config_dir(),
+            '-data',
+            get_jdtls_workspace_dir(),
+            get_jdtls_jvm_args(),
+          }
+        '';
+      filetypes = ["java"];
+      root_markers = [
+        # Multi-module projects
+        ".git"
+        "build.gradle"
+        "build.gradle.kts"
+        # Single-module projects
+        "build.xml" # Ant
+        "pom.xml" # Maven
+        "settings.gradle" # Gradle
+        "settings.gradle.kts" # Gradle
+      ];
+      init_options = {
+        workspace = mkLuaInline "get_jdtls_workspace_dir()";
+        jvm_args = {};
+        os_config = mkLuaInline "nil";
+      };
+      handlers = {
+        "textDocument/codeAction" = mkLuaInline "jdtls_on_textdocument_codeaction";
+        "textDocument/rename" = mkLuaInline "jdtls_on_textdocument_rename";
+        "workspace/applyEdit" = mkLuaInline "jdtls_on_workspace_applyedit";
+        "language/status" = mkLuaInline "vim.schedule_wrap(jdtls_on_language_status)";
+      };
+    };
+  };
 in {
   options.vim.languages.java = {
     enable = mkEnableOption "Java language support";
@@ -23,30 +72,107 @@ in {
     };
 
     lsp = {
-      enable = mkEnableOption "Java LSP support (java-language-server)" // {default = config.vim.lsp.enable;};
+      enable = mkEnableOption "Java LSP support" // {default = config.vim.lsp.enable;};
-      package = mkOption {
+      servers = mkOption {
-        description = "java language server package, or the command to run as a list of strings";
+        description = "Java LSP server to use";
-        example = ''[lib.getExe pkgs.jdt-language-server "-data" "~/.cache/jdtls/workspace"]'';
+        type = listOf (enum (attrNames servers));
-        type = either package (listOf str);
+        default = defaultServers;
-        default = pkgs.jdt-language-server;
       };
     };
   };
 
   config = mkIf cfg.enable (mkMerge [
     (mkIf cfg.lsp.enable {
-      vim.lsp.lspconfig.enable = true;
+      vim.luaConfigRC.java-stuff =
-      vim.lsp.lspconfig.sources.jdtls = ''
+        entryBefore ["lsp-servers"]
-        lspconfig.jdtls.setup {
+        /*
-          capabilities = capabilities,
+        lua
-          on_attach = default_on_attach,
+        */
-          cmd = ${
+        ''
-          if isList cfg.lsp.package
+          local jdtls_handlers = require 'vim.lsp.handlers'
-          then expToLua cfg.lsp.package
+
-          else ''{"${getExe cfg.lsp.package}", "-data", vim.fn.stdpath("cache").."/jdtls/workspace"}''
+          local jdtls_env = {
-        },
+            HOME = vim.uv.os_homedir(),
+            XDG_CACHE_HOME = os.getenv 'XDG_CACHE_HOME',
+            JDTLS_JVM_ARGS = os.getenv 'JDTLS_JVM_ARGS',
           }
+
+          local function get_cache_dir()
+            return jdtls_env.XDG_CACHE_HOME and jdtls_env.XDG_CACHE_HOME or jdtls_env.HOME .. '/.cache'
+          end
+
+          local function get_jdtls_cache_dir()
+            return get_cache_dir() .. '/jdtls'
+          end
+
+          local function get_jdtls_config_dir()
+            return get_jdtls_cache_dir() .. '/config'
+          end
+
+          local function get_jdtls_workspace_dir()
+            return get_jdtls_cache_dir() .. '/workspace'
+          end
+
+          local function get_jdtls_jvm_args()
+            local args = {}
+            for a in string.gmatch((jdtls_env.JDTLS_JVM_ARGS or '''), '%S+') do
+              local arg = string.format('--jvm-arg=%s', a)
+              table.insert(args, arg)
+            end
+            return unpack(args)
+          end
+
+          -- TextDocument version is reported as 0, override with nil so that
+          -- the client doesn't think the document is newer and refuses to update
+          -- See: https://github.com/eclipse/eclipse.jdt.ls/issues/1695
+          local function jdtls_fix_zero_version(workspace_edit)
+            if workspace_edit and workspace_edit.documentChanges then
+              for _, change in pairs(workspace_edit.documentChanges) do
+                local text_document = change.textDocument
+                if text_document and text_document.version and text_document.version == 0 then
+                  text_document.version = nil
+                end
+              end
+            end
+            return workspace_edit
+          end
+
+          local function jdtls_on_textdocument_codeaction(err, actions, ctx)
+            for _, action in ipairs(actions) do
+              -- TODO: (steelsojka) Handle more than one edit?
+              if action.command == 'java.apply.workspaceEdit' then -- 'action' is Command in java format
+                action.edit = jdtls_fix_zero_version(action.edit or action.arguments[1])
+              elseif type(action.command) == 'table' and action.command.command == 'java.apply.workspaceEdit' then -- 'action' is CodeAction in java format
+                action.edit = jdtls_fix_zero_version(action.edit or action.command.arguments[1])
+              end
+            end
+
+            jdtls_handlers[ctx.method](err, actions, ctx)
+          end
+
+          local function jdtls_on_textdocument_rename(err, workspace_edit, ctx)
+            jdtls_handlers[ctx.method](err, jdtls_fix_zero_version(workspace_edit), ctx)
+          end
+
+          local function jdtls_on_workspace_applyedit(err, workspace_edit, ctx)
+            jdtls_handlers[ctx.method](err, jdtls_fix_zero_version(workspace_edit), ctx)
+          end
+
+          -- Non-standard notification that can be used to display progress
+          local function jdtls_on_language_status(_, result)
+            local command = vim.api.nvim_command
+            command 'echohl ModeMsg'
+            command(string.format('echo "%s"', result.message))
+            command 'echohl None'
+          end
         '';
+
+      vim.lsp.servers =
+        mapListToAttrs (n: {
+          name = n;
+          value = servers.${n};
+        })
+        cfg.lsp.servers;
     })
 
     (mkIf cfg.treesitter.enable {