feat: macro support in the start ls command

Fixes 336

Signed-off-by: azerr <[email protected]>

docs/DeveloperGuide.md

@@ -250,6 +250,8 @@ Here is a sample snippet to associate the `XML` language with the `myLanguageSer
 </extensions>
 ```
 
+#### Language ID
+
 Some language servers use
 the [TextDocumentItem#languageId](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocumentItem)
 field to identify the document on the server side.
@@ -267,6 +269,8 @@ To do that, you can declare it with the `languageId` attribute:
 </extensions>
 ```
 
+#### Document Matcher
+
 If the language check is not enough, you can implement a
 custom [DocumentMatcher](https://github.com/redhat-developer/lsp4ij/blob/main/src/main/java/com/redhat/devtools/lsp4ij/DocumentMatcher.java).
 For instance your language server could be mapped to the `Java` language, and you could implement a DocumentMatcher

docs/UserDefinedLanguageServer.md

@@ -9,12 +9,12 @@ The main idea is to:
 
  * install the language server and its requirements(ex : `Node.js` to 
 execute a language server written in JavaScript/TypeScript), 
- * declare the command which starts the language server.
+ * declare the command that starts the language server.
  * associate the language server with the proper files (identified by IntelliJ Language, File Type or file name pattern)
 
 ## New Language Server dialog
 
-To create a new `User-defined language server` you need to open the `New Language Server` dialog, either:
+In order to create a new `User-defined language server`, you need to open the `New Language Server` dialog, either:
 
  * from the menu on the right of the LSP console:
 
@@ -30,7 +30,7 @@ Once you clicked on either of them, the dialog will appear:
 
 ### Server tab
 
-The `Server tab` requires to fill the `server name` and the `command` which will start the language server.
+The `Server tab` requires the `server name` and `command` fields to be set.
 
 Here is a sample with the [typescript-language-server](https://github.com/typescript-language-server/typescript-language-server):
 
@@ -42,7 +42,7 @@ The environment variables accessible by the process are populated with
 [EnvironmentUtil.getEnvironmentMap()](https://github.com/JetBrains/intellij-community/blob/3a527a2c9b56209c09852ba7bc89d80bc31e1c04/platform/util/src/com/intellij/util/EnvironmentUtil.java#L85) 
 which retrieves system variables.
 
-It is possible too to add custom environment variables via the field `Environment variables`:
+It is also possible to add custom environment variables via the `Environment variables` field:
 
 ![Environment Variables](./images/user-defined-ls/EnvironmentVariables.png)
 
@@ -51,6 +51,21 @@ Depending on your OS, the environment variables may not be accessible. To make s
 * with `Windows OS`: `cmd /c command_to_start_your_ls`
 * with `Linux`, `Mac OS`: `sh -c command_to_start_your_ls`
 
+#### Macro syntax
+
+You can use [built-in macros](https://www.jetbrains.com/help/idea/built-in-macros.html) in your command. You could, for instance, store the language server in your project (to share it with your team) 
+and write a command that references it in a portable way to start it.
+
+That command might look like this:
+
+`$PROJECT_DIR$/path/to/your/start/command`
+
+Here is an example with Scala Language Server's `metals.bat` stored at the root of the project:
+
+![Macro syntax](./images/user-defined-ls/Macro.png)
+
+When commands contain macros, their resolved value is visible below the `Command` field.
+
 ### Mappings tab
 
 The `Mappings tab` provides the capability to `associate the language server with the proper files` identified by: 
@@ -73,6 +88,14 @@ NOTE: it is better to use file name pattern instead of creating custom file type
 IntelliJ Community support `TypeScript syntax coloration` with `TextMate`. If you define a file type, you will
 lose syntax coloration.
 
+#### Language ID
+
+When you declare mapping, you can fill the `Language ID` column which is used to declare the LSP [TextDocumentItem#languageId](https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocumentItem)
+to identify the document on the server side.
+
+For instance the [vscode-css-languageservice](https://github.com/microsoft/vscode-css-languageservice) (used by the vscode CSS language server) expects the `languageId` to be `css` or `less`.
+To do that, you can declare it with the `languageId` attribute:
+
 ### Configuration tab
 
 The `Configuration tab` allows to configure the language server with the expected (generally JSON format) configuration. 

src/main/java/com/redhat/devtools/lsp4ij/launching/ui/NewLanguageServerDialog.java

@@ -84,7 +84,7 @@ public NewLanguageServerDialog(@NotNull Project project) {
         // Template combo
         createTemplateCombo(builder);
         // Create server name,  command line, mappings, configuration UI
-        this.languageServerPanel = new LanguageServerPanel(builder, null, LanguageServerPanel.EditionMode.NEW_USER_DEFINED);
+        this.languageServerPanel = new LanguageServerPanel(builder, null, LanguageServerPanel.EditionMode.NEW_USER_DEFINED, project);
 
         // Add validation
         addValidator(this.languageServerPanel.getServerName());

src/main/java/com/redhat/devtools/lsp4ij/server/definition/launching/UserDefinedLanguageServerDefinition.java

@@ -15,6 +15,7 @@
 
 import com.google.gson.JsonParser;
 import com.google.gson.annotations.SerializedName;
+import com.intellij.execution.util.ProgramParametersUtil;
 import com.intellij.openapi.project.Project;
 import com.redhat.devtools.lsp4ij.client.LanguageClientImpl;
 import com.redhat.devtools.lsp4ij.server.StreamConnectionProvider;
@@ -64,7 +65,22 @@ public UserDefinedLanguageServerDefinition(@NotNull String id,
 
     @Override
     public @NotNull StreamConnectionProvider createConnectionProvider(@NotNull Project project) {
-        return new UserDefinedStreamConnectionProvider(commandLine, userEnvironmentVariables, includeSystemEnvironmentVariables, this);
+        String resolvedCommandLine = resolveCommandLine(commandLine, project);
+        return new UserDefinedStreamConnectionProvider(resolvedCommandLine,
+                userEnvironmentVariables,
+                includeSystemEnvironmentVariables,
+                this);
+    }
+
+    /**
+     * Returns the resolved command line with expanded macros.
+     *
+     * @param project the project.
+     * @return the resolved command line with expanded macros.
+     * @see <a href="https://www.jetbrains.com/help/idea/built-in-macros.html">Built In Macro</a>
+     */
+    public static String resolveCommandLine(@NotNull String commandLine, @NotNull Project project) {
+        return ProgramParametersUtil.expandPathAndMacros(commandLine, null, project);
     }
 
     @Override

src/main/java/com/redhat/devtools/lsp4ij/settings/LanguageServerView.java

@@ -285,7 +285,7 @@ private JPanel createSettings(JComponent description, boolean launchingServerDef
         this.languageServerPanel = new LanguageServerPanel(builder,
                 description,
                 launchingServerDefinition ? LanguageServerPanel.EditionMode.EDIT_USER_DEFINED :
-                        LanguageServerPanel.EditionMode.EDIT_EXTENSION);
+                        LanguageServerPanel.EditionMode.EDIT_EXTENSION, project);
         this.mappingPanel = languageServerPanel.getMappingsPanel();
         return builder
                 .addComponentFillVertically(new JPanel(), 50)

src/main/java/com/redhat/devtools/lsp4ij/settings/ui/LanguageServerPanel.java

@@ -12,7 +12,9 @@
 
 import com.intellij.execution.configuration.EnvironmentVariablesComponent;
 import com.intellij.ide.BrowserUtil;
+import com.intellij.openapi.project.Project;
 import com.intellij.openapi.ui.ComboBox;
+import com.intellij.openapi.util.NlsContexts;
 import com.intellij.ui.ContextHelpLabel;
 import com.intellij.ui.PortField;
 import com.intellij.ui.SimpleListCellRenderer;
@@ -22,13 +24,17 @@
 import com.intellij.ui.components.JBTextField;
 import com.intellij.ui.scale.JBUIScale;
 import com.intellij.util.ui.FormBuilder;
+import com.intellij.util.ui.UIUtil;
 import com.intellij.util.ui.components.BorderLayoutPanel;
 import com.redhat.devtools.lsp4ij.LanguageServerBundle;
+import com.redhat.devtools.lsp4ij.server.definition.launching.UserDefinedLanguageServerDefinition;
 import com.redhat.devtools.lsp4ij.settings.ErrorReportingKind;
 import com.redhat.devtools.lsp4ij.settings.ServerTrace;
 import org.jetbrains.annotations.NotNull;
 
 import javax.swing.*;
+import javax.swing.event.DocumentEvent;
+import javax.swing.event.DocumentListener;
 import java.awt.*;
 
 /**
@@ -43,6 +49,10 @@
  */
 public class LanguageServerPanel {
 
+    private static final int COMMAND_LENGTH_MAX = 140;
+
+    private final Project project;
+
     public enum EditionMode {
         NEW_USER_DEFINED,
         EDIT_USER_DEFINED,
@@ -62,7 +72,8 @@ public enum EditionMode {
 
     private LanguageServerInitializationOptionsWidget initializationOptionsWidget;
 
-    public LanguageServerPanel(FormBuilder builder, JComponent description, EditionMode mode) {
+    public LanguageServerPanel(FormBuilder builder, JComponent description, EditionMode mode, Project project) {
+        this.project = project;
         createUI(builder, description, mode);
     }
 
@@ -184,7 +195,58 @@ private void createCommandLineField(FormBuilder builder) {
         commandLine = new CommandLineWidget();
         JBScrollPane scrollPane = new JBScrollPane(commandLine);
         scrollPane.setMinimumSize(new Dimension(JBUIScale.scale(600), JBUIScale.scale(100)));
+        JLabel previewCommandLabel = createLabelForComponent("", scrollPane);
+        updatePreviewCommand(commandLine, previewCommandLabel, project);
         builder.addLabeledComponent(LanguageServerBundle.message("language.server.command"), scrollPane, true);
+        builder.addComponent(previewCommandLabel, 0);
+    }
+
+    /**
+     * Update preview command label with expanded macro result if needed.
+     *
+     * @param commandLine         the command line which could contains macro syntax.
+     * @param previewCommandLabel the preview command label.
+     * @param project             the project.
+     * @see <a href="https://www.jetbrains.com/help/idea/built-in-macros.html">Built In Macro</a>
+     */
+    private static void updatePreviewCommand(@NotNull CommandLineWidget commandLine,
+                                             @NotNull JLabel previewCommandLabel,
+                                             @NotNull Project project) {
+        commandLine.getDocument().addDocumentListener(new DocumentListener() {
+            @Override
+            public void insertUpdate(DocumentEvent e) {
+                updateLabel(previewCommandLabel);
+            }
+
+            private void updateLabel(JLabel previewCommandLabel) {
+                String preview = UserDefinedLanguageServerDefinition.resolveCommandLine(commandLine.getText(), project);
+                if (preview.equals(commandLine.getText())) {
+                    previewCommandLabel.setToolTipText("");
+                    previewCommandLabel.setText("");
+                } else {
+                    previewCommandLabel.setToolTipText(preview);
+                    String shortPreview = preview.length() > COMMAND_LENGTH_MAX ? preview.substring(0, COMMAND_LENGTH_MAX) + "..." : preview;
+                    previewCommandLabel.setText(shortPreview);
+                }
+            }
+
+            @Override
+            public void removeUpdate(DocumentEvent e) {
+                updateLabel(previewCommandLabel);
+            }
+
+            @Override
+            public void changedUpdate(DocumentEvent e) {
+                updateLabel(previewCommandLabel);
+            }
+        });
+    }
+
+
+    private static JLabel createLabelForComponent(@NotNull @NlsContexts.Label String labelText, @NotNull JComponent component) {
+        JLabel label = new JLabel(UIUtil.replaceMnemonicAmpersand(labelText));
+        label.setLabelFor(component);
+        return label;
     }
 
     private void createConfigurationField(FormBuilder builder) {