Fixes eclipse-che#2592: Filter code completion proposals from language server (eclipse-che#2658)

* Fixes eclipse-che#2592: Filter code completion proposals from language server

Implements filtering based on the existing FuzzyMatches used for the
GoToSymbolAction.

Signed-off-by: Kaloyan Raev <kaloyan.r@zend.com>

* Add empty line at end of file.

Author: kaloyan-raev

ide/che-core-ide-api/src/main/java/org/eclipse/che/ide/api/theme/Theme.java

@@ -662,6 +662,13 @@ public interface Theme {
      */
     String completionPopupItemSubtitleTextColor();
 
+    /**
+     * Item highlight text color for completion popup.
+     *
+     * @return color
+     */
+    String completionPopupItemHighlightTextColor();
+
     /**
      * Background color of the window widget.
      *

ide/che-core-ide-api/src/main/resources/org/eclipse/che/ide/api/ui/style.css

@@ -146,6 +146,7 @@
 @eval completionPopupSelectedItemBackgroundColor org.eclipse.che.ide.api.theme.Style.theme.completionPopupSelectedItemBackgroundColor();
 @eval completionPopupItemTextColor org.eclipse.che.ide.api.theme.Style.theme.completionPopupItemTextColor();
 @eval completionPopupItemSubtitleTextColor org.eclipse.che.ide.api.theme.Style.theme.completionPopupItemSubtitleTextColor();
+@eval completionPopupItemHighlightTextColor org.eclipse.che.ide.api.theme.Style.theme.completionPopupItemHighlightTextColor();
 
 @eval editorInfoBorderColor org.eclipse.che.ide.api.theme.Style.getEditorInfoBorderColor();
 @eval editorInfoBorderShadowColor org.eclipse.che.ide.api.theme.Style.getEditorInfoBorderShadowColor();

ide/che-core-ide-app/src/main/java/org/eclipse/che/ide/theme/DarkTheme.java

@@ -506,6 +506,11 @@ public String completionPopupItemSubtitleTextColor() {
         return "#727272";
     }
 
+    @Override
+    public String completionPopupItemHighlightTextColor() {
+        return "#4EABFF";
+    }
+
     @Override
     public String getWindowContentBackground() {
         return "#292C2F";

ide/che-core-ide-app/src/main/java/org/eclipse/che/ide/theme/LightTheme.java

@@ -487,6 +487,11 @@ public String completionPopupItemSubtitleTextColor() {
         return "#909090";
     }
 
+    @Override
+    public String completionPopupItemHighlightTextColor() {
+        return "#1A68AF";
+    }
+
     @Override
     public String getWindowContentBackground() {
         return "#ECECEC";

ide/che-core-ide-ui/src/main/resources/org/eclipse/che/ide/ui/popup/popup.css

@@ -110,7 +110,3 @@
 
     color: completionPopupItemTextColor;
 }
-
-.label span {
-    color: completionPopupItemSubtitleTextColor !important;
-}

plugins/plugin-languageserver/che-plugin-languageserver-ide/src/main/java/org/eclipse/che/plugin/languageserver/ide/LanguageServerResources.java

@@ -24,7 +24,7 @@ public interface LanguageServerResources extends ClientBundle {
 
     LanguageServerResources INSTANCE = GWT.create(LanguageServerResources.class);
 
-    @Source("languageserver.css")
+    @Source({"languageserver.css", "org/eclipse/che/ide/api/ui/style.css"})
     LSCss css();
 
     @Source({"QuickOpenList.css", "org/eclipse/che/ide/ui/constants.css", "org/eclipse/che/ide/api/ui/style.css"})
@@ -103,6 +103,9 @@ interface LSCss extends CssResource {
 
         @ClassName("codeassistant-detail")
         String codeassistantDetail();
+
+        @ClassName("codeassistant-highlight")
+        String codeassistantHighlight();
     }
 
     interface QuickOpenListCss extends SimpleList.Css{

plugins/plugin-languageserver/che-plugin-languageserver-ide/src/main/java/org/eclipse/che/plugin/languageserver/ide/editor/codeassist/CompletionItemBasedCompletionProposal.java

@@ -17,6 +17,8 @@
 import com.google.gwt.user.client.ui.Label;
 import com.google.gwt.user.client.ui.Widget;
 
+import java.util.List;
+
 import org.eclipse.che.api.languageserver.shared.lsapi.CompletionItemDTO;
 import org.eclipse.che.api.languageserver.shared.lsapi.RangeDTO;
 import org.eclipse.che.api.languageserver.shared.lsapi.TextDocumentIdentifierDTO;
@@ -31,31 +33,35 @@
 import org.eclipse.che.ide.api.icon.Icon;
 import org.eclipse.che.ide.util.loging.Log;
 import org.eclipse.che.plugin.languageserver.ide.LanguageServerResources;
+import org.eclipse.che.plugin.languageserver.ide.filters.Match;
 import org.eclipse.che.plugin.languageserver.ide.service.TextDocumentServiceClient;
 
 /**
  * @author Anatolii Bazko
  */
 public class CompletionItemBasedCompletionProposal implements CompletionProposal {
 
+    private final CompletionItemDTO         completionItem;
     private final TextDocumentServiceClient documentServiceClient;
     private final TextDocumentIdentifierDTO documentId;
     private final LanguageServerResources   resources;
     private final Icon                      icon;
     private final ServerCapabilities        serverCapabilities;
-    private       CompletionItemDTO         completionItem;
+    private final List<Match>               highlights;
 
     CompletionItemBasedCompletionProposal(CompletionItemDTO completionItem,
                                           TextDocumentServiceClient documentServiceClient,
                                           TextDocumentIdentifierDTO documentId,
                                           LanguageServerResources resources, Icon icon,
-                                          ServerCapabilities serverCapabilities) {
+                                          ServerCapabilities serverCapabilities,
+                                          List<Match> highlights) {
         this.completionItem = completionItem;
         this.documentServiceClient = documentServiceClient;
         this.documentId = documentId;
         this.resources = resources;
         this.icon = icon;
         this.serverCapabilities = serverCapabilities;
+        this.highlights = highlights;
     }
 
     @Override
@@ -72,14 +78,48 @@ public Widget getAdditionalProposalInfo() {
 
     @Override
     public String getDisplayString() {
+        SafeHtmlBuilder builder = new SafeHtmlBuilder();
+        
+        String label = completionItem.getLabel();
+        int pos = 0;
+        for (Match highlight : highlights) {
+            if (highlight.getStart() == highlight.getEnd()) {
+                continue;
+            }
+            
+            if (pos < highlight.getStart()) {
+                appendPlain(builder, label.substring(pos, highlight.getStart()));
+            }
+            
+            appendHighlighted(builder, label.substring(highlight.getStart(), highlight.getEnd()));
+            pos = highlight.getEnd();
+        }
+        
+        if (pos < label.length()) {
+            appendPlain(builder, label.substring(pos));
+        }
+        
         if (completionItem.getDetail() != null) {
-            SafeHtmlBuilder builder = new SafeHtmlBuilder();
-            builder.appendEscaped(completionItem.getLabel());
-            builder.appendHtmlConstant(" <span class=\"" + resources.css().codeassistantDetail() + "\">");
-            builder.appendEscaped(completionItem.getDetail());
-            builder.appendHtmlConstant("</span>");
+            appendDetail(builder, completionItem.getDetail());
         }
-        return completionItem.getLabel();
+        
+        return builder.toSafeHtml().asString();
+    }
+    
+    private void appendPlain(SafeHtmlBuilder builder, String text) {
+        builder.appendEscaped(text);
+    }
+    
+    private void appendHighlighted(SafeHtmlBuilder builder, String text) {
+        builder.appendHtmlConstant("<span class=\"" + resources.css().codeassistantHighlight() + "\">");
+        builder.appendEscaped(text);
+        builder.appendHtmlConstant("</span>");
+    }
+    
+    private void appendDetail(SafeHtmlBuilder builder, String text) {
+        builder.appendHtmlConstant(" <span class=\"" + resources.css().codeassistantDetail() + "\">");
+        builder.appendEscaped(text);
+        builder.appendHtmlConstant("</span>");
     }
 
     @Override

plugins/plugin-languageserver/che-plugin-languageserver-ide/src/main/java/org/eclipse/che/plugin/languageserver/ide/editor/codeassist/LanguageServerCodeAssistProcessor.java

@@ -26,9 +26,12 @@
 import org.eclipse.che.ide.api.editor.codeassist.CompletionProposal;
 import org.eclipse.che.ide.api.editor.texteditor.TextEditor;
 import org.eclipse.che.plugin.languageserver.ide.LanguageServerResources;
+import org.eclipse.che.plugin.languageserver.ide.filters.FuzzyMatches;
+import org.eclipse.che.plugin.languageserver.ide.filters.Match;
 import org.eclipse.che.plugin.languageserver.ide.service.TextDocumentServiceClient;
 import org.eclipse.che.plugin.languageserver.ide.util.DtoBuildHelper;
 
+import java.util.ArrayList;
 import java.util.List;
 
 import static com.google.common.collect.Lists.newArrayList;
@@ -41,40 +44,49 @@ public class LanguageServerCodeAssistProcessor implements CodeAssistProcessor {
     private final DtoBuildHelper            dtoBuildHelper;
     private final LanguageServerResources   resources;
     private final CompletionImageProvider   imageProvider;
-    private final ServerCapabilities        serverCapabilities;
-    private       TextDocumentServiceClient documentServiceClient;
-    private       String                    lastErrorMessage;
+    private final ServerCapabilities serverCapabilities;
+    private final TextDocumentServiceClient documentServiceClient;
+    private final FuzzyMatches fuzzyMatches;
+    private String lastErrorMessage;
 
     @Inject
     public LanguageServerCodeAssistProcessor(TextDocumentServiceClient documentServiceClient,
                                              DtoBuildHelper dtoBuildHelper,
                                              LanguageServerResources resources,
                                              CompletionImageProvider imageProvider,
-                                             @Assisted ServerCapabilities serverCapabilities) {
+                                             @Assisted ServerCapabilities serverCapabilities,
+                                             FuzzyMatches fuzzyMatches) {
         this.documentServiceClient = documentServiceClient;
         this.dtoBuildHelper = dtoBuildHelper;
         this.resources = resources;
         this.imageProvider = imageProvider;
         this.serverCapabilities = serverCapabilities;
+        this.fuzzyMatches = fuzzyMatches;
     }
 
     @Override
     public void computeCompletionProposals(TextEditor editor, int offset, final CodeAssistCallback callback) {
         TextDocumentPositionParamsDTO documentPosition = dtoBuildHelper.createTDPP(editor.getDocument(), offset);
         final TextDocumentIdentifierDTO documentId = documentPosition.getTextDocument();
+        String currentLine = editor.getDocument().getLineContent(documentPosition.getPosition().getLine());
+        final String currentIdentifier = getCurrentIdentifier(currentLine, documentPosition.getPosition().getCharacter());
         this.lastErrorMessage = null;
         documentServiceClient.completion(documentPosition).then(new Operation<List<CompletionItemDTO>>() {
 
             @Override
             public void apply(List<CompletionItemDTO> items) throws OperationException {
                 List<CompletionProposal> proposals = newArrayList();
                 for (CompletionItemDTO item : items) {
-                    proposals.add(new CompletionItemBasedCompletionProposal(item,
-                                                                            documentServiceClient,
-                                                                            documentId,
-                                                                            resources,
-                                                                            imageProvider.getIcon(item.getKind()),
-                                                                            serverCapabilities));
+                    List<Match> highlights = filter(currentIdentifier, item);
+                    if (highlights != null ) {
+                        proposals.add(new CompletionItemBasedCompletionProposal(item,
+                                                                                documentServiceClient,
+                                                                                documentId,
+                                                                                resources,
+                                                                                imageProvider.getIcon(item.getKind()),
+                                                                                serverCapabilities,
+                                                                                highlights));
+                    }
                 }
                 callback.proposalComputed(proposals);
             }
@@ -91,4 +103,42 @@ public String getErrorMessage() {
         return lastErrorMessage;
     }
 
+    private String getCurrentIdentifier(String text, int offset) {
+        int i = offset - 1;
+        while (i >= 0 && isIdentifierChar(text.charAt(i))) {
+            i--;
+        }
+        return text.substring(i + 1, offset);
+    }
+    
+    private boolean isIdentifierChar(char c) {
+        return c >= 'a' && c <= 'z' ||
+            c >= 'A' && c <= 'Z' ||
+            c >= '0' && c <= '9' ||
+            c >= '\u007f' && c <= '\u00ff' ||
+            c == '$' ||
+            c == '_' ||
+            c == '-';
+    }
+    
+    private List<Match> filter(String word, CompletionItemDTO item) {
+        return filter(word, item.getLabel(), item.getFilterText());
+    }
+    
+    private List<Match> filter(String word, String label, String filterText) {
+        if (filterText == null || filterText.isEmpty()) {
+            filterText = label;
+        }
+        
+        // check if the word matches the filterText
+        if (fuzzyMatches.fuzzyMatch(word, filterText) != null) {
+            // return the highlights based on the label
+            List<Match> highlights = fuzzyMatches.fuzzyMatch(word, label);
+            // return empty list of highlights if nothing matches the label
+            return (highlights == null) ? new ArrayList<Match>() : highlights;
+        }
+        
+        return null;
+    }
+
 }

plugins/plugin-languageserver/che-plugin-languageserver-ide/src/main/resources/org/eclipse/che/plugin/languageserver/ide/languageserver.css

@@ -49,5 +49,9 @@
 }
 
 .codeassistant-detail {
-    color: #326EED;
-}
+    color: completionPopupItemSubtitleTextColor;
+}
+
+.codeassistant-highlight {
+    color: completionPopupItemHighlightTextColor;
+}