draft of completion provider

src/main/java/com/github/_1c_syntax/bsl/languageserver/BSLLanguageServer.java

@@ -37,6 +37,7 @@
 import org.eclipse.lsp4j.CodeActionOptions;
 import org.eclipse.lsp4j.CodeLensOptions;
 import org.eclipse.lsp4j.ColorProviderOptions;
+import org.eclipse.lsp4j.CompletionOptions;
 import org.eclipse.lsp4j.DefinitionOptions;
 import org.eclipse.lsp4j.DocumentFormattingOptions;
 import org.eclipse.lsp4j.DocumentLinkOptions;
@@ -123,6 +124,7 @@ public CompletableFuture<InitializeResult> initialize(InitializeParams params) {
     capabilities.setRenameProvider(getRenameProvider(params));
     capabilities.setInlayHintProvider(getInlayHintProvider());
     capabilities.setExecuteCommandProvider(getExecuteCommandProvider());
+    capabilities.setCompletionProvider(getCompletionProvider());
 
     var result = new InitializeResult(capabilities, serverInfo);
 
@@ -336,4 +338,13 @@ private ExecuteCommandOptions getExecuteCommandProvider() {
     executeCommandOptions.setWorkDoneProgress(Boolean.FALSE);
     return executeCommandOptions;
   }
+
+  private CompletionOptions getCompletionProvider() {
+    var completionOptions = new CompletionOptions();
+    completionOptions.setTriggerCharacters(List.of("."));
+    completionOptions.setResolveProvider(Boolean.FALSE);
+    completionOptions.setWorkDoneProgress(Boolean.FALSE);
+
+    return completionOptions;
+  }
 }

src/main/java/com/github/_1c_syntax/bsl/languageserver/BSLTextDocumentService.java

@@ -32,6 +32,7 @@
 import com.github._1c_syntax.bsl.languageserver.providers.CodeActionProvider;
 import com.github._1c_syntax.bsl.languageserver.providers.CodeLensProvider;
 import com.github._1c_syntax.bsl.languageserver.providers.ColorProvider;
+import com.github._1c_syntax.bsl.languageserver.providers.CompletionProvider;
 import com.github._1c_syntax.bsl.languageserver.providers.DefinitionProvider;
 import com.github._1c_syntax.bsl.languageserver.providers.DiagnosticProvider;
 import com.github._1c_syntax.bsl.languageserver.providers.DocumentLinkProvider;
@@ -60,6 +61,9 @@
 import org.eclipse.lsp4j.ColorPresentation;
 import org.eclipse.lsp4j.ColorPresentationParams;
 import org.eclipse.lsp4j.Command;
+import org.eclipse.lsp4j.CompletionItem;
+import org.eclipse.lsp4j.CompletionList;
+import org.eclipse.lsp4j.CompletionParams;
 import org.eclipse.lsp4j.DefinitionParams;
 import org.eclipse.lsp4j.DidChangeTextDocumentParams;
 import org.eclipse.lsp4j.DidCloseTextDocumentParams;
@@ -125,6 +129,7 @@ public class BSLTextDocumentService implements TextDocumentService, ProtocolExte
   private final ColorProvider colorProvider;
   private final RenameProvider renameProvider;
   private final InlayHintProvider inlayHintProvider;
+  private final CompletionProvider completionProvider;
 
   private final ExecutorService executorService = Executors.newCachedThreadPool(new CustomizableThreadFactory("text-document-service-"));
 
@@ -370,6 +375,19 @@ public CompletableFuture<List<InlayHint>> inlayHint(InlayHintParams params) {
     );
   }
 
+  @Override
+  public CompletableFuture<Either<List<CompletionItem>, CompletionList>> completion(CompletionParams params) {
+    var documentContext = context.getDocument(params.getTextDocument().getUri());
+    if (documentContext == null) {
+      return CompletableFuture.completedFuture(null);
+    }
+
+    return CompletableFuture.supplyAsync(
+      () -> completionProvider.getCompletions(documentContext, params),
+      executorService
+    );
+  }
+
   @Override
   public void didOpen(DidOpenTextDocumentParams params) {
     var textDocumentItem = params.getTextDocument();

src/main/java/com/github/_1c_syntax/bsl/languageserver/providers/CompletionProvider.java

@@ -0,0 +1,86 @@
+package com.github._1c_syntax.bsl.languageserver.providers;
+
+import com.github._1c_syntax.bsl.languageserver.context.DocumentContext;
+import com.github._1c_syntax.bsl.languageserver.context.symbol.SourceDefinedSymbol;
+import com.github._1c_syntax.bsl.languageserver.context.symbol.Symbol;
+import com.github._1c_syntax.bsl.languageserver.types.KnownTypes;
+import com.github._1c_syntax.bsl.languageserver.types.TypeResolver;
+import com.github._1c_syntax.bsl.languageserver.utils.Ranges;
+import com.github._1c_syntax.bsl.languageserver.utils.Trees;
+import com.github._1c_syntax.bsl.parser.BSLLexer;
+import lombok.RequiredArgsConstructor;
+import org.eclipse.lsp4j.CompletionItem;
+import org.eclipse.lsp4j.CompletionItemKind;
+import org.eclipse.lsp4j.CompletionList;
+import org.eclipse.lsp4j.CompletionParams;
+import org.eclipse.lsp4j.Range;
+import org.eclipse.lsp4j.SymbolKind;
+import org.eclipse.lsp4j.jsonrpc.messages.Either;
+import org.springframework.stereotype.Component;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Optional;
+
+@Component
+@RequiredArgsConstructor
+public class CompletionProvider {
+
+  private final TypeResolver typeResolver;
+  private final KnownTypes knownTypes;
+
+  public Either<List<CompletionItem>, CompletionList> getCompletions(DocumentContext documentContext, CompletionParams params) {
+
+    var completionList = new CompletionList();
+
+    var position = params.getPosition();
+    var terminalNode = Trees.findTerminalNodeContainsPosition(documentContext.getAst(), position).orElseThrow();
+
+    if (terminalNode.getSymbol().getType() != BSLLexer.DOT) {
+      return Either.forRight(completionList);
+    }
+
+    var previousToken = Trees.getPreviousTokenFromDefaultChannel(documentContext.getTokens(), terminalNode.getSymbol().getTokenIndex() - 1);
+    var completionItems = previousToken
+      .map(Ranges::create)
+      .map(Range::getStart)
+      .map(previousTokenPosition -> typeResolver.findTypes(documentContext.getUri(), previousTokenPosition))
+      .stream()
+      .flatMap(Collection::stream)
+      .map(knownTypes::getSymbolByType)
+      .filter(Optional::isPresent)
+      .map(Optional::get)
+      .flatMap(symbol -> getChildren(symbol).stream())
+      .map(symbol -> {
+        var completionItem = new CompletionItem();
+        completionItem.setLabel(symbol.getName());
+        completionItem.setKind(getCompletionItemKind(symbol.getSymbolKind()));
+
+        return completionItem;
+      })
+      .toList();
+
+    completionList.setItems(completionItems);
+
+    return Either.forRight(completionList);
+  }
+
+  private CompletionItemKind getCompletionItemKind(SymbolKind symbolKind) {
+    return switch (symbolKind) {
+      case Class -> CompletionItemKind.Class;
+      case Method -> CompletionItemKind.Method;
+      case Variable -> CompletionItemKind.Variable;
+      case Module -> CompletionItemKind.Module;
+      default -> CompletionItemKind.Text;
+    };
+  }
+
+  private List<? extends Symbol> getChildren(Symbol symbol) {
+    if (!(symbol instanceof SourceDefinedSymbol sourceDefinedSymbol)) {
+      return Collections.emptyList();
+    }
+
+    return sourceDefinedSymbol.getChildren();
+  }
+}

src/main/java/com/github/_1c_syntax/bsl/languageserver/types/KnownTypes.java

@@ -0,0 +1,39 @@
+package com.github._1c_syntax.bsl.languageserver.types;
+
+import com.github._1c_syntax.bsl.languageserver.context.events.DocumentContextContentChangedEvent;
+import com.github._1c_syntax.bsl.languageserver.context.symbol.Symbol;
+import org.apache.commons.io.FilenameUtils;
+import org.springframework.context.event.EventListener;
+import org.springframework.stereotype.Component;
+
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.ConcurrentHashMap;
+
+@Component
+public class KnownTypes {
+
+  private final Map<Type, Symbol> knownTypes = new ConcurrentHashMap<>();
+
+  public void addType(Type type, Symbol symbol) {
+    knownTypes.put(type, symbol);
+  }
+
+  public Optional<Symbol> getSymbolByType(Type type) {
+    return Optional.ofNullable(knownTypes.get(type));
+  }
+
+  public void clear() {
+    knownTypes.clear();
+  }
+
+  @EventListener
+  public void handleEvent(DocumentContextContentChangedEvent event) {
+    var documentContext = event.getSource();
+    // TODO: this logic should be moved to somewhere else. It will break for BSL files.
+    var typeName = FilenameUtils.getBaseName(documentContext.getUri().getPath());
+    var module = documentContext.getSymbolTree().getModule();
+
+    addType(new Type(typeName), module);
+  }
+}

src/test/java/com/github/_1c_syntax/bsl/languageserver/providers/CompletionProviderTest.java

@@ -0,0 +1,57 @@
+package com.github._1c_syntax.bsl.languageserver.providers;
+
+import com.github._1c_syntax.bsl.languageserver.context.ServerContext;
+import com.github._1c_syntax.bsl.languageserver.util.CleanupContextBeforeClassAndAfterClass;
+import com.github._1c_syntax.bsl.languageserver.util.TestUtils;
+import jakarta.annotation.PostConstruct;
+import org.eclipse.lsp4j.CompletionItemKind;
+import org.eclipse.lsp4j.CompletionParams;
+import org.eclipse.lsp4j.Position;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import java.nio.file.Paths;
+
+import static com.github._1c_syntax.bsl.languageserver.util.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@SpringBootTest
+@CleanupContextBeforeClassAndAfterClass
+class CompletionProviderTest {
+
+  @Autowired
+  private CompletionProvider completionProvider;
+
+  @Autowired
+  private ServerContext serverContext;
+
+  private static final String PATH_TO_FILE = "./src/test/resources/providers/completion.os";
+
+  @PostConstruct
+  void prepareServerContext() {
+    serverContext.setConfigurationRoot(Paths.get("src/test/resources/metadata/oslib"));
+    serverContext.populateContext();
+  }
+
+  @Test
+  void completionAfterDotOnOSClass() {
+    // given
+    var documentContext = TestUtils.getDocumentContextFromFile(PATH_TO_FILE);
+
+    var params = new CompletionParams();
+    params.setPosition(new Position(3, 13));
+
+    // when
+    var completions = completionProvider.getCompletions(documentContext, params);
+
+    // then
+    assertTrue(completions.isRight());
+
+    var completionList = completions.getRight();
+    assertThat(completionList.getItems()).hasSize(1);
+    assertThat(completionList.getItems().get(0).getLabel()).isEqualTo("NewObject");
+    assertThat(completionList.getItems().get(0).getKind()).isEqualTo(CompletionItemKind.Method);
+  }
+
+}

src/test/resources/metadata/oslib/Классы/МойКласс.os

@@ -0,0 +1,17 @@
+Перем ЭкспортнаяПеременная Экспорт;
+Перем НеЭкспортнаяПеременная;
+
+Функция ЭкспортнаяФункция() Экспорт
+    Возврат "";
+КонецФункции
+
+Функция НеЭкспортнаяФункция()
+    Возврат "";
+КонецФункции
+
+Процедура ЭкспортнаяПроцедура() Экспорт
+КонецПроцедуры
+
+Процедура НеЭкспортнаяПроцедура()
+КонецПроцедуры
+

src/test/resources/providers/completion.os

@@ -0,0 +1,4 @@
+#Использовать "metadata/oslib"
+
+КакойТоКласс = Новый МойКласс();
+КакойТоКласс.