Multiple Completion Bug Fixes (#34)

* Squashed commit of the following:

commit 384be64
Author: Zee Vasilyev <[email protected]>
Date:   Wed Aug 13 16:27:03 2025 -0500

    Removed unused import

commit b5d44c5
Author: Zee Vasilyev <[email protected]>
Date:   Wed Aug 13 15:20:34 2025 -0500

    Fixed import completions not working

* Squashed commit of the following:

commit 867a2f0
Author: Zee Vasilyev <[email protected]>
Date:   Wed Aug 13 11:49:09 2025 -0500

    removed fault and def; added faultdef, typedef, and alias

* Squashed commit of the following:

commit 5f74b70
Author: Zee Vasilyev <[email protected]>
Date:   Wed Aug 13 17:08:44 2025 -0500

    Implemented an C3StdLibRootsProvider so that the STD lib is indexed and provide completion

Author: Zeejfps

src/main/java/org/c3lang/intellij/C3StdLibRootsProvider.java

@@ -0,0 +1,28 @@
+package org.c3lang.intellij;
+
+import com.intellij.openapi.project.Project;
+import com.intellij.openapi.roots.AdditionalLibraryRootsProvider;
+import com.intellij.openapi.roots.SyntheticLibrary;
+import com.intellij.openapi.vfs.LocalFileSystem;
+import com.intellij.openapi.vfs.VirtualFile;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.Collections;
+
+public class C3StdLibRootsProvider extends AdditionalLibraryRootsProvider {
+    @Override
+    public @NotNull Collection<SyntheticLibrary> getAdditionalProjectLibraries(Project project) {
+
+        var settings = C3SettingsState.getInstance();
+        var stdLibPath = settings.stdlibPath;
+
+        VirtualFile stdLibRoot = LocalFileSystem.getInstance().findFileByPath(stdLibPath);
+        if (stdLibRoot != null) {
+            return Collections.singletonList(
+                    SyntheticLibrary.newImmutableLibrary(Collections.singletonList(stdLibRoot))
+            );
+        }
+        return Collections.emptyList();
+    }
+}

src/main/java/org/c3lang/intellij/C3Util.kt

@@ -156,8 +156,8 @@ object C3Util
             }
 
         // search stdlib after
-        File(stdLibPath).walk()
-            .asSequence()
+        File(stdLibPath)
+            .walk()
             .filter { file ->
                 file.isFile && file.extension == "c3"
             }

src/main/java/org/c3lang/intellij/completion/ImportCompletionContributor.kt

@@ -3,12 +3,11 @@ package org.c3lang.intellij.completion
 import com.intellij.codeInsight.completion.CompletionParameters
 import com.intellij.codeInsight.completion.CompletionProvider
 import com.intellij.codeInsight.completion.CompletionResultSet
-import com.intellij.openapi.project.Project
+import com.intellij.codeInsight.lookup.LookupElementBuilder
 import com.intellij.patterns.PlatformPatterns.psiElement
 import com.intellij.patterns.StandardPatterns.or
 import com.intellij.util.ProcessingContext
 import org.c3lang.intellij.C3Util.findC3ModulesStartingWith
-import org.c3lang.intellij.completion.CompletionUtil.provideCompletionsAfterSymbol
 import org.c3lang.intellij.psi.C3ImportPath
 
 @Suppress("DuplicatedCode")
@@ -18,18 +17,32 @@ object ImportCompletionContributor : CompletionProvider<CompletionParameters>()
 
     override fun addCompletions(parameters: CompletionParameters, context: ProcessingContext, result: CompletionResultSet)
     {
-        if (!pattern.accepts(parameters.position) && !pattern.accepts(parameters.originalPosition))
+        val matches = pattern.accepts(parameters.position)
+        if (!matches)
         {
             return
         }
 
-        val leaf = parameters.originalFile.findElementAt(parameters.offset)?.prevSibling
+        val position = parameters.position
+        val packagePathElement = position.parent
 
-        provideCompletionsAfterSymbol(parameters, result, "::", getPossibleCompletions(parameters.editor.project!!, leaf?.text ?: "NONE"))
-    }
+        // Example: "std::some::dummy"
+        val fullTextWithDummy = packagePathElement.text
+        val parentStartOffset = packagePathElement.textRange.startOffset
+        val caretOffset = parameters.offset
+        val prefixLength = caretOffset - parentStartOffset
+        if (prefixLength < 0 || prefixLength > fullTextWithDummy.length) {
+            return
+        }
 
-    private fun getPossibleCompletions(project: Project, path: String): List<String>
-    {
-        return findC3ModulesStartingWith(project, path).toList().map { it.replace(path, "") }
+        val project = parameters.editor.project!!
+        val prefix = fullTextWithDummy.take(prefixLength)
+        val modules = findC3ModulesStartingWith(project, prefix)
+
+        val resultSetWithPrefix = result.withPrefixMatcher(prefix)
+
+        modules.forEach { module ->
+            resultSetWithPrefix.addElement(LookupElementBuilder.create(module))
+        }
     }
 }

src/main/java/org/c3lang/intellij/completion/TopLevelCompletionContributor.kt

@@ -35,9 +35,10 @@ object TopLevelCompletionContributor : CompletionProvider<CompletionParameters>(
             listOf(
                 "fn",
                 "struct",
-                "fault",
+                "faultdef",
                 "macro",
-                "def",
+                "alias",
+                "typedef",
                 "module",
                 "import",
                 "extern",

src/main/resources/META-INF/plugin.xml

@@ -24,6 +24,8 @@
     <stubIndex implementation="org.c3lang.intellij.index.StructDeclarationIndex"/>
     <stubIndex implementation="org.c3lang.intellij.index.StructMemberDeclarationIndex"/>
 
+    <additionalLibraryRootsProvider implementation="org.c3lang.intellij.C3StdLibRootsProvider"/>
+
     <fileType name="C3 File" implementationClass="org.c3lang.intellij.C3SourceFileType" fieldName="INSTANCE" language="C3" extensions="c3;c3t"/>
     <fileType name="C3 Interface File" implementationClass="org.c3lang.intellij.C3InterfaceFileType" fieldName="INSTANCE" language="C3" extensions="c3i"/>
 <!--    <fileType name="C3 Library File" implementationClass="org.c3lang.intellij.C3LibFileType" fieldName="INSTANCE" language="C3" extensions="c3l"/>-->