Phase 5: add rename and find usages

src/main/kotlin/dev/hgh/jai/findusages/JaiFindUsagesProvider.kt

@@ -0,0 +1,41 @@
+package dev.hgh.jai.findusages
+
+import com.intellij.lang.cacheBuilder.DefaultWordsScanner
+import com.intellij.lang.cacheBuilder.WordsScanner
+import com.intellij.lang.findUsages.FindUsagesProvider
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiNameIdentifierOwner
+import com.intellij.psi.PsiNamedElement
+import com.intellij.psi.tree.TokenSet
+import dev.hgh.jai.lexer.JaiLexer
+import dev.hgh.jai.lexer.JaiTokenTypes
+import dev.hgh.jai.psi.JaiRefExpr
+
+/** Supplies word indexing and descriptions for Jai declaration usages. */
+class JaiFindUsagesProvider : FindUsagesProvider {
+    override fun getWordsScanner(): WordsScanner =
+        DefaultWordsScanner(
+            JaiLexer(),
+            TokenSet.create(JaiTokenTypes.IDENT),
+            JaiTokenTypes.COMMENTS,
+            JaiTokenTypes.STRINGS,
+        )
+
+    override fun canFindUsagesFor(psiElement: PsiElement): Boolean = psiElement is PsiNameIdentifierOwner || psiElement is JaiRefExpr
+
+    override fun getHelpId(psiElement: PsiElement): String? = null
+
+    override fun getType(element: PsiElement): String =
+        if (element is PsiNameIdentifierOwner || element is JaiRefExpr) {
+            "Jai declaration"
+        } else {
+            ""
+        }
+
+    override fun getDescriptiveName(element: PsiElement): String = (element as? PsiNamedElement)?.name ?: element.text
+
+    override fun getNodeText(
+        element: PsiElement,
+        useFullName: Boolean,
+    ): String = element.text
+}

src/main/kotlin/dev/hgh/jai/psi/JaiPsiElementFactory.kt

@@ -0,0 +1,23 @@
+package dev.hgh.jai.psi
+
+import com.intellij.openapi.project.Project
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiFileFactory
+import com.intellij.psi.util.PsiTreeUtil
+import dev.hgh.jai.JaiLanguage
+import dev.hgh.jai.lexer.JaiTokenTypes
+
+/** Creates small Jai PSI fragments for AST replacements used by rename refactoring. */
+object JaiPsiElementFactory {
+    fun createIdentifier(
+        project: Project,
+        name: String,
+    ): PsiElement {
+        val file = PsiFileFactory.getInstance(project).createFileFromText("rename.jai", JaiLanguage, "$name :: 0;")
+        val declarationName =
+            PsiTreeUtil.findChildOfType(file, JaiDeclName::class.java)
+                ?: error("Could not parse a Jai declaration name for '$name'")
+        return declarationName.node.findChildByType(JaiTokenTypes.IDENT)?.psi
+            ?: error("Jai name '$name' is not an identifier")
+    }
+}

src/main/kotlin/dev/hgh/jai/psi/mixin/JaiNamedElementMixin.kt

@@ -0,0 +1,28 @@
+package dev.hgh.jai.psi.mixin
+
+import com.intellij.extapi.psi.ASTWrapperPsiElement
+import com.intellij.lang.ASTNode
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiNameIdentifierOwner
+import dev.hgh.jai.lexer.JaiTokenTypes
+import dev.hgh.jai.psi.JaiPsiElementFactory
+
+/** Gives declaration names the standard PSI naming contract used by rename/find-usages. */
+abstract class JaiNamedElementMixin(
+    node: ASTNode,
+) : ASTWrapperPsiElement(node),
+    PsiNameIdentifierOwner {
+    override fun getNameIdentifier(): PsiElement? = node.findChildByType(JaiTokenTypes.IDENT)?.psi
+
+    override fun getName(): String? = nameIdentifier?.text
+
+    override fun setName(name: String): PsiElement {
+        val identifier = nameIdentifier ?: return this
+        identifier.replace(JaiPsiElementFactory.createIdentifier(project, name))
+        return this
+    }
+
+    override fun getNavigationElement(): PsiElement = nameIdentifier ?: this
+
+    override fun getTextOffset(): Int = nameIdentifier?.textOffset ?: super.getTextOffset()
+}

src/main/kotlin/dev/hgh/jai/refactoring/JaiNamesValidator.kt

@@ -0,0 +1,26 @@
+package dev.hgh.jai.refactoring
+
+import com.intellij.lang.refactoring.NamesValidator
+import com.intellij.openapi.project.Project
+import dev.hgh.jai.lexer.JaiTokenTypes
+
+/** Applies Jai's ASCII identifier and keyword rules to rename input. */
+class JaiNamesValidator : NamesValidator {
+    override fun isKeyword(
+        name: String,
+        project: Project?,
+    ): Boolean = name in JaiTokenTypes.KEYWORD_MAP
+
+    override fun isIdentifier(
+        name: String,
+        project: Project?,
+    ): Boolean {
+        if (name.isEmpty() || isKeyword(name, project)) return false
+        if (!isIdentifierStart(name.first())) return false
+        return name.drop(1).all(::isIdentifierPart)
+    }
+
+    private fun isIdentifierStart(character: Char): Boolean = character in 'a'..'z' || character in 'A'..'Z' || character == '_'
+
+    private fun isIdentifierPart(character: Char): Boolean = isIdentifierStart(character) || character in '0'..'9'
+}

src/main/kotlin/dev/hgh/jai/refactoring/JaiRefactoringSupportProvider.kt

@@ -0,0 +1,14 @@
+package dev.hgh.jai.refactoring
+
+import com.intellij.lang.refactoring.RefactoringSupportProvider
+import com.intellij.psi.PsiElement
+import com.intellij.psi.PsiNameIdentifierOwner
+import dev.hgh.jai.JaiLanguage
+
+/** Enables standard and in-place rename for Jai declaration names. */
+class JaiRefactoringSupportProvider : RefactoringSupportProvider() {
+    override fun isMemberInplaceRenameAvailable(
+        elementToRename: PsiElement,
+        context: PsiElement?,
+    ): Boolean = elementToRename is PsiNameIdentifierOwner && elementToRename.language == JaiLanguage
+}

src/main/kotlin/dev/hgh/jai/reference/JaiReferenceContributor.kt

@@ -22,6 +22,7 @@ import dev.hgh.jai.psi.JaiDeclName
 import dev.hgh.jai.psi.JaiDeclaration
 import dev.hgh.jai.psi.JaiDirectiveExpr
 import dev.hgh.jai.psi.JaiLiteralExpr
+import dev.hgh.jai.psi.JaiPsiElementFactory
 import dev.hgh.jai.psi.JaiRefExpr
 
 /** Adds file references for directives and symbol references for Jai identifiers. */
@@ -106,6 +107,12 @@ private class JaiSymbolReference(
 ) : PsiReferenceBase<JaiRefExpr>(sourceElement, TextRange(0, sourceElement.textLength), true) {
     override fun resolve(): PsiElement? = JaiSymbolResolver.resolve(sourceElement)
 
+    override fun handleElementRename(newElementName: String): PsiElement {
+        val identifier = sourceElement.node.findChildByType(JaiTokenTypes.IDENT)?.psi ?: return sourceElement
+        identifier.replace(JaiPsiElementFactory.createIdentifier(sourceElement.project, newElementName))
+        return sourceElement
+    }
+
     override fun getVariants(): Array<Any> = emptyArray()
 }