Simplify call chain fix: extract 'apply'

idea/src/org/jetbrains/kotlin/idea/inspections/collections/SimplifyCallChainFix.kt

@@ -34,71 +34,73 @@ class SimplifyCallChainFix(private val newCallText: String) : LocalQuickFix {
 
     override fun getFamilyName() = name
 
-    override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
+    private fun apply(secondQualifiedExpression: KtQualifiedExpression) {
-        (descriptor.psiElement as? KtQualifiedExpression)?.let { secondQualifiedExpression ->
+        val factory = KtPsiFactory(secondQualifiedExpression)
-            val factory = KtPsiFactory(secondQualifiedExpression)
+        val firstExpression = secondQualifiedExpression.receiverExpression
-            val firstExpression = secondQualifiedExpression.receiverExpression
 
-            val operationSign = when (firstExpression) {
+        val operationSign = when (firstExpression) {
-                is KtSafeQualifiedExpression -> "?."
+            is KtSafeQualifiedExpression -> "?."
-                is KtQualifiedExpression -> "."
+            is KtQualifiedExpression -> "."
-                else -> ""
+            else -> ""
-            }
-
-            val receiverExpression = (firstExpression as? KtQualifiedExpression)?.receiverExpression
-
-            val firstCallExpression = AbstractCallChainChecker.getCallExpression(firstExpression) ?: return
-            val secondCallExpression = secondQualifiedExpression.selectorExpression as? KtCallExpression ?: return
-
-            val lastArgumentName = if (newCallText.startsWith("joinTo")) Name.identifier("transform") else null
-            if (lastArgumentName != null) {
-                val lastArgument = firstCallExpression.valueArgumentList?.arguments?.singleOrNull()
-                val argumentExpression = lastArgument?.getArgumentExpression()
-                if (argumentExpression != null) {
-                    lastArgument.replace(factory.createArgument(argumentExpression, lastArgumentName))
-                }
-            }
-            val firstCallArgumentList = firstCallExpression.valueArgumentList
-            val secondCallArgumentList = secondCallExpression.valueArgumentList
-
-            fun KtValueArgumentList.getTextInsideParentheses(): String {
-                val range = PsiChildRange(leftParenthesis?.nextSibling ?: firstChild, rightParenthesis?.prevSibling ?: lastChild)
-                return range.joinToString(separator = "") { it.text }
-            }
-
-            val lambdaExpression = firstCallExpression.lambdaArguments.singleOrNull()?.getLambdaExpression()
-            val argumentsText = listOfNotNull(
-                secondCallArgumentList.takeIf { it?.arguments?.isNotEmpty() == true },
-                firstCallArgumentList.takeIf { it?.arguments?.isNotEmpty() == true }
-            ).let {
-                if (it.isEmpty()) ""
-                else it.joinToString(
-                    separator = ", ",
-                    prefix = "(",
-                    postfix = ")"
-                ) { callArgumentList ->
-                    callArgumentList.getTextInsideParentheses()
-                }
-            }
-
-            val newQualifiedExpression = if (lambdaExpression != null) factory.createExpressionByPattern(
-                "$0$1$2 $3 $4",
-                receiverExpression ?: "",
-                operationSign,
-                newCallText,
-                argumentsText,
-                lambdaExpression.text
-            )
-            else factory.createExpressionByPattern(
-                "$0$1$2 $3",
-                receiverExpression ?: "",
-                operationSign,
-                newCallText,
-                argumentsText
-            )
-
-            val result = secondQualifiedExpression.replaced(newQualifiedExpression)
-            ShortenReferences.DEFAULT.process(result)
         }
+
+        val receiverExpression = (firstExpression as? KtQualifiedExpression)?.receiverExpression
+
+        val firstCallExpression = AbstractCallChainChecker.getCallExpression(firstExpression) ?: return
+        val secondCallExpression = secondQualifiedExpression.selectorExpression as? KtCallExpression ?: return
+
+        val lastArgumentName = if (newCallText.startsWith("joinTo")) Name.identifier("transform") else null
+        if (lastArgumentName != null) {
+            val lastArgument = firstCallExpression.valueArgumentList?.arguments?.singleOrNull()
+            val argumentExpression = lastArgument?.getArgumentExpression()
+            if (argumentExpression != null) {
+                lastArgument.replace(factory.createArgument(argumentExpression, lastArgumentName))
+            }
+        }
+        val firstCallArgumentList = firstCallExpression.valueArgumentList
+        val secondCallArgumentList = secondCallExpression.valueArgumentList
+
+        fun KtValueArgumentList.getTextInsideParentheses(): String {
+            val range = PsiChildRange(leftParenthesis?.nextSibling ?: firstChild, rightParenthesis?.prevSibling ?: lastChild)
+            return range.joinToString(separator = "") { it.text }
+        }
+
+        val lambdaExpression = firstCallExpression.lambdaArguments.singleOrNull()?.getLambdaExpression()
+        val argumentsText = listOfNotNull(
+            secondCallArgumentList.takeIf { it?.arguments?.isNotEmpty() == true },
+            firstCallArgumentList.takeIf { it?.arguments?.isNotEmpty() == true }
+        ).let {
+            if (it.isEmpty()) ""
+            else it.joinToString(
+                separator = ", ",
+                prefix = "(",
+                postfix = ")"
+            ) { callArgumentList ->
+                callArgumentList.getTextInsideParentheses()
+            }
+        }
+
+        val newQualifiedExpression = if (lambdaExpression != null) factory.createExpressionByPattern(
+            "$0$1$2 $3 $4",
+            receiverExpression ?: "",
+            operationSign,
+            newCallText,
+            argumentsText,
+            lambdaExpression.text
+        )
+        else factory.createExpressionByPattern(
+            "$0$1$2 $3",
+            receiverExpression ?: "",
+            operationSign,
+            newCallText,
+            argumentsText
+        )
+
+        val result = secondQualifiedExpression.replaced(newQualifiedExpression)
+        ShortenReferences.DEFAULT.process(result)
+    }
+
+    override fun applyFix(project: Project, descriptor: ProblemDescriptor) {
+        (descriptor.psiElement as? KtQualifiedExpression)?.let(this::apply)
     }
 }