Paste inside indented .trimIndent() raw string: respect indentation (KT-31810)

#KT-31810 Fixed

idea/src/org/jetbrains/kotlin/idea/editor/KotlinLiteralCopyPasteProcessor.kt

@@ -28,8 +28,11 @@ import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiFile
 import org.jetbrains.annotations.TestOnly
 import org.jetbrains.kotlin.idea.editor.fixers.range
+import org.jetbrains.kotlin.idea.inspections.collections.isCalling
+import org.jetbrains.kotlin.idea.intentions.callExpression
 import org.jetbrains.kotlin.lexer.KotlinLexer
 import org.jetbrains.kotlin.lexer.KtTokens
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.KtEscapeStringTemplateEntry
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtStringTemplateExpression
@@ -41,8 +44,8 @@ private val PsiElement.templateContentRange: TextRange?
     }
 
 
-private fun PsiFile.getTemplateIfAtLiteral(offset: Int): KtStringTemplateExpression? {
-    val at = this.findElementAt(offset) ?: return null
+private fun PsiFile.getTemplateIfAtLiteral(offset: Int, at: PsiElement? = findElementAt(offset)): KtStringTemplateExpression? {
+    if (at == null) return null
     return when (at.node?.elementType) {
         KtTokens.REGULAR_STRING_PART, KtTokens.ESCAPE_SEQUENCE, KtTokens.LONG_TEMPLATE_ENTRY_START, KtTokens.SHORT_TEMPLATE_ENTRY_START -> at.parent.parent as? KtStringTemplateExpression
         KtTokens.CLOSING_QUOTE -> if (offset == at.startOffset) at.parent as? KtStringTemplateExpression else null
@@ -123,7 +126,8 @@ class KotlinLiteralCopyPasteProcessor : CopyPastePreProcessor {
         }
         PsiDocumentManager.getInstance(project).commitDocument(editor.document)
         val selectionModel = editor.selectionModel
-        val beginTp = file.getTemplateIfAtLiteral(selectionModel.selectionStart) ?: return text
+        val begin = file.findElementAt(selectionModel.selectionStart) ?: return text
+        val beginTp = file.getTemplateIfAtLiteral(selectionModel.selectionStart, begin) ?: return text
         val endTp = file.getTemplateIfAtLiteral(selectionModel.selectionEnd) ?: return text
         if (beginTp.isSingleQuoted() != endTp.isSingleQuoted()) {
             return text
@@ -147,13 +151,23 @@ class KotlinLiteralCopyPasteProcessor : CopyPastePreProcessor {
                 res.toString()
             }
         } else {
+            val indent = if (beginTp.firstChild?.text == "\"\"\"" &&
+                beginTp.getQualifiedExpressionForReceiver()?.callExpression?.isCalling(FqName("kotlin.text.trimIndent")) == true
+            ) {
+                begin.parent?.prevSibling?.takeIf { it.text != "\n" }?.text ?: ""
+            } else {
+                ""
+            }            
             val tripleQuoteRe = Regex("[\"]{3,}")
-            TemplateTokenSequence(text).map { chunk ->
+            TemplateTokenSequence(text).mapIndexed { index, chunk ->
                 when (chunk) {
-                    is LiteralChunk -> chunk.text.replace("\$", "\${'$'}").let { escapedDollar ->
-                        tripleQuoteRe.replace(escapedDollar) { "\"\"" + "\${'\"'}".repeat(it.value.count() - 2) }
+                    is LiteralChunk -> {
+                        val replaced = chunk.text.replace("\$", "\${'$'}").let { escapedDollar ->
+                            tripleQuoteRe.replace(escapedDollar) { "\"\"" + "\${'\"'}".repeat(it.value.count() - 2) }
+                        }
+                        if (index == 0) replaced else indent + replaced
                     }
-                    is EntryChunk -> chunk.text
+                    is EntryChunk -> if (index == 0) chunk.text else indent + chunk.text
                     is NewLineChunk -> "\n"
                 }
             }.joinToString(separator = "")

idea/testData/copyPaste/plainTextLiteral/TrimIndent.expected.kt

@@ -0,0 +1,9 @@
+fun test() = doTest("""
+    def foo(a)
+        a ? 0 : 1
+    end
+""".trimIndent())
+
+fun doTest(rubyCode: String) {
+    // some code here
+}

idea/testData/copyPaste/plainTextLiteral/TrimIndent.kt

@@ -0,0 +1,7 @@
+fun test() = doTest("""
+    <caret>
+""".trimIndent())
+
+fun doTest(rubyCode: String) {
+    // some code here
+}

idea/testData/copyPaste/plainTextLiteral/TrimIndent.txt

@@ -0,0 +1,3 @@
+def foo(a)
+    a ? 0 : 1
+end

idea/testData/copyPaste/plainTextLiteral/TrimIndent2.expected.kt

@@ -0,0 +1,9 @@
+fun test() = doTest("""
+def foo(a)
+    a ? 0 : 1
+end
+""".trimIndent())
+
+fun doTest(rubyCode: String) {
+    // some code here
+}

idea/testData/copyPaste/plainTextLiteral/TrimIndent2.kt

@@ -0,0 +1,7 @@
+fun test() = doTest("""
+<caret>
+""".trimIndent())
+
+fun doTest(rubyCode: String) {
+    // some code here
+}

idea/testData/copyPaste/plainTextLiteral/TrimIndent2.txt

@@ -0,0 +1,3 @@
+def foo(a)
+    a ? 0 : 1
+end

idea/tests/org/jetbrains/kotlin/idea/conversion/copy/LiteralTextToKotlinCopyPasteTestGenerated.java

@@ -59,6 +59,16 @@ public class LiteralTextToKotlinCopyPasteTestGenerated extends AbstractLiteralTe
         runTest("idea/testData/copyPaste/plainTextLiteral/TrailingLines.txt");
     }
 
+    @TestMetadata("TrimIndent.txt")
+    public void testTrimIndent() throws Exception {
+        runTest("idea/testData/copyPaste/plainTextLiteral/TrimIndent.txt");
+    }
+
+    @TestMetadata("TrimIndent2.txt")
+    public void testTrimIndent2() throws Exception {
+        runTest("idea/testData/copyPaste/plainTextLiteral/TrimIndent2.txt");
+    }
+
     @TestMetadata("WithBackslashes.txt")
     public void testWithBackslashes() throws Exception {
         runTest("idea/testData/copyPaste/plainTextLiteral/WithBackslashes.txt");