feat(amazonq): implement TextDocumentService message handler

plugins/amazonq/shared/jetbrains-community/src/software/aws/toolkits/jetbrains/services/amazonq/lsp/AmazonQLspService.kt

@@ -48,6 +48,7 @@
 import software.aws.toolkits.jetbrains.services.amazonq.lsp.auth.DefaultAuthCredentialsService
 import software.aws.toolkits.jetbrains.services.amazonq.lsp.encryption.JwtEncryptionManager
 import software.aws.toolkits.jetbrains.services.amazonq.lsp.model.createExtendedClientMetadata
+import software.aws.toolkits.jetbrains.services.amazonq.lsp.textdocument.TextDocumentServiceHandler
 import software.aws.toolkits.jetbrains.services.telemetry.ClientMetadata
 import java.io.IOException
 import java.io.OutputStreamWriter
@@ -306,6 +307,7 @@
         }
 
         DefaultAuthCredentialsService(project, encryptionManager, this)
+        TextDocumentServiceHandler(project, this)
     }
 
     override fun dispose() {

plugins/amazonq/shared/jetbrains-community/src/software/aws/toolkits/jetbrains/services/amazonq/lsp/textdocument/TextDocumentServiceHandler.kt

@@ -0,0 +1,131 @@
+// Copyright 2025 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package software.aws.toolkits.jetbrains.services.amazonq.lsp.textdocument
+
+import com.intellij.openapi.Disposable
+import com.intellij.openapi.editor.Document
+import com.intellij.openapi.fileEditor.FileDocumentManager
+import com.intellij.openapi.fileEditor.FileDocumentManagerListener
+import com.intellij.openapi.fileEditor.FileEditorManager
+import com.intellij.openapi.fileEditor.FileEditorManagerListener
+import com.intellij.openapi.project.Project
+import com.intellij.openapi.vfs.VirtualFile
+import com.intellij.openapi.vfs.VirtualFileManager
+import com.intellij.openapi.vfs.newvfs.BulkFileListener
+import com.intellij.openapi.vfs.newvfs.events.VFileContentChangeEvent
+import com.intellij.openapi.vfs.newvfs.events.VFileEvent
+import org.eclipse.lsp4j.DidChangeTextDocumentParams
+import org.eclipse.lsp4j.DidCloseTextDocumentParams
+import org.eclipse.lsp4j.DidOpenTextDocumentParams
+import org.eclipse.lsp4j.DidSaveTextDocumentParams
+import org.eclipse.lsp4j.TextDocumentContentChangeEvent
+import org.eclipse.lsp4j.TextDocumentIdentifier
+import org.eclipse.lsp4j.TextDocumentItem
+import org.eclipse.lsp4j.VersionedTextDocumentIdentifier
+import software.aws.toolkits.jetbrains.services.amazonq.lsp.AmazonQLspService
+import software.aws.toolkits.jetbrains.utils.pluginAwareExecuteOnPooledThread
+
+class TextDocumentServiceHandler(
+    private val project: Project,
+    serverInstance: Disposable,
+) : FileDocumentManagerListener,
+    FileEditorManagerListener,
+    BulkFileListener {
+
+    init {
+        // didOpen & didClose events
+        project.messageBus.connect(serverInstance).subscribe(
+            FileEditorManagerListener.FILE_EDITOR_MANAGER,
+            this
+        )
+
+        // didChange events
+        project.messageBus.connect(serverInstance).subscribe(
+            VirtualFileManager.VFS_CHANGES,
+            this
+        )
+
+        // didSave events
+        project.messageBus.connect(serverInstance).subscribe(
+            FileDocumentManagerListener.TOPIC,
+            this
+        )
+    }
+
+    override fun beforeDocumentSaving(document: Document) {
+        AmazonQLspService.executeIfRunning(project) { languageServer ->
+            val file = FileDocumentManager.getInstance().getFile(document) ?: return@executeIfRunning
+            file.toNioPath().toUri().toString().takeIf { it.isNotEmpty() }?.let { uri ->
+                languageServer.textDocumentService.didSave(
+                    DidSaveTextDocumentParams().apply {
+                        textDocument = TextDocumentIdentifier().apply {
+                            this.uri = uri
+                        }
+                        text = document.text
+                    }
+                )
+            }
+        }
+    }
+
+    override fun after(events: MutableList<out VFileEvent>) {
+        AmazonQLspService.executeIfRunning(project) { languageServer ->
+            pluginAwareExecuteOnPooledThread {
+                events.filterIsInstance<VFileContentChangeEvent>().forEach { event ->
+                    val document = FileDocumentManager.getInstance().getCachedDocument(event.file) ?: return@forEach
+                    event.file.toNioPath().toUri().toString().takeIf { it.isNotEmpty() }?.let { uri ->
+                        languageServer.textDocumentService.didChange(
+                            DidChangeTextDocumentParams().apply {
+                                textDocument = VersionedTextDocumentIdentifier().apply {
+                                    this.uri = uri
+                                    version = document.modificationStamp.toInt()
+                                }
+                                contentChanges = listOf(
+                                    TextDocumentContentChangeEvent().apply {
+                                        text = document.text
+                                    }
+                                )
+                            }
+                        )
+                    }
+                }
+            }
+        }
+    }
+
+    override fun fileOpened(
+        source: FileEditorManager,
+        file: VirtualFile,
+    ) {
+        AmazonQLspService.executeIfRunning(project) { languageServer ->
+            file.toNioPath().toUri().toString().takeIf { it.isNotEmpty() }?.let { uri ->
+                languageServer.textDocumentService.didOpen(
+                    DidOpenTextDocumentParams().apply {
+                        textDocument = TextDocumentItem().apply {
+                            this.uri = uri
+                            text = file.inputStream.readAllBytes().decodeToString()
+                        }
+                    }
+                )
+            }
+        }
+    }
+
+    override fun fileClosed(
+        source: FileEditorManager,
+        file: VirtualFile,
+    ) {
+        AmazonQLspService.executeIfRunning(project) { languageServer ->
+            file.toNioPath().toUri().toString().takeIf { it.isNotEmpty() }?.let { uri ->
+                languageServer.textDocumentService.didClose(
+                    DidCloseTextDocumentParams().apply {
+                        textDocument = TextDocumentIdentifier().apply {
+                            this.uri = uri
+                        }
+                    }
+                )
+            }
+        }
+    }
+}