From 6fedc115aa9f8e732bf91967977bb8ab027b4386 Mon Sep 17 00:00:00 2001
From: Lanius Trolling <lanius@laniustrolling.dev>
Date: Tue, 9 Apr 2024 12:19:38 -0400
Subject: [PATCH] Add serial transfer

---
 build.gradle.kts                              |  12 ++
 .../info/mechyrdia/data/MigrateFilesSerial.kt | 103 ++++++++++++++++++
 2 files changed, 115 insertions(+)
 create mode 100644 src/jvmMain/kotlin/info/mechyrdia/data/MigrateFilesSerial.kt

diff --git a/build.gradle.kts b/build.gradle.kts
index c9f6d7f..c9753d9 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -287,6 +287,18 @@ tasks.register("migrateToGridFs", JavaExec::class) {
 	setArgs(listOf("config", "gridfs"))
 }
 
+tasks.register("migrateToGridFsSerial", JavaExec::class) {
+	group = "administration"
+	
+	val runShadow: JavaExec by tasks
+	val main by sourceSets
+	
+	javaLauncher.convention(runShadow.javaLauncher)
+	classpath = main.runtimeClasspath
+	mainClass.set("info.mechyrdia.data.MigrateFilesSerial")
+	setArgs(listOf("config", "gridfs"))
+}
+
 tasks.withType<JavaExec> {
 	javaLauncher.set(javaToolchains.launcherFor {
 		languageVersion.set(JavaLanguageVersion.of(17))
diff --git a/src/jvmMain/kotlin/info/mechyrdia/data/MigrateFilesSerial.kt b/src/jvmMain/kotlin/info/mechyrdia/data/MigrateFilesSerial.kt
new file mode 100644
index 0000000..784b6bc
--- /dev/null
+++ b/src/jvmMain/kotlin/info/mechyrdia/data/MigrateFilesSerial.kt
@@ -0,0 +1,103 @@
+@file:JvmName("MigrateFilesSerial")
+
+package info.mechyrdia.data
+
+import info.mechyrdia.Configuration
+import info.mechyrdia.FileStorageConfig
+import kotlinx.coroutines.runBlocking
+import kotlin.system.exitProcess
+
+private fun printUsage(): Nothing {
+	println("Usage: <FROM> <TO>")
+	println("Both arguments are of either following format:")
+	println("    gridfs - use GridFS (database connection indicated by config.json)")
+	println("    config - storage indicated in config file")
+	println("    file:<relative-path> - use flat-file storage")
+	exitProcess(-1)
+}
+
+private fun String.parseStorage(): FileStorageConfig {
+	val configuration = Configuration.Current
+	
+	return if (this == "config")
+		configuration.storage
+	else if (this == "gridfs")
+		FileStorageConfig.GridFs
+	else if (startsWith("file:"))
+		FileStorageConfig.Flat(removePrefix("file:"))
+	else {
+		println("Invalid format for argument value $this")
+		printUsage()
+	}
+}
+
+private suspend fun migrateFile(path: StoragePath, from: FileStorage, into: FileStorage): List<String> {
+	println("[Message] Starting transfer of /$path")
+	
+	val bytes = from.readFile(path) ?: return listOf("[Source Error] File does not exist at /$path")
+	if (!into.writeFile(path, bytes))
+		return listOf("[Target Error] File at /$path cannot be written to")
+	
+	println("[Message] Done transferring /$path")
+	return emptyList()
+}
+
+private suspend fun migrateDir(path: StoragePath, from: FileStorage, into: FileStorage): List<String> {
+	if (!into.createDir(path))
+		return listOf("[Target Error] Directory at /$path cannot be created")
+	
+	val inDir = from.listDir(path) ?: return listOf("[Source Error] Directory at /$path does not exist")
+	
+	return inDir.flatMap { entry ->
+		val entryPath = path / entry.name
+		when (entry.type) {
+			StoredFileType.FILE -> migrateFile(entryPath, from, into)
+			StoredFileType.DIRECTORY -> migrateDir(entryPath, from, into)
+		}
+	}
+}
+
+private suspend fun migrateRoot(from: FileStorage, into: FileStorage): List<String> {
+	val inRoot = from.listDir(StoragePath.Root)
+		?: return listOf("[Source Error] Root directory does not exist")
+	
+	return inRoot.flatMap { entry ->
+		val entryPath = StoragePath.Root / entry.name
+		when (entry.type) {
+			StoredFileType.FILE -> migrateFile(entryPath, from, into)
+			StoredFileType.DIRECTORY -> migrateDir(entryPath, from, into)
+		}
+	}
+}
+
+fun main(args: Array<String>) {
+	if (args.size != 2) {
+		println("Invalid number of arguments ${args.size}, expected 2")
+		printUsage()
+	}
+	
+	val (from, into) = args.map { it.parseStorage() }
+	if (from == into) {
+		println("Cannot migrate storage to itself")
+		printUsage()
+	}
+	
+	val errors = runBlocking {
+		System.setProperty("logback.statusListenerClass", "ch.qos.logback.core.status.NopStatusListener")
+		
+		ConnectionHolder.initialize(Configuration.Current.dbConn, Configuration.Current.dbName)
+		
+		val fromStorage = FileStorage(from)
+		val intoStorage = FileStorage(into)
+		
+		migrateRoot(fromStorage, intoStorage)
+	}
+	
+	if (errors.isEmpty())
+		println("Successful migration! No errors encountered!")
+	else {
+		println("Migration encountered ${errors.size} ${errors.size.pluralize("error")}")
+		for (error in errors)
+			println(error)
+	}
+}
-- 
2.25.1