MessagePack Integration

/**
 * Write the given Scala value as a MessagePack struct (upack.Msg)
 * @param t Value to serialize
 * @return upack.Msg representation
 */
def writeMsg[T: Writer](t: T): upack.Msg

import upickle.default._
import upack._

case class Person(name: String, age: Int)
val person = Person("Alice", 30)

// Convert to upack AST
val msgAst = writeMsg(person)
// Result: upack.Obj("name" -> upack.Str("Alice"), "age" -> upack.Int32(30))

// Convert to binary  
val binary = upack.write(msgAst)

// Convert back from binary
val parsed = upack.read(binary)

// Transform to JSON for inspection
val jsonAst = upack.transform(msgAst, ujson.Value)
val jsonString = ujson.write(jsonAst)

/**
 * Reader for generic upack.Msg
 */
implicit val MsgValueR: Reader[upack.Msg]

/**
 * Writer for generic upack.Msg
 */
implicit val MsgValueW: Writer[upack.Msg]

import upickle.default._
import upack._

// Create MessagePack data
val msgData = upack.Obj(
  "users" -> upack.Arr(
    upack.Obj("name" -> upack.Str("Alice"), "age" -> upack.Int32(30)),
    upack.Obj("name" -> upack.Str("Bob"), "age" -> upack.Int32(25))
  ),
  "count" -> upack.Int32(2)
)

// Serialize to binary using uPickle
val binary = writeBinary(msgData)

// Deserialize back to upack.Msg
val parsed = readBinary[upack.Msg](binary)

// Access values
val users = parsed.obj("users").arr
val firstUser = users(0).obj  
val userName = firstUser("name").str  // "Alice"
val userAge = firstUser("age").int32  // 30

/**
 * Reads the given MessagePack input into a Scala value
 * @param s MessagePack binary input (Array[Byte], InputStream, etc.)
 * @param trace Enable tracing for debugging
 * @return Deserialized Scala value of type T
 */
def readBinary[T: Reader](s: upack.Readable, trace: Boolean = false): T

/**
 * Write the given Scala value as a MessagePack binary
 * @param t Value to serialize
 * @param sortKeys Whether to sort object keys alphabetically
 * @return MessagePack byte array
 */
def writeBinary[T: Writer](t: T, sortKeys: Boolean = false): Array[Byte]

import upickle.default._

case class Product(id: Int, name: String, price: Double, tags: List[String])

val product = Product(123, "Laptop", 999.99, List("electronics", "computers"))

// Binary serialization
val binary = writeBinary(product)
println(s"JSON size: ${write(product).getBytes.length} bytes")
println(s"MessagePack size: ${binary.length} bytes")

// Binary deserialization
val parsed = readBinary[Product](binary)
assert(parsed == product)

// Sorted keys for deterministic output
val sortedBinary = writeBinary(product, sortKeys = true)

import upickle.default._
import upack._

// Primitive type mappings
val intMsg = writeMsg(42)         // upack.Int32(42)
val longMsg = writeMsg(42L)       // upack.Int64(42L) 
val floatMsg = writeMsg(3.14f)    // upack.Float32(3.14f)
val doubleMsg = writeMsg(3.14)    // upack.Float64(3.14)
val stringMsg = writeMsg("hello") // upack.Str("hello")
val boolMsg = writeMsg(true)      // upack.True
val nullMsg = writeMsg[Option[Int]](None) // upack.Null

// Collection type mappings
val arrayMsg = writeMsg(Array(1, 2, 3))           // upack.Arr(Int32(1), Int32(2), Int32(3))
val listMsg = writeMsg(List("a", "b"))            // upack.Arr(Str("a"), Str("b"))
val mapMsg = writeMsg(Map("key" -> "value"))      // upack.Obj("key" -> Str("value"))

// Binary data mapping (byte arrays are stored efficiently)
val binaryData = Array[Byte](1, 2, 3, 4, 5)
val binaryMsg = writeMsg(binaryData)              // upack.Binary(Array(1, 2, 3, 4, 5))

import upickle.default._
import ujson._
import upack._

case class Data(id: Int, values: List[Double], metadata: Map[String, String])
val data = Data(42, List(1.1, 2.2, 3.3), Map("version" -> "1.0", "type" -> "test"))

// JSON to MessagePack conversion
val jsonString = write(data)
val parsedData = read[Data](jsonString)
val msgPackBinary = writeBinary(parsedData)

// MessagePack to JSON conversion  
val fromBinary = readBinary[Data](msgPackBinary)
val backToJson = write(fromBinary)

// Direct AST conversion
val jsonAst = writeJs(data)         // ujson.Value
val msgAst = writeMsg(data)         // upack.Msg

// Transform between AST types
val jsonFromMsg = upack.transform(msgAst, ujson.Value)
val msgFromJson = ujson.transform(jsonAst, upack.Msg)

// Size comparison
println(s"JSON string: ${jsonString.getBytes("UTF-8").length} bytes")
println(s"MessagePack binary: ${msgPackBinary.length} bytes")

import upickle.default._
import java.io.{FileInputStream, FileOutputStream, ByteArrayOutputStream}

case class LogEntry(timestamp: Long, level: String, message: String)

// Write large dataset to MessagePack file
def writeLogFile(entries: Iterator[LogEntry], filename: String): Unit = {
  val output = new FileOutputStream(filename)
  try {
    entries.foreach { entry =>
      val binary = writeBinary(entry) 
      output.write(binary.length)  // Write length prefix
      output.write(binary)         // Write data
    }
  } finally {
    output.close()
  }
}

// Read MessagePack file
def readLogFile(filename: String): Iterator[LogEntry] = {
  val input = new FileInputStream(filename)
  new Iterator[LogEntry] {
    def hasNext: Boolean = input.available() > 0
    
    def next(): LogEntry = {
      val length = input.read()
      val buffer = new Array[Byte](length)
      input.read(buffer)
      readBinary[LogEntry](buffer)
    }
  }
}

// Streaming with upack directly
def streamLargeArray[T: Writer](items: Iterator[T]): Array[Byte] = {
  val output = new ByteArrayOutputStream()
  val writer = new upack.MsgPackWriter(output)
  
  writer.visitArray(items.size, -1)
  items.foreach { item =>
    writer.visitValue(transform(item).transform(writer), -1)
  }
  writer.visitEnd(-1)
  
  output.toByteArray
}

/**
 * Read MessagePack input into upack.Msg AST
 * @param s MessagePack binary input
 * @param trace Enable tracing for debugging
 * @return upack.Msg AST representation
 */
def upack.read(s: upack.Readable, trace: Boolean = false): upack.Msg

/**
 * Write upack.Msg to MessagePack binary
 * @param t upack.Msg to serialize
 * @return MessagePack byte array
 */
def upack.write(t: upack.Msg): Array[Byte]

/**
 * Write upack.Msg directly to OutputStream
 * @param t upack.Msg to serialize
 * @param out OutputStream to write to
 */
def upack.writeTo(t: upack.Msg, out: java.io.OutputStream): Unit

/**
 * Write upack.Msg to byte array
 * @param t upack.Msg to serialize  
 * @return MessagePack byte array
 */
def upack.writeToByteArray(t: upack.Msg): Array[Byte]

import upack._

// Create MessagePack AST directly
val msgData = upack.Obj(
  "user" -> upack.Str("Alice"),
  "score" -> upack.Int32(85),
  "active" -> upack.True,
  "metadata" -> upack.Obj(
    "version" -> upack.Float64(1.2),
    "tags" -> upack.Arr(upack.Str("premium"), upack.Str("verified"))
  )
)

// Write to binary
val binary = upack.write(msgData)
println(s"MessagePack size: ${binary.length} bytes")

// Read back from binary
val parsed = upack.read(binary)

// Access values
val userName = parsed.obj("user").str                    // "Alice"
val userScore = parsed.obj("score").int32               // 85
val isActive = parsed.obj("active") == upack.True       // true
val version = parsed.obj("metadata").obj("version").float64 // 1.2

// Write to file
val outputStream = new java.io.FileOutputStream("data.msgpack")
try {
  upack.writeTo(msgData, outputStream)
} finally {
  outputStream.close()
}

// Read from file
val inputStream = new java.io.FileInputStream("data.msgpack")
val fileData = try {
  upack.read(inputStream)
} finally {
  inputStream.close()
}

/**
 * Validate MessagePack format without full parsing
 * @param s MessagePack input to validate
 * @throws upack.UpackException if invalid MessagePack
 */
def upack.validate(s: upack.Readable): Unit

import upack._

// Validate MessagePack byte arrays
try {
  val binaryData = Array[Byte](-108, 4, 85, 115, 101, 114, -91, 65, 108, 105, 99, 101)
  upack.validate(binaryData)
  println("Valid MessagePack")
} catch {
  case e: upack.UpackException => println(s"Invalid MessagePack: ${e.getMessage}")
}

// Validate before expensive parsing
def safeParseMessagePack(input: Array[Byte]): Option[upack.Msg] = {
  try {
    upack.validate(input)
    Some(upack.read(input))
  } catch {
    case _: upack.UpackException => None
  }
}

// Validate large files
def validateMessagePackFile(filename: String): Boolean = {
  val inputStream = new java.io.FileInputStream(filename)
  try {
    upack.validate(inputStream)
    true
  } catch {
    case _: upack.UpackException => false
  } finally {
    inputStream.close()
  }
}

/**
 * Transform MessagePack using custom visitor
 * @param t MessagePack input
 * @param v Custom visitor for processing
 * @return Processed result
 */
def upack.transform[T](t: upack.Readable, v: upickle.core.Visitor[_, T]): T

/**
 * Copy upack.Msg creating a deep clone
 * @param t upack.Msg to copy
 * @return Deep copy of the input
 */
def upack.copy(t: upack.Msg): upack.Msg

import upack._
import upickle.core._

// Custom visitor to analyze MessagePack structure
class MessagePackAnalyzer extends Visitor[Any, Map[String, Int]] {
  private var typeCounts = Map.empty[String, Int]
  
  private def increment(typeName: String): Unit = {
    typeCounts = typeCounts.updated(typeName, typeCounts.getOrElse(typeName, 0) + 1)
  }
  
  override def visitArray(length: Int, index: Int) = new ArrVisitor[Any, Map[String, Int]] {
    def subVisitor = MessagePackAnalyzer.this
    def visitValue(v: Any, index: Int): Unit = increment("array_element")
    def visitEnd(index: Int) = { increment("array"); typeCounts }
  }
  
  override def visitObject(length: Int, jsonableKeys: Boolean, index: Int) = new ObjVisitor[Any, Map[String, Int]] {
    def subVisitor = MessagePackAnalyzer.this
    def visitKey(index: Int) = MessagePackAnalyzer.this
    def visitKeyValue(s: Any): Unit = increment("object_key")
    def visitValue(v: Any, index: Int): Unit = increment("object_value")
    def visitEnd(index: Int) = { increment("object"); typeCounts }
  }
  
  override def visitString(s: CharSequence, index: Int) = { increment("string"); typeCounts }
  override def visitInt32(i: Int, index: Int) = { increment("int32"); typeCounts }
  override def visitInt64(i: Long, index: Int) = { increment("int64"); typeCounts }
  override def visitFloat64(d: Double, index: Int) = { increment("float64"); typeCounts }
  override def visitBool(b: Boolean, index: Int) = { increment("boolean"); typeCounts }
  override def visitNull(index: Int) = { increment("null"); typeCounts }
}

// Analyze MessagePack structure
val binaryData = upack.write(upack.Obj(
  "numbers" -> upack.Arr(upack.Int32(1), upack.Int64(2L), upack.Float64(3.14)),
  "text" -> upack.Str("hello"),
  "flag" -> upack.True
))

val analysis = upack.transform(binaryData, new MessagePackAnalyzer())
println("MessagePack structure analysis:")
analysis.foreach { case (typeName, count) =>
  println(s"  $typeName: $count")
}

// Deep copy MessagePack values
val original = upack.Obj("data" -> upack.Arr(upack.Int32(1), upack.Int32(2)))
val copied = upack.copy(original)

// Modify copy without affecting original
copied.obj("data").arr :+ upack.Int32(3)

import upickle.default._
import upack._

// Custom extension type for timestamps
case class Timestamp(epochMillis: Long)

implicit val timestampRW: ReadWriter[Timestamp] = readwriter[Long].bimap(
  (ts: Timestamp) => ts.epochMillis,
  (millis: Long) => Timestamp(millis)
)

// Serialize with extension type
val timestamp = Timestamp(System.currentTimeMillis())
val binary = writeBinary(timestamp)

// Custom binary data handling
case class BinaryData(contentType: String, data: Array[Byte])

implicit val binaryDataRW: ReadWriter[BinaryData] = macroRW

val pdfData = BinaryData("application/pdf", loadPdfBytes())
val binaryPdf = writeBinary(pdfData)
val parsedPdf = readBinary[BinaryData](binaryPdf)

// Efficient binary arrays
val imageBytes: Array[Byte] = loadImageBytes()
val msgWithImage = writeMsg(Map(
  "filename" -> "photo.jpg",
  "size" -> imageBytes.length,
  "data" -> imageBytes  // Stored efficiently as binary
))

// Working with MessagePack extension types directly
val extData = upack.Ext(42.toByte, Array[Byte](1, 2, 3, 4))
val extBinary = upack.write(extData)
val parsedExt = upack.read(extBinary).asInstanceOf[upack.Ext]
println(s"Extension type: ${parsedExt.tag}, data: ${parsedExt.data.mkString(",")}")

/**
 * upack.Msg is the base type for all MessagePack AST nodes
 */
sealed trait upack.Msg

/**
 * Specific upack message types
 */
case class upack.Obj(value: Map[upack.Msg, upack.Msg]) extends upack.Msg
case class upack.Arr(value: Seq[upack.Msg]) extends upack.Msg
case class upack.Str(value: String) extends upack.Msg
case class upack.Int32(value: Int) extends upack.Msg
case class upack.Int64(value: Long) extends upack.Msg
case class upack.UInt64(value: Long) extends upack.Msg
case class upack.Float32(value: Float) extends upack.Msg
case class upack.Float64(value: Double) extends upack.Msg
case class upack.Binary(value: Array[Byte]) extends upack.Msg
case object upack.True extends upack.Msg
case object upack.False extends upack.Msg
case object upack.Null extends upack.Msg

/**
 * upack.Readable represents sources that can provide MessagePack data
 */
trait upack.Readable {
  def transform[T](f: upack.Visitor[_, T]): T
}

/**
 * Writer for MessagePack binary output
 */
class upack.MsgPackWriter(out: java.io.OutputStream) extends upack.Visitor[Any, Unit]