package com.helloaihub.core

// Scala 3 Significant Indentation & ADT Enums
enum AccountStatus:
  case Active, Suspended, Frozen

// Zero-Allocation Opaque Type Alias (Treated as String at runtime with zero heap wrapper!)
opaque type AccountId = String
object AccountId:
  def apply(raw: String): AccountId = raw
  extension (id: AccountId)
    def value: String = id

// Immutable Case Class Domain Entity
case class CustomerAccount(
  id: AccountId,
  holder: String,
  balance: BigDecimal,
  status: AccountStatus
)

// Type Class Pattern in Scala 3
trait JsonCodec[T]:
  def toJson(value: T): String

// Defining Given Type Class Instances
given JsonCodec[String] with
  def toJson(value: String): String = s""$value""

given JsonCodec[BigDecimal] with
  def toJson(value: BigDecimal): String = value.toString

// Contextual Function utilizing Using parameter
def serializeEntity[T](entity: T)(using codec: JsonCodec[T]): String =
  codec.toJson(entity)

// Type-Level Match Type computation
type Elem[X] = X match
  case String      => Char
  case Array[t]    => t
  case Iterable[t] => t

// Compiles with exact type inference!
val charElem: Elem[String] = 'A'
val intElem: Elem[List[Int]] = 42

// Compile-Time Type-Safe Actor in Apache Pekko Typed
import org.apache.pekko.actor.typed.scaladsl.Behaviors
import org.apache.pekko.actor.typed.{ActorRef, Behavior}

object BankAccountActor:
  sealed trait Command
  case class Deposit(amount: BigDecimal, replyTo: ActorRef[StatusReply]) extends Command
  case class GetBalance(replyTo: ActorRef[BigDecimal]) extends Command
  case class StatusReply(success: Boolean, currentBalance: BigDecimal)

  def apply(balance: BigDecimal = 0.0): Behavior[Command] =
    Behaviors.receiveMessage {
      case Deposit(amount, replyTo) =>
        val newBalance = balance + amount
        replyTo ! StatusReply(true, newBalance)
        BankAccountActor(newBalance) // Pure state transition!

      case GetBalance(replyTo) =>
        replyTo ! balance
        Behaviors.same
    }