package wacc

object assemblyIR {

  sealed trait Operand

  // did not use option because we'd have to wrap each op around Some(). can refactor
  case object NoOperand extends Operand {
    override def toString = ""
  }
  sealed trait Src extends Operand // mem location, register and imm value
  sealed trait Dest extends Operand // mem location and register
  enum RegSize {
    case R64
    case E32

    override def toString = this match {
      case R64 => "r"
      case E32 => "e"
    }
  }

  //arguments
  enum CLibFunc extends Operand {
    case Scanf,
    Puts,
    Fflush,
    Exit,
    PrintF

    private val plt = "@plt"

    override def toString = this match {
      case Scanf  => "scanf" + plt
      case Puts   => "puts" + plt
      case Fflush => "fflush" + plt
      case Exit   => "exit" + plt
      case PrintF => "printf" + plt
    }
  }

  enum Register extends Dest with Src {
    case Named(name: String, size: RegSize)
    case Scratch(num: Int, size: RegSize)
    override def toString = this match {
      case Named(name, size) => s"${size}${name.toLowerCase()}"
      case Scratch(num, size) => s"${size}${num}"
    }
  }
  case class MemLocation(pointer: Long | Register) extends Dest with Src {
    override def toString = pointer match {
      case hex: Long => f"[0x$hex%X]"
      case reg: Register => s"[$reg]"
    }
  }

  case class ImmediateVal(value: Int) extends Src {
    override def toString = s"#${value.toString}"
  }

  case class LabelArg(name: String) extends Operand {
    override def toString = name
  }

  //TODO Check if dest and src are not both memory locations
  abstract class Operation(ins: String, op1: Operand = NoOperand, op2: Operand = NoOperand) {
    override def toString: String = if (op2 == NoOperand) {
      s"$ins ${op1.toString}"
    } else {
      s"$ins ${op1.toString}, ${op2.toString}"
    }
  }
  case class Add(op1: Dest, op2: Src) extends Operation("add", op1, op2)
  case class Subtract(op1: Dest, op2: Src) extends Operation("sub", op1, op2)
  case class Multiply(op1: Src) extends Operation("mul", op1)
  case class Divide(op1: Src) extends Operation("div", op1)

  case class And(op1: Dest, op2: Src) extends Operation("and", op1, op2)
  case class Or(op1: Dest, op2: Src) extends Operation("or", op1, op2)
  case class Compare(op1: Dest, op2: Src) extends Operation("cmp", op1, op2)

  //stack operations
  case class Push(op1: Src) extends Operation("push", op1)
  case class Pop(op1: Src) extends Operation("pop", op1)
  case class Call(op1: CLibFunc) extends Operation("call", op1)

  case class Return() extends Operation("ret")

  case class Jump(op1: LabelArg) extends Operation("jmp", op1)
  case class JumpIfEqual(op1: LabelArg) extends Operation("je", op1)

  case class LabelDef(name: String) {
    override def toString = s"$name:"
  }

}