package ixee.re.disasm

import ixee.cryptopals.utils.ByteUtils._
import ixee.cryptopals.utils.FunctionUtils._

import scala.collection.mutable.Map

case class Source(value: Int)
case class Destination(value: Int)

sealed trait AddressingMode {
  def modeName: String
  override def toString: String = modeName
  def nameifyRegister(reg: Int): String = reg match {
    case 0 => "pc"
    case 1 => "sp"
    case 2 => "sr"
    case 3 => "cg"
    case num @ _ => s"r$num"
  }
  def stringifyWith(reg: Int): String
}

sealed trait OneOpAddressing extends AddressingMode
sealed trait TwoOpAddressing extends AddressingMode
sealed trait TwoOpSourceAddressing extends TwoOpAddressing
sealed trait TwoOpDestAddressing extends TwoOpAddressing

object TwoOpSourceAddressingModes {
  // just alias the apply over to make names look right at call sites.
  // think hard about refactoring this
  def apply(register: Int, mode: Int): Option[TwoOpSourceAddressing] = OneOpAddressingModes(register, mode)
}

object OneOpAddressingModes {
  case class AddressingMode(as: Int, name: String, stringifier: String => String) extends OneOpAddressing with TwoOpSourceAddressing {
    def modeName = name
    def stringifyWith(reg: Int): String = stringifier(nameifyRegister(reg))
  }

  def apply(register: Int, mode: Int): Option[AddressingMode] = register match {
    case 0 => PCModes(mode) orElse General(mode)
    case 2 => SRModes(mode) orElse General(mode)
    case 3 => CGModes(mode) orElse General(mode)
    case _ => General(mode)
  }

  trait Modes {
    private val modeMap: Map[Int, AddressingMode] = Map()
    def Mode(as: Int, name: String, stringifier: String => String) = AddressingMode(as, name, stringifier).tap(modeMap += as -> _)

    def apply(x: Int): Option[AddressingMode] = modeMap.get(x)
  }

  object PCModes extends Modes {
    Mode(3, "NextWord", reg => s"@$reg+ (next word)")
  }
  object SRModes extends Modes {
    Mode(2, "Const4", reg => "#4")
    Mode(3, "Const8", reg => "#8")
  }
  object CGModes extends Modes {
    Mode(0, "Const0", reg => "#0")
    Mode(1, "Const1", reg => "#1")
    Mode(2, "Const2", reg => "#2")
    Mode(3, "ConstNeg1", reg => "#-1")
  }
  object General extends Modes {
    Mode(0, "RegisterDirect", ident)
    Mode(1, "Indexed", reg => s"@PC+($reg)")
    Mode(2, "RegisterIndirect", reg => s"@$reg")
    Mode(3, "IndirectAutoInc", reg => s"@$reg+")
  }

  PCModes
  SRModes
  CGModes
  General
}


object TwoOpDestAddressingModes {
  case class AddressingMode(as: Int, name: String, stringifier: String => String) extends TwoOpDestAddressing {
    def modeName = name
    def stringifyWith(reg: Int): String = stringifier(nameifyRegister(reg))
  }

  def apply(register: Int, mode: Int): Option[AddressingMode] = register match {
    case 0 => PCModes(mode) orElse General(mode)
    case 2 => SRModes(mode) orElse General(mode)
    case _ => General(mode)
  }

  trait Modes {
    private val modeMap: Map[Int, AddressingMode] = Map()
    def Mode(as: Int, name: String, stringifier: String => String) = AddressingMode(as, name, stringifier).tap(modeMap += as -> _)

    def apply(x: Int): Option[AddressingMode] = modeMap.get(x)
  }

  object PCModes extends Modes {
    Mode(1, "Symbolic", reg => s"<??> (symbolic? x(PC)?")
  }
  object SRModes extends Modes {
    Mode(1, "Absolute", reg => s"&@PC+ (value at nextWord)")
  }
  object General extends Modes {
    Mode(0, "RegisterDirect", reg => s"$reg")
    Mode(1, "Indexed", reg => s"@PC+($reg)")
  }

  PCModes
  SRModes
  General
}

sealed trait OpCode {
  def instrName: String
  override def toString: String = instrName
}

sealed trait NoOpCode extends OpCode
sealed trait OneOpCode extends OpCode
sealed trait TwoOpCode extends OpCode

object Opcodes {
  def opcodes: Map[Int, OpCode] = noOpCodes ++ oneOpCodes ++ twoOpCodes
  val noOpCodes: Map[Int, NoOpCode] = Map()
  val oneOpCodes: Map[Int, OneOpCode] = Map()
  val twoOpCodes: Map[Int, TwoOpCode] = Map()

  def apply(value: Int) = opcodes.get(value)
  def noOp(value: Int) = noOpCodes.get(value)
  def oneOp(value: Int) = oneOpCodes.get(value)
  def twoOp(value: Int) = twoOpCodes.get(value)

  object NoOpCodes {
    val Prefix = 0x01
    case class Code(value: Byte, name: String) extends NoOpCode { def instrName = name }
    object Code {
      def apply(value: Int, name: String) = new Code(value.toByte, name).tap(code => noOpCodes += ((((Prefix << 3) + value) << 10) -> code))
    }

    Code(0x00, "JNE")
    Code(0x01, "JEQ")
    Code(0x02, "JNC")
    Code(0x03, "JC ")
    Code(0x04, "JN ")
    Code(0x05, "JGE")
    Code(0x06, "JL ")
    Code(0x07, "JMP")
  }

  object OneOpCodes {
    val Prefix = 0x04
    case class Code(value: Byte, name: String) extends OneOpCode { def instrName = name }
    object Code {
      def apply(value: Int, name: String) = new Code(value.toByte, name).tap(code => oneOpCodes += ((((Prefix << 3) + value) << 7) -> code))
    }

    Code(0x00, "RRC")
    Code(0x01, "SWPB")
    Code(0x02, "RRA")
    Code(0x03, "SXT")
    Code(0x04, "PUSH")
    Code(0x05, "CALL")
    Code(0x06, "RETI")
//    Code(0x07, "NotImplemented")
  }

  object TwoOpCodes {
    val Prefix = 0x1
    case class Code(value: Byte, name: String) extends TwoOpCode { def instrName = name }
    object Code {
      def apply(value: Int, name: String) = new Code(value.toByte, name).tap(code => twoOpCodes += ((value @<< 12) -> code))
    }

    Code(0x04, "MOV")
    Code(0x05, "ADD")
    Code(0x06, "ADDC")
    Code(0x07, "SUBC")
    Code(0x08, "SUB")
    Code(0x09, "CMP")
    Code(0x0a, "DADD")
    Code(0x0b, "BIT")
    Code(0x0c, "BIC")
    Code(0x0d, "BIS")
    Code(0x0e, "XOR")
    Code(0x0f, "AND")
  }

  // forces the various opcode bodies to be evaluated. kinda weird, but it works so welp.
  NoOpCodes
  OneOpCodes
  TwoOpCodes
}

sealed trait Instruction

case class NoOpInst(code: NoOpCode, offset: Int) extends Instruction {
  override def toString: String = {
    s"$code -> $offset"
  }
}
case class OneOpInst(code: OneOpCode, byte: Boolean, dest: Int, addressMode: OneOpAddressing) extends Instruction {
  override def toString: String = {
    val byteStr = if (byte) ".B" else "  "
    s"$code$byteStr ${addressMode.stringifyWith(dest)}"
  }
}
case class TwoOpInst(code: TwoOpCode, byte: Boolean, src: Int, srcMode: TwoOpSourceAddressing, dest: Int, dstMode: TwoOpDestAddressing) extends Instruction {
  override def toString: String = {
    val byteStr = if (byte) ".B" else "  "
    s"$code$byteStr ${srcMode.stringifyWith(src)}, ${dstMode.stringifyWith(dest)}"
  }
}

object NoOp {
  def info(bytes: (Byte, Byte)): (Int, Int) = {
    val op = (bytes._1 & 0xfc) >> 2
    val offset = ((bytes._1 & 0x03) << 8) | bytes._2
    (op, offset)
  }

  def apply(bytes: (Byte, Byte)): Option[NoOpInst] = {
    val (opVal, offset) = info(bytes)
    for {
      opcode <- Opcodes.noOp(opVal << 10)
    } yield NoOpInst(opcode, offset)
  }
}

object OneOp {
  def info(bytes: (Byte, Byte)): (Int, Int, Int, Int) = {
    val dest = (bytes._2 & 0x0f)
    val destMode = ((bytes._2 & 0x30) >> 4)
    val byteBit = ((bytes._2 & 0x40) >> 6)
    val opcode = ((bytes._1 & 0xff) << 1) | ((bytes._2 & 0x80) >> 7)
    (opcode, byteBit, dest, destMode)
  }

  def apply(bytes: (Byte, Byte)): Option[OneOpInst] = {
    val (opVal, byteInstr, dest, rawDestMode) = info(bytes)
    for {
      opcode <- Opcodes.oneOp(opVal << 7)
      isByteOp = if (byteInstr == 1) true else false
      destMode <- OneOpAddressingModes(dest, rawDestMode)
    } yield OneOpInst(opcode, isByteOp, dest, destMode)
  }
}

object TwoOp {
  def info(bytes: (Byte, Byte)): (Int, Int, Int, Int, Int, Int) = {
    val dest = (bytes._2 & 0x0f)
    val sourceMode = (bytes._2 & 0x30) >> 4
    val byteBit = (bytes._2 & 0x40) >> 6
    val destMode = (bytes._2 & 0x80) >> 7
    val source = (bytes._1 & 0x0f)
    val opcode = (bytes._1 & 0xf0) >> 4
    (opcode, byteBit, source, destMode, dest, sourceMode)
  }

  def apply(bytes: (Byte, Byte)): Option[TwoOpInst] = {
    val (opVal, byteInstr, source, rawDestMode, dest, rawSourceMode) = info(bytes)

    for {
      opcode <- Opcodes.twoOp(opVal << 12)
      isByteOp = if (byteInstr == 1) true else false
      destMode <- TwoOpDestAddressingModes(dest, rawDestMode)
      sourceMode <- TwoOpSourceAddressingModes(source, rawSourceMode)
    } yield TwoOpInst(opcode, isByteOp, source, sourceMode, dest, destMode)
  }
}

object Instruction {
  def apply(instruction: (Byte, Byte)): Option[Instruction] = NoOp(instruction) orElse OneOp(instruction) orElse TwoOp(instruction)
  def littleEndian(instruction: String): Option[Instruction] = {
    val instr = Integer.parseInt(instruction, 16)
    val hi = (instr & 0xff00) >> 8
    val lo = instr & 0x00ff
    apply((hi.toByte, lo.toByte))
  }
  def apply(instruction: String): Option[Instruction] = {
    val instr = Integer.parseInt(instruction, 16)
    val hi = (instr & 0xff00) >> 8
    val lo = instr & 0x00ff
    apply((lo.toByte, hi.toByte))
  }

  def noOp(instruction: (Byte, Byte)): Option[NoOpInst] = NoOp.apply(instruction)

  def oneOp(instruction: (Byte, Byte)): Option[OneOpInst] = OneOp.apply(instruction)

  def twoOp(instruction: (Byte, Byte)): Option[TwoOpInst] = TwoOp.apply(instruction)

  def isNoOp(instruction: (Byte ,Byte)) = noOp(instruction).isDefined

  def isOneOp(instruction: (Byte, Byte)) = oneOp(instruction).isDefined

  def isTwoOp(instruction: (Byte, Byte)) = twoOp(instruction).isDefined
}

sealed trait ByteOp {
  override def toString = s"(Single Byte: ${super.toString})"
}