// SPDX-License-Identifier: Apache-2.0

package firrtl

import scala.collection.Seq
import Utils._
import firrtl.ir._
import WrappedExpression._
import WrappedWidth._
import firrtl.passes.CheckTypes.legalResetType

trait Kind
case object WireKind extends Kind
case object PoisonKind extends Kind
case object RegKind extends Kind
case object InstanceKind extends Kind
case object PortKind extends Kind
case object NodeKind extends Kind
case object MemKind extends Kind
case object ExpKind extends Kind
case object UnknownKind extends Kind

trait Flow
case object SourceFlow extends Flow
case object SinkFlow extends Flow
case object DuplexFlow extends Flow
case object UnknownFlow extends Flow

object WRef {

  /** Creates a WRef from a Wire */
  def apply(wire: DefWire): WRef = new WRef(wire.name, wire.tpe, WireKind, UnknownFlow)

  /** Creates a WRef from a Register */
  def apply(reg: DefRegister): WRef = new WRef(reg.name, reg.tpe, RegKind, UnknownFlow)

  /** Creates a WRef from a Node */
  def apply(node: DefNode): WRef = new WRef(node.name, node.value.tpe, NodeKind, SourceFlow)

  /** Creates a WRef from a Port */
  def apply(port: Port): WRef = new WRef(port.name, port.tpe, PortKind, UnknownFlow)

  /** Creates a WRef from a WDefInstance */
  def apply(wi: WDefInstance): WRef = new WRef(wi.name, wi.tpe, InstanceKind, UnknownFlow)

  /** Creates a WRef from a DefMemory */
  def apply(mem: DefMemory): WRef = new WRef(mem.name, passes.MemPortUtils.memType(mem), MemKind, UnknownFlow)

  /** Creates a WRef from an arbitrary string name */
  def apply(n: String, t: Type = UnknownType, k: Kind = ExpKind): WRef = Reference(n, t, k, UnknownFlow)

  def apply(name:  String, tpe: Type, kind: Kind, flow: Flow): WRef = Reference(name, tpe, kind, flow)
  def unapply(ref: Reference): Option[(String, Type, Kind, Flow)] = Some((ref.name, ref.tpe, ref.kind, ref.flow))
}

object WSubField {
  def apply(expr:  Expression, n:    String): WSubField = new WSubField(expr, n, field_type(expr.tpe, n), UnknownFlow)
  def apply(expr:  Expression, name: String, tpe: Type): WSubField = new WSubField(expr, name, tpe, UnknownFlow)
  def apply(expr:  Expression, name: String, tpe: Type, flow: Flow): WSubField = new WSubField(expr, name, tpe, flow)
  def unapply(wsf: WSubField): Option[(Expression, String, Type, Flow)] = Some((wsf.expr, wsf.name, wsf.tpe, wsf.flow))
}

object WSubIndex {
  def apply(expr:  Expression, value: Int, tpe: Type, flow: Flow): WSubIndex = new WSubIndex(expr, value, tpe, flow)
  def unapply(wsi: WSubIndex): Option[(Expression, Int, Type, Flow)] = Some((wsi.expr, wsi.value, wsi.tpe, wsi.flow))
}

object WSubAccess {
  def apply(expr: Expression, index: Expression, tpe: Type, flow: Flow): WSubAccess =
    new WSubAccess(expr, index, tpe, flow)
  def unapply(wsa: WSubAccess): Option[(Expression, Expression, Type, Flow)] = Some(
    (wsa.expr, wsa.index, wsa.tpe, wsa.flow)
  )
}

case object WVoid extends Expression with UseSerializer {
  def tpe = UnknownType
  def mapExpr(f:      Expression => Expression): Expression = this
  def mapType(f:      Type => Type):             Expression = this
  def mapWidth(f:     Width => Width):           Expression = this
  def foreachExpr(f:  Expression => Unit):       Unit = ()
  def foreachType(f:  Type => Unit):             Unit = ()
  def foreachWidth(f: Width => Unit):            Unit = ()
}
case object WInvalid extends Expression with UseSerializer {
  def tpe = UnknownType
  def mapExpr(f:      Expression => Expression): Expression = this
  def mapType(f:      Type => Type):             Expression = this
  def mapWidth(f:     Width => Width):           Expression = this
  def foreachExpr(f:  Expression => Unit):       Unit = ()
  def foreachType(f:  Type => Unit):             Unit = ()
  def foreachWidth(f: Width => Unit):            Unit = ()
}
// Useful for splitting then remerging references
case object EmptyExpression extends Expression with UseSerializer {
  def tpe = UnknownType
  def mapExpr(f:      Expression => Expression): Expression = this
  def mapType(f:      Type => Type):             Expression = this
  def mapWidth(f:     Width => Width):           Expression = this
  def foreachExpr(f:  Expression => Unit):       Unit = ()
  def foreachType(f:  Type => Unit):             Unit = ()
  def foreachWidth(f: Width => Unit):            Unit = ()
}

object WDefInstance {
  def apply(name: String, module: String): WDefInstance = new WDefInstance(NoInfo, name, module, UnknownType)
  def apply(info: Info, name:     String, module: String, tpe: Type): WDefInstance =
    new WDefInstance(info, name, module, tpe)
  def unapply(wi: WDefInstance): Option[(Info, String, String, Type)] = {
    Some((wi.info, wi.name, wi.module, wi.tpe))
  }
}

case class WDefInstanceConnector(
  info:     Info,
  name:     String,
  module:   String,
  tpe:      Type,
  portCons: Seq[(Expression, Expression)])
    extends Statement
    with IsDeclaration
    with UseSerializer {
  def mapExpr(f: Expression => Expression): Statement =
    this.copy(portCons = portCons.map { case (e1, e2) => (f(e1), f(e2)) })
  def mapStmt(f:       Statement => Statement): Statement = this
  def mapType(f:       Type => Type):           Statement = this.copy(tpe = f(tpe))
  def mapString(f:     String => String):       Statement = this.copy(name = f(name))
  def mapInfo(f:       Info => Info):           Statement = this.copy(f(info))
  def foreachStmt(f:   Statement => Unit):      Unit = ()
  def foreachExpr(f:   Expression => Unit):     Unit = portCons.foreach { case (e1, e2) => (f(e1), f(e2)) }
  def foreachType(f:   Type => Unit):           Unit = f(tpe)
  def foreachString(f: String => Unit):         Unit = f(name)
  def foreachInfo(f:   Info => Unit):           Unit = f(info)
}

// Resultant width is the same as the maximum input width
case object Addw extends PrimOp {
  override def toString = "addw"
  import constraint._
  import PrimOps._
  import Implicits.{constraint2width, width2constraint}

  override def propagateType(e: DoPrim): Type = {
    (e.args(0).tpe, e.args(1).tpe) match {
      case (_: UIntType, _: UIntType) => UIntType(IsMax(w1(e), w2(e)))
      case (_: SIntType, _: SIntType) => SIntType(IsMax(w1(e), w2(e)))
      case _ => UnknownType
    }
  }
}
// Resultant width is the same as the maximum input width
case object Subw extends PrimOp {
  override def toString = "subw"
  import constraint._
  import PrimOps._
  import Implicits.{constraint2width, width2constraint}

  override def propagateType(e: DoPrim): Type = {
    (e.args(0).tpe, e.args(1).tpe) match {
      case (_: UIntType, _: UIntType) => UIntType(IsMax(w1(e), w2(e)))
      case (_: SIntType, _: SIntType) => SIntType(IsMax(w1(e), w2(e)))
      case _ => UnknownType
    }
  }
}
// Resultant width is the same as input argument width
case object Dshlw extends PrimOp {
  override def toString = "dshlw"

  import PrimOps._

  override def propagateType(e: DoPrim): Type = {
    e.args(0).tpe match {
      case _: UIntType => UIntType(w1(e))
      case _: SIntType => SIntType(w1(e))
      case _ => UnknownType
    }
  }
}

/** Internal class used for propagating [[Info]] across [[Expression]]s
  *
  * In particular, this is useful in "Netlist" datastructures mapping node or other [[Statement]]s
  * to [[Expression]]s
  *
  * @note This is not allowed to leak from any transform
  */
private[firrtl] case class InfoExpr(info: Info, expr: Expression) extends Expression {
  def foreachExpr(f:  Expression => Unit):       Unit = f(expr)
  def foreachType(f:  Type => Unit):             Unit = ()
  def foreachWidth(f: Width => Unit):            Unit = ()
  def mapExpr(f:      Expression => Expression): Expression = this.copy(expr = f(this.expr))
  def mapType(f:      Type => Type):             Expression = this
  def mapWidth(f:     Width => Width):           Expression = this
  def tpe: Type = expr.tpe

  // Members declared in firrtl.ir.FirrtlNode
  override def serialize: String = s"(${expr.serialize}: ${info.serialize})"
}

private[firrtl] object InfoExpr {
  def wrap(info: Info, expr: Expression): Expression =
    if (info == NoInfo) expr else InfoExpr(info, expr)

  def unwrap(expr: Expression): (Info, Expression) = expr match {
    case InfoExpr(i, e) => (i, e)
    case other          => (NoInfo, other)
  }

  def orElse(info: Info, alt: => Info): Info = if (info == NoInfo) alt else info

  // TODO this the right name?
  def map(expr: Expression)(f: Expression => Expression): Expression = expr match {
    case ie: InfoExpr => ie.mapExpr(f)
    case e => f(e)
  }
}

object WrappedExpression {
  def apply(e: Expression) = new WrappedExpression(e)
  def we(e:    Expression) = new WrappedExpression(e)
  def weq(e1:  Expression, e2: Expression) = we(e1) == we(e2)
}
class WrappedExpression(val e1: Expression) {
  override def equals(we: Any) = we match {
    case (we: WrappedExpression) =>
      (e1, we.e1) match {
        case (e1x: UIntLiteral, e2x: UIntLiteral) => e1x.value == e2x.value && eqw(e1x.width, e2x.width)
        case (e1x: SIntLiteral, e2x: SIntLiteral) => e1x.value == e2x.value && eqw(e1x.width, e2x.width)
        case (e1x: WRef, e2x: WRef) => e1x.name.equals(e2x.name)
        case (e1x: WSubField, e2x: WSubField) => (e1x.name.equals(e2x.name)) && weq(e1x.expr, e2x.expr)
        case (e1x: WSubIndex, e2x: WSubIndex) => (e1x.value == e2x.value) && weq(e1x.expr, e2x.expr)
        case (e1x: WSubAccess, e2x: WSubAccess) => weq(e1x.index, e2x.index) && weq(e1x.expr, e2x.expr)
        case (WVoid, WVoid)       => true
        case (WInvalid, WInvalid) => true
        case (e1x: DoPrim, e2x: DoPrim) =>
          e1x.op == e2x.op &&
            ((e1x.consts.zip(e2x.consts)).forall { case (x, y) => x == y }) &&
            ((e1x.args.zip(e2x.args)).forall { case (x, y) => weq(x, y) })
        case (e1x: Mux, e2x: Mux) => weq(e1x.cond, e2x.cond) && weq(e1x.tval, e2x.tval) && weq(e1x.fval, e2x.fval)
        case (e1x: ValidIf, e2x: ValidIf) => weq(e1x.cond, e2x.cond) && weq(e1x.value, e2x.value)
        case (e1x, e2x) => false
      }
    case _ => false
  }
  override def hashCode = e1.serialize.hashCode
  override def toString = e1.serialize
}

private[firrtl] sealed trait HasMapWidth {
  def mapWidth(f: Width => Width): Width
}

object WrappedType {
  def apply(t: Type) = new WrappedType(t)
  def wt(t:    Type) = apply(t)
  // Check if it is legal for the source type to drive the sink type
  // Which is which matters because ResetType can be driven by itself, Bool, or AsyncResetType, but
  //   it cannot drive Bool nor AsyncResetType
  private def compare(sink: Type, source: Type): Boolean =
    (sink, source) match {
      case (_: UIntType, _: UIntType) => true
      case (_: SIntType, _: SIntType) => true
      case (ClockType, ClockType)           => true
      case (AsyncResetType, AsyncResetType) => true
      case (ResetType, tpe)                 => legalResetType(tpe)
      case (tpe, ResetType)                 => legalResetType(tpe)
      case (_: FixedType, _: FixedType) => true
      case (_: IntervalType, _: IntervalType) => true
      // Analog totally skips out of the Firrtl type system.
      // The only way Analog can play with another Analog component is through Attach.
      // Ohterwise, we'd need to special case it during ExpandWhens, Lowering,
      // ExpandConnects, etc.
      case (_: AnalogType, _: AnalogType) => false
      case (sink: VectorType, source: VectorType) =>
        sink.size == source.size && compare(sink.tpe, source.tpe)
      case (sink: BundleType, source: BundleType) =>
        (sink.fields.size == source.fields.size) &&
          sink.fields.zip(source.fields).forall {
            case (f1, f2) =>
              (f1.flip == f2.flip) && (f1.name == f2.name) && (f1.flip match {
                case Default => compare(f1.tpe, f2.tpe)
                // We allow UInt<1> and AsyncReset to drive Reset but not the other way around
                case Flip => compare(f2.tpe, f1.tpe)
              })
          }
      case _ => false
    }
}
class WrappedType(val t: Type) {
  def wt(tx: Type) = new WrappedType(tx)
  // TODO Better name?
  /** Strict comparison except Reset accepts AsyncReset, Reset, and `UInt<1>`
    */
  def superTypeOf(that: WrappedType): Boolean = WrappedType.compare(this.t, that.t)

  override def equals(o: Any): Boolean = o match {
    case (t2: WrappedType) => WrappedType.compare(this.t, t2.t)
    case _ => false
  }
}

object WrappedWidth {
  def eqw(w1: Width, w2: Width): Boolean = new WrappedWidth(w1) == new WrappedWidth(w2)
}

class WrappedWidth(val w: Width) {
  def ww(w: Width): WrappedWidth = new WrappedWidth(w)
  override def toString = w match {
    case (w: VarWidth) => w.name
    case (w: IntWidth) => w.width.toString
    case UnknownWidth => "?"
  }
  override def equals(o: Any): Boolean = o match {
    case (w2: WrappedWidth) =>
      (w, w2.w) match {
        case (w1: VarWidth, w2: VarWidth) => w1.name.equals(w2.name)
        case (w1: IntWidth, w2: IntWidth) => w1.width == w2.width
        case (UnknownWidth, UnknownWidth) => true
        case _                            => false
      }
    case _ => false
  }
}

abstract class MPortDir extends FirrtlNode
case object MInfer extends MPortDir {
  def serialize: String = "infer"
}
case object MRead extends MPortDir {
  def serialize: String = "read"
}
case object MWrite extends MPortDir {
  def serialize: String = "write"
}
case object MReadWrite extends MPortDir {
  def serialize: String = "rdwr"
}

case class CDefMemory(
  info:           Info,
  name:           String,
  tpe:            Type,
  size:           BigInt,
  seq:            Boolean,
  readUnderWrite: ReadUnderWrite.Value = ReadUnderWrite.Undefined)
    extends Statement
    with HasInfo
    with UseSerializer {
  def mapExpr(f:       Expression => Expression): Statement = this
  def mapStmt(f:       Statement => Statement):   Statement = this
  def mapType(f:       Type => Type):             Statement = this.copy(tpe = f(tpe))
  def mapString(f:     String => String):         Statement = this.copy(name = f(name))
  def mapInfo(f:       Info => Info):             Statement = this.copy(f(info))
  def foreachStmt(f:   Statement => Unit):        Unit = ()
  def foreachExpr(f:   Expression => Unit):       Unit = ()
  def foreachType(f:   Type => Unit):             Unit = f(tpe)
  def foreachString(f: String => Unit):           Unit = f(name)
  def foreachInfo(f:   Info => Unit):             Unit = f(info)
}
case class CDefMPort(info: Info, name: String, tpe: Type, mem: String, exps: Seq[Expression], direction: MPortDir)
    extends Statement
    with HasInfo
    with UseSerializer {
  def mapExpr(f:       Expression => Expression): Statement = this.copy(exps = exps.map(f))
  def mapStmt(f:       Statement => Statement):   Statement = this
  def mapType(f:       Type => Type):             Statement = this.copy(tpe = f(tpe))
  def mapString(f:     String => String):         Statement = this.copy(name = f(name))
  def mapInfo(f:       Info => Info):             Statement = this.copy(f(info))
  def foreachStmt(f:   Statement => Unit):        Unit = ()
  def foreachExpr(f:   Expression => Unit):       Unit = exps.foreach(f)
  def foreachType(f:   Type => Unit):             Unit = f(tpe)
  def foreachString(f: String => Unit):           Unit = f(name)
  def foreachInfo(f:   Info => Unit):             Unit = f(info)
}
