// See LICENSE for license details.

package uncore.tilelink2

import Chisel._
import scala.collection.mutable.ListBuffer
import scala.math.max
import chisel3.internal.sourceinfo.SourceInfo

// A potentially empty half-open range; [start, end)
case class IntRange(start: Int, end: Int)
{
  require (start >= 0)
  require (start <= end)
  def size = end - start
  def overlaps(x: IntRange) = start < x.end && x.start < end
  def offset(x: Int) = IntRange(x+start, x+end)
}
object IntRange
{
  implicit def apply(end: Int): IntRange = apply(0, end)
}

case class IntSourceParameters(device: String, range: IntRange)

case class IntSinkPortParameters()
case class IntSourcePortParameters(sources: Seq[IntSourceParameters])
{
  val num = sources.map(_.range.size).sum
  // The interrupts mapping must not overlap
  sources.map(_.range).combinations(2).foreach { case Seq(a, b) => require (!a.overlaps(b)) }
  // The interrupts must perfectly cover the range
  require (sources.map(_.range.end).max == num)
}
case class IntEdge(source: IntSourcePortParameters, sink: IntSinkPortParameters)

object IntImp extends NodeImp[IntSourcePortParameters, IntSinkPortParameters, IntEdge, IntEdge, Vec[Bool]]
{
  def edgeO(po: IntSourcePortParameters, pi: IntSinkPortParameters): IntEdge = IntEdge(po, pi)
  def edgeI(po: IntSourcePortParameters, pi: IntSinkPortParameters): IntEdge = IntEdge(po, pi)
  def bundleO(eo: Seq[IntEdge]): Vec[Vec[Bool]] = {
    if (eo.isEmpty) Vec(0, Vec(0, Bool())) else
    Vec(eo.size, Vec(eo.map(_.source.num).max, Bool()))
  }
  def bundleI(ei: Seq[IntEdge]): Vec[Vec[Bool]] = {
    require (!ei.isEmpty)
    Vec(ei.size, Vec(ei.map(_.source.num).max, Bool())).flip
  }

  def connect(bo: Vec[Bool], eo: IntEdge, bi: Vec[Bool], ei: IntEdge)(implicit sourceInfo: SourceInfo): Unit = {
    require (eo == ei)
    // Cannot use bulk connect, because the widths could differ
    (bo zip bi) foreach { case (o, i) => i := o }
  }
}

case class IntIdentityNode() extends IdentityNode(IntImp)
case class IntOutputNode() extends OutputNode(IntImp)
case class IntInputNode() extends InputNode(IntImp)

case class IntSourceNode(device: String, num: Int) extends SourceNode(IntImp)(
  IntSourcePortParameters(Seq(IntSourceParameters(device, num))),
  (if (num == 0) 0 else 1) to 1)
case class IntSinkNode() extends SinkNode(IntImp)(IntSinkPortParameters())

case class IntAdapterNode(
  sourceFn:       Seq[IntSourcePortParameters] => IntSourcePortParameters,
  sinkFn:         Seq[IntSinkPortParameters]   => IntSinkPortParameters,
  numSourcePorts: Range.Inclusive = 1 to 1,
  numSinkPorts:   Range.Inclusive = 1 to 1)
  extends InteriorNode(IntImp)(sourceFn, sinkFn, numSourcePorts, numSinkPorts)

class IntXbar extends LazyModule
{
  val intnode = IntAdapterNode(
    numSourcePorts = 1 to 1, // does it make sense to have more than one interrupt sink?
    numSinkPorts   = 1 to 128,
    sinkFn         = { _ => IntSinkPortParameters() },
    sourceFn       = { seq =>
      IntSourcePortParameters((seq zip seq.map(_.num).scanLeft(0)(_+_).init).map {
        case (s, o) => s.sources.map(z => z.copy(range = z.range.offset(o)))
      }.flatten)
    })

  lazy val module = new LazyModuleImp(this) {
    val io = new Bundle {
      val in  = intnode.bundleIn
      val out = intnode.bundleOut
    }

    val cat = (intnode.edgesIn zip io.in).map{ case (e, i) => i.take(e.source.num) }.flatten
    io.out.foreach { _ := cat }
  }
}