// SPDX-License-Identifier: Apache-2.0

package chisel3.aop.injecting

import chisel3.{Module, ModuleAspect, MultiIOModule, RawModule, experimental, withClockAndReset}
import chisel3.aop._
import chisel3.internal.{Builder, DynamicContext}
import chisel3.internal.firrtl.DefModule
import chisel3.stage.DesignAnnotation
import firrtl.annotations.ModuleTarget
import firrtl.stage.RunFirrtlTransformAnnotation
import firrtl.{ir, _}

import scala.collection.mutable

/** Aspect to inject Chisel code into a module of type M
  *
  * @param selectRoots Given top-level module, pick the instances of a module to apply the aspect (root module)
  * @param injection Function to generate Chisel hardware that will be injected to the end of module m
  *                  Signals in m can be referenced and assigned to as if inside m (yes, it is a bit magical)
  * @tparam T Type of top-level module
  * @tparam M Type of root module (join point)
  */
case class InjectingAspect[T <: RawModule, M <: RawModule](
    selectRoots: T => Iterable[M],
    injection: M => Unit
) extends InjectorAspect[T, M](
    selectRoots,
    injection
)

/** Extend to inject Chisel code into a module of type M
  *
  * @param selectRoots Given top-level module, pick the instances of a module to apply the aspect (root module)
  * @param injection Function to generate Chisel hardware that will be injected to the end of module m
  *                  Signals in m can be referenced and assigned to as if inside m (yes, it is a bit magical)
  * @tparam T Type of top-level module
  * @tparam M Type of root module (join point)
  */
abstract class InjectorAspect[T <: RawModule, M <: RawModule](
    selectRoots: T => Iterable[M],
    injection: M => Unit
) extends Aspect[T] {
  final def toAnnotation(top: T): AnnotationSeq = {
    val moduleNames = Select.collectDeep(top) { case i => i.name }.toSeq
    toAnnotation(selectRoots(top), top.name, moduleNames)
  }

 
  /** Returns annotations which contain all injection logic
    *
    * @param modules The modules to inject into
    * @param circuit Top level circuit
    * @return
    */
  @deprecated("Use other toAnnotation method to pass in names of all existing modules", "3.4.1")
  final def toAnnotation(modules: Iterable[M], circuit: String): AnnotationSeq = toAnnotation(modules, circuit, Nil)
 
  /** Returns annotations which contain all injection logic
    *
    * @param modules The modules to inject into
    * @param circuit Top level circuit
    * @param moduleNames The names of all existing modules in the original circuit, to avoid name collisions
    * @return
    */
  final def toAnnotation(modules: Iterable[M], circuit: String, moduleNames: Seq[String]): AnnotationSeq = {
    val dynamicContext = new DynamicContext()
    // Add existing module names into the namespace. If injection logic instantiates new modules
    //  which would share the same name, they will get uniquified accordingly
    moduleNames.foreach { n =>
      dynamicContext.globalNamespace.name(n)
    }
    RunFirrtlTransformAnnotation(new InjectingTransform) +: modules.map { module =>
      val (chiselIR, _) = Builder.build(Module(new ModuleAspect(module) {
        module match {
          case x: MultiIOModule => withClockAndReset(x.clock, x.reset) { injection(module) }
          case x: RawModule => injection(module)
        }
      }), dynamicContext)

      val comps = chiselIR.components.map {
        case x: DefModule if x.name == module.name => x.copy(id = module)
        case other => other
      }

      val annotations = chiselIR.annotations.map(_.toFirrtl).filterNot{ a => a.isInstanceOf[DesignAnnotation[_]] }

      val stmts = mutable.ArrayBuffer[ir.Statement]()
      val modules = Aspect.getFirrtl(chiselIR.copy(components = comps)).modules.flatMap {
        case m: firrtl.ir.Module if m.name == module.name =>
          stmts += m.body
          Nil
        case other: firrtl.ir.DefModule =>
          Seq(other)
      }

      InjectStatement(ModuleTarget(circuit, module.name), ir.Block(stmts), modules, annotations)
    }.toSeq
  }
}

