// See LICENSE for license details.

package chisel3.core

import scala.collection.mutable.{ArrayBuffer, HashMap}
import scala.collection.JavaConversions._
import scala.language.experimental.macros

import chisel3.internal._
import chisel3.internal.Builder._
import chisel3.internal.firrtl._
import chisel3.internal.firrtl.{Command => _, _}
import chisel3.internal.sourceinfo.UnlocatableSourceInfo

/** Abstract base class for Modules that contain Chisel RTL.
  */
abstract class UserModule(implicit moduleCompileOptions: CompileOptions)
    extends BaseModule {
  //
  // RTL construction internals
  //
  private val _commands = ArrayBuffer[Command]()
  private[chisel3] def addCommand(c: Command) {
    require(!_closed, "Can't write to module after module close")
    _commands += c
  }
  protected def getCommands = {
    require(_closed, "Can't get commands before module close")
    _commands.toSeq
  }

  //
  // Other Internal Functions
  //
  // For debuggers/testers, TODO: refactor out into proper public API
  private var _firrtlPorts: Option[Seq[firrtl.Port]] = None
  lazy val getPorts = _firrtlPorts.get

  val compileOptions = moduleCompileOptions

  private[chisel3] def namePorts(names: HashMap[HasId, String]): Unit = {
    for (port <- getModulePorts) {
      port.suggestedName.orElse(names.get(port)) match {
        case Some(name) =>
          if (_namespace.contains(name)) {
            Builder.error(s"""Unable to name port $port to "$name" in $this,""" +
              " name is already taken by another port!")
          }
          port.setRef(ModuleIO(this, _namespace.name(name)))
        case None => Builder.error(s"Unable to name port $port in $this, " +
          "try making it a public field of the Module")
      }
    }
  }


  private[core] override def generateComponent(): Component = {
    require(!_closed, "Can't generate module more than once")
    _closed = true

    val names = nameIds(classOf[UserModule])

    // Ports get first naming priority, since they are part of a Module's IO spec
    namePorts(names)

    // Then everything else gets named
    for ((node, name) <- names) {
      node.suggestName(name)
    }

    // All suggestions are in, force names to every node.
    for (id <- getIds) {
      id match {
        case id: BaseModule => id.forceName(default=id.desiredName, _namespace)
        case id: MemBase[_] => id.forceName(default="_T", _namespace)
        case id: Data if id.topBindingOpt.isDefined => id.topBinding match {
          case OpBinding(_) | MemoryPortBinding(_) | PortBinding(_) | RegBinding(_) | WireBinding(_) =>
            id.forceName(default="_T", _namespace)
          case _ =>  // don't name literals
        }
        case id: Data if id.topBindingOpt.isEmpty =>  // don't name unbound types
      }
      id._onModuleClose
    }

    val firrtlPorts = getModulePorts map {port => Port(port, port.specifiedDirection)}
    _firrtlPorts = Some(firrtlPorts)

    // Generate IO invalidation commands to initialize outputs as unused,
    //  unless the client wants explicit control over their generation.
    val invalidateCommands = {
      if (!compileOptions.explicitInvalidate) {
        getModulePorts map { port => DefInvalid(UnlocatableSourceInfo, port.ref) }
      } else {
        Seq()
      }
    }
    val component = DefModule(this, name, firrtlPorts, invalidateCommands ++ getCommands)
    _component = Some(component)
    component
  }

  private[core] def initializeInParent(parentCompileOptions: CompileOptions): Unit = {
    implicit val sourceInfo = UnlocatableSourceInfo

    if (!parentCompileOptions.explicitInvalidate) {
      for (port <- getModulePorts) {
        pushCommand(DefInvalid(sourceInfo, port.ref))
      }
    }
  }
}

/** Abstract base class for Modules, which behave much like Verilog modules.
  * These may contain both logic and state which are written in the Module
  * body (constructor).
  *
  * @note Module instantiations must be wrapped in a Module() call.
  */
abstract class ImplicitModule(implicit moduleCompileOptions: CompileOptions)
    extends UserModule {
  // Implicit clock and reset pins
  val clock: Clock = IO(Input(Clock()))
  val reset: Reset = IO(Input(Bool()))

  // Setup ClockAndReset
  Builder.currentClockAndReset = Some(ClockAndReset(clock, reset))

  private[core] override def initializeInParent(parentCompileOptions: CompileOptions): Unit = {
    implicit val sourceInfo = UnlocatableSourceInfo

    super.initializeInParent(parentCompileOptions)
    clock := Builder.forcedClock
    reset := Builder.forcedReset
  }
}

/** Legacy Module class that restricts IOs to just io, clock, and reset, and provides a constructor
  * for threading through explicit clock and reset.
  *
  * While this class isn't planned to be removed anytime soon (there are benefits to restricting
  * IO), the clock and reset constructors will be phased out. Recommendation is to wrap the module
  * in a withClock/withReset/withClockAndReset block, or directly hook up clock or reset IO pins.
  */
abstract class LegacyModule(implicit moduleCompileOptions: CompileOptions)
    extends ImplicitModule {
  // These are to be phased out
  protected var override_clock: Option[Clock] = None
  protected var override_reset: Option[Bool] = None

  // _clock and _reset can be clock and reset in these 2ary constructors
  // once chisel2 compatibility issues are resolved
  @chiselRuntimeDeprecated
  @deprecated("Module constructor with override_clock and override_reset deprecated, use withClockAndReset", "chisel3")
  def this(override_clock: Option[Clock]=None, override_reset: Option[Bool]=None)
      (implicit moduleCompileOptions: CompileOptions) = {
    this()
    this.override_clock = override_clock
    this.override_reset = override_reset
  }

  @chiselRuntimeDeprecated
  @deprecated("Module constructor with override _clock deprecated, use withClock", "chisel3")
  def this(_clock: Clock)(implicit moduleCompileOptions: CompileOptions) = this(Option(_clock), None)(moduleCompileOptions)

  @chiselRuntimeDeprecated
  @deprecated("Module constructor with override _reset deprecated, use withReset", "chisel3")
  def this(_reset: Bool)(implicit moduleCompileOptions: CompileOptions)  = this(None, Option(_reset))(moduleCompileOptions)

  @chiselRuntimeDeprecated
  @deprecated("Module constructor with override _clock, _reset deprecated, use withClockAndReset", "chisel3")
  def this(_clock: Clock, _reset: Bool)(implicit moduleCompileOptions: CompileOptions) = this(Option(_clock), Option(_reset))(moduleCompileOptions)

  // IO for this Module. At the Scala level (pre-FIRRTL transformations),
  // connections in and out of a Module may only go through `io` elements.
  def io: Record

  // Allow access to bindings from the compatibility package
  protected def _compatIoPortBound() = portsContains(io)

  protected override def nameIds(rootClass: Class[_]): HashMap[HasId, String] = {
    val names = super.nameIds(rootClass)

    // Allow IO naming without reflection
    names.put(io, "io")
    names.put(clock, "clock")
    names.put(reset, "reset")

    names
  }

  private[chisel3] override def namePorts(names: HashMap[HasId, String]): Unit = {
    for (port <- getModulePorts) {
      // This should already have been caught
      if (!names.contains(port)) throwException(s"Unable to name port $port in $this")
      val name = names(port)
      port.setRef(ModuleIO(this, _namespace.name(name)))
    }
  }

  private[core] override def generateComponent(): Component = {
    _compatAutoWrapPorts()  // pre-IO(...) compatibility hack

    // Restrict IO to just io, clock, and reset
    require(io != null, "Module must have io")
    require(portsContains(io), "Module must have io wrapped in IO(...)")
    require((portsContains(clock)) && (portsContains(reset)), "Internal error, module did not have clock or reset as IO")
    require(portsSize == 3, "Module must only have io, clock, and reset as IO")

    super.generateComponent()
  }

  private[core] override def initializeInParent(parentCompileOptions: CompileOptions): Unit = {
    // Don't generate source info referencing parents inside a module, since this interferes with
    // module de-duplication in FIRRTL emission.
    implicit val sourceInfo = UnlocatableSourceInfo

    if (!parentCompileOptions.explicitInvalidate) {
      pushCommand(DefInvalid(sourceInfo, io.ref))
    }

    override_clock match {
      case Some(override_clock) => clock := override_clock
      case _ => clock := Builder.forcedClock
    }

    override_reset match {
      case Some(override_reset) => reset := override_reset
      case _ => reset := Builder.forcedReset
    }
  }
}
