// See LICENSE for license details.

// This file transform macro definitions to explicitly add implicit source info to Chisel method
// calls.

package chisel3.internal.sourceinfo

import scala.language.experimental.macros
import scala.reflect.macros.blackbox.Context
import scala.reflect.macros.whitebox


/** Transforms a function call so that it can both provide implicit-style source information and
  * have a chained apply call. Without macros, only one is possible, since having a implicit
  * argument in the definition will cause the compiler to interpret a chained apply as an
  * explicit implicit argument and give type errors.
  *
  * Instead of an implicit argument, the public-facing function no longer takes a SourceInfo at all.
  * The macro transforms the public-facing function into a call to an internal function that takes
  * an explicit SourceInfo by inserting an implicitly[SourceInfo] as the explicit argument.
  */
trait SourceInfoTransformMacro {
  val c: Context
  import c.universe._
  def thisObj: Tree = c.prefix.tree
  def implicitSourceInfo = q"implicitly[_root_.chisel3.internal.sourceinfo.SourceInfo]"
  def implicitCompileOptions = q"implicitly[_root_.chisel3.CompileOptions]"
}

// Workaround for https://github.com/sbt/sbt/issues/3966
object UIntTransform
class UIntTransform(val c: Context) extends SourceInfoTransformMacro {
  import c.universe._
  def bitset(off: c.Tree, dat: c.Tree): c.Tree = {
    q"$thisObj.do_bitSet($off, $dat)($implicitSourceInfo, $implicitCompileOptions)"
  }
}

// Workaround for https://github.com/sbt/sbt/issues/3966
object InstTransform
// Module instantiation transform
class InstTransform(val c: Context) extends SourceInfoTransformMacro {
  import c.universe._
  def apply[T: c.WeakTypeTag](bc: c.Tree): c.Tree = {
    q"$thisObj.do_apply($bc)($implicitSourceInfo, $implicitCompileOptions)"
  }
}

// Workaround for https://github.com/sbt/sbt/issues/3966
object MemTransform
class MemTransform(val c: Context) extends SourceInfoTransformMacro {
  import c.universe._
  def apply[T: c.WeakTypeTag](size: c.Tree, t: c.Tree): c.Tree = {
    q"$thisObj.do_apply($size, $t)($implicitSourceInfo, $implicitCompileOptions)"
  }
}

// Workaround for https://github.com/sbt/sbt/issues/3966
object MuxTransform
class MuxTransform(val c: Context) extends SourceInfoTransformMacro {
  import c.universe._
  def apply[T: c.WeakTypeTag](cond: c.Tree, con: c.Tree, alt: c.Tree): c.Tree = {
    val tpe = weakTypeOf[T]
    q"$thisObj.do_apply[$tpe]($cond, $con, $alt)($implicitSourceInfo, $implicitCompileOptions)"
  }
}

// Workaround for https://github.com/sbt/sbt/issues/3966
object VecTransform
class VecTransform(val c: Context) extends SourceInfoTransformMacro {
  import c.universe._
  def apply_elts(elts: c.Tree): c.Tree = {
    q"$thisObj.do_apply($elts)($implicitSourceInfo, $implicitCompileOptions)"
  }
  def apply_elt0(elt0: c.Tree, elts: c.Tree*): c.Tree = {
    q"$thisObj.do_apply($elt0, ..$elts)($implicitSourceInfo, $implicitCompileOptions)"
  }
  def tabulate(n: c.Tree)(gen: c.Tree): c.Tree = {
    q"$thisObj.do_tabulate($n)($gen)($implicitSourceInfo, $implicitCompileOptions)"
  }
  def fill(n: c.Tree)(gen: c.Tree): c.Tree = {
    q"$thisObj.do_fill($n)($gen)($implicitSourceInfo, $implicitCompileOptions)"
  }
  def contains(x: c.Tree)(ev: c.Tree): c.Tree = {
    q"$thisObj.do_contains($x)($implicitSourceInfo, $ev, $implicitCompileOptions)"
  }
}

/** "Automatic" source information transform / insertion macros, which generate the function name
  * based on the macro invocation (instead of explicitly writing out every transform).
  */
abstract class AutoSourceTransform extends SourceInfoTransformMacro {
  import c.universe._
  /** Returns the TermName of the transformed function, which is the applied function name with do_
    * prepended.
    */
  def doFuncTerm: TermName = {
    val funcName = c.macroApplication match {
      case q"$_.$funcName[..$_](...$_)" => funcName
      case _ => throw new Exception(s"Chisel Internal Error: Could not resolve function name from macro application: ${showCode(c.macroApplication)}") // scalastyle:ignore line.size.limit
    }
    TermName("do_" + funcName)
  }
}

// Workaround for https://github.com/sbt/sbt/issues/3966
object SourceInfoTransform
class SourceInfoTransform(val c: Context) extends AutoSourceTransform {
  import c.universe._

  def noArg(): c.Tree = {
    q"$thisObj.$doFuncTerm($implicitSourceInfo, $implicitCompileOptions)"
  }

  def thatArg(that: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($that)($implicitSourceInfo, $implicitCompileOptions)"
  }

  def nArg(n: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($n)($implicitSourceInfo, $implicitCompileOptions)"
  }

  def pArg(p: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($p)($implicitSourceInfo, $implicitCompileOptions)"
  }

  def inArg(in: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($in)($implicitSourceInfo, $implicitCompileOptions)"
  }

  def xArg(x: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($x)($implicitSourceInfo, $implicitCompileOptions)"
  }

  def xyArg(x: c.Tree, y: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($x, $y)($implicitSourceInfo, $implicitCompileOptions)"
  }

  def xEnArg(x: c.Tree, en: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($x, $en)($implicitSourceInfo, $implicitCompileOptions)"
  }
}

// Workaround for https://github.com/sbt/sbt/issues/3966
object CompileOptionsTransform
class CompileOptionsTransform(val c: Context) extends AutoSourceTransform {
  import c.universe._

  def thatArg(that: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($that)($implicitCompileOptions)"
  }

  def inArg(in: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($in)($implicitCompileOptions)"
  }

  def pArg(p: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($p)($implicitCompileOptions)"
  }
}

// Workaround for https://github.com/sbt/sbt/issues/3966
object SourceInfoWhiteboxTransform
/** Special whitebox version of the blackbox SourceInfoTransform, used when fun things need to
  * happen to satisfy the type system while preventing the use of macro overrides.
  */
class SourceInfoWhiteboxTransform(val c: whitebox.Context) extends AutoSourceTransform {
  import c.universe._

  def noArg(): c.Tree = {
    q"$thisObj.$doFuncTerm($implicitSourceInfo, $implicitCompileOptions)"
  }

  def thatArg(that: c.Tree): c.Tree = {
    q"$thisObj.$doFuncTerm($that)($implicitSourceInfo, $implicitCompileOptions)"
  }
}
