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wvlet.airframe.surface.CompileTimeSurfaceFactory.scala Maven / Gradle / Ivy

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package wvlet.airframe.surface
import java.util.concurrent.atomic.AtomicInteger
import scala.collection.immutable.ListMap
import scala.quoted.*
import scala.reflect.ClassTag

private[surface] object CompileTimeSurfaceFactory:

  type SurfaceMatcher = PartialFunction[Type[_], Expr[Surface]]

  def surfaceOf[A](using tpe: Type[A], quotes: Quotes): Expr[Surface] =
    import quotes.*
    import quotes.reflect.*

    val f           = new CompileTimeSurfaceFactory(using quotes)
    val surfaceExpr = f.surfaceOf(tpe)
    val t           = TypeRepr.of[A]
    val flags       = t.typeSymbol.flags
    if !flags.is(Flags.JavaStatic) && flags.is(Flags.NoInits) then
      t.typeSymbol.maybeOwner match
        // For inner-class definitions
        case s: Symbol
            if !s.isNoSymbol &&
              s.isClassDef &&
              !s.isPackageDef &&
              !s.flags.is(Flags.Module) &&
              !s.flags.is(Flags.Trait) =>
          // println(s"${t}\n${flags.show}\nowner:${s}\n${s.flags.show}")
          '{ ${ surfaceExpr }.withOuter(${ This(s).asExpr }.asInstanceOf[AnyRef]) }
        case _ =>
          surfaceExpr
    else surfaceExpr

  def methodsOf[A](using tpe: Type[A], quotes: Quotes): Expr[Seq[MethodSurface]] =
    val f = new CompileTimeSurfaceFactory(using quotes)
    f.methodsOf(tpe)

private[surface] class CompileTimeSurfaceFactory[Q <: Quotes](using quotes: Q):
  import quotes.*
  import quotes.reflect.*

  private def fullTypeNameOf(t: Type[?]): String =
    fullTypeNameOf(TypeRepr.of(using t))

  private def fullTypeNameOf(t: TypeRepr): String =
    def sanitize(symbol: Symbol): String =
      val nameParts: List[String] = symbol.fullName.split("\\.").toList match
        case "scala" :: "Predef$" :: tail =>
          tail
        case "scala" :: "collection" :: "immutable" :: tail =>
          tail
        case "scala" :: nme :: Nil =>
          List(nme)
        case other =>
          other
      nameParts
        .mkString(".").stripSuffix("$").replaceAll("\\.package\\$", ".").replaceAll("\\$+", ".")
        .replaceAll("\\.\\.", ".")
    t match
      case a: AppliedType if a.args.nonEmpty =>
        s"${sanitize(a.typeSymbol)}[${a.args.map(pt => fullTypeNameOf(pt.asType)).mkString(",")}]"
      case other =>
        sanitize(other.typeSymbol)

  private type Factory = PartialFunction[TypeRepr, Expr[Surface]]

  def surfaceOf(tpe: Type[?]): Expr[Surface] =
    surfaceOf(TypeRepr.of(using tpe))

  private var observedSurfaceCount = new AtomicInteger(0)
  private var seen                 = ListMap[TypeRepr, Int]()
  private val memo                 = scala.collection.mutable.Map[TypeRepr, Expr[Surface]]()
  private val lazySurface          = scala.collection.mutable.Set[TypeRepr]()

  private def surfaceOf(t: TypeRepr, useVarRef: Boolean = true): Expr[Surface] =
    def buildLazySurface: Expr[Surface] =
      '{ LazySurface(${ clsOf(t) }, ${ Expr(fullTypeNameOf(t)) }) }

    if useVarRef && surfaceToVar.contains(t) then
      if lazySurface.contains(t) then buildLazySurface
      else Ref(surfaceToVar(t)).asExprOf[Surface]
    else if seen.contains(t) then
      if memo.contains(t) then memo(t)
      else
        lazySurface += t
        buildLazySurface
    else
      seen += t -> observedSurfaceCount.getAndIncrement()
      // For debugging
      // println(s"[${typeNameOf(t)}]\n  ${t}\nfull type name: ${fullTypeNameOf(t)}\nclass: ${t.getClass}")
      val generator = factory.andThen { expr =>
        if !lazySurface.contains(t) then
          // Generate the surface code without using the cache
          expr
        else
          // Need to cache the recursive Surface to be referenced in a LazySurface
          val cacheKey =
            if typeNameOf(t) == "scala.Any" then
              t match
                case ParamRef(TypeLambda(typeNames, _, _), _) =>
                  // Distinguish scala.Any and type bounds (such as _)
                  s"${fullTypeNameOf(t)} for ${t}"
                case TypeBounds(_, _) =>
                  // This ensures different cache key for each Type Parameter (such as T and U).
                  // This is required because fullTypeNameOf of every Type Parameters is `scala.Any`.
                  s"${fullTypeNameOf(t)} for ${t}"
                case _ =>
                  fullTypeNameOf(t)
            else fullTypeNameOf(t)
          val key = Literal(StringConstant(cacheKey)).asExprOf[String]
          '{
            if !wvlet.airframe.surface.surfaceCache.contains(${ key }) then
              wvlet.airframe.surface.surfaceCache += ${ key } -> ${ expr }
            wvlet.airframe.surface.surfaceCache.apply(${ key })
          }
      }
      val surface = generator(t)
      memo += (t -> surface)
      surface

  private def factory: Factory =
    taggedTypeFactory orElse
      andOrTypeFactory orElse
      aliasFactory orElse
      higherKindedTypeFactory orElse
      primitiveTypeFactory orElse
      arrayFactory orElse
      optionFactory orElse
      tupleFactory orElse
      javaUtilFactory orElse
      javaEnumFactory orElse
      exisitentialTypeFactory orElse
      genericTypeWithConstructorFactory orElse
      genericTypeFactory

  private def primitiveTypeFactory: Factory = {
    case t if t =:= TypeRepr.of[String]               => '{ Primitive.String }
    case t if t =:= TypeRepr.of[Boolean]              => '{ Primitive.Boolean }
    case t if t =:= TypeRepr.of[Int]                  => '{ Primitive.Int }
    case t if t =:= TypeRepr.of[Long]                 => '{ Primitive.Long }
    case t if t =:= TypeRepr.of[Float]                => '{ Primitive.Float }
    case t if t =:= TypeRepr.of[Double]               => '{ Primitive.Double }
    case t if t =:= TypeRepr.of[Short]                => '{ Primitive.Short }
    case t if t =:= TypeRepr.of[Byte]                 => '{ Primitive.Byte }
    case t if t =:= TypeRepr.of[Char]                 => '{ Primitive.Char }
    case t if t =:= TypeRepr.of[Unit]                 => '{ Primitive.Unit }
    case t if t =:= TypeRepr.of[BigInt]               => '{ Primitive.BigInt }
    case t if t =:= TypeRepr.of[java.math.BigInteger] => '{ Primitive.BigInteger }
  }

  private def typeNameOf(t: TypeRepr): String =
    t.typeSymbol.fullName.stripSuffix("$").replaceAll("\\.package\\$", ".").replaceAll("\\$+", ".")

  private def isTaggedType(t: TypeRepr): Boolean =
    typeNameOf(t).startsWith("wvlet.airframe.surface.tag.")

  private def taggedTypeFactory: Factory = {
    case a: AppliedType if a.args.length == 2 && isTaggedType(a) =>
      '{ TaggedSurface(${ surfaceOf(a.args(0)) }, ${ surfaceOf(a.args(1)) }) }
  }

  private def belongsToScalaDefault(t: TypeRepr): Boolean =
    val scalaDefaultPackages = Seq("scala.", "scala.Predef$.", "scala.util.")
    val nme                  = t.typeSymbol.fullName
    scalaDefaultPackages.exists(p => nme.startsWith(p))

  private def andOrTypeFactory: Factory = {
    case t: AndType =>
      '{ IntersectionSurface(${ surfaceOf(t.left) }, ${ surfaceOf(t.right) }) }
    case t: OrType =>
      '{ UnionSurface(${ surfaceOf(t.left) }, ${ surfaceOf(t.right) }) }
  }

  private def extractSymbol(t: TypeRepr): Expr[Surface] =
    // t.dealias may not dealias the refernced type for path dependent types,
    // so extracting the dealiased type from the type definition in the owner
    val symbolInOwner = t.typeSymbol.maybeOwner.declarations.find(_.name == t.typeSymbol.name)
    symbolInOwner.map(_.typeRef.dealias) match
      case Some(tpe) =>
        surfaceOf(tpe)
      case _ =>
        val dealiased = t.dealias
        if t != dealiased then surfaceOf(dealiased)
        else surfaceOf(t.simplified)

  private def aliasFactory: Factory = {
    case t if t.typeSymbol.typeRef.isOpaqueAlias =>
      // Treat opaque types in Scala 3 as alias types
      val alias    = t.typeSymbol
      val inner    = extractSymbol(t)
      val name     = Expr(alias.name)
      val fullName = Expr(fullTypeNameOf(t))
      val expr     = '{ Alias(${ name }, ${ fullName }, ${ inner }) }
      expr
    case t if t.typeSymbol.isType && t.typeSymbol.isAliasType && !belongsToScalaDefault(t) =>
      val inner    = extractSymbol(t)
      val s        = t.typeSymbol
      val name     = Expr(s.name)
      val fullName = Expr(fullTypeNameOf(t.asType))
      '{ Alias(${ name }, ${ fullName }, ${ inner }) }
  }

  private def higherKindedTypeFactory: Factory = {
    case h: TypeLambda =>
      val name     = h.typeSymbol.name
      val fullName = fullTypeNameOf(h)
      val inner    = surfaceOf(h.resType)

      val len    = h.paramNames.size
      val params = (0 until len).map { i => h.param(i) }
      val args   = params.map(surfaceOf(_))
      '{ HigherKindedTypeSurface(${ Expr(name) }, ${ Expr(fullName) }, ${ inner }, ${ Expr.ofSeq(args) }) }
    case a @ AppliedType if a.typeSymbol.name.contains("$") =>
      '{ wvlet.airframe.surface.ExistentialType }
    case a: AppliedType if !a.typeSymbol.isClassDef =>
      val name     = a.typeSymbol.name
      val fullName = fullTypeNameOf(a)
      val args     = a.args.map(surfaceOf(_))
      // TODO support type erasure instead of using AnyRefSurface
      '{ HigherKindedTypeSurface(${ Expr(name) }, ${ Expr(fullName) }, AnyRefSurface, ${ Expr.ofSeq(args) }) }
    case p @ ParamRef(TypeLambda(typeNames, _, _), _) =>
      val name     = typeNames.mkString(",")
      val fullName = fullTypeNameOf(p)
      '{ HigherKindedTypeSurface(${ Expr(name) }, ${ Expr(fullName) }, AnyRefSurface, Seq.empty) }
  }

  private def typeArgsOf(t: TypeRepr): List[TypeRepr] =
    t match
      case a: AppliedType =>
        a.args
      case other =>
        List.empty

  private def elementTypeSurfaceOf(t: TypeRepr): Expr[Surface] =
    typeArgsOf(t).map(surfaceOf(_)).headOption match
      case Some(expr) =>
        expr
      case None =>
        // FIXME: Is this right ?
        '{ AnyRefSurface }

  private def arrayFactory: Factory = {
    case t if typeNameOf(t) == "scala.Array" =>
      '{ ArraySurface(${ clsOf(t) }, ${ elementTypeSurfaceOf(t) }) }
  }

  private def optionFactory: Factory = {
    case t if typeNameOf(t) == "scala.Option" =>
      '{ OptionSurface(${ clsOf(t) }, ${ elementTypeSurfaceOf(t) }) }
  }

  private def tupleFactory: Factory = {
    case t if t <:< TypeRepr.of[Product] && typeNameOf(t).startsWith("scala.Tuple") =>
      val paramTypes = typeArgsOf(t).map(surfaceOf(_))
      '{ new TupleSurface(${ clsOf(t) }, ${ Expr.ofSeq(paramTypes) }.toIndexedSeq) }
  }

  private def javaUtilFactory: Factory = {
    // For common Java classes, stop with this rule so as not to extract internal parameters
    case t
        if t =:= TypeRepr.of[java.io.File] ||
          t =:= TypeRepr.of[java.util.Date] ||
          t =:= TypeRepr.of[java.time.temporal.Temporal] =>
      newGenericSurfaceOf(t)
  }

  private def isEnum(t: TypeRepr): Boolean =
    t.baseClasses.exists(x => x.fullName.startsWith("java.lang.Enum"))

  private def javaEnumFactory: Factory = {
    case t if isEnum(t) =>
      '{ JavaEnumSurface(${ clsOf(t) }) }
  }

  private def exisitentialTypeFactory: Factory = {
    case t: TypeBounds if t.hi =:= TypeRepr.of[Any] =>
      // TODO Represent low/hi bounds
      '{ ExistentialType }
  }

  private def clsOf(t: TypeRepr): Expr[Class[_]] =
    Literal(ClassOfConstant(t)).asExpr.asInstanceOf[Expr[Class[_]]]

  private def newGenericSurfaceOf(t: TypeRepr): Expr[Surface] =
    '{ new GenericSurface(${ clsOf(t) }) }

  private def genericTypeWithConstructorFactory: Factory = {
    case t
        if !t.typeSymbol.flags.is(Flags.Abstract) && !t.typeSymbol.flags.is(Flags.Trait)
          && Option(t.typeSymbol.primaryConstructor)
            .exists { p =>
              p.exists && !p.flags.is(Flags.Private) && !p.flags.is(Flags.Protected) &&
              p.privateWithin.isEmpty && p.paramSymss.nonEmpty
            } =>
      val typeArgs     = typeArgsOf(t.simplified).map(surfaceOf(_))
      val methodParams = constructorParametersOf(t)
      // val isStatic     = !t.typeSymbol.flags.is(Flags.Local)
      val factory = createObjectFactoryOf(t) match
        case Some(x) => '{ Some(${ x }) }
        case None    => '{ None }

      '{
        new wvlet.airframe.surface.GenericSurface(
          ${ clsOf(t) },
          ${ Expr.ofSeq(typeArgs) }.toIndexedSeq,
          params = ${ methodParams },
          objectFactory = ${ factory }
        )
      }
  }

  // Build a table for resolving type parameters, e.g., class MyClass[A, B]  -> Map("A" -> TypeRepr, "B" -> TypeRepr)
  private def typeMappingTable(t: TypeRepr, method: Symbol): Map[String, TypeRepr] =
    val classTypeParams = t.typeSymbol.typeMembers.filter(_.isTypeParam)
    val classTypeArgs: List[TypeRepr] = t match
      case a: AppliedType => a.args
      case _              => List.empty[TypeRepr]

    (classTypeParams zip classTypeArgs)
      .map { (paramType, argType) =>
        paramType.name -> argType
      }.toMap[String, TypeRepr]

  // Get a constructor with its generic types are resolved
  private def getResolvedConstructorOf(t: TypeRepr): Option[Term] =
    val ts = t.typeSymbol
    ts.primaryConstructor match
      case pc if pc == Symbol.noSymbol =>
        None
      case pc =>
        // val cstr = Select.apply(New(TypeIdent(ts)), "")
        val cstr = New(Inferred(t)).select(pc)
        if ts.typeMembers.isEmpty then Some(cstr)
        else
          val lookupTable = typeMappingTable(t, pc)
          // println(s"--- ${lookupTable}")
          val typeArgs = pc.paramSymss.headOption.getOrElse(List.empty).filter(_.isTypeParam).map { p =>
            lookupTable.getOrElse(p.name, TypeRepr.of[AnyRef])
          }
          Some(cstr.appliedToTypes(typeArgs))

  private def createObjectFactoryOf(targetType: TypeRepr): Option[Expr[ObjectFactory]] =
    val ts    = targetType.typeSymbol
    val flags = ts.flags
    if flags.is(Flags.Abstract) || flags.is(Flags.Module) || hasAbstractMethods(targetType) || isPathDependentType(
        targetType
      )
    then None
    else
      getResolvedConstructorOf(targetType).map { cstr =>
        val argListList = methodArgsOf(targetType, ts.primaryConstructor)
        val newClassFn = Lambda(
          owner = Symbol.spliceOwner,
          tpe = MethodType(List("args"))(_ => List(TypeRepr.of[Seq[Any]]), _ => TypeRepr.of[Any]),
          rhsFn = (sym: Symbol, paramRefs: List[Tree]) =>
            val args  = paramRefs.head.asExprOf[Seq[Any]].asTerm
            var index = 0
            val fn = argListList.foldLeft[Term](cstr) { (prev, argList) =>
              val argExtractors = argList.map { a =>
                // args(i+1)
                val extracted = Select.unique(args, "apply").appliedTo(Literal(IntConstant(index)))
                index += 1
                // classOf[A].cast(args(i+1))
                clsCast(extracted, a.tpe)
              }
              Apply(prev, argExtractors.toList)
            }
            // println(s"== ${fn.show}")
            fn.changeOwner(sym)
        )
        val expr = '{
          ObjectFactory.newFactory(${ newClassFn.asExprOf[Seq[Any] => Any] })
        }
        expr
      }

  private def hasAbstractMethods(t: TypeRepr): Boolean =
    t.typeSymbol.methodMembers.exists(_.flags.is(Flags.Abstract))

  private def isPathDependentType(t: TypeRepr): Boolean =
    !t.typeSymbol.flags.is(Flags.JavaStatic) && (t match
      case t: TypeBounds => true
      case _             => false
    )

  private def genericTypeFactory: Factory = {
    case t if t =:= TypeRepr.of[Any] =>
      '{ Alias("Any", "scala.Any", AnyRefSurface) }
    case a: AppliedType =>
      val typeArgs = a.args.map(surfaceOf(_))
      '{ new GenericSurface(${ clsOf(a) }, typeArgs = ${ Expr.ofSeq(typeArgs) }.toIndexedSeq) }
    // special treatment for type Foo = Foo[Buz]
    case TypeBounds(a1: AppliedType, a2: AppliedType) if a1 == a2 =>
      val typeArgs = a1.args.map(surfaceOf(_))
      '{ new GenericSurface(${ clsOf(a1) }, typeArgs = ${ Expr.ofSeq(typeArgs) }.toIndexedSeq) }
    case r: Refinement =>
      newGenericSurfaceOf(r.info)
    case t if t <:< TypeRepr.of[scala.reflect.Enum] && !(t =:= TypeRepr.of[Nothing]) =>
      /**
        * Build a code for finding Enum instance from an input string value: {{ (cl: Class[_], s: String) =>
        * Try(EnumType.valueOf(s)).toOption }}
        */
      val enumType = t.typeSymbol.companionModule
      val valueOfMethod = enumType.methodMember("valueOf").headOption match
        case Some(m) => m
        case None =>
          sys.error(s"valueOf method not found in ${t}")
      val newFn = Lambda(
        owner = Symbol.spliceOwner,
        tpe = MethodType(List("cl", "s"))(
          _ => List(TypeRepr.of[Class[_]], TypeRepr.of[String]),
          _ => TypeRepr.of[Option[Any]]
        ),
        rhsFn = (sym: Symbol, paramRefs: List[Tree]) =>
          val strVarRef = paramRefs(1).asExprOf[String].asTerm
          val expr: Term =
            Select
              .unique(
                Apply(Select.unique(Ref(t.typeSymbol.companionModule), "valueOf"), List(strVarRef)),
                "asInstanceOf"
              ).appliedToType(TypeRepr.of[Any])
          val expr2 = ('{
            scala.util.Try(${ expr.asExprOf[Any] }).toOption
          }).asExprOf[Option[Any]].asTerm
          expr2.changeOwner(sym)
      )

      '{
        EnumSurface(
          ${ clsOf(t) },
          ${ newFn.asExprOf[(Class[_], String) => Option[Any]] }
        )
      }
    case t if hasStringUnapply(t) =>
      // Build EnumSurface.apply code
      // EnumSurface(classOf[t], { (cl: Class[_], s: String) => (companion object).unapply(s).asInstanceOf[Option[Any]] }
      val unapplyMethod = getStringUnapply(t).get
      val m             = Ref(t.typeSymbol.companionModule).select(unapplyMethod)
      val newFn = Lambda(
        owner = Symbol.spliceOwner,
        tpe = MethodType(List("cl", "s"))(
          _ => List(TypeRepr.of[Class[_]], TypeRepr.of[String]),
          _ => TypeRepr.of[Option[Any]]
        ),
        rhsFn = (sym: Symbol, paramRefs: List[Tree]) =>
          val strVarRef = paramRefs(1).asExprOf[String].asTerm
          val expr = Select.unique(Apply(m, List(strVarRef)), "asInstanceOf").appliedToType(TypeRepr.of[Option[Any]])
          expr.changeOwner(sym)
      )
      '{
        EnumSurface(
          ${ clsOf(t) },
          ${ newFn.asExprOf[(Class[_], String) => Option[Any]] }
        )
      }
    case t =>
      newGenericSurfaceOf(t)
  }

  private def hasOptionReturnType(d: DefDef, retElementType: TypeRepr): Boolean =
    if d.returnTpt.tpe <:< TypeRepr.of[Option[_]] then
      val typeArgs = typeArgsOf(d.returnTpt.tpe)
      typeArgs.headOption match
        case Some(t) if t =:= retElementType => true
        case _                               => false
    else false

  private def hasStringUnapply(t: TypeRepr): Boolean =
    getStringUnapply(t).isDefined

  private def getStringUnapply(t: TypeRepr): Option[Symbol] =
    t.typeSymbol.companionClass match
      case cp: Symbol =>
        val methodOpt = cp.methodMember("unapply").headOption
        methodOpt.map(_.tree) match
          case Some(m: DefDef) if m.paramss.size == 1 && hasOptionReturnType(m, t) =>
            val args: List[ParamClause] = m.paramss
            args.headOption.flatMap(_.params.headOption) match
              // Is the first argument type String? def unapply(s: String)
              case Some(v: ValDef) if v.tpt.tpe =:= TypeRepr.of[String] =>
                methodOpt
              case _ =>
                None
          case _ =>
            None
      case null =>
        None

  private case class MethodArg(
      name: String,
      tpe: TypeRepr,
      defaultValueGetter: Option[Symbol],
      defaultMethodArgGetter: Option[Symbol],
      isImplicit: Boolean,
      isRequired: Boolean,
      isSecret: Boolean
  )

  private def resolveType(t: TypeRepr, typeArgTable: Map[String, TypeRepr]): TypeRepr =
    t match
      case a: AppliedType =>
        // println(s"===  a.args ${a.args}")
        // println(s"===  typeArgTable ${typeArgTable}")
        val resolvedTypeArgs = a.args.map {
          case p if p.typeSymbol.isTypeParam && typeArgTable.contains(p.typeSymbol.name) =>
            typeArgTable(p.typeSymbol.name)
          case other =>
            resolveType(other, typeArgTable)
        }
        // println(s"===  resolvedTypeArgs ${resolvedTypeArgs}")
        // Need to use the base type of the applied type to replace the type parameters
        a.tycon.appliedTo(resolvedTypeArgs)
      case TypeRef(_, name) if typeArgTable.contains(name) =>
        typeArgTable(name)
      case other =>
        other

  private def methodArgsOf(t: TypeRepr, method: Symbol): List[List[MethodArg]] =
    // println(s"==== method args of ${fullTypeNameOf(t)}")

    val defaultValueMethods = t.typeSymbol.companionClass.declaredMethods.filter { m =>
      m.name.startsWith("apply$default$") || m.name.startsWith("$lessinit$greater$default$")
    }

    val typeArgTable = typeMappingTable(t, method)

    val paramss: List[List[Symbol]] = method.paramSymss.filter { lst =>
      // Empty arg is allowed
      lst.isEmpty ||
      // Remove type params or implicit ClassTag evidences as MethodSurface can't pass type parameters
      !lst.forall { x =>
        def hasFlag(flag: Flags) = x.flags.is(flag)
        def isClassTag           = x.typeRef <:< TypeRepr.of[ClassTag[_]]
        // Since Scala 3.6 context bounds are mapped to using parameters
        // In Scala 3.5 and earlier context bounds are mapped to implicit arguments
        x.isTypeParam ||
        ((hasFlag(Flags.Implicit) || hasFlag(Flags.Given)) && isClassTag)
      }
    }

    paramss.map { params =>
      params.zipWithIndex
        .map((x, i) => (x, i + 1, t.memberType(x)))
        .collect { case (s: Symbol, i: Int, v: TypeRepr) =>
          // E.g. case class Foo(a: String)(implicit b: Int)
          // println(s"=== ${v.show} ${s.flags.show} ${s.flags.is(Flags.Implicit)}")
          // Substitute type param to actual types

          val resolved = resolveType(v, typeArgTable)

          val isSecret           = hasSecretAnnotation(s)
          val isRequired         = hasRequiredAnnotation(s)
          val isImplicit         = s.flags.is(Flags.Implicit)
          val defaultValueGetter = defaultValueMethods.find(m => m.name.endsWith(s"$$${i}"))

          val defaultMethodArgGetter =
            val targetMethodName = method.name + "$default$" + i
            t.typeSymbol.declaredMethods.find { m =>
              // println(s"=== target: ${m.name}, ${m.owner.name}")
              m.name == targetMethodName
            }
          MethodArg(s.name, resolved, defaultValueGetter, defaultMethodArgGetter, isImplicit, isRequired, isSecret)
        }
    }

  private def hasSecretAnnotation(s: Symbol): Boolean =
    val t = TypeRepr.of[wvlet.airframe.surface.secret]
    s.hasAnnotation(t.typeSymbol)
  private def hasRequiredAnnotation(s: Symbol): Boolean =
    val t = TypeRepr.of[wvlet.airframe.surface.required]
    s.hasAnnotation(t.typeSymbol)

  private def constructorParametersOf(t: TypeRepr): Expr[Seq[MethodParameter]] =
    methodParametersOf(t, t.typeSymbol.primaryConstructor)

  private def methodParametersOf(t: TypeRepr, method: Symbol): Expr[Seq[MethodParameter]] =
    val methodName = method.name
    val methodArgs = methodArgsOf(t, method).flatten
    val argClasses = methodArgs.map { arg =>
      clsOf(arg.tpe.dealias)
    }
    val isConstructor = t.typeSymbol.primaryConstructor == method
    val constructorRef: Expr[MethodRef] = '{
      MethodRef(
        owner = ${ clsOf(t) },
        name = ${ Expr(methodName) },
        paramTypes = ${ Expr.ofSeq(argClasses) },
        isConstructor = ${ Expr(isConstructor) }
      )
    }

    // println(s"======= ${t.typeSymbol.memberMethods}")

    val paramExprs = for ((field, i) <- methodArgs.zipWithIndex) yield
      val paramType = field.tpe
      val paramName = field.name

      // Related example:
      // https://github.com/lampepfl/dotty-macro-examples/blob/aed51833db652f67741089721765ad5a349f7383/defaultParamsInference/src/macro.scala
      val defaultValue: Expr[Option[Any]] = field.defaultValueGetter match
        case Some(m) =>
          val companion = Ref(t.typeSymbol.companionModule)
          // Populate method type parameters with Any type
          val dummyTypeList: List[TypeRepr] = m.paramSymss.flatten.map { tp => TypeRepr.of[Any] }.toList
          val dv: Term                      = companion.select(m).appliedToTypes(dummyTypeList)
          '{ Some(${ dv.asExprOf[Any] }) }
        case _ => '{ None }

      // Generate a field accessor { (x:Any) => x.asInstanceOf[A].(field name) }
      val paramIsAccessible =
        t.typeSymbol.fieldMember(paramName) match
          case nt if nt == Symbol.noSymbol      => false
          case m if m.flags.is(Flags.Private)   => false
          case m if m.flags.is(Flags.Protected) => false
          case m if m.flags.is(Flags.Artifact)  => false
          case m if m.privateWithin.nonEmpty    => false
          case _                                => true
      // println(s"${paramName} ${paramIsAccessible}")

      val accessor: Expr[Option[Any => Any]] = if method.isClassConstructor && paramIsAccessible then
        // MethodParameter.accessor[(owner type), (parameter type]]
        val accessorMethod: Symbol = TypeRepr.of[MethodParameter.type].typeSymbol.methodMember("accessor").head
        val objRef                 = Ref(TypeRepr.of[MethodParameter].typeSymbol.companionModule)

        def resolveType(tpe: TypeRepr): TypeRepr = tpe match
          case b: TypeBounds =>
            TypeRepr.of[Any]
          case _ =>
            tpe

        val t1 = resolveType(t)
        val t2 = resolveType(paramType)

        val typedAccessor = objRef.select(accessorMethod).appliedToTypes(List(t1, t2))
        val methodCall    = typedAccessor.appliedToArgs(List(Literal(ClassOfConstant(t1))))

        val lambda = Lambda(
          owner = Symbol.spliceOwner,
          tpe = MethodType(List("x"))(_ => List(t1), _ => t2),
          rhsFn = (sym, params) =>
            val x    = params.head.asInstanceOf[Term]
            val expr = Select.unique(x, paramName)
            expr.changeOwner(sym)
        )
        val accMethod = methodCall.appliedToArgs(List(lambda))
        // println(s"=== ${accMethod.show}")

        // Generate code like :
        // {{{
        //   MethodParameter.accessor[t1, t2](classOf[t1]){(x:t1) => x.(field name) }
        // }}}
        '{ Some(${ accMethod.asExprOf[Any => Any] }) }
      else '{ None }

      val methodArgAccessor: Expr[Option[Any => Any]] = field.defaultMethodArgGetter match
        case None =>
          '{ None }
        case Some(m) =>
          val lambda = Lambda(
            owner = Symbol.spliceOwner,
            tpe = MethodType(List("x"))(_ => List(TypeRepr.of[Any]), _ => TypeRepr.of[Any]),
            rhsFn = (sym, params) =>
              val x    = params.head.asInstanceOf[Term]
              val expr = clsCast(x, t).select(m)
              expr.changeOwner(sym)
          )
          '{ Some(${ lambda.asExprOf[Any => Any] }) }

      // Using StaticMethodParameter when supportin Scala.js in Scala 3.
      // TODO: Deprecate RuntimeMethodParameter
      '{
        wvlet.airframe.surface.StaticMethodParameter(
          method = ${ constructorRef },
          index = ${ Expr(i) },
          name = ${ Expr(paramName) },
          isRequired = ${ Expr(field.isRequired) },
          isSecret = ${ Expr(field.isSecret) },
          surface = ${ surfaceOf(paramType) },
          defaultValue = ${ defaultValue },
          accessor = ${ accessor },
          methodArgAccessor = ${ methodArgAccessor }
        )
      }
    Expr.ofSeq(paramExprs)

  private def getTree(e: Expr[?]): Tree =
    val f = e.getClass().getDeclaredField("tree")
    f.setAccessible(true)
    val tree = f.get(e)
    tree.asInstanceOf[Tree]

  def methodsOf(t: Type[?]): Expr[Seq[MethodSurface]] =
    methodsOf(TypeRepr.of(using t))

  // To reduce the byte code size, we need to memoize the generated surface bound to a variable
  private var surfaceToVar = ListMap.empty[TypeRepr, Symbol]

  private def methodsOf(t: TypeRepr): Expr[Seq[MethodSurface]] =
    // Run just for collecting known surfaces. seen variable will be updated
    methodsOfInternal(t)

    // Create a var def table for replacing surfaceOf[xxx] to __s0, __s1, ...
    var surfaceVarCount = 0
    seen
      // Exclude primitive type surface
      .toSeq
      // Exclude primitive surfaces as it is already defined in Primitive object
      .filterNot(x => primitiveTypeFactory.isDefinedAt(x._1))
      .map { (tpe, order) =>
        // first list all lazy vals, otherwise there is a risk of forward reference error across strict vals
        (tpe, (!lazySurface.contains(tpe), order))
      }.sortBy(_._2)
      .reverse
      .foreach { (tpe, order) =>
        // Update the cache so that the next call of surfaceOf method will use the local varaible reference
        surfaceToVar += tpe -> Symbol.newVal(
          Symbol.spliceOwner,
          // Use alphabetically ordered variable names
          f"__s${surfaceVarCount}%03X",
          TypeRepr.of[Surface],
          if lazySurface.contains(tpe) then
            // If the surface itself is lazy, we need to eagerly initialize it to update the surface cache
            Flags.EmptyFlags
          else
            // Use lazy val to avoid forward reference error
            Flags.Lazy
          ,
          Symbol.noSymbol
        )
        surfaceVarCount += 1
      }

    // Clear surface cache
    memo.clear()
    seen = ListMap.empty
    seenMethodParent.clear()

    val surfaceDefs: List[ValDef] = surfaceToVar.toSeq.map { case (tpe, sym) =>
      ValDef(sym, Some(surfaceOf(tpe, useVarRef = false).asTerm.changeOwner(sym)))
    }.toList

    /**
      * Generate a code like this:
      *
      * {{ lazy val __s000 = Surface.of[A]; lazy val __s001 = Surface.of[B] ...
      *
      * ClassMethodSurface( .... ) }}
      */
    val expr = Block(
      surfaceDefs,
      methodsOfInternal(t).asTerm
    ).asExprOf[Seq[MethodSurface]]

    // println(s"===  methodOf: ${t.typeSymbol.fullName} => \n${expr.show}")
    expr

  private val seenMethodParent = scala.collection.mutable.Set[TypeRepr]()

  private def methodsOfInternal(targetType: TypeRepr): Expr[Seq[MethodSurface]] =
    if seenMethodParent.contains(targetType) then
      sys.error(s"recursive method found in: ${targetType.typeSymbol.fullName}")
    else
      seenMethodParent += targetType
      val localMethods = localMethodsOf(targetType).distinct.sortBy(_.name)
      val methodSurfaces = localMethods.map(m => (m, m.tree)).collect { case (m, df: DefDef) =>
        val mod          = Expr(modifierBitMaskOf(m))
        val owner        = surfaceOf(targetType)
        val name         = Expr(m.name)
        val typeArgTable = typeMappingTable(targetType, m)
        val returnType   = resolveType(df.returnTpt.tpe, typeArgTable)
        // println(s"======= ${returnType.show}")
        val ret = surfaceOf(returnType)
        // println(s"==== method of: def ${m.name}")
        val params       = methodParametersOf(targetType, m)
        val args         = methodArgsOf(targetType, m)
        val methodCaller = createMethodCaller(targetType, m, args)
        '{
          ClassMethodSurface(${ mod }, ${ owner }, ${ name }, ${ ret }, ${ params }.toIndexedSeq, ${ methodCaller })
        }
      }
      val expr = Expr.ofSeq(methodSurfaces)
      expr

  private def isTypeParam(t: TypeRepr): Boolean =
    t match
      case TypeRef(prefix, typeName) if prefix.toString == "NoPrefix" => true
      case _                                                          => false

  private def clsCast(term: Term, t: TypeRepr): Term =
    Select.unique(term, "asInstanceOf").appliedToType(t)

  private def createMethodCaller(
      objectType: TypeRepr,
      m: Symbol,
      methodArgss: List[List[MethodArg]]
  ): Expr[Option[(Any, Seq[Any]) => Any]] =
    // Build { (x: Any, args: Seq[Any]) => x.asInstanceOf[t].(.. args) }
    val methodTypeParams: List[TypeParamClause] = m.tree match
      case df: DefDef =>
        df.paramss.collect { case t: TypeParamClause =>
          t
        }
      case _ =>
        List.empty

    val lambda = Lambda(
      owner = Symbol.spliceOwner,
      tpe = MethodType(List("x", "args"))(_ => List(TypeRepr.of[Any], TypeRepr.of[Seq[Any]]), _ => TypeRepr.of[Any]),
      rhsFn = (sym, params) =>
        val x    = params(0).asInstanceOf[Term]
        val args = params(1).asInstanceOf[Term]
        val expr = clsCast(x, objectType).select(m)

        var index = 0
        val argList: List[List[Term]] = methodArgss.map { lst =>
          lst.collect {
            // If the arg is implicit, no need to explicitly bind it
            case arg if !arg.isImplicit =>
              val extracted = Select.unique(args, "apply").appliedTo(Literal(IntConstant(index)))
              index += 1
              clsCast(extracted, arg.tpe)
          }
        }
        if argList.isEmpty then
          val newExpr = m.tree match
            case d: DefDef if d.trailingParamss.nonEmpty =>
              // An empty arg method, e.g., def methodName()
              expr.appliedToNone
            case _ =>
              // No arg method, e.g., def methodName: Unit
              expr
          newExpr.changeOwner(sym)
        else
          // Bind to function arguments
          val newExpr =
            if methodTypeParams.isEmpty then expr.appliedToArgss(argList)
            else
              // For generic functions, type params also need to be applied
              val dummyTypeParams = methodTypeParams.map(x => TypeRepr.of[Any])
              // println(s"---> ${m.name} type param count: ${methodTypeParams.size}, arg size: ${argList.size}")
              expr
                .appliedToTypes(dummyTypeParams)
                .appliedToArgss(argList)
          newExpr.changeOwner(sym)
    )
    '{ Some(${ lambda.asExprOf[(Any, Seq[Any]) => Any] }) }

  private def localMethodsOf(t: TypeRepr): Seq[Symbol] =
    def allMethods =
      t.typeSymbol.methodMembers
        .filter { x =>
          nonObject(x.owner) &&
          x.isDefDef &&
          // x.isPublic &&
          x.privateWithin.isEmpty &&
          !x.flags.is(Flags.Private) &&
          !x.flags.is(Flags.Protected) &&
          !x.flags.is(Flags.PrivateLocal) &&
          !x.isClassConstructor &&
          !x.flags.is(Flags.Artifact) &&
          !x.flags.is(Flags.Synthetic) &&
          !x.flags.is(Flags.Macro) &&
          !x.flags.is(Flags.Implicit) &&
          !x.flags.is(Flags.FieldAccessor) &&
          // Exclude methods from Java
          !x.flags.is(Flags.JavaDefined)
        }
        .filter { x =>
          val name = x.name
          !name.startsWith("$") &&
          name != ""
        }

    allMethods.filter(m => isOwnedByTargetClass(m, t))

  private def nonObject(x: Symbol): Boolean =
    !x.flags.is(Flags.Synthetic) &&
      !x.flags.is(Flags.Artifact) &&
      x.fullName != "scala.Any" &&
      x.fullName != "java.lang.Object" &&
      // Exclude caes class methods
      x.fullName != "scala.Product"

  private def isOwnedByTargetClass(m: Symbol, t: TypeRepr): Boolean =
    m.owner == t.typeSymbol || t.baseClasses.filter(nonObject).exists(_ == m.owner)

  private def modifierBitMaskOf(m: Symbol): Int =
    var mod = 0

    if !m.flags.is(Flags.Private) && !m.flags.is(Flags.Protected) && !m.flags.is(Flags.PrivateLocal) then
      mod |= MethodModifier.PUBLIC
    if m.flags.is(Flags.Private) then mod |= MethodModifier.PRIVATE
    if m.flags.is(Flags.Protected) then mod |= MethodModifier.PROTECTED
    if m.flags.is(Flags.JavaStatic) then mod |= MethodModifier.STATIC
    if m.flags.is(Flags.Final) then mod |= MethodModifier.FINAL
    if m.flags.is(Flags.Abstract) then mod |= MethodModifier.ABSTRACT
    mod

  def surfaceFromClass(cl: Class[?]): Expr[Surface] =
    val name         = cl.getName
    val rawType      = Class.forName(name)
    val constructors = rawType.getConstructors
    val (typeArgs, params) = if constructors.nonEmpty then
      val primaryConstructor = constructors(0)
      val paramSurfaces: Seq[Expr[Surface]] = primaryConstructor.getParameterTypes.map { paramType =>
        val tastyType = quotes.reflect.TypeRepr.typeConstructorOf(paramType)
        surfaceOf(tastyType)
      }.toSeq
      // FIXME: Use TastyInspector as runtime-like reflection for Scala 3
      val params: Seq[Expr[Parameter]] = Seq.empty
      (Expr.ofSeq(paramSurfaces), Expr.ofSeq(params))
    else ('{ Seq.empty[Surface] }, '{ Seq.empty[Parameter] })

    '{
      new wvlet.airframe.surface.GenericSurface(
        rawType = Class.forName(${ Expr(name) }),
        typeArgs = ${ typeArgs }
      )
    }




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