/* BSD 2-Clause License - see OPAL/LICENSE for details. */
package org.opalj
package ai
package fpcf
package domain

import scala.util.boundary.Break

import org.opalj.ai.domain.MethodCallsHandling
import org.opalj.ai.domain.TheCode
import org.opalj.ai.domain.TheProject
import org.opalj.ai.fpcf.properties.MethodReturnValue
import org.opalj.br.ClassType
import org.opalj.br.Method
import org.opalj.br.MethodDescriptor
import org.opalj.br.PC
import org.opalj.br.ReferenceType
import org.opalj.fpcf.PropertyKind
import org.opalj.log.OPALLogger
import org.opalj.log.Warn

/**
 * @author Michael Eichberg
 */
trait RefinedTypeLevelInvokeInstructions
    extends MethodCallsDomainWithMethodLockup
    with PropertyStoreBased {
    domain: ValuesFactory & ReferenceValuesDomain & Configuration & TheProject & TheCode =>

    abstract override def usesProperties: Set[PropertyKind] = {
        super.usesProperties ++ Set(MethodReturnValue)
    }

    override protected def tryLookup(
        declaringType: ClassType,
        name:          String,
        descriptor:    MethodDescriptor
    ): Boolean = {
        val returnType = descriptor.returnType
        returnType.isClassType || super.tryLookup(declaringType, name, descriptor)
    }

    /**
     * Provides a hook for subclasses that need to track the information for which methods
     * refined return value information is actually used.
     *
     * @note Intended to be overridden by subclasses. Subclasses should simply call this
     *       method last to get the correct behavior.
     */
    protected def doInvokeWithRefinedReturnValue(
        calledMethod: Method,
        result:       MethodCallResult
    ): MethodCallResult = {
        result
    }

    protected def doInvoke(
        pc:                     PC,
        invokeMethodDescriptor: MethodDescriptor,
        method:                 Method,
        operands:               Operands,
        fallback:               () => MethodCallResult
    ): MethodCallResult = {
        val returnType = method.returnType
        if (!returnType.isClassType ||
            returnType != invokeMethodDescriptor.returnType // <= to handle MethodHandle.invoke(Exact) calls
        ) {
            return fallback();
        }

        dependees.getOrQueryAndUpdate(method, MethodReturnValue.key) match {
            case UsedPropertiesBound(mrvProperty: MethodReturnValue) =>
                mrvProperty.returnValue match {
                    case Some(mrvi) =>
                        val vi = domain.InitializedDomainValue(pc, mrvi)
                        val result = MethodCallResult(vi, getPotentialExceptions(pc))
                        doInvokeWithRefinedReturnValue(method, result)
                    case None =>
                        // the method always throws an exception... but we don't know which one
                        val potentialExceptions = getPotentialExceptions(pc)
                        ThrowsException(potentialExceptions)
                }
            case _ =>
                fallback()
        }
    }
}

/**
 * @author Michael Eichberg
 */
trait MethodCallsDomainWithMethodLockup extends MethodCallsHandling {
    callingDomain: ValuesFactory & ReferenceValuesDomain & Configuration & TheProject & TheCode =>

    /**
     * Invokes the specified method.
     *
     * @param invokeMethodDescriptor The descriptor specified by the invoke instruction.
     * @param method The called method. In case of MethodHandles, the invoked method's descriptor
     *               will most likely not match the descriptor specified by the invoke instruction.
     */
    protected def doInvoke(
        pc:                     PC,
        invokeMethodDescriptor: MethodDescriptor,
        method:                 Method,
        operands:               Operands,
        fallback:               () => MethodCallResult
    ): MethodCallResult

    /**
     * Currently, if we have multiple targets, `fallback` is called and that result is
     * returned.
     */
    protected def doVirtualInvoke(
        pc:            PC,
        declaringType: ClassType,
        isInterface:   Boolean,
        name:          String,
        descriptor:    MethodDescriptor,
        operands:      Operands,
        fallback:      () => MethodCallResult
    ): MethodCallResult = {

        val DomainReferenceValueTag(receiver) = operands.last: @unchecked
        val receiverUTB = receiver.upperTypeBound
        if (!receiverUTB.isSingletonSet || !receiver.upperTypeBound.head.isClassType)
            return fallback();

        val receiverType = receiverUTB.head.asClassType
        // We can resolve (statically) all calls where the type information is precise
        // or where the called method is final.

        if (receiver.isPrecise) {
            // IMPROVE Use project.instanceMethods ....
            classHierarchy.isInterface(receiverType) match {
                case Yes =>
                    doNonVirtualInvoke(pc, receiverType, true, name, descriptor, operands, fallback)
                case No =>
                    doNonVirtualInvoke(pc, receiverType, false, name, descriptor, operands, fallback)
                case Unknown =>
                    fallback()
            }
        } else {
            project.classFile(receiverType).map { receiverClassFile =>
                val targetMethod =
                    if (receiverClassFile.isInterfaceDeclaration)
                        project.resolveInterfaceMethodReference(receiverType, name, descriptor)
                    else
                        project.resolveMethodReference(receiverType, name, descriptor)

                targetMethod match {
                    case Some(method) if method.isFinal =>
                        doInvoke(pc, descriptor, method, operands, fallback)
                    case _ =>
                        fallback()
                }
            }.getOrElse {
                fallback()
            }
        }
    }

    protected def doNonVirtualInvoke(
        pc:            PC,
        declaringType: ClassType,
        isInterface:   Boolean,
        name:          String,
        descriptor:    MethodDescriptor,
        operands:      Operands,
        fallback:      () => MethodCallResult
    ): MethodCallResult = {

        try {
            val resolvedMethod =
                project.classFile(declaringType) match {
                    case Some(classFile) =>
                        if (classFile.isInterfaceDeclaration)
                            project.resolveInterfaceMethodReference(declaringType, name, descriptor)
                        else
                            project.resolveMethodReference(declaringType, name, descriptor)
                    case _ =>
                        return fallback();
                }

            resolvedMethod match {
                case Some(method) =>
                    if (method.body.isDefined)
                        doInvoke(pc, descriptor, method, operands, fallback)
                    else
                        fallback() // only happens if the project is incomplete/broken
                case _ =>
                    OPALLogger.logOnce(Warn(
                        "project configuration",
                        "method reference cannot be resolved: " +
                            declaringType.toJava +
                            "{ /*non virtual*/ " + descriptor.toJava(name) + "}"
                    ))
                    fallback()
            }
        } catch {
            case b: Break[?]  => throw b
            case t: Throwable =>
                OPALLogger.error(
                    "internal, project configuration",
                    "resolving the method reference resulted in an exception: " +
                        project.classFile(declaringType).map(cf =>
                            if (cf.isInterfaceDeclaration) "interface " else "class "
                        ).getOrElse("") +
                        declaringType.toJava + "{ /*non virtual*/ " + descriptor.toJava(name) + "}",
                    t
                )
                fallback()
        }
    }

    // -----------------------------------------------------------------------------------
    //
    // Implementation of the invoke instructions
    //
    // -----------------------------------------------------------------------------------

    /**
     * Returns `true` for those methods for which we try to look up the target method.
     * This filter is collaboratively implemented (stackable trait).
     *
     * @note Domains reusing this template domain have to be able to cope with ALL methods; this
     *       filter is only intended to provide performance optimizations if not all
     *       method lookups are actually required by all clients of this domain.
     * @return The default is to return `false`.
     */
    protected def tryLookup(
        declaringType: ClassType,
        name:          String,
        descriptor:    MethodDescriptor
    ): Boolean = false

    abstract override def invokevirtual(
        pc:            PC,
        declaringType: ReferenceType,
        name:          String,
        descriptor:    MethodDescriptor,
        operands:      Operands
    ): MethodCallResult = {

        def fallback(): MethodCallResult = {
            super.invokevirtual(pc, declaringType, name, descriptor, operands)
        }

        if (declaringType.isArrayType)
            return fallback();

        val declaringClassType = declaringType.asClassType
        if (!tryLookup(declaringClassType, name, descriptor))
            return fallback();

        doVirtualInvoke(pc, declaringClassType, false, name, descriptor, operands, fallback)
    }

    abstract override def invokeinterface(
        pc:            PC,
        declaringType: ClassType,
        name:          String,
        descriptor:    MethodDescriptor,
        operands:      Operands
    ): MethodCallResult = {

        def fallback(): MethodCallResult = {
            super.invokeinterface(pc, declaringType, name, descriptor, operands)
        }

        if (!tryLookup(declaringType, name, descriptor))
            return fallback();

        doVirtualInvoke(pc, declaringType, true, name, descriptor, operands, fallback)
    }

    abstract override def invokespecial(
        pc:            PC,
        declaringType: ClassType,
        isInterface:   Boolean,
        name:          String,
        descriptor:    MethodDescriptor,
        operands:      Operands
    ): MethodCallResult = {

        def fallback(): MethodCallResult = {
            super.invokespecial(pc, declaringType, isInterface, name, descriptor, operands)
        }

        if (!tryLookup(declaringType, name, descriptor))
            return fallback();

        doNonVirtualInvoke(pc, declaringType, isInterface, name, descriptor, operands, fallback)
    }

    /**
     * Those `invokestatic` calls for which we have no concrete method (e.g.,
     * the respective class file was never loaded or the method is native) or
     * if we have a recursive invocation are delegated to the super class.
     */
    abstract override def invokestatic(
        pc:            PC,
        declaringType: ClassType,
        isInterface:   Boolean,
        name:          String,
        descriptor:    MethodDescriptor,
        operands:      Operands
    ): MethodCallResult = {

        def fallback(): MethodCallResult = {
            super.invokestatic(pc, declaringType, isInterface, name, descriptor, operands)
        }

        if (!tryLookup(declaringType, name, descriptor))
            return fallback();

        doNonVirtualInvoke(pc, declaringType, isInterface, name, descriptor, operands, fallback)
    }

}