/**
 * Copyright (c) 2021 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "returnStatement.h"

#include <ir/base/methodDefinition.h>
#include <ir/base/scriptFunction.h>
#include <compiler/core/pandagen.h>
#include <typescript/checker.h>

#include <ir/astDump.h>
#include <ir/expression.h>
#include <ir/typeNode.h>

namespace panda::es2panda::ir {

void ReturnStatement::Iterate(const NodeTraverser &cb) const
{
    if (argument_) {
        cb(argument_);
    }
}

void ReturnStatement::Dump(ir::AstDumper *dumper) const
{
    dumper->Add({{"type", "ReturnStatement"}, {"argument", AstDumper::Nullable(argument_)}});
}

void ReturnStatement::Compile(compiler::PandaGen *pg) const
{
    if (argument_) {
        argument_->Compile(pg);
    } else {
        pg->LoadConst(this, compiler::Constant::JS_UNDEFINED);
    }

    if (pg->CheckControlFlowChange()) {
        compiler::RegScope rs(pg);
        compiler::VReg res = pg->AllocReg();

        pg->StoreAccumulator(this, res);
        pg->ControlFlowChangeReturn();
        pg->LoadAccumulator(this, res);
    }

    if (argument_) {
        pg->ValidateClassDirectReturn(this);
        pg->ExplicitReturn(this);
    } else {
        pg->ImplicitReturn(this);
    }
}

checker::Type *ReturnStatement::Check(checker::Checker *checker) const
{
    const ir::AstNode *ancestor = checker::Checker::FindAncestorGivenByType(this, ir::AstNodeType::SCRIPT_FUNCTION);
    CHECK_NOT_NULL(ancestor);
    ASSERT(ancestor && ancestor->IsScriptFunction());
    const ir::ScriptFunction *containingFunc = ancestor->AsScriptFunction();

    if (containingFunc->Parent()->Parent()->IsMethodDefinition()) {
        const ir::MethodDefinition *containingClassMethod = containingFunc->Parent()->Parent()->AsMethodDefinition();
        if (containingClassMethod->Kind() == ir::MethodDefinitionKind::SET) {
            checker->ThrowTypeError("Setters cannot return a value", Start());
        }
    }

    if (containingFunc->ReturnTypeAnnotation()) {
        checker::Type *returnType = checker->GlobalUndefinedType();
        checker::Type *funcReturnType = containingFunc->ReturnTypeAnnotation()->AsTypeNode()->GetType(checker);

        if (argument_) {
            checker->ElaborateElementwise(funcReturnType, argument_, Start());
            returnType = checker->CheckTypeCached(argument_);
        }

        checker->IsTypeAssignableTo(returnType, funcReturnType,
                                    {"Type '", returnType, "' is not assignable to type '", funcReturnType, "'."},
                                    Start());
    }

    return nullptr;
}

void ReturnStatement::UpdateSelf(const NodeUpdater &cb, [[maybe_unused]] binder::Binder *binder)
{
    if (argument_) {
        argument_ = std::get<ir::AstNode *>(cb(argument_))->AsExpression();
    }
}

}  // namespace panda::es2panda::ir