/**
 * Copyright (c) 2023-2024 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 "util.h"

#include "compiler/lowering/scopesInit/scopesInitPhase.h"
#include "ir/expressions/identifier.h"

namespace ark::es2panda::compiler {

varbinder::Scope *NearestScope(const ir::AstNode *ast)
{
    while (ast != nullptr && !ast->IsScopeBearer()) {
        ast = ast->Parent();
    }

    return ast == nullptr ? nullptr : ast->Scope();
}

checker::ETSObjectType const *ContainingClass(const ir::AstNode *ast)
{
    while (ast != nullptr && !ast->IsClassDefinition()) {
        ast = ast->Parent();
    }

    return ast == nullptr ? nullptr : ast->AsClassDefinition()->TsType()->AsETSObjectType();
}

ir::Identifier *Gensym(ArenaAllocator *const allocator)
{
    util::UString const s = GenName(allocator);
    return allocator->New<ir::Identifier>(s.View(), allocator);
}

util::UString GenName(ArenaAllocator *const allocator)
{
    static std::string const GENSYM_CORE = "gensym$_";
    static std::size_t gensymCounter = 0U;

    return util::UString {GENSYM_CORE + std::to_string(++gensymCounter), allocator};
}

// Function to clear expression node types and identifier node variables (for correct re-binding and re-checking)
void ClearTypesVariablesAndScopes(ir::AstNode *node) noexcept
{
    auto doNode = [](ir::AstNode *nn) {
        if (nn->IsScopeBearer()) {
            nn->ClearScope();
        }
        if (nn->IsTyped() && !(nn->IsExpression() && nn->AsExpression()->IsTypeNode())) {
            nn->AsTyped()->SetTsType(nullptr);
        }
        if (nn->IsIdentifier()) {
            nn->AsIdentifier()->SetVariable(nullptr);
        }
    };

    doNode(node);
    node->Iterate([doNode](ir::AstNode *child) -> void {
        doNode(child);
        ClearTypesVariablesAndScopes(child);
    });
}

ArenaSet<varbinder::Variable *> FindCaptured(ArenaAllocator *allocator, ir::AstNode *scopeBearer) noexcept
{
    auto result = ArenaSet<varbinder::Variable *> {allocator->Adapter()};
    auto scopes = ArenaSet<varbinder::Scope *> {allocator->Adapter()};
    scopeBearer->IterateRecursivelyPreorder([&result, &scopes](ir::AstNode *ast) {
        if (ast->IsScopeBearer() && ast->Scope() != nullptr) {
            scopes.insert(ast->Scope());
            if (ast->Scope()->IsFunctionScope()) {
                scopes.insert(ast->Scope()->AsFunctionScope()->ParamScope());
            } else if (ast->IsForUpdateStatement() || ast->IsForInStatement() || ast->IsForOfStatement() ||
                       ast->IsCatchClause()) {
                // NOTE(gogabr) LoopScope _does not_ currently respond to IsLoopScope().
                // For now, this is the way to reach LoopDeclarationScope.
                scopes.insert(ast->Scope()->Parent());
            }
        }
        if (ast->IsIdentifier()) {
            auto *var = ast->AsIdentifier()->Variable();
            if (var == nullptr || !var->HasFlag(varbinder::VariableFlags::LOCAL)) {
                return;
            }
            auto *sc = var->GetScope();
            if (sc != nullptr && !sc->IsClassScope() && !sc->IsGlobalScope() && scopes.count(var->GetScope()) == 0) {
                result.insert(var);
            }
        }
    });
    return result;
}

// Rerun varbinder and checker on the node.
void Recheck(varbinder::ETSBinder *varBinder, checker::ETSChecker *checker, ir::AstNode *node)
{
    auto *scope = NearestScope(node);
    auto bscope = varbinder::LexicalScope<varbinder::Scope>::Enter(varBinder, scope);

    ClearTypesVariablesAndScopes(node);
    InitScopesPhaseETS::RunExternalNode(node, varBinder);
    varBinder->ResolveReferencesForScopeWithContext(node, scope);

    auto *containingClass = ContainingClass(node);
    // NOTE(gogabr: should determine checker status more finely.
    auto checkerCtx = checker::SavedCheckerContext(
        checker, (containingClass == nullptr) ? checker::CheckerStatus::NO_OPTS : checker::CheckerStatus::IN_CLASS,
        containingClass);
    auto scopeCtx = checker::ScopeContext(checker, scope);

    node->Check(checker);
}

}  // namespace ark::es2panda::compiler