// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements. See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership. The ASF licenses this file

// to you 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.

#pragma once

#include <mutex>

#include <string>

#include "exprs/lambda_function/lambda_function.h"

namespace doris {

class LambdaFunctionFactory;

void register_function_array_map(LambdaFunctionFactory& factory);

void register_function_array_filter(LambdaFunctionFactory& factory);

void register_function_array_sort(LambdaFunctionFactory& factory);

class LambdaFunctionFactory {

using Creator = std::function<LambdaFunctionPtr()>;

using FunctionCreators = phmap::flat_hash_map<std::string, Creator>;

public:

void register_function(const std::string& name, const Creator& ptr) {

function_creators[name] = ptr;

}

template <class Function>

void register_function() {

register_function(Function::name, &Function::create);

}

LambdaFunctionPtr get_function(const std::string& name) {

auto iter = function_creators.find(name);

if (iter != function_creators.end()) {

return iter->second();

}

LOG(WARNING) << fmt::format("Function signature {} is not found", name);

return nullptr;

}

private:

FunctionCreators function_creators;

public:

static LambdaFunctionFactory& instance() {

static std::once_flag oc;

static LambdaFunctionFactory instance;

std::call_once(oc, []() {

register_function_array_map(instance);

register_function_array_filter(instance);

register_function_array_sort(instance);

});

return instance;

}

};

} // namespace doris