// Copyright (C) 2019-2020 Zilliz. All rights reserved.
//
// 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 "Status.h"

#include <cstring>

namespace milvus {

constexpr int CODE_WIDTH = sizeof(StatusCode);

Status::Status(StatusCode code, const std::string& msg) {
    // 4 bytes store code
    // 4 bytes store message length
    // the left bytes store message string
    const uint32_t length = (uint32_t)msg.size();
    auto result = new char[length + sizeof(length) + CODE_WIDTH];
    memcpy(result, &code, CODE_WIDTH);
    memcpy(result + CODE_WIDTH, &length, sizeof(length));
    memcpy(result + sizeof(length) + CODE_WIDTH, msg.data(), length);

    state_ = result;
}

Status::Status() : state_(nullptr) {
}

Status::~Status() {
    delete state_;
}

Status::Status(const Status& s) : state_(nullptr) {
    CopyFrom(s);
}

Status&
Status::operator=(const Status& s) {
    CopyFrom(s);
    return *this;
}

Status::Status(Status&& s) : state_(nullptr) {
    MoveFrom(s);
}

Status&
Status::operator=(Status&& s) {
    MoveFrom(s);
    return *this;
}

void
Status::CopyFrom(const Status& s) {
    delete state_;
    state_ = nullptr;
    if (s.state_ == nullptr) {
        return;
    }

    uint32_t length = 0;
    memcpy(&length, s.state_ + CODE_WIDTH, sizeof(length));
    int buff_len = length + sizeof(length) + CODE_WIDTH;
    state_ = new char[buff_len];
    memcpy(state_, s.state_, buff_len);
}

void
Status::MoveFrom(Status& s) {
    delete state_;
    state_ = s.state_;
    s.state_ = nullptr;
}

std::string
Status::message() const {
    if (state_ == nullptr) {
        return "OK";
    }

    std::string msg;
    uint32_t length = 0;
    memcpy(&length, state_ + CODE_WIDTH, sizeof(length));
    if (length > 0) {
        msg.append(state_ + sizeof(length) + CODE_WIDTH, length);
    }

    return msg;
}

}  // namespace milvus