// Copyright (c) 2017, Baidu.com, Inc. 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 "exec/local_file_writer.h"
#include "util/error_util.h"

namespace palo {

LocalFileWriter::LocalFileWriter(const std::string& path, int64_t start_offset)
        : _path(path), _start_offset(start_offset), _fp(nullptr) {
}

LocalFileWriter::~LocalFileWriter() {
    close();
}

Status LocalFileWriter::open() {
    _fp = fopen(_path.c_str(), "w+");
    if (_fp == nullptr) {
        std::stringstream ss;
        ss << "Open file failed. path=" << _path
            << ", errno= " << errno
            << ", description=" << get_str_err_msg();
        return Status(ss.str());
    }

    if (_start_offset != 0) {
        int success = fseek(_fp, _start_offset, SEEK_SET);
        if (success != 0) {
            std::stringstream ss;
            ss << "Seek to start_offset failed. offset=" << _start_offset
                << ", errno= " << errno
                << ", description=" << get_str_err_msg();
            return Status(ss.str());
        }
    }

    return Status::OK;
}

Status LocalFileWriter::write(const uint8_t* buf, size_t buf_len, size_t* written_len) {
    size_t bytes_written = fwrite(buf, 1, buf_len, _fp);
    if (bytes_written < buf_len) {
        std::stringstream error_msg;
        error_msg << "fail to write to file. "
                << " len=" << buf_len
                << ", path=" << _path
                << ", failed with errno=" << errno
                << ", description=" << get_str_err_msg();
        return Status(error_msg.str());
    }

    *written_len = bytes_written;
    return Status::OK;
}

void LocalFileWriter::close() {
    if (_fp != nullptr) {
        fclose(_fp);
        _fp = nullptr;
    }
}

} // end namespace palo