// Copyright (C) 2017-2018 Baidu, Inc. All Rights Reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
//  * Redistributions of source code must retain the above copyright
//    notice, this list of conditions and the following disclaimer.
//  * Redistributions in binary form must reproduce the above copyright
//    notice, this list of conditions and the following disclaimer in
//    the documentation and/or other materials provided with the
//    distribution.
//  * Neither the name of Baidu, Inc., nor the names of its
//    contributors may be used to endorse or promote products derived
//    from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "AbstractNetworkOps.h"
#include <boost/lexical_cast.hpp>
#include <boost/algorithm/string.hpp>

using namespace util;

AbstractNetworkOps::AbstractNetworkOps(boost::asio::io_service& io_service, boost::asio::ssl::context& context) : socket_(io_service, context) {}

AbstractNetworkOps::~AbstractNetworkOps() {}


AbstractNetworkOps::ssl_socket::lowest_layer_type& AbstractNetworkOps::socket() {
    return socket_.lowest_layer();
}


void AbstractNetworkOps::saveCloseSocket() {
    boost::system::error_code ec;

    socket_.lowest_layer().cancel();

    if (ec) {
        stringstream ss;
        Log("Socket shutdown error: %s", ec.message());
    } else {
        socket_.lowest_layer().close();
    }
}


void AbstractNetworkOps::read() {

    this->read_state = MSG_HEADER;
    memset(this->read_buffer_header, '\0', 20);
    boost::asio::async_read(
        socket_,
        boost::asio::buffer(this->read_buffer_header, 20),
        boost::bind(
            &AbstractNetworkOps::handle_read,
            this,
            boost::asio::placeholders::error,
            boost::asio::placeholders::bytes_transferred));
}

void AbstractNetworkOps::handle_read(const boost::system::error_code& error, size_t bytes_transferred)
{
    if (error) {
        if ((boost::asio::error::eof == error) || (boost::asio::error::connection_reset == error)) {
            Log("Connection has been closed by remote host");
        } else {
            Log("Unknown socket error while reading occured!", log::error);
        }
        return;
    }

    vector<string> header;
    boost::split(header, this->read_buffer_header, boost::is_any_of("@"));

    int msg_size = boost::lexical_cast<int>(header[0]);
    int type = boost::lexical_cast<int>(header[1]);

    if (this->read_state == MSG_HEADER) {

        this->read_state = MSG_BODY;
        this->read_buffer_message = (char*) malloc(sizeof(char) * msg_size);
        memset(this->read_buffer_message, '\0', sizeof(char) * msg_size);
        boost::asio::async_read(
            socket_,
            boost::asio::buffer(this->read_buffer_message, msg_size),
            boost::bind(
                &AbstractNetworkOps::handle_read,
                this,
                boost::asio::placeholders::error,
                boost::asio::placeholders::bytes_transferred));

    } else if (this->read_state == MSG_BODY) {
        process_read(this->read_buffer_message, msg_size, type);
    }
}

void AbstractNetworkOps::send(vector<string> v) {
    string type = v[0];
    string msg = v[1];

    if (msg.size() <= 0) {
        this->saveCloseSocket();
        return;
    }

    const char *msg_c = msg.c_str();
    int msg_length = msg.size();

    string header = to_string(msg_length) + "@" + type;
    memset(this->write_buffer_header, '\0', 20);
    memcpy(this->write_buffer_header, header.c_str(), header.length());

    this->write_buffer_message = (char*) malloc(sizeof(char) * msg_length);
    memset(this->write_buffer_message, '\0', sizeof(char) * msg_length);
    memcpy(this->write_buffer_message, msg_c, msg_length);
    this->write_state = MSG_HEADER;

    boost::asio::async_write(
        socket_,
        boost::asio::buffer(this->write_buffer_header, 20),
        boost::asio::transfer_at_least(20),
        boost::bind(
            &AbstractNetworkOps::handle_write,
            this,
            boost::asio::placeholders::error,
            boost::asio::placeholders::bytes_transferred));
}

void AbstractNetworkOps::handle_write(const boost::system::error_code& error, size_t bytes_transferred)
{
    if (error) {
        if ((boost::asio::error::eof == error) || (boost::asio::error::connection_reset == error)) {
            Log("Connection has been closed by remote host");
        } else {
            Log("Unknown socket error while writing occured!", log::error);
        }
        return;
    }

    vector<string> header;
    boost::split(header, this->write_buffer_header, boost::is_any_of("@"));

    int msg_size = boost::lexical_cast<int>(header[0]);
    int type = boost::lexical_cast<int>(header[1]);

    if (this->write_state == MSG_HEADER) {

        this->write_state = MSG_BODY;
        boost::asio::async_write(
            socket_,
            boost::asio::buffer(this->write_buffer_message, msg_size),
            boost::asio::transfer_at_least(msg_size),
            boost::bind(
                &AbstractNetworkOps::handle_write,
                this,
                boost::asio::placeholders::error,
                boost::asio::placeholders::bytes_transferred));

    } else if (this->write_state == MSG_BODY) {

        free(this->write_buffer_message);
        this->read();
    }
}

void AbstractNetworkOps::setCallbackHandler(CallbackHandler cb) {
    this->callback_handler = cb;
}


void AbstractNetworkOps::process_read(char* buffer, int msg_size, int type) {
    std::string str(reinterpret_cast<const char*>(buffer), msg_size);

    free(buffer);
    auto msg = this->callback_handler(str, type);

    if (msg.size() > 0 && msg[0].size() > 0) {
        send(msg);
    } else {
        Log("Close connection");
        this->saveCloseSocket();
    }
}