/*
 * Copyright (c) 2011-2015, Intel Corporation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. Neither the name of the copyright holder 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 HOLDER 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;
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 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include "RemoteProcessorServer.h"
#include <iostream>
#include <memory>
#include <assert.h>
#include <string.h>
#include <unistd.h>
#include "RequestMessage.h"
#include "AnswerMessage.h"
#include "RemoteCommandHandler.h"
#include "Socket.h"
#include "convert.hpp"

using std::string;

CRemoteProcessorServer::CRemoteProcessorServer(std::string bindAddress)
    : _bindAddress(bindAddress), _io_service(), _acceptor(_io_service), _socket(_io_service)
{
}

CRemoteProcessorServer::~CRemoteProcessorServer()
{
    stop();
}

// State
bool CRemoteProcessorServer::start(string &error)
{
    using namespace asio;

    try {
        generic::stream_protocol::endpoint endpoint;
        uint16_t port;
        std::string endpointName;
        bool isInet;

        // For backward compatibility, tcp port referred by its value only
        if (convertTo(_bindAddress, port)) {
            isInet = true;
        } else {
            // required form is <protocol>://<host:port|port_name>
            const std::string tcpProtocol{"tcp"};
            const std::string unixProtocol{"unix"};
            const std::vector<std::string> supportedProtocols{ tcpProtocol, unixProtocol };
            const std::string protocolDel{"://"};

            size_t protocolDelPos = _bindAddress.find(protocolDel);
            if (protocolDelPos == std::string::npos) {
                error = "bindaddress " + _bindAddress + " ill formed, missing " + protocolDel;
                return false;
            }
            std::string protocol = _bindAddress.substr(0, protocolDelPos);

            if (std::find(begin(supportedProtocols), end(supportedProtocols), protocol) ==
                    end(supportedProtocols)) {
                error = "bindaddress " + _bindAddress + " has invalid protocol " + protocol;
                return false;
            }
            isInet = (_bindAddress.find(tcpProtocol) != std::string::npos);
            if (isInet) {
                size_t portDelPos = _bindAddress.find(':', protocolDelPos + protocolDel.size());
                if (portDelPos == std::string::npos) {
                    error = "bindaddress " + _bindAddress + " ill formed, missing " + ":";
                    return false;
                }
                std::string portLiteral{_bindAddress.substr(portDelPos + 1)};
                if (!convertTo(portLiteral, port)) {
                    error = "bindaddress " + _bindAddress + " port " + portLiteral + " ill formed";
                    return false;
                }
            } else {
                endpointName = _bindAddress.substr(protocolDelPos + protocolDel.size());
            }
        }

        if (isInet) {
            endpoint = ip::tcp::endpoint(ip::tcp::v6(), port);
        } else {
            endpoint = local::stream_protocol::endpoint(endpointName);
        }

        _acceptor.open(endpoint.protocol());

        if (endpoint.protocol().protocol() == ASIO_OS_DEF(IPPROTO_TCP)) {
            _acceptor.set_option(ip::tcp::acceptor::reuse_address(true));
        } else if (endpoint.protocol().protocol() == AF_UNSPEC) {
            // In case of reuse, remote it first
            unlink(endpointName.c_str());
        }
        _acceptor.set_option(socket_base::linger(true, 0));
        _acceptor.set_option(socket_base::enable_connection_aborted(true));

        _acceptor.bind(endpoint);
        _acceptor.listen();
    } catch (std::exception &e) {
        error = "Unable to listen on " + _bindAddress + ": " + e.what();
        return false;
    }

    return true;
}

bool CRemoteProcessorServer::stop()
{
    _io_service.stop();

    return true;
}

void CRemoteProcessorServer::acceptRegister(IRemoteCommandHandler &commandHandler)
{
    auto peerHandler = [this, &commandHandler](asio::error_code ec) {
        if (ec) {
            std::cerr << "Accept failed: " << ec.message() << std::endl;
            return;
        }

        const auto &endpoint = _socket.local_endpoint();
        if (endpoint.protocol().protocol() == ASIO_OS_DEF(IPPROTO_TCP)) {
            _socket.set_option(asio::ip::tcp::no_delay(true));
        }
        handleNewConnection(commandHandler);

        _socket.close();

        acceptRegister(commandHandler);
    };

    _acceptor.async_accept(_socket, peerHandler);
}

bool CRemoteProcessorServer::process(IRemoteCommandHandler &commandHandler)
{
    acceptRegister(commandHandler);

    asio::error_code ec;

    _io_service.run(ec);

    if (ec) {
        std::cerr << "Server failed: " << ec.message() << std::endl;
    }

    return ec.value() == 0;
}

// New connection
void CRemoteProcessorServer::handleNewConnection(IRemoteCommandHandler &commandHandler)
{
    // Process all incoming requests from the client
    while (true) {

        // Process requests
        // Create command message
        CRequestMessage requestMessage;

        string strError;
        ///// Receive command
        CRequestMessage::Result res;
        res = requestMessage.serialize(Socket(_socket), false, strError);

        switch (res) {
        case CRequestMessage::error:
            std::cout << "Error while receiving message: " << strError << std::endl;
        // fall through
        case CRequestMessage::peerDisconnected:
            // Consider peer disconnection as normal, no log
            return; // Bail out
        case CRequestMessage::success:
            break; // No error, continue
        }

        // Actually process the request
        bool bSuccess;

        string strResult;

        bSuccess = commandHandler.remoteCommandProcess(requestMessage, strResult);

        // Send back answer
        // Create answer message
        CAnswerMessage answerMessage(strResult, bSuccess);

        ///// Send answer
        res = answerMessage.serialize(_socket, true, strError);

        switch (res) {
        case CRequestMessage::peerDisconnected:
        // Peer should not disconnect while waiting for an answer
        // Fall through to log the error and bail out
        case CRequestMessage::error:
            std::cout << "Error while receiving message: " << strError << std::endl;
            return; // Bail out
        case CRequestMessage::success:
            break; // No error, continue
        }
    }
}