/*
 Copyright (C) 2019-2020 Fredrik Öhrström

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include"wmbus.h"
#include"wmbus_utils.h"
#include"serial.h"

#include<assert.h>
#include<pthread.h>
#include<semaphore.h>
#include<errno.h>
#include<unistd.h>

using namespace std;

struct WMBusRawTTY : public virtual WMBusCommonImplementation
{
    bool ping();
    string getDeviceId();
    LinkModeSet getLinkModes();
    void deviceReset();
    void deviceSetLinkModes(LinkModeSet lms);
    LinkModeSet supportedLinkModes() { return Any_bit; }
    int numConcurrentLinkModes() { return 0; }
    bool canSetLinkModes(LinkModeSet desired_modes) { return true; }

    void processSerialData();
    void simulate() { }

    WMBusRawTTY(shared_ptr<SerialDevice> serial, shared_ptr<SerialCommunicationManager> manager);
    ~WMBusRawTTY() { }

private:

    vector<uchar> read_buffer_;
    LinkModeSet link_modes_;
    vector<uchar> received_payload_;
};

shared_ptr<WMBus> openRawTTY(string device, int baudrate, shared_ptr<SerialCommunicationManager> manager, shared_ptr<SerialDevice> serial_override)
{
    assert(device != "");

    if (serial_override)
    {
        WMBusRawTTY *imp = new WMBusRawTTY(serial_override, manager);
        return shared_ptr<WMBus>(imp);
    }
    auto serial = manager->createSerialDeviceTTY(device.c_str(), baudrate, "rawtty");
    WMBusRawTTY *imp = new WMBusRawTTY(serial, manager);
    return shared_ptr<WMBus>(imp);
}

WMBusRawTTY::WMBusRawTTY(shared_ptr<SerialDevice> serial, shared_ptr<SerialCommunicationManager> manager) :
    WMBusCommonImplementation(DEVICE_RAWTTY, manager, serial)
{
    reset();
}

bool WMBusRawTTY::ping()
{
    return true;
}

string WMBusRawTTY::getDeviceId()
{
    return "?";
}

LinkModeSet WMBusRawTTY::getLinkModes() {
    return link_modes_;
}

void WMBusRawTTY::deviceReset()
{
}

void WMBusRawTTY::deviceSetLinkModes(LinkModeSet lms)
{
}

void WMBusRawTTY::processSerialData()
{
    vector<uchar> data;

    // Receive and accumulated serial data until a full frame has been received.
    serial()->receive(&data);

    read_buffer_.insert(read_buffer_.end(), data.begin(), data.end());

    size_t frame_length;
    int payload_len, payload_offset;

    for (;;)
    {
        FrameStatus status = checkWMBusFrame(read_buffer_, &frame_length, &payload_len, &payload_offset);

        if (status == PartialFrame)
        {
            // Partial frame, stop eating.
            break;
        }
        if (status == ErrorInFrame)
        {
            verbose("(rawtty) protocol error in message received!\n");
            string msg = bin2hex(read_buffer_);
            debug("(rawtty) protocol error \"%s\"\n", msg.c_str());
            read_buffer_.clear();
            break;
        }
        if (status == FullFrame)
        {
            vector<uchar> payload;
            if (payload_len > 0)
            {
                uchar l = payload_len;
                payload.insert(payload.end(), &l, &l+1); // Re-insert the len byte.
                payload.insert(payload.end(), read_buffer_.begin()+payload_offset, read_buffer_.begin()+payload_offset+payload_len);
            }
            read_buffer_.erase(read_buffer_.begin(), read_buffer_.begin()+frame_length);
            AboutTelegram about("", 0);
            handleTelegram(about, payload);
        }
    }
}

AccessCheck detectRAWTTY(Detected *detected, shared_ptr<SerialCommunicationManager> manager)
{
    string tty = detected->specified_device.file;
    int bps = atoi(detected->specified_device.bps.c_str());

    // Since we do not know how to talk to the other end, it might not
    // even respond. The only thing we can do is to try to open the serial device.
    auto serial = manager->createSerialDeviceTTY(tty.c_str(), bps, "detect rawtty");
    AccessCheck rc = serial->open(false);
    if (rc != AccessCheck::AccessOK) return AccessCheck::NotThere;

    serial->close();

    detected->setAsFound("", WMBusDeviceType::DEVICE_RAWTTY, bps, false, false);

    return AccessCheck::AccessOK;
}