//
// Copyright 2017 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: GPL-3.0-or-later
//


#include <mpm/exception.hpp>
#include <mpm/spi/spi_iface.hpp>
extern "C" {
#include "spidev.h"
}
#include <fcntl.h>
#include <linux/spi/spidev.h>
#include <boost/format.hpp>
#include <iostream>

using namespace mpm::spi;

/******************************************************************************
 * Implementation
 *****************************************************************************/
class spidev_iface_impl : public spi_iface
{
public:
    spidev_iface_impl(
        const std::string& device, const int max_speed_hz, const int spi_mode)
        : _speed(max_speed_hz), _mode(spi_mode)
    {
        if (init_spi(&_fd, device.c_str(), _mode, _speed, _bits, _delay) < 0) {
            throw mpm::runtime_error(
                str(boost::format("Could not initialize spidev device %s") % device));
        }

        if (_fd < 0) {
            throw mpm::runtime_error(
                str(boost::format("Could not open spidev device %s") % device));
        }
    }

    ~spidev_iface_impl()
    {
        close(_fd);
    }

    uint32_t transfer24_8(const uint32_t data_)
    {
        int ret(0);

        uint32_t data    = data_;
        uint8_t* tx_data = reinterpret_cast<uint8_t*>(&data);

        // Create tx and rx buffers:
        uint8_t tx[] = {tx_data[2], tx_data[1], tx_data[0]}; // FIXME guarantee endianness
        uint8_t rx[3]; // Buffer length must match tx buffer

        if (transfer(_fd, &tx[0], &rx[0], 3, _speed, _bits, _delay) != 0) {
            throw mpm::runtime_error(str(boost::format("SPI Transaction failed!")));
        }

        return uint32_t(rx[2]);
    }

    uint32_t transfer24_16(const uint32_t data_)
    {
        int ret(0);

        uint32_t data    = data_;
        uint8_t* tx_data = reinterpret_cast<uint8_t*>(&data);

        // Create tx and rx buffers:
        uint8_t tx[] = {tx_data[2], tx_data[1], tx_data[0]}; // FIXME guarantee endianness
        uint8_t rx[3]; // Buffer length must match tx buffer

        if (transfer(_fd, &tx[0], &rx[0], 3, _speed, _bits, _delay) != 0) {
            throw mpm::runtime_error(str(boost::format("SPI Transaction failed!")));
        }

        return uint32_t(rx[1] << 8 | rx[2]);
    }

private:
    int _fd;
    const uint32_t _mode;
    uint32_t _speed = 2000000;
    uint8_t _bits   = 8;
    uint16_t _delay = 0;
};

/******************************************************************************
 * Factory
 *****************************************************************************/
spi_iface::sptr spi_iface::make_spidev(
    const std::string& device, const int speed_hz, const int spi_mode)
{
    return std::make_shared<spidev_iface_impl>(device, speed_hz, spi_mode);
}