/*
 *
 *  mur.sat
 *
 *  Somewhen in the year 2012, mur.at will have a nano satellite launched
 *  into a low earth orbit (310 km above the surface of our planet). The
 *  satellite itself is a TubeSat personal satellite kit, developed and
 *  launched by interorbital systems. mur.sat is a joint venture of mur.at,
 *  ESC im Labor and realraum.
 *
 *  Please visit the project hompage at sat.mur.at for further information.
 *
 *
 *  Copyright (C) 2012 Bernhard Tittelbach <xro@realraum.at>
 *
 *  This file is part of mur.sat.
 *
 *  mur.sat 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
 *  any later version.
 *
 *  mur.sat 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 mur.sat. If not, see <http://www.gnu.org/licenses/>.
 *
 */
#include "avr/io.h"
#include "util/delay.h"

#include "c1101lib.h"
#include "spi.h"
//#include "usb_rawhid.h"

/**** Helper Functions ****/

char spi_c1101_exchange(char *data, int len)
{
    char rbyte;
    spi_cs_enable();
    while (len--)
    {
        while ( ! (SPIC1101_SB_CHIPRDY(spi_read_byte())));
        spi_write_byte(*(data++));
    }
    rbyte = spi_read_byte();
    spi_cs_disable();
    return rbyte;
}

// note addresses range from 0x00 to 0x2F for normal registers and 0xF0 to 0xFD for special status registers
char spi_c1101_read_register(char address)
{
    char data[1];
    data[0]=address | 0x80;
    return spi_c1101_exchange(data, 1);
}

// note addresses range from 0x00 to 0x2F for normal registers
char spi_c1101_write_register(char address, char byte)
{
    char data[2];
    data[0]=address & 0x2F;
    data[1]=byte;
    return spi_c1101_exchange(data, 2);
}

// note addresses range from 0x30 to 0x3D for command strobes
char spi_c1101_strobe_command(char address)
{
    char data[1];
    data[0]=address;
    return spi_c1101_exchange(data, 1);
}

int spi_c1101_read_rxfifo(int leave_num_bytes, char *buffer, int maxlen)
{
    char sb;
    int num_read = 0;
    int num_fifo_available = 0;
    spi_cs_enable();
    while ( ! (SPIC1101_SB_CHIPRDY(spi_read_byte())));
    spi_write_byte(SPIC1101_ADDR_FIFO_READ_BURST);
    do
    {
        sb = spi_read_byte();
    } while ( ! (SPIC1101_SB_CHIPRDY(sb)));
    num_fifo_available = SPIC1101_SB_FIFO_BYTES_AVAILABLE(sb);
    
    while (maxlen-- && num_fifo_available - num_read <= leave_num_bytes)
    {
        //hope this works !!
        buffer[num_read++] = spi_read_byte();
    }
    spi_cs_disable();
    return num_read;
}

//note: always check if num_written returned == len given
int spi_c1101_write_txfifo(char *buffer, int len)
{
    char sb;
    int num_written = 0;
    int num_fifo_available = 0;
    spi_cs_enable();
    while ( ! (SPIC1101_SB_CHIPRDY(spi_read_byte())));
    spi_write_byte(SPIC1101_ADDR_FIFO_WRITE_BURST);
    do
    {
        sb = spi_read_byte();
    } while ( ! (SPIC1101_SB_CHIPRDY(sb)));
    num_fifo_available = SPIC1101_SB_FIFO_BYTES_AVAILABLE(sb);
    
    //if there is less space in tx-fifo than num-byte we want to send, only fill fifo until full and leave rest of buffer unsent (for now)
    if (num_fifo_available < len)
        len = num_fifo_available;
    
    while (len--)
    {
        //hope this works !!
        spi_write_byte(buffer[num_written++]);
    }
    spi_cs_disable();
    return num_written;
}



/**** External Functions ****/


//max len: 64 bytes
void writeTXFifo(char *buffer, unsigned int len)
{
    //check TXBYTES.NUM_TXBYTES
    // never write more bytes than avaiblabe or doom ensues
    
    
}

//max returned: 64 bytes
int readRXFifo(char *buffer)
{
    //check RXBYTES.NUM_RXBYTES
    // never read more bytes than avaiblabe or we will read garbage
    
    //note: if RX transmission fills fifo buffer at exact same time as last RX Fifo Bit is read via SPI, Fifo Pointer will not be properly updated 
    //            and last read byte will be duplicated.
    // thus: don't last avialable FIFO Bytes unless we can be sure that it will be the last byte of a packet and we can be sure that a following duplicated byte is actually an Fifo duplication and not an actually recieved byte !
    
    return 0;
}