#include "W433DataReciver.h"
#include "writepin.h"
#include <stdlib.h>
#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include "serial.h"

W433DataReciver* W433DataReciver::instance = nullptr;

W433DataReciver::W433DataReciver(volatile unsigned char* const port , const unsigned char pin, volatile uint16_t * timerRegister, volatile uint8_t* const timerOverflowRegister, void (* const packetCallback)(uint32_t, void*), void* const userData ): 
_port(port), _pin(pin),  _timerRegister(timerRegister), _timerOverflowRegister(timerOverflowRegister), _packetCallback(packetCallback), _userData(userData)
{
    instance = this;
    for(uint8_t i = 0; i < 33; i++) timesBuffer[i] = 0;
}

W433DataReciver::~W433DataReciver()
{
    instance = nullptr;
}

void W433DataReciver::staticInterrupt()
{
    if(instance != nullptr) instance->interrupt();
}

int8_t W433DataReciver::reciveBit(uint8_t index)
{
    if( 
        timesBuffer[index] < 0                          && 
        isTime(timesBuffer[index+1], SMALL_TIME, true)  && 
        isTime(timesBuffer[index+2], LARGE_TIME, false) && 
        isTime(timesBuffer[index+3], SMALL_TIME, true)
      )
    {
        return 1;
    }
    else if( 
        timesBuffer[index] < 0                          && 
        isTime(timesBuffer[index+1], LARGE_TIME, true)  && 
        isTime(timesBuffer[index+2], SMALL_TIME, false) && 
        isTime(timesBuffer[index+3], SMALL_TIME, true)
      )
    {
        return 0;
    }
    else return -1;
}


bool W433DataReciver::isTime(int16_t input, const uint16_t time, const bool state, const uint16_t tollerance)
{
    if((state && input < 0) || (!state && input > 0)) return false;
    input = abs(input);
    return input < (int16_t)(time+tollerance) && input > (int16_t)(time-tollerance);
}

bool W433DataReciver::reciveSync(const uint16_t elapsedTime)
{
    if(elapsedTime < SYNC_TIME+50 && elapsedTime > SYNC_TIME-50) 
    {
        ++syncCount;
    }
    else syncCount = 0;
    if(syncCount > 10) return true;
    else return false;
}

bool W433DataReciver::recivedByte(const uint16_t elapsedTime)
{
    timesBuffer[timesBufferIndex] = readPin(_port, _pin) ? 0-elapsedTime : elapsedTime;
    ++timesBufferIndex;
    return timesBufferIndex == 32;
}

uint8_t W433DataReciver::assmbleByte()
{
    uint8_t byte = 0;
    for(uint8_t i = 0; i < 8; ++i) 
    {
        int8_t bit = reciveBit(i*4);
        if(bit >= 0) byte = byte | (bit << (7-i));
        else setState(LOOKING_FOR_SYNC);
    }
    timesBufferIndex = 0;
    return byte;
}

void W433DataReciver::setState(const uint8_t stateIn)
{
    state = stateIn;
    timesBufferIndex = 0;
    packetIndex = 0;
}

void W433DataReciver::interrupt()
{
    uint16_t elapsedTime = polarity*(((*_timerOverflowRegister & 0x01) ? *_timerRegister+(UINT16_MAX - previousTime) : *_timerRegister - previousTime)/TICKS_PER_US);
	
    if(elapsedTime < SMALL_TIME/4) return;
    
    previousTime = *_timerRegister;
	*_timerOverflowRegister = *_timerOverflowRegister | 0x01;
    
    if(state == LOOKING_FOR_SYNC && reciveSync(elapsedTime)) 
    {
        setState(LOOKING_FOR_SYNC_END);
    }
    else if(state == LOOKING_FOR_SYNC_END) 
    {
        if(elapsedTime > SYNC_TIME + 50)
        {
            if(elapsedTime < LARGE_TIME + 50) setState(LOOKING_FOR_SYNC);
            else
            {
                timesBuffer[0] = -LARGE_TIME;
                setState(LOOKING_FOR_SIGNATURE);
                ++timesBufferIndex;
            }
        }
    }
    else if(state == LOOKING_FOR_SIGNATURE)
    {
        if(recivedByte(elapsedTime))
        {
            uint8_t recivedSignature = assmbleByte();
            if( recivedSignature == signature) setState(RECVING_PACKET);
            else setState(LOOKING_FOR_SYNC);
        }
    }
    else if( state == RECVING_PACKET )
    {
        
        if(recivedByte(elapsedTime))
        {
            uint8_t packetByte = assmbleByte();
                    
            packet = packet | ((uint32_t)packetByte) << ((3-packetIndex)*8);
            ++packetIndex;
            if(packetIndex > 3)
            {
                packetIndex = 0;
                timesBufferIndex = 0;
                setState(RECVING_PACKET_CHECKSUM);
            }
        }
    }
    else if(state == RECVING_PACKET_CHECKSUM)
    {
        if(recivedByte(elapsedTime))
        {
            uint8_t recivedChecksum = assmbleByte();
            
            volatile uint8_t* buffer = reinterpret_cast<volatile uint8_t*>(&packet);
            
            uint8_t computedChecksum = 0;
            for(uint8_t j = 0; j < sizeof(packet); j++) for(uint8_t i = 0; i < 8; i++) computedChecksum = computedChecksum + (buffer[j] & ( 1 << (8 - i)));
            
            if(computedChecksum == recivedChecksum)
            {
                _ringBuffer.write(const_cast<uint8_t*>(buffer), sizeof(packet));
                if(_packetCallback != nullptr)(*_packetCallback)(packet, _userData);
            }
            packet = 0;
            setState(LOOKING_FOR_SYNC);
        }
    }
}

RingBuffer<W433DataReciver::RINGBUFFER_LENGTH, uint8_t>* W433DataReciver::getRingBuffer()
{
    return &_ringBuffer;
}