#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include "modbus.h"

#define receiveOkay (modbusGetBusState() & (1<<ReceiveCompleted))

void timer2_init()
{
    TCCR2A = (1<<WGM21); //TIMER0 SET-UP: CTC MODE
    TCCR2B|=(1<<CS21); //prescaler 8
    OCR2A = 200; 
	TIMSK2|=(1<<OCIE2A);
}

void modbus_master_init(){
    modbusSetAddress(1); //better set this to sth.
	modbusInit();
    timer2_init(); // modbus tick timer
}

int8_t wait_receive(uint8_t len, uint16_t dest[], uint8_t timeout){

    uint8_t breaker = timeout;
    while(!receiveOkay && breaker) { //wait for client response, time out after 1s
        breaker--;
        _delay_ms(1);
        if(breaker==0)
            return -1;
    }

    if(receiveOkay) { //if this fails, there was either no response or a crc error
        if(rxbuffer[1]&0x80) { //client responded with an error code
            //handle the error
            return -1;
        }
        else {
            for(uint8_t x=0;x<len;x++) { //rxbuffer[2] should be 8 (4 registers => 8 bytes). You might want to check this at this point.
                dest[x]=(rxbuffer[3+x*2]<<8)+rxbuffer[4+x*2]; //do sth with the acquired data.
            }
        }

    }
    return 0;
}

int8_t wait_write(uint8_t timeout){                              
    uint8_t breaker = timeout;                                   
    while(!receiveOkay && breaker) { //wait for client response, time out after 1s
        breaker--;            
        _delay_ms(1);             
        if(breaker==0)            
            return -1;            
    }                        
                         
    if(receiveOkay) { //if this fails, there was either no response or a crc error
        if(rxbuffer[1]&0x80) { //client responded with an error code
            return rxbuffer[1]&0x80;                              
        }                                                         
    }                                                             
    return 0;                 
}

void readReg(uint8_t slaveid, uint16_t address, uint8_t amount) {
    _delay_ms(2);
    rxbuffer[0]=slaveid;
    modbusSetAddress(slaveid);
    rxbuffer[1]=0x03;
    rxbuffer[2]=(address>>8)&0xFF;
    rxbuffer[3]=address&0xFF;
    rxbuffer[4]=0x00;
    rxbuffer[5]=amount;
    modbusSendMessage(5);
}

void writeReg(uint8_t slaveid, uint16_t address, uint16_t value) {
    _delay_ms(2);
    rxbuffer[0]=slaveid;
    modbusSetAddress(slaveid);
    rxbuffer[1]=0x06;
    rxbuffer[2]=(address>>8)&0xFF;
    rxbuffer[3]=address&0xFF;
    rxbuffer[4]=(value>>8)&0xFF;;
    rxbuffer[5]=value&0xFF;
    modbusSendMessage(5);
}

void readInputReg(uint8_t slaveid, uint16_t address, uint16_t amount) {
    _delay_ms(2);
    rxbuffer[0]=slaveid;
    modbusSetAddress(slaveid);
    rxbuffer[1]=0x04;
    rxbuffer[2]=(address>>8)&0xFF;
    rxbuffer[3]=address&0xFF;
    rxbuffer[4]=0;
    rxbuffer[5]=amount;
    modbusSendMessage(5);
}

void readInputState(uint8_t slaveid, uint16_t address, uint16_t amount) {
    _delay_ms(2);
    rxbuffer[0]=slaveid;
    modbusSetAddress(slaveid);
    rxbuffer[1]=0x02;
    rxbuffer[2]=(address>>8)&0xFF;
    rxbuffer[3]=address&0xFF;
    rxbuffer[4]=0;
    rxbuffer[5]=amount;
    modbusSendMessage(5);
}

void writeCoil(uint8_t slaveid, uint16_t address, uint16_t value) {
    _delay_ms(2);
    rxbuffer[0]=slaveid;
    modbusSetAddress(slaveid);
    rxbuffer[1]=0x05;
    rxbuffer[2]=(address>>8)&0xFF;
    rxbuffer[3]=address&0xFF;
    rxbuffer[4]=value?0xFF:0x00;
    rxbuffer[5]=0;
    modbusSendMessage(5);
}

ISR(TIMER2_COMPA_vect) { //this ISR is called 9765.625 times per second
	modbusTickTimer();
}