#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>


#include "lm75.h"

extern int file;
extern void bus_err(int ern);
extern void print_help(void);
unsigned char buf[5];
  

void lm75_print_all(void)
{
    printf(
        "00: Temperature data  [°C]     (reg: 0x00)\n"
        "01: Configuration     [hex]    (reg: 0x01)\n"
        "02: Tos (Overtemp)    [°C]     (reg: 0x03)\n"
        "03: Thys (Hysteresis) [°C]     (reg: 0x04)\n"
        "\n");
} 

 

void lm75_get_data(void){

	if(write(file, buf, 1) != 1){
        bus_err(errno);
    }

    if(read(file, buf, 2) != 2) {
        bus_err(errno);
    } 
}

void lm75_conf_set(const char *opts){
    // printf("");
}


float lm75_read_temp(float offset)
{
    signed int rawtemp = 0;
    float temp;

    buf[0] = 0x00;
    
    lm75_get_data();
     
    rawtemp = (buf[0]*256 + buf[1]) >> 5;  //(buf[0] << 8), and (>> 5), 11bit device is also supported

	if((rawtemp & 0x400) == 0x400)         //check if the msb(bit11) is 1 (1024 = 0x400),  2'complement negative number
	{
	    rawtemp = rawtemp - 2048;          //2^11 = 2048 
	}

	temp = rawtemp * 0.125 ;               //11bit->0.125°C  or  9bit->0.5°C	
    return (temp + offset);    
}



float lm75_read_tos(void)          
{                                           
    int rawtemp = 0;                        
                                            
    buf[0] = 0x02;                          
                                            
    lm75_get_data();                                                         
                                                           
    rawtemp = buf[0]*256 + buf[1];                           
    rawtemp = (rawtemp) >> 7;           //9bit data
    
    if((rawtemp & 256) == 256)          // check if the msb  2'complement negative number
    {
        rawtemp = rawtemp - 512 ;       // 2^9 = 512;
    }
    
    return (rawtemp * 0.5);             //9bit -> 0.5 celsius                                                                                                                 
}                       



float lm75_read_thys(void)          
{                                           
    int rawtemp = 0;                        
                                            
    buf[0] = 0x03;                          
                                            
    lm75_get_data();                                                      
                                                           
    rawtemp = buf[0]*256 + buf[1];                           
    rawtemp = (rawtemp) >> 7;           //9bit data
    
    if((rawtemp & 256) == 256)          // check if the msb  2'complement negative number
    {
        rawtemp = rawtemp - 512 ;       // 2^9 = 512;
    }
    
    return (rawtemp * 0.5);             //9bit -> 0.5 celsius                                                                                                                 
}                       
     

char lm75_read_conf(void)                                                                                                         
{
    
    buf[0] = 0x01;                                                                                                                 
    
    lm75_get_data();
    
    return buf[0];                                                                                                                                   
}



void lm75_read_all(const char *opts)
{
    // if(opts != NULL)
    // {
    //     printf("00:%f\n", lm75_read_temp(strtof(opts, NULL)));
    // }
    // else
    // {
        printf("00:%f\n", lm75_read_temp(0.0));
    // }     

    printf("01:0x%x\n", lm75_read_conf()); 
    printf("02:%f\n", lm75_read_tos()); 
    printf("03:%f\n", lm75_read_thys()); 
}



void lm75_read_one(const char *opts)
{
    int id,i;
    //char *ptr;
    char temp[256];

    if(opts != NULL){
        for(i = 0; i < strlen(opts); i++){
            if (*(opts+i) == ','){
                break;
            }
            temp[i] = *(opts+i);
            temp[i+1] = '\0';
        }

        id = atoi(temp);
        strncpy(temp, opts+i+1, 255);
        // id = strtol (opts,&ptr,0); //all format allowed
        // ptr++;      //one separator allowed

        switch (id)
        {
            case 0x00:
                printf("00:%f\n", lm75_read_temp(atof(temp)));
                break;
            case 0x01:
                printf("01:0x%x\n", lm75_read_conf());
                break;
            case 0x02:
                printf("02:%f\n", lm75_read_tos());
                break;
            case 0x03:
                printf("03:%f\n", lm75_read_thys()); 
                break;
            default:
                print_help();
        } 
    }
}