#!/usr/bin/env python
import RPi.GPIO as GPIO
from time import sleep
import os
import glob
import time

os.system('modprobe w1-gpio')
os.system('modprobe w1-therm')
 
base_dir = '/sys/bus/w1/devices/'
device_folder = glob.glob(base_dir + '28*')[0]
device_file = device_folder + '/w1_slave'

def read_temp_raw():
    f = open(device_file, 'r')
    lines = f.readlines()
    f.close()
    return lines

def read_temp():
    lines = read_temp_raw()
    while lines[0].strip()[-3:] != 'YES':
        time.sleep(0.2)
        lines = read_temp_raw()
    equals_pos = lines[1].find('t=')
    if equals_pos != -1:
        temp_string = lines[1][equals_pos+2:]
        temp_c = float(temp_string) / 1000.0
        temp_f = temp_c * 9.0 / 5.0 + 32.0
        #return temp_c #for celsius
        return temp_f #for fahrenheit
        #return temp_c, temp_f #for both
    

# Define GPIO to LCD mapping
LCD_RS = 7
LCD_E  = 8
LCD_D4 = 25
LCD_D5 = 24
LCD_D6 = 23
LCD_D7 = 18
 
# Define some device constants
LCD_CHR = True # Character mode
LCD_CMD = False # Command mode
LCD_CHARS = 16 # Characters per line (16 max)
LCD_LINE_1 = 0x80 # LCD memory location for 1st line
LCD_LINE_2 = 0xC0 # LCD memory location 2nd line
 
def main():
  # Main program block
  GPIO.setwarnings(False)
  GPIO.setmode(GPIO.BCM)       # Use BCM GPIO numbers
  GPIO.setup(LCD_E, GPIO.OUT)  # E
  GPIO.setup(LCD_RS, GPIO.OUT) # RS
  GPIO.setup(LCD_D4, GPIO.OUT) # DB4
  GPIO.setup(LCD_D5, GPIO.OUT) # DB5
  GPIO.setup(LCD_D6, GPIO.OUT) # DB6
  GPIO.setup(LCD_D7, GPIO.OUT) # DB7
 
  # Initialise display
  lcd_init()
  print("running")
 
  while True:
 
    # Send some test
    t = round(read_temp())
    lcd_text(str(t) + " Degrees",LCD_LINE_1)
    lcd_text("Time: %s" %time.strftime("%H:%M"),LCD_LINE_2)
    sleep(30) # 30 second delay
      
def lcd_init():
    lcd_write(0x33,LCD_CMD) # Initialize
    lcd_write(0x32,LCD_CMD) # Set to 4-bit mode
    lcd_write(0x06,LCD_CMD) # Cursor move direction
    lcd_write(0x0C,LCD_CMD) # Turn cursor off
    lcd_write(0x28,LCD_CMD) # 2 line display
    lcd_write(0x01,LCD_CMD) # Clear display
    time.sleep(0.0005) # Delay to allow commands to process

 
#def lcd_display(bits, mode):
def lcd_write(bits, mode):
# High bits
 GPIO.output(LCD_RS, mode) # RS

 GPIO.output(LCD_D4, False)
 GPIO.output(LCD_D5, False)
 GPIO.output(LCD_D6, False)
 GPIO.output(LCD_D7, False)
 if bits&0x10==0x10:
     GPIO.output(LCD_D4, True)
 if bits&0x20==0x20:
     GPIO.output(LCD_D5, True)
 if bits&0x40==0x40:
     GPIO.output(LCD_D6, True)
 if bits&0x80==0x80:
     GPIO.output(LCD_D7, True)

# Toggle 'Enable' pin
 lcd_toggle_enable()

# Low bits
 GPIO.output(LCD_D4, False)
 GPIO.output(LCD_D5, False)
 GPIO.output(LCD_D6, False)
 GPIO.output(LCD_D7, False)
 if bits&0x01==0x01:
     GPIO.output(LCD_D4, True)
 if bits&0x02==0x02:
     GPIO.output(LCD_D5, True)
 if bits&0x04==0x04:
     GPIO.output(LCD_D6, True)
 if bits&0x08==0x08:
     GPIO.output(LCD_D7, True)

# Toggle 'Enable' pin
 lcd_toggle_enable()

 
def lcd_toggle_enable():
 time.sleep(0.0005)
 GPIO.output(LCD_E, True)
 time.sleep(0.0005)
 GPIO.output(LCD_E, False)
 time.sleep(0.0005)
 
#def lcd_string(message,line):
def lcd_text(message,line):
 # Send text to display
 message = message.ljust(LCD_CHARS," ")

 lcd_write(line, LCD_CMD)

 for i in range(LCD_CHARS):
     lcd_write(ord(message[i]),LCD_CHR)


#Begin program
try:
 main()
 
except KeyboardInterrupt:
 pass
 
finally:
 lcd_write(0x01, LCD_CMD)
 GPIO.cleanup()