import i2c_lib
from time import *
# LCD Address
ADDRESS = 0x3f
# commands
LCD_CLEARDISPLAY = 0x01
LCD_RETURNHOME = 0x02
LCD_ENTRYMODESET = 0x04
LCD_DISPLAYCONTROL = 0x08
LCD_CURSORSHIFT = 0x10
LCD_FUNCTIONSET = 0x20
LCD_SETCGRAMADDR = 0x40
LCD_SETDDRAMADDR = 0x80
# flags for display entry mode
LCD_ENTRYRIGHT = 0x00
LCD_ENTRYLEFT = 0x02
LCD_ENTRYSHIFTINCREMENT = 0x01
LCD_ENTRYSHIFTDECREMENT = 0x00

# flags for display on/off control
LCD_DISPLAYON = 0x04
LCD_DISPLAYOFF = 0x00
LCD_CURSORON = 0x02
LCD_CURSOROFF = 0x00
LCD_BLINKON = 0x01
LCD_BLINKOFF = 0x00

# flags for display/cursor shift
LCD_DISPLAYMOVE = 0x08
LCD_CURSORMOVE = 0x00
LCD_MOVERIGHT = 0x04
LCD_MOVELEFT = 0x00
# flags for function set
LCD_8BITMODE = 0x10
LCD_4BITMODE = 0x00
LCD_2LINE = 0x08
LCD_1LINE = 0x00
LCD_5x10DOTS = 0x04
LCD_5x8DOTS = 0x00

# flags for backlight control
LCD_BACKLIGHT = 0x08
LCD_NOBACKLIGHT = 0x00

En = 0b00000100 # Enable bit
Rw = 0b00000010 # Read/Write bit
Rs = 0b00000001 # Register select bit

class lcd:
	#initializes objects and lcd
	def __init__(self):
		self.lcd_device = i2c_lib.i2c_device(ADDRESS)

		self.lcd_write(0x03)
		self.lcd_write(0x03)
		self.lcd_write(0x03)
		self.lcd_write(0x02)

		self.lcd_write(LCD_FUNCTIONSET | LCD_2LINE | LCD_5x8DOTS | LCD_4BITMODE)
		self.lcd_write(LCD_DISPLAYCONTROL | LCD_DISPLAYON)
		self.lcd_write(LCD_CLEARDISPLAY)   
		self.lcd_write(LCD_ENTRYMODESET | LCD_ENTRYLEFT)
		sleep(0.2)   

       # clocks EN to latch command
	def lcd_strobe(self, data):
		self.lcd_device.write_cmd(data | En | LCD_BACKLIGHT)
		sleep(.0005)
		self.lcd_device.write_cmd(((data & ~En) | LCD_BACKLIGHT))
		sleep(.0001)   

	def lcd_write_four_bits(self, data):
		self.lcd_device.write_cmd(data | LCD_BACKLIGHT)
		self.lcd_strobe(data)

		# write a command to lcd
	def lcd_write(self, cmd, mode=0):
		self.lcd_write_four_bits(mode | (cmd & 0xF0))
		self.lcd_write_four_bits(mode | ((cmd << 4) & 0xF0))
		# put string function
	def lcd_display_string(self, string, line):
		if line == 1:
			self.lcd_write(0x80)
		if line == 2:
			self.lcd_write(0xC0)
		if line == 3:
			self.lcd_write(0x94)
		if line == 4:
			self.lcd_write(0xD4)

		for char in string:
			self.lcd_write(ord(char), Rs)

		# clear lcd and set to hom
	def lcd_clear(self):
		self.lcd_write(LCD_CLEARDISPLAY)
		self.lcd_write(LCD_RETURNHOME)
		
	# define backlight on/off (lcd.backlight(1); off= lcd.backlight(0)
	def backlight(self, state): # for state, 1 = on, 0 = off
		if state == 1:
			self.lcd_device.write_cmd(LCD_BACKLIGHT)
		elif state == 0:
			self.lcd_device.write_cmd(LCD_NOBACKLIGHT)