#!/usr/bin/python
#--------------------------------------
#  RPM Zero.
#  A program meant to run in the background, and
#  reset the RPM display to 0 RPM if there haven't been
#  any changes in about 5 seconds.
#
#  Modified and extended for the MotoMast Control
#  By Courtney E. Krehbiel, October 2015
#
#--------------------------------------

# The wiring for the LCD is as follows:
# 1 : GND
# 2 : 5V
# 3 : Contrast (0-5V)*
# 4 : RS (Register Select)
# 5 : R/W (Read Write)       - GROUND THIS PIN
# 6 : Enable or Strobe
# 7 : Data Bit 0             - NOT USED
# 8 : Data Bit 1             - NOT USED
# 9 : Data Bit 2             - NOT USED
# 10: Data Bit 3             - NOT USED
# 11: Data Bit 4
# 12: Data Bit 5
# 13: Data Bit 6
# 14: Data Bit 7
# 15: LCD Backlight +5V**
# 16: LCD Backlight GND

#import
import RPi.GPIO as GPIO
import time
import json

# Define GPIO to LCD mapping
LCD_RS = 14
LCD_E  = 15
LCD_D4 = 17
LCD_D5 = 18
LCD_D6 = 27
LCD_D7 = 22


# Define some device constants
LCD_WIDTH = 16    # Maximum characters per line
LCD_CHR = True
LCD_CMD = False

LCD_LINE_1 = 0x80 # LCD RAM address for the 1st line
LCD_LINE_2 = 0xC0 # LCD RAM address for the 2nd line

# Timing constants
E_PULSE = 0.0005
E_DELAY = 0.0005

#CEK Global Variables for MotoMast
sRPM = "RPM: 0.00"
SavedHeight = 0
JustClearedRPM = 0
MovementDetected = 0
SmallSleep = 3
def setup():
	# Setup 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()
  

	with open('ids.json', "r") as fp:	# Get current position count from disk
		SavedHeight = json.load(fp)	
	fp.close()



def swcount(ev=None):	#This is the routine that runs and checks to see if there's activity in ids.json
	global SavedHeight
	global MovementDetected
	
	with open('ids.json', "r") as fp:	# Get current position count from disk
		HeightNow = json.load(fp)	
	fp.close()

	if HeightNow == SavedHeight:		# No movement has occurred.
		MovementDetected = 0
		time.sleep(SmallSleep)		# No sense checking every millisecond
		pass
	else: 
		MovementDetected = 1		# ids.json has changed, so movement is occurring.
		SavedHeight = HeightNow		# Setup to see if it keeps moving
		time.sleep(SmallSleep)		# wait 5 seconds 
		with open('ids.json', "r") as fp:	# Get current position count from disk
			HeightNow = json.load(fp)	
		fp.close()
		if HeightNow == SavedHeight:	# No movement for 5 seconds, so let's set RPM display to 0
			lcd_string(sRPM, LCD_LINE_2)
						# Let's also check to see if we should reset height at 10 feet to eliminate small click errors.
			if abs(HeightNow) <= 3:
				with open ('ids.json', 'w') as fp:	# If we are within 3 revs of bottom, reset height to 0 which is 10 foot dock height.
					json.dump(0, fp)
				fp.close()
				lcd_string("Height Ft: 10.00", LCD_LINE_1)	# Write this out to the display too
				HeightNow = 0
				SavedHeight = 0					# Update these guys too
		else:
			pass			# Must still be moving

	

# A few more lines from CEK to set the overall loop
	
def loop():
	while True:	
		swcount()

def destroy():
	lcd_byte(0x01, LCD_CMD)				#Clear display
	lcd_string("Goodbye!",LCD_LINE_1)

	GPIO.cleanup()			#Release resources



# End of CEK code
  
  
  
def lcd_init():
  # Initialise display
  lcd_byte(0x33,LCD_CMD) # 110011 Initialise
  lcd_byte(0x32,LCD_CMD) # 110010 Initialise
  lcd_byte(0x06,LCD_CMD) # 000110 Cursor move direction
  lcd_byte(0x0C,LCD_CMD) # 001100 Display On,Cursor Off, Blink Off
  lcd_byte(0x28,LCD_CMD) # 101000 Data length, number of lines, font size
  lcd_byte(0x01,LCD_CMD) # 000001 Clear display
  time.sleep(E_DELAY)

def lcd_byte(bits, mode):
  # Send byte to data pins
  # bits = data
  # mode = True  for character
  #        False for command

  GPIO.output(LCD_RS, mode) # RS

  # High bits
  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():
  # Toggle enable
  time.sleep(E_DELAY)
  GPIO.output(LCD_E, True)
  time.sleep(E_PULSE)
  GPIO.output(LCD_E, False)
  time.sleep(E_DELAY)

def lcd_string(message,line):
  # Send string to display
  message = message.ljust(LCD_WIDTH," ")
  lcd_byte(line, LCD_CMD)
  for i in range(LCD_WIDTH):
    lcd_byte(ord(message[i]),LCD_CHR)


if __name__ == '__main__':
	setup()
	try:
		loop()
	except KeyboardInterrupt:  #When 'Ctrl-C' is pressed, the child program destroy() will be executed.
		pass
	finally:
		destroy()