import time
import RPi.GPIO as GPIO
import urllib2
import simplejson

# Zuordnung der GPIO Pins (ggf. anpassen)
LCD_RS = 4
LCD_E  = 17
LCD_DATA4 = 18
LCD_DATA5 = 22
LCD_DATA6 = 23
LCD_DATA7 = 24

LCD_WIDTH = 16 		# Zeichen je Zeile
LCD_LINE_1 = 0x80 	# Adresse der ersten Display Zeile
LCD_LINE_2 = 0xC0 	# Adresse der zweiten Display Zeile
LCD_CHR = GPIO.HIGH
LCD_CMD = GPIO.LOW
E_PULSE = 0.0005
E_DELAY = 0.0005


# URL, ggf. Parameter anpassen
# Link zu den Parameter Beschreibungen:
# https://developers.google.com/news-search/v1/jsondevguide#json_urlbase

URL = ('https://ajax.googleapis.com/ajax/services/search/news?' +
       'v=1.0&q=%20&topic=h&hl=de')

# Alle wie viele Minuten auf neue Nachrichten gecheckt werden soll
REFRESH_TIME = 5	# (Minuten)



# HDD44780 Funktionen
def lcd_send_byte(bits, mode):
	# Pins auf LOW setzen
	GPIO.output(LCD_RS, mode)
	GPIO.output(LCD_DATA4, GPIO.LOW)
	GPIO.output(LCD_DATA5, GPIO.LOW)
	GPIO.output(LCD_DATA6, GPIO.LOW)
	GPIO.output(LCD_DATA7, GPIO.LOW)
	if bits & 0x10 == 0x10:
	  GPIO.output(LCD_DATA4, GPIO.HIGH)
	if bits & 0x20 == 0x20:
	  GPIO.output(LCD_DATA5, GPIO.HIGH)
	if bits & 0x40 == 0x40:
	  GPIO.output(LCD_DATA6, GPIO.HIGH)
	if bits & 0x80 == 0x80:
	  GPIO.output(LCD_DATA7, GPIO.HIGH)
	time.sleep(E_DELAY)    
	GPIO.output(LCD_E, GPIO.HIGH)  
	time.sleep(E_PULSE)
	GPIO.output(LCD_E, GPIO.LOW)  
	time.sleep(E_DELAY)      
	GPIO.output(LCD_DATA4, GPIO.LOW)
	GPIO.output(LCD_DATA5, GPIO.LOW)
	GPIO.output(LCD_DATA6, GPIO.LOW)
	GPIO.output(LCD_DATA7, GPIO.LOW)
	if bits&0x01==0x01:
	  GPIO.output(LCD_DATA4, GPIO.HIGH)
	if bits&0x02==0x02:
	  GPIO.output(LCD_DATA5, GPIO.HIGH)
	if bits&0x04==0x04:
	  GPIO.output(LCD_DATA6, GPIO.HIGH)
	if bits&0x08==0x08:
	  GPIO.output(LCD_DATA7, GPIO.HIGH)
	time.sleep(E_DELAY)    
	GPIO.output(LCD_E, GPIO.HIGH)  
	time.sleep(E_PULSE)
	GPIO.output(LCD_E, GPIO.LOW)  
	time.sleep(E_DELAY)  

def display_init():
	lcd_send_byte(0x33, LCD_CMD)
	lcd_send_byte(0x32, LCD_CMD)
	lcd_send_byte(0x28, LCD_CMD)
	lcd_send_byte(0x0C, LCD_CMD)  
	lcd_send_byte(0x06, LCD_CMD)
	lcd_send_byte(0x01, LCD_CMD)  

def lcd_message(message):
	message = message.ljust(LCD_WIDTH," ")  
	for i in range(LCD_WIDTH):
	  lcd_send_byte(ord(message[i]),LCD_CHR)

# Funktionen
def loadURL():
	request = urllib2.Request(URL, None, {})
	response = urllib2.urlopen(request)
	return simplejson.load(response)

# Um die 
def formatString(string):
	new = u''
	for i in range(len(string)):
		if ord(string[i]) > 127:
			new = new + unichr(ord(string[i]) - 7)
		else:
			new = new + string[i]
	return new

def printTopics(results):
	for obj in results["responseData"]["results"]:
		topic = formatString(obj['titleNoFormatting']+" ")
		while len(topic) > 0:
			idx1 = len(topic) if len(topic) <= LCD_WIDTH  else (LCD_WIDTH if topic[LCD_WIDTH-1] == " " or topic[LCD_WIDTH] == " " or topic[:LCD_WIDTH].rfind(" ") == -1 else topic[:LCD_WIDTH].rfind(" "))
			idx2 = LCD_WIDTH if idx1 == len(topic) or idx1-LCD_WIDTH < 0 or topic[min(idx1+1, LCD_WIDTH):][LCD_WIDTH-1] == " " or topic[min(idx1+1, LCD_WIDTH):][LCD_WIDTH] == " " or topic[min(idx1+1, LCD_WIDTH):][:LCD_WIDTH].rfind(" ") == -1 else topic[min(idx1+1, LCD_WIDTH):][:LCD_WIDTH].rfind(" ")
			topic1 = topic[:idx1].lstrip()
			topic2 = topic[min(idx1+1, LCD_WIDTH):][:idx2].lstrip()
			
			lcd_send_byte(LCD_LINE_1, LCD_CMD)
			lcd_message(topic1)
			lcd_send_byte(LCD_LINE_2, LCD_CMD)
			lcd_message(topic2)
			print topic1
			print topic2
			time.sleep(1.5)
			topic = topic[min(idx1+1, LCD_WIDTH):][idx2:].lstrip()
		
		lcd_send_byte(LCD_LINE_1, LCD_CMD)
		lcd_message("")
		lcd_send_byte(LCD_LINE_2, LCD_CMD)
		lcd_message("")
		time.sleep(3)
	
if __name__ == '__main__':
	
	# initialisieren
	GPIO.setmode(GPIO.BCM)
	GPIO.setwarnings(False)
	GPIO.setup(LCD_E, GPIO.OUT)
	GPIO.setup(LCD_RS, GPIO.OUT)
	GPIO.setup(LCD_DATA4, GPIO.OUT)
	GPIO.setup(LCD_DATA5, GPIO.OUT)
	GPIO.setup(LCD_DATA6, GPIO.OUT)
	GPIO.setup(LCD_DATA7, GPIO.OUT)

	display_init()
	
	try:
		results = loadURL()
		counter = time.time()
		while True:
			if counter + REFRESH_TIME*60 <= time.time():
				results = loadURL()
			printTopics(results)
	
	except KeyboardInterrupt:
		print "Abbruch"
	except:
		print "Hoppla. Es ist etwas schief gelaufen"
	finally:
		GPIO.cleanup()