#!/usr/bin/env python

import sys
import os
import getopt


def printUsage():
	print '\nUsage:'
	print 'gpioutil SYSTEM_NAME -n GPIO_NAME  [-v value]'
	print 'gpioutil SYSTEM_NAME -i GPIO_NUM  -d <DIRECTION = in,out,falling,rising,both> [-v value]'
	print 'gpioutil SYSTEM_NAME -p PIN_NAME  -d <DIRECTION = in,out,falling,rising,both> [-v value]'
	print 'gpioutil SYSTEM_NAME -l PIN_NAME     (lookup pin name only)'
	exit(1)


if (len(sys.argv) < 3):
	printUsage()

sys.argv.pop(0)
libr = sys.argv.pop(0)
System = __import__(libr)

GPIO_SYSFS = '/sys/class/gpio/'

class Gpio:
	def __init__(self,gpio_num):
		self.gpio_num = str(gpio_num)
		self.direction = ''
		self.interrupt = ''
		self.exported = False

	def getPath(self,name):
		return GPIO_SYSFS+'gpio'+self.gpio_num+'/'+name
	
	def export(self):
		if (os.path.exists(GPIO_SYSFS+'export') == False):
			raise Exception("ERROR - GPIO_SYSFS path does not exist.  Does this platform support GPIOS?")
		if (os.path.exists(GPIO_SYSFS+'gpio'+self.gpio_num) == False):
			self.write(GPIO_SYSFS+'export',self.gpio_num)
			
		self.exported = True

	def setDirection(self,dir):
		if (self.exported == False):
			raise Exception("ERROR - Not exported: "+self.getPath())

		self.direction = ''
		self.interrupt = ''
		if (dir == 'in' or dir == 'out'):
			self.direction = dir
		elif (dir == 'rising' or 
		      dir == 'falling' or
		      dir == 'both'):
			self.direction = 'in'
			self.interrupt = dir
			self.write(self.getPath('edge'),self.interrupt)
		else:
			raise Exception("ERROR - Invalid Direction: "+dir)
		
			
		self.write(self.getPath('direction'),self.direction)
			
	def setValue(self,value):
		if (value == '0'):
			self.write(self.getPath('value'),'0')
		elif (value == '1'):
			self.write(self.getPath('value'),'1')
		else:
			raise Exception("ERROR - Invalid value: "+value)
	
	def getValue(self):
		return self.read(self.getPath('value'))	

	def write(self,path,data):
		f = open(path,'w')
		f.write(data)
		f.close()


	def read(self,path):
		f = open(path,'r')
		data = f.readline()
		f.close()
		return data


if __name__ == '__main__':

	try:
		opts, args = getopt.getopt(sys.argv,"hn:i:d:v:p:l:")
 	except getopt.GetoptError:
 		printUsage()


	lookup = False
	gpio_name = ""
	value = ""
	direction = ""
	for opt, arg in opts:
 		if opt == '-h':
			printUsage()

 		elif opt in ("-n"):
 			gpio_name = arg
			lookup = True
 		elif opt in ("-i"):
 			gpio_name = arg
 		elif opt in ("-d"):
			direction = arg
 		elif opt in ("-v"):
			value = arg
		elif opt in ("-p"):
			gpio_name = System.convertGpio(arg) 
		elif opt in ("-l"):
			gpio_name = System.convertGpio(arg)
			print gpio_name
			exit(0) 

	gpio_info = {}
	if (lookup == True):
		if (System.GPIO_CONFIG.has_key(gpio_name) == False):
			print "ERROR - GPIO Name doesn't exist"
			print "Valid names: "
			for n in System.GPIO_CONFIG:
				print "\t"+n
			exit(0)
		gpio_info = System.GPIO_CONFIG[gpio_name]
		direction = gpio_info['direction']
		if (gpio_info.has_key('gpio_num')):
			gpio_name = str(gpio_info['gpio_num'])
		else:
			gpio_name = str(System.convertGpio(gpio_info['gpio_pin']))
		print "GPIO ID: "+gpio_name+"; DIRECTION: "+direction


	## Rules
	if (gpio_name == ""):
		print "ERROR - Gpio not specified"
		printUsage()

	if (direction == "in" and value != ""):
		print "ERROR - Value cannot be specified when direction = in"
		printUsage()

	gpio = Gpio(gpio_name)
	try:
		gpio.export()
		if (direction != ""):
			gpio.setDirection(direction)

		if (value == ""):
			print gpio.getValue()
		else:
			gpio.setValue(value)

	except Exception as e:
		print e