#!/usr/local/bin/python

## pigcam is intended to film our guinea pigs using stop motion
## scripts have been taken from various blogs (listed below) and modified)
## The general process is:
##  - use an LDR to only record when it's light
##  - record timelapse images to a directory
##  - when it is dark (very dark to allow for cloud cover) convert the stillss to a video
##  - upload the video somewhere (youtube or flickr)

## still image generation from
## http://designspark.com/blog/time-lapse-photography-with-the-raspberry-pi-camera

## LDR code from 
## http://www.element14.com/community/community/raspberrypi_projects/blog/2013/08/22/light-sensor-with-1-gpio


import RPi.GPIO as GPIO, time, subprocess, os, sys

from datetime import datetime

##Set global Variables
dark = True ## stores if it is currently dark
wasDark = True ## stores if it was dark on previous check
lightLevel = 0 ## stores the light level
diskSpaceToReserve = 40 * 1024 * 1024 # Keep 40 mb free on disk
SAVEDIR='/var/pigcam/stills' ## Directory to store the stills


# Tell the GPIO library to use
# Broadcom GPIO references
GPIO.setmode(GPIO.BCM)

# Define function to measure charge time
def RCtime (PiPin):
  measurement = 0
#  return 30
  # Discharge capacitor
  GPIO.setup(PiPin, GPIO.OUT)
  GPIO.output(PiPin, GPIO.LOW)
  time.sleep(0.1)

  GPIO.setup(PiPin, GPIO.IN)
  # Count loops until voltage across
  # capacitor reads high on GPIO
  while (GPIO.input(PiPin) == GPIO.LOW):
    measurement += 1

  return measurement/1000

# Get available disk space
def getFreeSpace():
    st = os.statvfs(SAVEDIR)
    du = st.f_bavail * st.f_frsize
    return du

# Generate the video from the stills
def generateVideo():
  os.system('ls ' + SAVEDIR + '/*.jpg > ' + SAVEDIR + '/stills.txt')
  os.system('mencoder -nosound -ovc lavc -lavcopts vcodec=mpeg4:aspect=16/9:vbitrate=8000000 -vf scale=1920:1080 -o ' + SAVEDIR + '/pigcam.avi -mf type=jpeg:fps=24 mf://@' + SAVEDIR + '/stills.txt')
  print('Video Generated at /var/pigcam/stills/pigcam.avi')
  ## Remove th stills
  os.system("rm " + SAVEDIR + "/*.jpg")
  return

def uploadVideo():
  os.system('youtube-upload --email=<youtube account id> --password=<password> --title=\"Guinea Pigs Upload' + str(ROLL) + '\" --description="timelapse video of guinea pigs using raspberrypi" --category=Animals --keywords="Guinea Pigs" ' + SAVEDIR + '/pigcam.avi')
  os.system('rm ' + SAVEDIR + '/*.avi')

  return

## Open the config file for writing
ROLL=open('/var/pigcam/series', 'rb').read()
##handle empty file
if ROLL == '':
  ROLL = 0

##Set up a pin to act as a switch to end the code
GPIO.setup(18, GPIO.IN)
 
## Main program loop
while GPIO.input(18) == GPIO.LOW:
 lightLevel = RCtime(4) # MEasure timing using GPIO4
 print  'light level indicator = ' + str(lightLevel) 
 
 if lightLevel < 50:
    dark = False
 else:
    dark = True
  
 ## If it was dark and is now light then increase the series log and start recording
 if wasDark == True and dark == False:
   #increment ROLL and save
   print('It was dark and is now light\n')
   print('setting roll value to ' + str(ROLL) + '\n')
   ROLL = int(ROLL) + 1
   f = open('/var/pigcam/series','w')
   f.write(str(ROLL))
     
 
  ## If it is not dark record
 elif dark == False and wasDark == False:
   print('recording image\n')
   timenow = datetime.now()
   filename="%s/%s-%04d%03d%02d_%02d%02d-%02d.jpg" % (SAVEDIR,str(ROLL),timenow.year, timenow.month, timenow.day, timenow.hour,timenow.minute, timenow.second)
   

   ##  Only record if there is space
   if getFreeSpace() < diskSpaceToReserve:
     print('not enough free space')
     generateVideo()
     uploadVideo()
   else:
     subprocess.call("raspistill -o " +  filename, shell=True)

 elif dark == True and wasDark == False: ## It must have changed from light to dark
   ## generate a video
   ## generate files to include
   print('it was light and is now dark\nGenerating video') 
   generateVideo()
   #Upload the video to youtube
   uploadVideo()
   
 else:
  ##it's dark so do nothing
   print("it's still dark")

 wasDark = dark;
 time.sleep(4)