import os, os.path
import glob
import sys
import getopt
import shutil

#this is the pulldown pattern for 48 fps
#0 is unique frame, 1 is dupe
VARICAM_PATTERN= "0000100001000010001"

def get_file_prefix(compare_1, compare_2):
	"""takes two filenames, and returns the bit at the beginning that's the same"""
	i=0
	prefix = ""
	for i in range(0, len(compare_1)):
		if compare_1[i] != compare_2[i]:
			break
		i+=1
	return compare_1[0:i]

def find_offset(files, VARICAM_PATTERN):
	skip_seq = []
	skip = 0

	old_size = 0
	for f in files:
		new_size = os.stat(f)[6]
	 	if new_size == old_size:
			skip_seq.append("1")
			skip = 0
		else:
			skip_seq.append("0")
			skip += 1
		old_size = new_size
	
		if len(skip_seq) >= len(VARICAM_PATTERN) * 2:
			skip_str = "".join(skip_seq)
			seek_offset = skip_str.find(VARICAM_PATTERN)
			if seek_offset > -1:
				seek_offset = seek_offset % len(VARICAM_PATTERN)
				print "found offset", seek_offset
				#print VARICAM_PATTERN[-seek_offset:] + VARICAM_PATTERN*10
				#print skip_str
				return seek_offset

def usage():
	print "Takes a folder with an image sequence at 60p and extracts a 24p image sequence into output folder"
	print """Need some options:
-i	--input			Directory containing files
-o	--output		Directory where you want to put the new files"""


try:
	opts, args = getopt.getopt(sys.argv[1:], "i:o:", ["input", "output"])
except:
	usage()
	sys.exit(1)
	
if len(opts) < 2:
	usage()
	sys.exit(2)
	
input_dir = None
output_dir = None
	
for o, a in opts:
	if o in ('-i', '--input'):
		input_dir = a
	elif o in ('-o', '--output'):
		output_dir = a
		
if not os.path.isdir(input_dir):
	usage()
	sys.exit(3)

if not os.path.isdir(output_dir):
	try:
		os.mkdir(output_dir)
	except:
		print "Couldn't create output folder"
		usage()
		sys.exit(4)
	
files = glob.glob(os.path.join(input_dir, '*.tif'))
files.sort()

prefix = get_file_prefix(files[0], files[-1])

seek_offset = find_offset(files, VARICAM_PATTERN)
pattern_offset = 0 - seek_offset

if seek_offset == -1:
	print "error getting seek offset"
	sys.exit(1)

old_size = 0
skip_seq = []
skip = 0
new_idx = 0
alternate = 0
for f in files:
	new_size = os.stat(f)[6]
 	if new_size == old_size:
		if VARICAM_PATTERN[pattern_offset] != "1":
			print "Unexpected dupe frame,", f
		skip_seq.append(skip)
		#print skip, expected_skip_seq[pattern_offset] - 1
		skip = 0
	else:
		if VARICAM_PATTERN[pattern_offset] == "1":
			print "Expected a dupe frame,", f
		skip += 1
		#print skip, expected_skip_seq[pattern_offset]
	old_size = new_size

	
	#print expected, pattern_offset
	if VARICAM_PATTERN[pattern_offset] == '1':
		#print "I would skip this (%i %i)" % (new_size, old_size)
		#print "offset"
		pass
	else:
		if alternate == 1:
			alternate = 0
		else:
			alternate = 1
			#TODO:  Actually copy a file, rename it, whatever
			new_filename = "%s_%06d.tif" % (prefix, new_idx)
			new_filename = os.path.join(output_dir, new_filename)
			try:
				os.stat(new_filename)
				print "Error, file already exists!  won't overwrite"
				sys.exit(4)
			except:
				pass
			new_idx += 1
			
			#print "cp %s %s" % (f, new_filename)
			shutil.copyfile(f, new_filename)
		
	pattern_offset += 1
	if pattern_offset >= len(VARICAM_PATTERN):
		pattern_offset = 0