#!/usr/bin/env python
"""Verda Steleto's Shopping List: A Chron X Desiderata Generator

Compare two deck files, a target and a collection. Make a list of cards
the collection lacks to make the target, in deck file format.

To produce a deck file in Chron X deck editor, 'Export to File...' from
a context menu.

Usage: desiderata.py [wants file] [haves file]

@version: 1.0
@since: 2005-12-31
@author: Robin Lionheart
@license: http://creativecommons.org/licenses/by-sa/2.5/
"""

DEFAULT_WANTS_FILE = "all.txt"
DEFAULT_HAVES_FILE = "collection.txt"
	
import sys

def desiderata(wants_filename, haves_filename):
	"""Compare cards we want to cards we have. List cards we don't have.

	@param wants_filename: name of deck file we wish to make
	@param haves_filename: name of deck file of cards we have

	@return: string listing cards we lack, in deck file format
	"""

	cards_in_order = []
	amounts_to_get = {}
	
	# Read file listing cards we want,
	# remembering order of cards and how many we want of each
	try:
		wants_file = file(wants_filename)
	except (IOError, OSError):
		sys.exit("Could not open deck file %s\n" % (wants_filename))

	for line in wants_file:
		quantity, card_name = line.rstrip().split('\t',2)
		cards_in_order.append(card_name)
		amounts_to_get[card_name] = int(quantity)
	# Chron X deck files are a tab separated list of quantities and cards:
	#	[quantity]<TAB>[card name]<CR><LF>
	# ex. "4	Zapp"

	wants_file.close()

	# Read file of cards we have,
	# subtracting what we have from what we want
	try:
		haves_file = file(haves_filename)
	except (IOError, OSError):
		sys.exit("Could not open deck file %s\n" % (haves_filename))
	
	for line in haves_file:
		quantity, card_name = line.rstrip().split('\t',2)
		if card_name in amounts_to_get:
			amounts_to_get[card_name] -= int(quantity)

	haves_file.close()

	# Return list of cards we want but do not have,
	# in string formatted to write to a deck file.
	# List cards in same order as target file.
	return "\n".join(["%d\t%s" % (amounts_to_get[card_name], card_name)
			  for card_name in cards_in_order
			  if amounts_to_get[card_name] > 0])

# Execute if run as program, not imported as module
if __name__ == "__main__":
	print desiderata(len(sys.argv)>1 and sys.argv[1] or DEFAULT_WANTS_FILE,
			 len(sys.argv)>2 and sys.argv[2] or DEFAULT_HAVES_FILE)