#!/usr/bin/env python
import os
import sys

def cheat_directories():
    default = [ default_dir for default_dir in [os.path.expanduser('~/.cheat')] if os.path.isdir(default_dir) ]
    if 'CHEATPATH' in os.environ and os.environ['CHEATPATH']:
        return [ path for path in os.environ['CHEATPATH'].split(os.pathsep) if os.path.isdir(path) ] + default
    else:
        return default

def cheat_files(cheat_directories):
    cheats = {}
    for cheat_dir in reversed(cheat_directories):
        cheats.update(dict([ (cheat, cheat_dir) for cheat in os.listdir(cheat_dir) ]))
    return cheats

# assemble a keyphrase out of all params passed to the script
keyphrase = ' '.join(sys.argv[1:])
cheat_dirs = cheat_directories()

# verify that we have at least one cheat directory
if not cheat_dirs:
  print >> sys.stderr, 'The ~/.cheat directory does not exist or the CHEATPATH variable is not set.'
  exit()

# list the files in the ~/.cheat directory
cheatsheets = cheat_files(cheat_dirs)

# print help if requested
if keyphrase.lower() in ['', 'help', '--help', '-h']:
  print "Usage: cheat [keyphrase]\n"
  print "Available keyphrases:"
  max_command = max([ len(x) for x in cheatsheets.keys() ]) + 3
  print '\n'.join(sorted([ '%s [%s]' % (key.ljust(max_command), value) for key, value in cheatsheets.items() ]))
  exit()

# print the cheatsheet if it exists
if keyphrase in cheatsheets:
  with open (os.path.join(cheatsheets[keyphrase], keyphrase), 'r') as cheatsheet:
    print cheatsheet.read()

# if it does not, say so
else:
  print 'No cheatsheet found for %s.' % keyphrase