#!/usr/bin/env python
''' Directory Monitoring Daemon class.
    Recognizes the following events:
        creation
        change [edit]
        move
        removal.
'''
import os, sys, re, time, glob, fnmatch

getmtime = os.path.getmtime
getsize = os.path.getsize

try:
    all
except:
    def all(s):
        for x in s:
            if not x:
                return False
        return True

try:
    set
except:
    print >> sys.stderr, "Please update your version of python to 2.4 or later."
    sys.exit(1)

class Monitor:
    ''' subclass this, and override removed, created, moved, and changed to do whatever you want.
        or, you can dynamically assign those methods to your functions.
        
        self.directories is a list of str's, and is passed either as the first argument to __init__, or as *args.
        self.mtimes maps filenames to mtimes [modification times].
    '''
    def __init__(self, *directories):
        if directories and (len(directories) == 1) and isinstance(directories[0], (tuple, list)):
            self.directories = list(directories[0])
        else:
            self.directories = list(directories)
        self.mtimes = {}
        self.sizes = {}
    
    def removed(self, filename):
        print 'removed:', filename
    
    def created(self, filename):
        print 'created:', filename
    
    def moved(self, old_filename, new_filename):
        print 'moved:', old_filename, new_filename
    
    def changed(self, filename):
        print 'changed:', filename
    
    def stop(self):
        self.running = False
    
    def __call__(self):
        self.running = True
        for directory in self.directories:
            for dirpath, dirnames, filenames in os.walk(directory):
                for filename in filenames:
                    filename = os.path.join(dirpath, filename)
                    self.mtimes[filename] = getmtime(filename)
                    self.sizes[filename] = getsize(filename)
        while self.running:
            previous_mtimes = dict(self.mtimes)
            previous_sizes = dict(self.sizes)
            changed = {}
            created = {}
            checked = {}
            for directory in self.directories:
                for dirpath, dirnames, filenames in os.walk(directory):
                    for filename in filenames:
                        filename = os.path.join(dirpath, filename)
                        new_mtime = getmtime(filename)
                        checked[filename] = new_mtime
                        if filename not in self.mtimes:
                            created[filename] = new_mtime
                            self.mtimes[filename] = new_mtime
                            self.sizes[filename] = getsize(filename)
                        elif new_mtime > self.mtimes[filename]:
                            self.changed(filename)
                            changed[filename] = self.mtimes[filename]
                            self.mtimes[filename] = new_mtime
                            self.sizes[filename] = getsize(filename)
            removed = set(previous_mtimes.items()) - set(checked.items()) - set(changed.items())
            if removed:
                if created:
                    created_reversed = dict([(mtime, fn) for fn, mtime in created.iteritems()])
                    for old_fn, old_mtime in removed:
                        if (old_mtime in created_reversed) and (self.sizes[created_reversed[old_mtime]] == previous_sizes[old_fn]):
                            self.moved(old_fn, created_reversed[old_mtime])
                            del created[created_reversed[old_mtime]]
                        else:
                            self.removed(old_fn)
                        del self.mtimes[old_fn]
                else:
                    for fn, mtime in removed:
                        self.removed(fn)
                        del self.mtimes[fn]
            for fn in created:
                self.created(fn)


def main(argv):
    '''
    '''
    Monitor(argv)()

if __name__ == '__main__':
    sys.exit(main(sys.argv[1:]))