#!/usr/bin/env python

# Copyright (C) 2006-2007 Richard Purdie
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License version 2 as published by the Free
# Software Foundation;
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

import optparse
import os, sys, stat

__version__ = "0.0.1"


def write_cache(cachefile, cachedata):
    fd = open(cachefile, 'w')
    for f in cachedata:
        s = f + '|' + str(cachedata[f]['ts']) + '|' + str(cachedata[f]['size'])
        fd.write(s + '\n')
    fd.close()

def read_cache(cachefile):
    cache = {}
    f = open(cachefile, 'r')
    lines = f.readlines()
    f.close()
    for l in lines:
        data = l.split('|')
        cache[data[0]] = {}
        cache[data[0]]['ts'] = int(data[1])
        cache[data[0]]['size'] = int(data[2])
        cache[data[0]]['seen'] = False
    return cache

def mkdirhier(dir):
    """Create a directory like 'mkdir -p', but does not complain if
    directory already exists like os.makedirs
    """
    try:
        os.makedirs(dir)
    except OSError, e:
        if e.errno != 17: raise e

if __name__ == "__main__":
    parser = optparse.OptionParser( version = "Metadata Stage Manager version %s" % ( __version__ ),
    usage = """%prog [options]\n\nPerforms mamagement tasks on a metadata staging area.""" )

    parser.add_option( "-p", "--parentdir", help = "the path to the metadata parent directory",
               action = "store", dest = "parentdir", default = None)

    parser.add_option( "-c", "--cachefile", help = "the cache file to use",
               action = "store", dest = "cachefile", default = None)

    parser.add_option( "-d", "--copydir", help = "copy changed files to this directory",
               action = "store", dest = "copydir", default = None)

    parser.add_option( "-u", "--update", help = "update the cache file",
               action = "store_true", dest = "update", default = False)

    (options, args) = parser.parse_args()

    if options.parentdir is None:
        print("Error, --parentdir option not supplied")
        sys.exit(1)

    if options.cachefile is None:
        print("Error, --cachefile option not supplied")
        sys.exit(1)

    if not options.parentdir.endswith('/'):
        options.parentdir = options.parentdir + '/'

    cache = {}
    if os.access(options.cachefile, os.F_OK):
	cache = read_cache(options.cachefile)

    found_difference = False

    def updateCache(path, fstamp):
        cache[path] = {}
        cache[path]['ts'] = fstamp[stat.ST_MTIME]
        cache[path]['size'] = fstamp[stat.ST_SIZE]
        cache[path]['seen'] = True
        found_difference = True

    def copyfile(path):
        if options.copydir:
            copypath = os.path.join(options.copydir, path.replace(options.parentdir, '', 1))
            mkdirhier(os.path.split(copypath)[0])
            os.system("cp -dp " + path + " " + copypath)

    def copydir(path, fstamp):
        if options.copydir:
            copypath = os.path.join(options.copydir, path.replace(options.parentdir, '', 1))
            if os.path.exists(copypath):
                os.system("rm -rf " + copypath)
            if os.path.islink(path):
                os.symlink(os.readlink(path), copypath)
            else:
                mkdirhier(copypath)
                os.utime(copypath, (fstamp[stat.ST_ATIME], fstamp[stat.ST_MTIME]))

    for root, dirs, files in os.walk(options.parentdir):
        for f in files:
            path = os.path.join(root, f)
            if not os.access(path, os.R_OK):
                continue
            fstamp = os.lstat(path)
            if path not in cache:
                print "new file %s" % path
		updateCache(path, fstamp)
                copyfile(path)
            else:
                if cache[path]['ts'] != fstamp[stat.ST_MTIME] or cache[path]['size'] != fstamp[stat.ST_SIZE]:
                    print "file %s changed" % path
                    updateCache(path, fstamp)
                    copyfile(path)
		cache[path]['seen'] = True
        for d in dirs:
            path = os.path.join(root, d)
            fstamp = os.lstat(path)
            if path not in cache:
                print "new dir %s" % path
		updateCache(path, fstamp)
                copydir(path, fstamp)
            else:
                if cache[path]['ts'] != fstamp[stat.ST_MTIME]:
                    print "dir %s changed" % path
                    updateCache(path, fstamp)
                    copydir(path, fstamp)
		cache[path]['seen'] = True

    todel = []
    for path in cache:
        if not cache[path]['seen']:
            print "%s removed" % path
            found_difference = True
            todel.append(path)

    if options.update:
        print "Updating"
        for path in todel:
            del cache[path]
        mkdirhier(os.path.split(options.cachefile)[0])
        write_cache(options.cachefile, cache)

    if found_difference:
        sys.exit(5)
    sys.exit(0)