import dircache, os, re, shutil

dir1 = 'english/'
dir2 = 'icelandic/'
dest = 'merged/'

# Stole this class from here: http://stackoverflow.com/questions/1165352/fast-comparison-between-two-python-dictionary
class DictDiffer(object):
    """
    Calculate the difference between two dictionaries as:
    (1) items added
    (2) items removed
    (3) keys same in both but changed values
    (4) keys same in both and unchanged values
    """
    def __init__(self, current_dict, past_dict):
        self.current_dict, self.past_dict = current_dict, past_dict
        self.set_current, self.set_past = set(current_dict.keys()), set(past_dict.keys())
        self.intersect = self.set_current.intersection(self.set_past)
    def added(self):
        return self.set_current - self.intersect
    def removed(self):
        return self.set_past - self.intersect
    def changed(self):
        return set(o for o in self.intersect if self.past_dict[o] != self.current_dict[o])
    def unchanged(self):
        return set(o for o in self.intersect if self.past_dict[o] == self.current_dict[o])

# Gets lines from translation files and creates a dict
def getLines(file):
    fh = open(file, 'r')
    lines = {}
    for l in fh.readlines():
        if l[:1] != '$':
            continue

        try:
            v = re.match("\$_\['(.*)'\].* '(.*?)';", l).groups()
            lines[v[0]] = v[1]
        except:
            continue
    fh.close()
    return lines

# Merge the contents of the files and return. file2 items will prevail if items exist in both files.
def mergeFiles(file1, file2):
    lines1, lines2 = getLines(file1), getLines(file2)

    merged = dict(lines1.items() + lines2.items())

    dd = DictDiffer(lines1, lines2)
    # Remove lines that are no longer in the new translation
    for k in dd.removed():
        merged.pop(k)

    if len(dd.added()) > 0:
        print "New lines: %s" % dd.added()

    return merged

# Creates a new language file
def writeFile(filename, contents):
    lines = ["<?php\n"]

    for k in contents.keys():
        lines.append("$_['%s'] = '%s';\n" % (k, contents[k]))

    lines.append("?>\n")

    fh = open(filename, 'w')
    fh.writelines(lines)
    fh.close()

# Duplicate the directory tree
shutil.copytree(dir1, dest)
for f in dircache.listdir(dir1):
    if os.path.isdir(dir1+f):
        # Go through subdirectories
        for file in dircache.listdir(dir1 + f):
            filename = str(f) + '/' + str(file)
            print filename

            if not os.path.exists(dir2 + filename):
                # Need to copy dir1 file to dest
                shutil.copyfile(dir1 + filename, dest + filename)
            else:
                # Compare contents (translation strings)
                merged = mergeFiles(dir1 + filename, dir2 + filename)
                writeFile(dest+filename, merged)

    else:
        # Is a file, probably <language>.php in the root folder.
        merged = mergeFiles(dir1 + f, dir2 + dir2[:-1] + '.php')
        writeFile(dest+dir2[:-1] + '.php',merged)