#!/usr/bin/env python

import os, re, sys

msgstr_re = re.compile('msgstr\[\d+\] "')

def parse_translation(f):
    """Read a single translation entry from the file F and return a
    tuple with the comments, msgid, msgid_plural and msgstr.  The comments is
    returned as a list of lines which do not end in new-lines.  The msgid is
    string.  The msgid_plural is string or None.  The msgstr is a list of
    strings.  The msgid, msgid_plural and msgstr strings can contain embedded
    newlines"""
    line = f.readline()

    # Parse comments
    comments = []
    while 1:
        if line.strip() == '':
            return comments, None, None, None
        elif line[0] == '#':
            comments.append(line[:-1])
        else:
            break
        line = f.readline()

    # Parse msgid
    if line[:7] != 'msgid "' or line[-2] != '"':
        raise RuntimeError("parse error")
    msgid = line[6:-1]
    while 1:
        line = f.readline()
        if line[0] != '"':
            break
        msgid += '\n' + line[:-1]

    # Parse optional msgid_plural
    msgid_plural = None
    if line[:14] == 'msgid_plural "':
        if line[-2] != '"':
            raise RuntimeError("parse error")
        msgid_plural = line[13:-1]
        while 1:
            line = f.readline()
            if line[0] != '"':
                break
            msgid_plural += '\n' + line[:-1]

    # Parse msgstr
    msgstr = []
    if not msgid_plural:
        if line[:8] != 'msgstr "' or line[-2] != '"':
            raise RuntimeError("parse error")
        msgstr.append(line[7:-1])
        while 1:
            line = f.readline()
            if len(line) == 0 or line[0] != '"':
                break
            msgstr[0] += '\n' + line[:-1]
    else:
        if line[:7] != 'msgstr[' or line[-2] != '"':
            raise RuntimeError("parse error")
        i = 0
        while 1:
            matched_msgstr = msgstr_re.match(line)
            if matched_msgstr:
                matched_msgstr_len = len(matched_msgstr.group(0))
                msgstr.append(line[matched_msgstr_len-1:-1])
            else:
                break
            while 1:
                line = f.readline()
                if len(line) == 0 or line[0] != '"':
                    break
                msgstr[i] += '\n' + line[:-1]
            i += 1

    if line.strip() != '':
        raise RuntimeError("parse error")

    return comments, msgid, msgid_plural, msgstr

def split_comments(comments):
    """Split COMMENTS into flag comments and other comments.  Flag
    comments are those that begin with '#,', e.g. '#,fuzzy'."""
    flags = []
    other = []
    for c in comments:
        if len(c) > 1 and c[1] == ',':
            flags.append(c)
        else:
            other.append(c)
    return flags, other

def main(argv):
    if len(argv) != 2:
        argv0 = os.path.basename(argv[0])
        sys.exit('Usage: %s <lang.po>\n'
                 '\n'
                 'This script will replace the translations and flags in lang.po with\n'
                 'the translations and flags in the source po file read from standard\n'
                 'input.  Strings that are not found in the source file are left untouched.\n'
                 'A backup copy of lang.po is saved as lang.po.bak.\n'
                 '\n'
                 'Example:\n'
                 '    svn cat http://svn.apache.org/repos/asf/subversion/trunk/subversion/po/sv.po | \\\n'
                 '        %s sv.po' % (argv0, argv0))

    # Read the source po file into a hash
    source = {}
    while 1:
        comments, msgid, msgid_plural, msgstr = parse_translation(sys.stdin)
        if not comments and msgid is None:
            break
        if msgid is not None:
            source[msgid] = msgstr, split_comments(comments)[0]

    # Make a backup of the output file, open the copy for reading
    # and the original for writing.
    os.rename(argv[1], argv[1] + '.bak')
    infile = open(argv[1] + '.bak')
    outfile = open(argv[1], 'w')

    # Loop thought the original and replace stuff as we go
    first = 1
    string_count = 0
    update_count = 0
    untranslated = 0
    while 1:
        comments, msgid, msgid_plural, msgstr = parse_translation(infile)
        if not comments and msgid is None:
            break
        if not first:
            outfile.write('\n')
        first = 0
        if msgid is None:
            outfile.write('\n'.join(comments) + '\n')
        else:
            string_count += 1
            # Do not update the header, and only update if the source
            # has a non-empty translation.
            if msgid != '""' and source.get(msgid, ['""', []])[0] != '""':
                other = split_comments(comments)[1]
                new_msgstr, new_flags = source[msgid]
                new_comments = other + new_flags
                if new_msgstr != msgstr or new_comments != comments:
                    update_count += 1
                    msgstr = new_msgstr
                    comments = new_comments
            outfile.write('\n'.join(comments) + '\n')
            outfile.write('msgid ' + msgid + '\n')
            if not msgid_plural:
                outfile.write('msgstr ' + msgstr[0] + '\n')
            else:
                outfile.write('msgid_plural ' + msgid_plural + '\n')
                n = 0
                for i in msgstr:
                    outfile.write('msgstr[%s] %s\n' % (n, msgstr[n]))
                    n += 1
        for m in msgstr:
            if m == '""':
                untranslated += 1

    # We're done.  Tell the user what we did.
    print(('%d strings updated. '
          '%d of %d strings are still untranslated (%.0f%%).' %
          (update_count, untranslated, string_count,
           100.0 * untranslated / string_count)))

if __name__ == '__main__':
    main(sys.argv)