#!/usr/bin/env python
#
# This Python file contains utility scripts to manage Django translations.
# It has to be run inside the django git root directory.
#
# The following commands are available:
#
# * update_catalogs: check for new strings in core and contrib catalogs, and
#                    output how much strings are new/changed.
#
# * lang_stats: output statistics for each catalog/language combination
#
# * fetch: fetch translations from transifex.com
#
# Each command support the --languages and --resources options to limit their
# operation to the specified language or resource. For example, to get stats
# for Spanish in contrib.admin, run:
#
#  $ python scripts/manage_translations.py lang_stats --language=es --resources=admin

import os
from argparse import ArgumentParser
from subprocess import run

import django
from django.conf import settings
from django.core.management import call_command

HAVE_JS = ['admin']


def _get_locale_dirs(resources, include_core=True):
    """
    Return a tuple (contrib name, absolute path) for all locale directories,
    optionally including the django core catalog.
    If resources list is not None, filter directories matching resources content.
    """
    contrib_dir = os.path.join(os.getcwd(), 'django', 'contrib')
    dirs = []

    # Collect all locale directories
    for contrib_name in os.listdir(contrib_dir):
        path = os.path.join(contrib_dir, contrib_name, 'locale')
        if os.path.isdir(path):
            dirs.append((contrib_name, path))
            if contrib_name in HAVE_JS:
                dirs.append(("%s-js" % contrib_name, path))
    if include_core:
        dirs.insert(0, ('core', os.path.join(os.getcwd(), 'django', 'conf', 'locale')))

    # Filter by resources, if any
    if resources is not None:
        res_names = [d[0] for d in dirs]
        dirs = [ld for ld in dirs if ld[0] in resources]
        if len(resources) > len(dirs):
            print("You have specified some unknown resources. "
                  "Available resource names are: %s" % (', '.join(res_names),))
            exit(1)
    return dirs


def _tx_resource_for_name(name):
    """ Return the Transifex resource name """
    if name == 'core':
        return "django.core"
    else:
        return "django.contrib-%s" % name


def _check_diff(cat_name, base_path):
    """
    Output the approximate number of changed/added strings in the en catalog.
    """
    po_path = '%(path)s/en/LC_MESSAGES/django%(ext)s.po' % {
        'path': base_path, 'ext': 'js' if cat_name.endswith('-js') else ''}
    p = run("git diff -U0 %s | egrep '^[-+]msgid' | wc -l" % po_path,
            capture_output=True, shell=True)
    num_changes = int(p.stdout.strip())
    print("%d changed/added messages in '%s' catalog." % (num_changes, cat_name))


def update_catalogs(resources=None, languages=None):
    """
    Update the en/LC_MESSAGES/django.po (main and contrib) files with
    new/updated translatable strings.
    """
    settings.configure()
    django.setup()
    if resources is not None:
        print("`update_catalogs` will always process all resources.")
    contrib_dirs = _get_locale_dirs(None, include_core=False)

    os.chdir(os.path.join(os.getcwd(), 'django'))
    print("Updating en catalogs for Django and contrib apps...")
    call_command('makemessages', locale=['en'])
    print("Updating en JS catalogs for Django and contrib apps...")
    call_command('makemessages', locale=['en'], domain='djangojs')

    # Output changed stats
    _check_diff('core', os.path.join(os.getcwd(), 'conf', 'locale'))
    for name, dir_ in contrib_dirs:
        _check_diff(name, dir_)


def lang_stats(resources=None, languages=None):
    """
    Output language statistics of committed translation files for each
    Django catalog.
    If resources is provided, it should be a list of translation resource to
    limit the output (e.g. ['core', 'gis']).
    """
    locale_dirs = _get_locale_dirs(resources)

    for name, dir_ in locale_dirs:
        print("\nShowing translations stats for '%s':" % name)
        langs = sorted(d for d in os.listdir(dir_) if not d.startswith('_'))
        for lang in langs:
            if languages and lang not in languages:
                continue
            # TODO: merge first with the latest en catalog
            po_path = '{path}/{lang}/LC_MESSAGES/django{ext}.po'.format(
                path=dir_, lang=lang, ext='js' if name.endswith('-js') else ''
            )
            p = run(
                ['msgfmt', '-vc', '-o', '/dev/null', po_path],
                capture_output=True,
                env={'LANG': 'C'},
                encoding='utf-8',
            )
            if p.returncode == 0:
                # msgfmt output stats on stderr
                print('%s: %s' % (lang, p.stderr.strip()))
            else:
                print(
                    'Errors happened when checking %s translation for %s:\n%s'
                    % (lang, name, p.stderr)
                )


def fetch(resources=None, languages=None):
    """
    Fetch translations from Transifex, wrap long lines, generate mo files.
    """
    locale_dirs = _get_locale_dirs(resources)
    errors = []

    for name, dir_ in locale_dirs:
        # Transifex pull
        if languages is None:
            run(['tx', 'pull', '-r', _tx_resource_for_name(name), '-a', '-f', '--minimum-perc=5'])
            target_langs = sorted(d for d in os.listdir(dir_) if not d.startswith('_') and d != 'en')
        else:
            for lang in languages:
                run(['tx', 'pull', '-r', _tx_resource_for_name(name), '-f', '-l', lang])
            target_langs = languages

        # msgcat to wrap lines and msgfmt for compilation of .mo file
        for lang in target_langs:
            po_path = '%(path)s/%(lang)s/LC_MESSAGES/django%(ext)s.po' % {
                'path': dir_, 'lang': lang, 'ext': 'js' if name.endswith('-js') else ''}
            if not os.path.exists(po_path):
                print("No %(lang)s translation for resource %(name)s" % {
                    'lang': lang, 'name': name})
                continue
            run(['msgcat', '--no-location', '-o', po_path, po_path])
            msgfmt = run(['msgfmt', '-c', '-o', '%s.mo' % po_path[:-3], po_path])
            if msgfmt.returncode != 0:
                errors.append((name, lang))
    if errors:
        print("\nWARNING: Errors have occurred in following cases:")
        for resource, lang in errors:
            print("\tResource %s for language %s" % (resource, lang))
        exit(1)


if __name__ == "__main__":
    RUNABLE_SCRIPTS = ('update_catalogs', 'lang_stats', 'fetch')

    parser = ArgumentParser()
    parser.add_argument('cmd', nargs=1, choices=RUNABLE_SCRIPTS)
    parser.add_argument("-r", "--resources", action='append', help="limit operation to the specified resources")
    parser.add_argument("-l", "--languages", action='append', help="limit operation to the specified languages")
    options = parser.parse_args()

    eval(options.cmd[0])(options.resources, options.languages)