"""
This script is used to simplify the translation process.

Django provides a framework for working out which strings are "translatable",
and these strings are then dumped in a file under InvenTree/locale/<lang>/LC_MESSAGES/django.po

This script presents the translator with a list of strings which have not yet been translated,
allowing for a simpler and quicker translation process.

If a string translation needs to be updated, this will still need to be done manually,
by editing the appropriate .po file.

"""

import argparse
import os
import sys


def manually_translate_file(filename, save=False):
    """
    Manually translate a .po file.
    Present any missing translation strings to the translator,
    and write their responses back to the file.
    """

    print("Add manual translations to '{f}'".format(f=filename))
    print("For each missing translation:")
    print("a) Directly enter a new tranlation in the target language")
    print("b) Leave empty to skip")
    print("c) Press Ctrl+C to exit")

    print("-------------------------")
    input("Press <ENTER> to start")
    print("")

    with open(filename, 'r') as f:
        lines = f.readlines()

    out = []

    # Context data
    source_line = ''
    msgid = ''

    for num, line in enumerate(lines):
        # Keep track of context data BEFORE an empty msgstr object
        line = line.strip()

        if line.startswith("#: "):
            source_line = line.replace("#: ", "")

        elif line.startswith("msgid "):
            msgid = line.replace("msgid ", "")

        if line.strip() == 'msgstr ""':
            # We have found an empty translation!

            if msgid and len(msgid) > 0 and not msgid == '""':
                print("Source:", source_line)
                print("Enter translation for {t}".format(t=msgid))

                try:
                    translation = str(input(">"))
                except KeyboardInterrupt:
                    break

                if translation and len(translation) > 0:
                    # Update the line with the new translation
                    line = 'msgstr "{msg}"'.format(msg=translation)

        out.append(line + "\r\n")

    if save:
        with open(filename, 'w') as output_file:
            output_file.writelines(out)

        print("Translation done: written to", filename)
        print("Run 'invoke translate' to rebuild translation data")


if __name__ == '__main__':

    MY_DIR = os.path.dirname(os.path.realpath(__file__))
    LOCALE_DIR = os.path.join(MY_DIR, '..', 'locale')

    if not os.path.exists(LOCALE_DIR):
        print("Error: {d} does not exist!".format(d=LOCALE_DIR))
        sys.exit(1)

    parser = argparse.ArgumentParser(description="InvenTree Translation Helper")

    parser.add_argument('language', help='Language code', action='store')

    parser.add_argument('--fake', help="Do not save updated translations", action='store_true')

    args = parser.parse_args()

    language = args.language

    LANGUAGE_DIR = os.path.abspath(os.path.join(LOCALE_DIR, language))

    # Check that a locale directory exists for the given language!
    if not os.path.exists(LANGUAGE_DIR):
        print("Error: Locale directory for language '{l}' does not exist".format(l=language))
        sys.exit(1)

    # Check that a .po file exists for the given language!
    PO_FILE = os.path.join(LANGUAGE_DIR, 'LC_MESSAGES', 'django.po')

    if not os.path.exists(PO_FILE):
        print("Error: File '{f}' does not exist".format(f=PO_FILE))
        sys.exit(1)

    # Ok, now we run the user through the translation file
    manually_translate_file(PO_FILE, save=args.fake is not True)