"""
https://github.com/pytorch/data/blob/main/examples/text/CC100.ipynb

Sample from multi-gigabyte-size compressed dataset without downloading the whole thing
This executes very fast
"""

import time
import os

from functools import partial
from operator import itemgetter
from torchdata.datapipes.iter import (
    FileOpener,
    HttpReader,
)

ROOT_DIR = os.path.expanduser('~/.torchdata/CC100')  # This directory needs to be crated and set


def _path_fn(root, x):
    return os.path.join(root, os.path.basename(x).rstrip(".xz"))


def _process_tuple(language_code, t):
    return language_code, t[1].decode()


# CC100 support (http://data.statmt.org/cc-100/)

URL = "http://data.statmt.org/cc-100/%s.txt.xz"
VALID_CODES = [
    "am", "ar", "as", "az", "be", "bg", "bn", "bn_rom", "br", "bs", "ca", "cs", "cy", "da", "de",
    "el", "en", "eo", "es", "et", "eu", "fa", "ff", "fi", "fr", "fy", "ga", "gd", "gl", "gn", "gu",
    "ha", "he", "hi", "hi_rom", "hr", "ht", "hu", "hy", "id", "ig", "is", "it", "ja", "jv", "ka",
    "kk", "km", "kn", "ko", "ku", "ky", "la", "lg", "li", "ln", "lo", "lt", "lv", "mg", "mk", "ml",
    "mn", "mr", "ms", "my", "my_zaw", "ne", "nl", "no", "ns", "om", "or", "pa", "pl", "ps", "pt",
    "qu", "rm", "ro", "ru", "sa", "si", "sc", "sd", "sk", "sl", "so", "sq", "sr", "ss", "su", "sv",
    "sw", "ta", "ta_rom", "te", "te_rom", "th", "tl", "tn", "tr", "ug", "uk", "ur", "ur_rom", "uz",
    "vi", "wo", "xh", "yi", "yo", "zh-Hans", "zh-Hant", "zu",
]


def CC100(root, language_code, use_caching=True):
    if language_code not in VALID_CODES:
        raise ValueError(f"Invalid language code {language_code}")
    url = URL % language_code
    if use_caching:
        cache_compressed_dp = HttpReader([url]).map(itemgetter(0))
        cache_compressed_dp = cache_compressed_dp.end_caching(mode="wb", same_filepath_fn=True)
        cache_decompressed_dp = cache_compressed_dp.on_disk_cache(filepath_fn=partial(_path_fn, root))
        cache_decompressed_dp = FileOpener(cache_decompressed_dp).read_from_xz()
        cache_decompressed_dp = cache_decompressed_dp.end_caching(mode="wb")
        data_dp = FileOpener(cache_decompressed_dp)
    else:
        data_dp = HttpReader([url]).load_from_xz()
    units_dp = data_dp.readlines().map(partial(_process_tuple, language_code))
    return units_dp


def download_head_10000():
    for lang in VALID_CODES:
        start_time = time.time()
        f_out = open(f"{lang}.txt", "w", encoding="utf-8")
        for i, x in enumerate(CC100(ROOT_DIR, lang, use_caching=False)):
            if i >= 10000:
                break
            f_out.write(x[1] + "\n")
        print(f"Execution time - {lang} - {(time.time() - start_time):.2f} secs")
        f_out.close()


if __name__ == "__main__":
    download_head_10000()