from langdetect import detect
from google_trans_new import google_translator
import pandas as pd
import multiprocessing as mp

from database import Data_table
from database import insert_translated

def translate(text, target_lang='en'):
    try:
        input_lang = detect(text)
    except Exception as e:
        print(f'error when detecting language: {e}')
        return ''
    if input_lang == target_lang: return text
    translator = google_translator()
    try:
        text_trans = translator.translate(text, lang_src=input_lang, lang_tgt=target_lang)
    except Exception as e:
        print(f'error when translating text: {e}')
        return ''
    return text_trans

def get_untranslated():
    with Data_table() as dt:
        query = (
            f'SELECT * FROM {dt._name} '
            'WHERE content_en IS NULL '
            'ORDER BY random() '
            'LIMIT 1 '
        )
        df = pd.read_sql_query(query, dt.con)
    if len(df)==0: return None
    val_dict = {
        'id': df['id'][0],
        'content': df['content'][0]
    }
    return val_dict

def process_translate(val_dict):
    # translate
    try:
        content_en = translate(val_dict['content'])
    except Exception as e:
        content_en = ''
    val_dict['content_en'] = content_en
    # upload to database
    insert_translated(val_dict)

def yield_untranslated():
    val_dict = get_untranslated()
    while val_dict is not None:
        yield val_dict
        val_dict = get_untranslated()

# def continued_translation():
#     while True:
#         # get untranslated
#         val_dict = get_untranslated()
#         if val_dict is None: break
#         # translate
#         try:
#             content_en = translate(val_dict['content'])
#         except Exception as e:
#             content_en = ''
#         val_dict['content_en'] = content_en
#         # upload to database
#         insert_translated(val_dict)

def translate_all_fast():
    with mp.get_context('spawn').Pool(mp.cpu_count()-1) as p:
        list(p.map(process_translate, yield_untranslated()))

if __name__ == '__main__':
    translate_all_fast()