#!/usr/bin/env python3

import os
import random
import sys
import time
import json.decoder
import urllib.parse

import googletrans
import pandocfilters
import requests

translator = googletrans.Translator()
target_language = os.environ.get('TARGET_LANGUAGE', 'ru')
is_debug = os.environ.get('DEBUG') is not None
is_yandex = os.environ.get('YANDEX') is not None


def debug(*args):
    if is_debug:
        print(*args, file=sys.stderr)


def translate(text):
    if target_language == 'en':
        return text
    else:
        if is_yandex:
            text = urllib.parse.quote(text)
            url = f'http://translate.yandex.net/api/v1/tr.json/translate?srv=docs&lang=en-{target_language}&text={text}'
            result = requests.get(url).json()
            debug(result)
            if result.get('code') == 200:
                return result['text'][0]
            else:
                print('Failed to translate', str(result), file=sys.stderr)
                sys.exit(1)
        else:
            time.sleep(random.random())
            return translator.translate(text, target_language).text


def process_buffer(buffer, new_value, item=None):
    if buffer:
        text = ''.join(buffer)

        try:
            translated_text = translate(text)
        except TypeError:
            translated_text = text
        except json.decoder.JSONDecodeError as e:
            print('Failed to translate', str(e), file=sys.stderr)
            sys.exit(1)

        debug('Translate', text, ' -> ', translated_text)

        if text and text[0].isupper() and not translated_text[0].isupper():
            translated_text = translated_text[0].upper() + translated_text[1:]

        if text.startswith(' ') and not translated_text.startswith(' '):
            translated_text = ' ' + translated_text
            
        if text.endswith(' ') and not translated_text.endswith(' '):
            translated_text = translated_text + ' '

        for token in translated_text.split(' '):
            new_value.append(pandocfilters.Str(token))
            new_value.append(pandocfilters.Space())

        if item is None and len(new_value):
            new_value.pop(len(new_value) - 1)
        else:
            new_value[-1] = item
    elif item:
        new_value.append(item)


def process_sentence(value):
    new_value = []
    buffer = []
    for item in value:
        t = item.get('t')
        c = item.get('c')
        if t == 'Str':
            buffer.append(c)
        elif t == 'Space':
            buffer.append(' ')
        elif t == 'DoubleQuote':
            buffer.append('"')
        else:
            process_buffer(buffer, new_value, item)
            buffer = []
    process_buffer(buffer, new_value)
    return new_value


def translate_filter(key, value, _format, _):
    debug(key, value)
    try:
        cls = getattr(pandocfilters, key)
    except AttributeError:
        return

    if key == 'Para' or key == 'Plain' or key == 'Strong' or key == 'Emph':
        return cls(process_sentence(value))
    elif key == 'Link':
        value[1] = process_sentence(value[1])
        return cls(*value)
    elif key == 'Header':
        value[2] = process_sentence(value[2])
        return cls(*value)

    return


if __name__ == "__main__":
    pandocfilters.toJSONFilter(translate_filter)