# -*- coding: utf-8 -*-
"""
A Translation module.

You can translate text using this module.
"""
import requests
import random

from googletrans import urls, utils
from googletrans.compat import PY3
from googletrans.gtoken import TokenAcquirer
from googletrans.constants import DEFAULT_USER_AGENT, LANGUAGES, SPECIAL_CASES
from googletrans.models import Translated, Detected


EXCLUDES = ('en', 'ca', 'fr')


class Translator(object):

    def __init__(self, service_urls=None, user_agent=DEFAULT_USER_AGENT):
        self.session = requests.Session()
        self.session.headers.update({
            'User-Agent': user_agent,
        })
        self.token_acquirer = TokenAcquirer(session=self.session)
        self.service_urls = service_urls or ['translate.google.com']

        # Use HTTP2 Adapter if hyper is installed
        try:  # pragma: nocover
            from hyper.contrib import HTTP20Adapter
            self.session.mount(urls.BASE, HTTP20Adapter())
        except ImportError:  # pragma: nocover
            pass

    def _pick_service_url(self):
        if len(self.service_urls) == 1:
            return self.service_urls[0]
        return random.choice(self.service_urls)

    def _translate(self, text, dest='en', src='auto'):
        if src != 'auto':
            if src not in LANGUAGES.keys() and src in SPECIAL_CASES.keys():
                src = SPECIAL_CASES[src]
            elif src not in LANGUAGES.keys():
                raise ValueError('invalid source language')

        if dest not in LANGUAGES.keys():
            if dest in SPECIAL_CASES.keys():
                dest = SPECIAL_CASES[dest]
            else:
                raise ValueError('invalid destination language')

        if not PY3 and isinstance(text, str):  # pragma: nocover
            text = text.decode('utf-8')

        token = self.token_acquirer.do(text)
        params = utils.build_params(query=text, src=src, dest=dest,
                                    token=token)
        url = urls.TRANSLATE.format(host=self._pick_service_url())
        r = self.session.get(url, params=params)

        data = utils.format_json(r.text)
        return data

    def translate(self, text, dest='en', src='auto'):
        """
        Translate the passed text into destination language.

        Basic usage:
            >>> from googletrans import Translator
            >>> translator = Translator()
            >>> translator.translate('안녕하세요.')
            <Translated src=ko dest=en text=Good evening. pronunciation=Good evening.>
            >>> translator.translate('안녕하세요.', dest='ja')
            <Translated src=ko dest=ja text=こんにちは。 pronunciation=Kon'nichiwa.>
            >>> translator.translate('veritas lux mea', src='la')
            <Translated src=la dest=en text=The truth is my light pronunciation=The truth is my light>

        Advanced usage:
            >>> translations = translator.translate(['The quick brown fox', 'jumps over', 'the lazy dog'], dest='ko')
            >>> for translation in translations:
            ...    print(translation.origin, ' -> ', translation.text)
            The quick brown fox  ->  빠른 갈색 여우
            jumps over  ->  이상 점프
            the lazy dog  ->  게으른 개

            :param text: the text you want to translate.
                you can pass this parameter as a list object, as shown in the advanced usage above.
            :param dest: the destination language you want to translate. (default: en)
            :param src: the source language you want to translate. (default: auto)

            :rtype: Translated
            :rtype: list (when list is passed)
        """
        if isinstance(text, list):
            result = []
            for item in text:
                translated = self.translate(item, dest=dest, src=src)
                result.append(translated)
            return result

        origin = text
        data = self._translate(text, dest, src)

        # this code will be updated when the format is changed.
        translated = data[0][0][0]

        # actual source language that will be recognized by Google Translator when the
        # src passed is equal to auto.
        try:
            src = data[-1][0][0]
        except Exception:  # pragma: nocover
            pass

        pron = origin
        try:
            pron = data[0][1][-1]
        except Exception:  # pragma: nocover
            pass
        if not PY3 and isinstance(pron, unicode) and isinstance(origin, str):  # pragma: nocover
            origin = origin.decode('utf-8')
        if dest in EXCLUDES and pron == origin:
            pron = translated

        # for python 2.x compatbillity
        if not PY3:  # pragma: nocover
            if isinstance(src, str):
                src = src.decode('utf-8')
            if isinstance(dest, str):
                dest = dest.decode('utf-8')
            if isinstance(translated, str):
                translated = translated.decode('utf-8')

        # put final values into a new Translated object
        result = Translated(src=src, dest=dest, origin=origin,
                            text=translated, pronunciation=pron)

        return result

    def detect(self, text):
        """
        Detect the language of a text.

        Basic usage:
            >>> from googletrans import Translator
            >>> translator = Translator()
            >>> translator.detect('이 문장은 한글로 쓰여졌습니다.')
            <Detected lang=ko confidence=0.27041003>
            >>> translator.detect('この文章は日本語で書かれました。')
            <Detected lang=ja confidence=0.64889508>
            >>> translator.detect('This sentence is written in English.')
            <Detected lang=en confidence=0.22348526>
            >>> translator.detect('Tiu frazo estas skribita en Esperanto.')
            <Detected lang=eo confidence=0.10538048>

        Advanced usage:
            >>> langs = translator.detect(['한국어', '日本語', 'English', 'le français'])
            >>> for lang in langs:
            ...    print(lang.lang, lang.confidence)
            ko 1
            ja 0.92929292
            en 0.96954316
            fr 0.043500196

            :param text: the text you want to detect.

            :rtype: Detected
            :rtype: list (when list is passed)
        """
        if isinstance(text, list):
            result = []
            for item in text:
                lang = self.detect(item)
                result.append(lang)
            return result

        data = self._translate(text, dest='en', src='auto')

        # actual source language that will be recognized by Google Translator when the
        # src passed is equal to auto.
        src = ''
        confidence = 0.0
        try:
            src = ''.join(data[8][0])
            confidence = data[8][-2][0]
        except Exception:  # pragma: nocover
            pass
        result = Detected(lang=src, confidence=confidence)

        return result