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"""NLLB translation provider implementation."""

import logging
from typing import Dict, List, Optional
from transformers import AutoTokenizer, AutoModelForSeq2SeqLM

from ..base.translation_provider_base import TranslationProviderBase
from ...domain.exceptions import TranslationFailedException

logger = logging.getLogger(__name__)


class NLLBTranslationProvider(TranslationProviderBase):
    """NLLB-200-3.3B translation provider implementation."""

    # NLLB language code mappings
    LANGUAGE_MAPPINGS = {
        'en': 'eng_Latn',
        'zh': 'zho_Hans',
        'zh-cn': 'zho_Hans',
        'zh-tw': 'zho_Hant',
        'es': 'spa_Latn',
        'fr': 'fra_Latn',
        'de': 'deu_Latn',
        'ja': 'jpn_Jpan',
        'ko': 'kor_Hang',
        'ar': 'arb_Arab',
        'hi': 'hin_Deva',
        'pt': 'por_Latn',
        'ru': 'rus_Cyrl',
        'it': 'ita_Latn',
        'nl': 'nld_Latn',
        'pl': 'pol_Latn',
        'tr': 'tur_Latn',
        'sv': 'swe_Latn',
        'da': 'dan_Latn',
        'no': 'nor_Latn',
        'fi': 'fin_Latn',
        'el': 'ell_Grek',
        'he': 'heb_Hebr',
        'th': 'tha_Thai',
        'vi': 'vie_Latn',
        'id': 'ind_Latn',
        'ms': 'zsm_Latn',
        'tl': 'tgl_Latn',
        'uk': 'ukr_Cyrl',
        'cs': 'ces_Latn',
        'sk': 'slk_Latn',
        'hu': 'hun_Latn',
        'ro': 'ron_Latn',
        'bg': 'bul_Cyrl',
        'hr': 'hrv_Latn',
        'sr': 'srp_Cyrl',
        'sl': 'slv_Latn',
        'et': 'est_Latn',
        'lv': 'lvs_Latn',
        'lt': 'lit_Latn',
        'mt': 'mlt_Latn',
        'ga': 'gle_Latn',
        'cy': 'cym_Latn',
        'is': 'isl_Latn',
        'mk': 'mkd_Cyrl',
        'sq': 'sqi_Latn',
        'eu': 'eus_Latn',
        'ca': 'cat_Latn',
        'gl': 'glg_Latn',
        'ast': 'ast_Latn',
        'oc': 'oci_Latn',
        'br': 'bre_Latn',
        'co': 'cos_Latn',
        'sc': 'srd_Latn',
        'rm': 'roh_Latn',
        'fur': 'fur_Latn',
        'lij': 'lij_Latn',
        'vec': 'vec_Latn',
        'pms': 'pms_Latn',
        'lmo': 'lmo_Latn',
        'nap': 'nap_Latn',
        'scn': 'scn_Latn',
        'wa': 'wln_Latn',
        'frp': 'frp_Latn',
        'gsw': 'gsw_Latn',
        'bar': 'bar_Latn',
        'ksh': 'ksh_Latn',
        'lb': 'ltz_Latn',
        'li': 'lim_Latn',
        'nds': 'nds_Latn',
        'pdc': 'pdc_Latn',
        'sli': 'sli_Latn',
        'vmf': 'vmf_Latn',
        'yi': 'yid_Hebr',
        'af': 'afr_Latn',
        'zu': 'zul_Latn',
        'xh': 'xho_Latn',
        'st': 'sot_Latn',
        'tn': 'tsn_Latn',
        'ss': 'ssw_Latn',
        'nr': 'nbl_Latn',
        've': 'ven_Latn',
        'ts': 'tso_Latn',
        'sw': 'swh_Latn',
        'rw': 'kin_Latn',
        'rn': 'run_Latn',
        'ny': 'nya_Latn',
        'sn': 'sna_Latn',
        'yo': 'yor_Latn',
        'ig': 'ibo_Latn',
        'ha': 'hau_Latn',
        'ff': 'fuv_Latn',
        'wo': 'wol_Latn',
        'bm': 'bam_Latn',
        'dyu': 'dyu_Latn',
        'ee': 'ewe_Latn',
        'tw': 'twi_Latn',
        'ak': 'aka_Latn',
        'gaa': 'gaa_Latn',
        'lg': 'lug_Latn',
        'luo': 'luo_Latn',
        'ki': 'kik_Latn',
        'kam': 'kam_Latn',
        'luy': 'luy_Latn',
        'mer': 'mer_Latn',
        'kln': 'kln_Latn',
        'kab': 'kab_Latn',
        'ber': 'ber_Latn',
        'am': 'amh_Ethi',
        'ti': 'tir_Ethi',
        'om': 'orm_Latn',
        'so': 'som_Latn',
        'mg': 'plt_Latn',
        'ny': 'nya_Latn',
        'bem': 'bem_Latn',
        'tum': 'tum_Latn',
        'loz': 'loz_Latn',
        'lua': 'lua_Latn',
        'umb': 'umb_Latn',
        'kmb': 'kmb_Latn',
        'kg': 'kon_Latn',
        'ln': 'lin_Latn',
        'sg': 'sag_Latn',
        'fon': 'fon_Latn',
        'mos': 'mos_Latn',
        'dga': 'dga_Latn',
        'kbp': 'kbp_Latn',
        'nus': 'nus_Latn',
        'din': 'din_Latn',
        'luo': 'luo_Latn',
        'ach': 'ach_Latn',
        'teo': 'teo_Latn',
        'mdt': 'mdt_Latn',
        'knc': 'knc_Latn',
        'fuv': 'fuv_Latn',
        'kr': 'kau_Latn',
        'dje': 'dje_Latn',
        'son': 'son_Latn',
        'tmh': 'tmh_Latn',
        'taq': 'taq_Latn',
        'ttq': 'ttq_Latn',
        'thv': 'thv_Latn',
        'taq': 'taq_Tfng',
        'shi': 'shi_Tfng',
        'tzm': 'tzm_Tfng',
        'rif': 'rif_Latn',
        'kab': 'kab_Latn',
        'shy': 'shy_Latn',
        'ber': 'ber_Latn',
        'acm': 'acm_Arab',
        'aeb': 'aeb_Arab',
        'ajp': 'ajp_Arab',
        'apc': 'apc_Arab',
        'ars': 'ars_Arab',
        'ary': 'ary_Arab',
        'arz': 'arz_Arab',
        'auz': 'auz_Arab',
        'avl': 'avl_Arab',
        'ayh': 'ayh_Arab',
        'ayn': 'ayn_Arab',
        'ayp': 'ayp_Arab',
        'bbz': 'bbz_Arab',
        'pga': 'pga_Arab',
        'shu': 'shu_Arab',
        'ssh': 'ssh_Arab',
        'fa': 'pes_Arab',
        'tg': 'tgk_Cyrl',
        'ps': 'pbt_Arab',
        'ur': 'urd_Arab',
        'sd': 'snd_Arab',
        'ks': 'kas_Arab',
        'dv': 'div_Thaa',
        'ne': 'npi_Deva',
        'si': 'sin_Sinh',
        'my': 'mya_Mymr',
        'km': 'khm_Khmr',
        'lo': 'lao_Laoo',
        'ka': 'kat_Geor',
        'hy': 'hye_Armn',
        'az': 'azj_Latn',
        'kk': 'kaz_Cyrl',
        'ky': 'kir_Cyrl',
        'uz': 'uzn_Latn',
        'tk': 'tuk_Latn',
        'mn': 'khk_Cyrl',
        'bo': 'bod_Tibt',
        'dz': 'dzo_Tibt',
        'ug': 'uig_Arab',
        'tt': 'tat_Cyrl',
        'ba': 'bak_Cyrl',
        'cv': 'chv_Cyrl',
        'sah': 'sah_Cyrl',
        'tyv': 'tyv_Cyrl',
        'kjh': 'kjh_Cyrl',
        'alt': 'alt_Cyrl',
        'krc': 'krc_Cyrl',
        'kum': 'kum_Cyrl',
        'nog': 'nog_Cyrl',
        'kaa': 'kaa_Cyrl',
        'crh': 'crh_Latn',
        'gag': 'gag_Latn',
        'tr': 'tur_Latn',
        'az': 'azb_Arab',
        'ku': 'ckb_Arab',
        'lrc': 'lrc_Arab',
        'mzn': 'mzn_Arab',
        'glk': 'glk_Arab',
        'fa': 'pes_Arab',
        'tg': 'tgk_Cyrl',
        'prs': 'prs_Arab',
        'haz': 'haz_Arab',
        'bal': 'bal_Arab',
        'bcc': 'bcc_Arab',
        'bgp': 'bgp_Arab',
        'bqi': 'bqi_Arab',
        'ckb': 'ckb_Arab',
        'diq': 'diq_Latn',
        'hac': 'hac_Arab',
        'kur': 'kmr_Latn',
        'lki': 'lki_Arab',
        'pnb': 'pnb_Arab',
        'ps': 'pbt_Arab',
        'sd': 'snd_Arab',
        'skr': 'skr_Arab',
        'ur': 'urd_Arab',
        'wne': 'wne_Arab',
        'xmf': 'xmf_Geor',
        'ka': 'kat_Geor',
        'hy': 'hye_Armn',
        'xcl': 'xcl_Armn',
        'he': 'heb_Hebr',
        'yi': 'yid_Hebr',
        'lad': 'lad_Hebr',
        'ar': 'arb_Arab',
        'mt': 'mlt_Latn',
        'ml': 'mal_Mlym',
        'kn': 'kan_Knda',
        'te': 'tel_Telu',
        'ta': 'tam_Taml',
        'or': 'ory_Orya',
        'as': 'asm_Beng',
        'bn': 'ben_Beng',
        'gu': 'guj_Gujr',
        'pa': 'pan_Guru',
        'hi': 'hin_Deva',
        'mr': 'mar_Deva',
        'ne': 'npi_Deva',
        'sa': 'san_Deva',
        'mai': 'mai_Deva',
        'bho': 'bho_Deva',
        'mag': 'mag_Deva',
        'sck': 'sck_Deva',
        'new': 'new_Deva',
        'bpy': 'bpy_Beng',
        'ctg': 'ctg_Beng',
        'rkt': 'rkt_Beng',
        'syl': 'syl_Beng',
        'sat': 'sat_Olck',
        'kha': 'kha_Latn',
        'grt': 'grt_Beng',
        'lus': 'lus_Latn',
        'mni': 'mni_Beng',
        'kok': 'kok_Deva',
        'gom': 'gom_Deva',
        'sd': 'snd_Deva',
        'doi': 'doi_Deva',
        'ks': 'kas_Deva',
        'ur': 'urd_Arab',
        'ps': 'pbt_Arab',
        'bal': 'bal_Arab',
        'bcc': 'bcc_Arab',
        'bgp': 'bgp_Arab',
        'brh': 'brh_Arab',
        'hnd': 'hnd_Arab',
        'lah': 'lah_Arab',
        'pnb': 'pnb_Arab',
        'pst': 'pst_Arab',
        'skr': 'skr_Arab',
        'wne': 'wne_Arab',
        'si': 'sin_Sinh',
        'dv': 'div_Thaa',
        'my': 'mya_Mymr',
        'shn': 'shn_Mymr',
        'mnw': 'mnw_Mymr',
        'kac': 'kac_Latn',
        'shn': 'shn_Mymr',
        'km': 'khm_Khmr',
        'lo': 'lao_Laoo',
        'th': 'tha_Thai',
        'vi': 'vie_Latn',
        'cjm': 'cjm_Arab',
        'bjn': 'bjn_Latn',
        'bug': 'bug_Latn',
        'jv': 'jav_Latn',
        'mad': 'mad_Latn',
        'ms': 'zsm_Latn',
        'min': 'min_Latn',
        'su': 'sun_Latn',
        'ban': 'ban_Latn',
        'bbc': 'bbc_Latn',
        'btk': 'btk_Latn',
        'gor': 'gor_Latn',
        'ilo': 'ilo_Latn',
        'pag': 'pag_Latn',
        'war': 'war_Latn',
        'hil': 'hil_Latn',
        'bcl': 'bcl_Latn',
        'pam': 'pam_Latn',
        'tl': 'tgl_Latn',
        'ceb': 'ceb_Latn',
        'akl': 'akl_Latn',
        'bik': 'bik_Latn',
        'cbk': 'cbk_Latn',
        'krj': 'krj_Latn',
        'tsg': 'tsg_Latn',
        'zh': 'zho_Hans',
        'yue': 'yue_Hant',
        'wuu': 'wuu_Hans',
        'hsn': 'hsn_Hans',
        'nan': 'nan_Hant',
        'hak': 'hak_Hant',
        'gan': 'gan_Hans',
        'cdo': 'cdo_Hant',
        'lzh': 'lzh_Hans',
        'ja': 'jpn_Jpan',
        'ko': 'kor_Hang',
        'ain': 'ain_Kana',
        'ryu': 'ryu_Kana',
        'eo': 'epo_Latn',
        'ia': 'ina_Latn',
        'ie': 'ile_Latn',
        'io': 'ido_Latn',
        'vo': 'vol_Latn',
        'nov': 'nov_Latn',
        'lfn': 'lfn_Latn',
        'jbo': 'jbo_Latn',
        'tlh': 'tlh_Latn',
        'na': 'nau_Latn',
        'ch': 'cha_Latn',
        'mh': 'mah_Latn',
        'gil': 'gil_Latn',
        'kos': 'kos_Latn',
        'pon': 'pon_Latn',
        'yap': 'yap_Latn',
        'chk': 'chk_Latn',
        'uli': 'uli_Latn',
        'wol': 'wol_Latn',
        'pau': 'pau_Latn',
        'sm': 'smo_Latn',
        'to': 'ton_Latn',
        'fj': 'fij_Latn',
        'ty': 'tah_Latn',
        'mi': 'mri_Latn',
        'haw': 'haw_Latn',
        'rap': 'rap_Latn',
        'tvl': 'tvl_Latn',
        'niu': 'niu_Latn',
        'tkl': 'tkl_Latn',
        'bi': 'bis_Latn',
        'ho': 'hmo_Latn',
        'kg': 'kon_Latn',
        'kj': 'kua_Latn',
        'rw': 'kin_Latn',
        'rn': 'run_Latn',
        'sg': 'sag_Latn',
        'sn': 'sna_Latn',
        'ss': 'ssw_Latn',
        'st': 'sot_Latn',
        'sw': 'swh_Latn',
        'tn': 'tsn_Latn',
        'ts': 'tso_Latn',
        've': 'ven_Latn',
        'xh': 'xho_Latn',
        'zu': 'zul_Latn',
        'nd': 'nde_Latn',
        'nr': 'nbl_Latn',
        'ny': 'nya_Latn',
        'bm': 'bam_Latn',
        'ee': 'ewe_Latn',
        'ff': 'fuv_Latn',
        'ha': 'hau_Latn',
        'ig': 'ibo_Latn',
        'ki': 'kik_Latn',
        'lg': 'lug_Latn',
        'ln': 'lin_Latn',
        'mg': 'plt_Latn',
        'om': 'orm_Latn',
        'rw': 'kin_Latn',
        'rn': 'run_Latn',
        'sg': 'sag_Latn',
        'sn': 'sna_Latn',
        'so': 'som_Latn',
        'sw': 'swh_Latn',
        'ti': 'tir_Ethi',
        'tw': 'twi_Latn',
        'wo': 'wol_Latn',
        'xh': 'xho_Latn',
        'yo': 'yor_Latn',
        'zu': 'zul_Latn'
    }

    def __init__(self, model_name: str = "facebook/nllb-200-3.3B", max_chunk_length: int = 1000):
        """
        Initialize NLLB translation provider.

        Args:
            model_name: The NLLB model name to use
            max_chunk_length: Maximum length for text chunks
        """
        # Build supported languages mapping
        supported_languages = {}
        for lang_code in self.LANGUAGE_MAPPINGS.keys():
            # For simplicity, assume all languages can translate to all other languages
            # In practice, you might want to be more specific about supported pairs
            supported_languages[lang_code] = [
                target for target in self.LANGUAGE_MAPPINGS.keys()
                if target != lang_code
            ]

        super().__init__(
            provider_name="NLLB-200-3.3B",
            supported_languages=supported_languages
        )

        self.model_name = model_name
        self.max_chunk_length = max_chunk_length
        self._tokenizer: Optional[AutoTokenizer] = None
        self._model: Optional[AutoModelForSeq2SeqLM] = None
        self._model_loaded = False

    def _translate_chunk(self, text: str, source_language: str, target_language: str) -> str:
        """
        Translate a single chunk of text using NLLB model.

        Args:
            text: The text chunk to translate
            source_language: Source language code
            target_language: Target language code

        Returns:
            str: The translated text chunk
        """
        try:
            # Ensure model is loaded
            self._ensure_model_loaded()

            # Map language codes to NLLB format
            source_nllb = self._map_language_code(source_language)
            target_nllb = self._map_language_code(target_language)

            logger.info(f"Translating chunk from {source_nllb} to {target_nllb}")

            # Tokenize with source language specification
            inputs = self._tokenizer(
                text,
                return_tensors="pt",
                max_length=1024,
                truncation=True
            )

            # Generate translation with target language specification
            outputs = self._model.generate(
                **inputs,
                forced_bos_token_id=self._tokenizer.convert_tokens_to_ids(target_nllb),
                max_new_tokens=1024,
                num_beams=4,
                early_stopping=True
            )

            # Decode the translation
            translated = self._tokenizer.decode(outputs[0], skip_special_tokens=True)

            # Post-process the translation
            translated = self._postprocess_text(translated)

            logger.info(f"Chunk translation completed: {len(text)} -> {len(translated)} chars")
            return translated

        except Exception as e:
            self._handle_provider_error(e, "chunk translation")

    def _ensure_model_loaded(self) -> None:
        """Ensure the NLLB model and tokenizer are loaded."""
        if self._model_loaded:
            return

        try:
            logger.info(f"Loading NLLB model: {self.model_name}")

            # Load tokenizer
            self._tokenizer = AutoTokenizer.from_pretrained(
                self.model_name,
                src_lang="eng_Latn"  # Default source language
            )

            # Load model
            self._model = AutoModelForSeq2SeqLM.from_pretrained(self.model_name)

            self._model_loaded = True
            logger.info("NLLB model loaded successfully")

        except Exception as e:
            logger.error(f"Failed to load NLLB model: {str(e)}")
            raise TranslationFailedException(f"Failed to load NLLB model: {str(e)}") from e

    def _map_language_code(self, language_code: str) -> str:
        """
        Map standard language code to NLLB format.

        Args:
            language_code: Standard language code (e.g., 'en', 'zh')

        Returns:
            str: NLLB language code (e.g., 'eng_Latn', 'zho_Hans')
        """
        # Normalize language code to lowercase
        normalized_code = language_code.lower()

        # Check direct mapping
        if normalized_code in self.LANGUAGE_MAPPINGS:
            return self.LANGUAGE_MAPPINGS[normalized_code]

        # Handle common variations
        if normalized_code.startswith('zh'):
            if 'tw' in normalized_code or 'hant' in normalized_code or 'traditional' in normalized_code:
                return 'zho_Hant'
            else:
                return 'zho_Hans'

        # Default fallback for unknown codes
        logger.warning(f"Unknown language code: {language_code}, defaulting to English")
        return 'eng_Latn'

    def is_available(self) -> bool:
        """
        Check if the NLLB translation provider is available.

        Returns:
            bool: True if provider is available, False otherwise
        """
        try:
            # Try to import required dependencies
            import transformers
            import torch

            # Check if we can load the tokenizer (lightweight check)
            if not self._model_loaded:
                try:
                    test_tokenizer = AutoTokenizer.from_pretrained(
                        self.model_name,
                        src_lang="eng_Latn"
                    )
                    return True
                except Exception as e:
                    logger.warning(f"NLLB model not available: {str(e)}")
                    return False
            else:
                return True

        except ImportError as e:
            logger.warning(f"NLLB dependencies not available: {str(e)}")
            return False

    def get_supported_languages(self) -> Dict[str, List[str]]:
        """
        Get supported language pairs for NLLB provider.

        Returns:
            dict: Mapping of source languages to supported target languages
        """
        return self.supported_languages.copy()

    def get_model_info(self) -> Dict[str, str]:
        """
        Get information about the loaded model.

        Returns:
            dict: Model information
        """
        return {
            'provider': self.provider_name,
            'model_name': self.model_name,
            'model_loaded': str(self._model_loaded),
            'supported_language_count': str(len(self.LANGUAGE_MAPPINGS)),
            'max_chunk_length': str(self.max_chunk_length)
        }

    def set_model_name(self, model_name: str) -> None:
        """
        Set a different NLLB model name.

        Args:
            model_name: The new model name to use
        """
        if model_name != self.model_name:
            self.model_name = model_name
            self._model_loaded = False
            self._tokenizer = None
            self._model = None
            logger.info(f"Model name changed to: {model_name}")

    def clear_model_cache(self) -> None:
        """Clear the loaded model from memory."""
        if self._model_loaded:
            self._tokenizer = None
            self._model = None
            self._model_loaded = False
            logger.info("NLLB model cache cleared")