import jax.numpy as jnp

from ...utils import logging
from ..t5.modeling_flax_t5 import FlaxT5EncoderModel, FlaxT5ForConditionalGeneration, FlaxT5Model
from .configuration_mt5 import MT5Config


logger = logging.get_logger(__name__)

_CONFIG_FOR_DOC = "T5Config"


# Copied from transformers.models.bart.modeling_flax_bart.shift_tokens_right
def shift_tokens_right(input_ids: jnp.ndarray, pad_token_id: int, decoder_start_token_id: int) -> jnp.ndarray:
    """
    Shift input ids one token to the right.
    """
    shifted_input_ids = jnp.zeros_like(input_ids)
    shifted_input_ids = shifted_input_ids.at[:, 1:].set(input_ids[:, :-1])
    shifted_input_ids = shifted_input_ids.at[:, 0].set(decoder_start_token_id)

    shifted_input_ids = jnp.where(shifted_input_ids == -100, pad_token_id, shifted_input_ids)
    return shifted_input_ids


class FlaxMT5Model(FlaxT5Model):

    model_type = "mt5"
    config_class = MT5Config


class FlaxMT5EncoderModel(FlaxT5EncoderModel):

    model_type = "mt5"
    config_class = MT5Config


class FlaxMT5ForConditionalGeneration(FlaxT5ForConditionalGeneration):

    model_type = "mt5"
    config_class = MT5Config