"""Hugging Face AutoConfig support for Ogma models."""

from __future__ import annotations

from enum import StrEnum
from typing import Any

from transformers import PretrainedConfig

__all__ = ["OgmaConfig", "VariantType", "PoolingType", "TaskToken"]


class VariantType(StrEnum):
    """Architecture variant identifiers."""

    TRANSFORMER = "transformer"
    DEEP_NARROW = "deep_narrow"
    CONV = "conv"
    LINEAR_ATTENTION = "linear_attention"
    MLP_MIXER = "mlp_mixer"
    TRANSFORMER_RESA = "transformer_resa"
    GLA = "gla"


class PoolingType(StrEnum):
    """Pooling strategy identifiers."""

    TASK_TOKEN = "task_token"
    LATENT_ATTENTION = "latent_attention"
    MEAN = "mean"


class TaskToken(StrEnum):
    """Task token identifiers for asymmetric encoding."""

    QRY = "QRY"
    DOC = "DOC"
    SYM = "SYM"


class OgmaConfig(PretrainedConfig):
    """Configuration for Ogma embedding models."""

    model_type = "ogma"

    def __init__(
        self,
        variant: str | VariantType = VariantType.TRANSFORMER,
        d_embed: int = 128,
        d_model: int = 256,
        n_layers: int = 1,
        n_heads: int = 4,
        vocab_size: int = 30_000,
        max_seq_len: int = 512,
        matryoshka_dims: list[int] | None = None,
        pooling: str | PoolingType = PoolingType.TASK_TOKEN,
        d_output: int = 256,
        ffn_mult: float = 8 / 3,
        conv_kernel_size: int = 7,
        spatial_rank: int = 32,
        n_random_features: int = 128,
        dropout: float = 0.0,
        scorer_type: str = "dot",
        scorer_alpha_init: float = 0.1,
        scorer_hidden: int = 0,
        gla_expand_k: float = 0.5,
        gla_expand_v: float = 1.0,
        gla_gate_low_rank_dim: int = 16,
        gla_gate_logit_normalizer: int = 16,
        gla_use_short_conv: bool = True,
        gla_conv_size: int = 4,
        pad_id: int = 0,
        unk_id: int = 1,
        bos_id: int = 2,
        eos_id: int = 3,
        qry_id: int = 4,
        doc_id: int = 5,
        sym_id: int = 6,
        n_special_tokens: int = 7,
        **kwargs: Any,
    ) -> None:
        kwargs.setdefault("pad_token_id", pad_id)
        kwargs.setdefault("bos_token_id", bos_id)
        kwargs.setdefault("eos_token_id", eos_id)
        super().__init__(**kwargs)
        self.variant = VariantType(variant)
        self.d_embed = d_embed
        self.d_model = d_model
        self.n_layers = n_layers
        self.n_heads = n_heads
        self.vocab_size = vocab_size
        self.max_seq_len = max_seq_len
        self.matryoshka_dims = matryoshka_dims or [32, 64, 128, 256]
        self.pooling = PoolingType(pooling)
        self.d_output = d_output
        self.ffn_mult = ffn_mult
        self.conv_kernel_size = conv_kernel_size
        self.spatial_rank = spatial_rank
        self.n_random_features = n_random_features
        self.dropout = dropout
        self.scorer_type = scorer_type
        self.scorer_alpha_init = scorer_alpha_init
        self.scorer_hidden = scorer_hidden
        self.gla_expand_k = gla_expand_k
        self.gla_expand_v = gla_expand_v
        self.gla_gate_low_rank_dim = gla_gate_low_rank_dim
        self.gla_gate_logit_normalizer = gla_gate_logit_normalizer
        self.gla_use_short_conv = gla_use_short_conv
        self.gla_conv_size = gla_conv_size
        self.pad_id = pad_id
        self.unk_id = unk_id
        self.bos_id = bos_id
        self.eos_id = eos_id
        self.qry_id = qry_id
        self.doc_id = doc_id
        self.sym_id = sym_id
        self.n_special_tokens = n_special_tokens

    @property
    def d_head(self) -> int:
        """Per-head dimension."""
        return self.d_model // self.n_heads

    @property
    def ffn_hidden(self) -> int:
        """SwiGLU FFN hidden dimension."""
        return int(self.d_model * self.ffn_mult)

    def task_token_id(self, task: TaskToken | str) -> int:
        """Return token ID for a task token."""
        task = TaskToken(task)
        return {
            TaskToken.QRY: self.qry_id,
            TaskToken.DOC: self.doc_id,
            TaskToken.SYM: self.sym_id,
        }[task]

    def to_dict(self) -> dict[str, Any]:
        """Serialize config to a JSON-compatible dictionary."""
        output = super().to_dict()
        output["variant"] = self.variant.value
        output["pooling"] = self.pooling.value
        return output