"""
Configuration for Healthcare-SLM: A Small Language Model for Healthcare & Medical domain.
LLaMA-style architecture with RoPE — supports up to 1M token context.
"""

from dataclasses import dataclass, field
from pathlib import Path
from typing import Optional


@dataclass
class SLMConfig:
    """All hyperparameters and paths in one place."""

    # ── Project paths ──────────────────────────────────────────────
    project_dir: Path = Path(__file__).resolve().parent
    data_dir: Path = field(default=None)
    tokenizer_dir: Path = field(default=None)
    checkpoint_dir: Path = field(default=None)

    # ── Domain ─────────────────────────────────────────────────────
    domain_name: str = "Healthcare"
    domain_slug: str = "healthcare"
    tokenizer_filename: str = "healthcare_tokenizer.json"

    # ── Tokenizer ──────────────────────────────────────────────────
    vocab_size: int = 16_000
    min_frequency: int = 2
    special_tokens: list = field(
        default_factory=lambda: [
            "<pad>", "<unk>", "<bos>", "<eos>",
            "<|system|>", "<|user|>", "<|assistant|>",
        ]
    )

    # ── Model (LLaMA-style with RoPE) ─────────────────────────────
    n_layer: int = 8
    n_head: int = 8
    n_embd: int = 512
    block_size: int = 512
    dropout: float = 0.1
    bias: bool = False
    ffn_multiplier: float = 2.667

    # ── RoPE ───────────────────────────────────────────────────────
    max_position_embeddings: int = 100_000_000_000  # 100B tokens via RoPE
    rope_theta: float = 50_000_000_000.0  # Scaled for 100B context

    # ── Sliding Window ─────────────────────────────────────────────
    sliding_window: Optional[int] = None

    # ── Training ───────────────────────────────────────────────────
    batch_size: int = 4
    gradient_accumulation_steps: int = 4
    learning_rate: float = 3e-4
    weight_decay: float = 0.1
    max_epochs: int = 20
    dataset_stride: int = 256
    warmup_steps: int = 20
    grad_clip: float = 1.0
    eval_interval: int = 50
    eval_samples: int = 20
    log_interval: int = 10
    device: str = "auto"

    # ── Generation ─────────────────────────────────────────────────
    max_new_tokens: int = 1_000_000  # 1M output tokens
    temperature: float = 0.8
    top_k: int = 50
    top_p: float = 0.9

    # ── Hugging Face ───────────────────────────────────────────────
    hf_repo_name: str = "healthcare-slm-1m"
    hf_model_card_tags: list = field(
        default_factory=lambda: [
            "healthcare", "medical", "clinical", "slm",
            "llama-style", "rope", "1m-context", "from-scratch",
        ]
    )

    def __post_init__(self):
        if self.data_dir is None:
            self.data_dir = self.project_dir / "data"
        if self.tokenizer_dir is None:
            self.tokenizer_dir = self.project_dir / "tokenizer"
        if self.checkpoint_dir is None:
            self.checkpoint_dir = self.project_dir / "checkpoints"

        self.data_dir.mkdir(parents=True, exist_ok=True)
        self.tokenizer_dir.mkdir(parents=True, exist_ok=True)
        self.checkpoint_dir.mkdir(parents=True, exist_ok=True)

        if self.device == "auto":
            import torch
            if torch.cuda.is_available():
                self.device = "cuda"
            elif torch.backends.mps.is_available():
                self.device = "mps"
            else:
                self.device = "cpu"


cfg = SLMConfig()