"""Tests for the core model module."""

import pytest
import torch
from src.model.base_model import load_model_and_tokenizer, ENCODER_DECODER_MODELS, DECODER_ONLY_MODELS
from src.model.style_conditioner import StyleConditioner, prepend_style_prefix
from src.model.lora_adapter import create_lora_config
from peft import TaskType


def test_model_registry_populated():
    """Test that model registries are defined."""
    assert len(ENCODER_DECODER_MODELS) > 0
    assert len(DECODER_ONLY_MODELS) > 0


def test_invalid_model_key():
    """Test that unknown model keys raise ValueError."""
    with pytest.raises(ValueError, match="Unknown model key"):
        load_model_and_tokenizer("nonexistent-model")


def test_style_conditioner_output_shape():
    """Test that style conditioner produces correct tensor shapes."""
    conditioner = StyleConditioner(style_dim=512, model_hidden_dim=256, n_prefix_tokens=5)
    batch_size = 2
    style_vec = torch.randn(batch_size, 512)
    prefix = conditioner(style_vec)
    assert prefix.shape == (batch_size, 5, 256)


def test_prepend_style_prefix():
    """Test prefix prepending dimensions."""
    embeddings = torch.randn(2, 10, 256)  # batch=2, seq=10, hidden=256
    prefix = torch.randn(2, 5, 256)       # batch=2, prefix=5, hidden=256
    result = prepend_style_prefix(embeddings, prefix)
    assert result.shape == (2, 15, 256)


def test_lora_config_creation():
    """Test LoRA config creation."""
    config = create_lora_config(TaskType.SEQ_2_SEQ_LM, r=8, lora_alpha=16)
    assert config.r == 8
    assert config.lora_alpha == 16