"""Shared pytest fixtures for the Obliteratus test suite."""

from __future__ import annotations

from unittest.mock import MagicMock

import pytest
import torch


# ---------------------------------------------------------------------------
# Fixtures
# ---------------------------------------------------------------------------


@pytest.fixture
def mock_model():
    """A minimal mock transformer model.

    Provides:
    - model.config  with config.num_hidden_layers = 4
    - model.named_parameters() returning fake weight tensors
    """
    model = MagicMock()

    # Config with num_hidden_layers
    config = MagicMock()
    config.num_hidden_layers = 4
    model.config = config

    # named_parameters returns fake weight tensors across 4 layers
    fake_params = []
    for layer_idx in range(4):
        weight = torch.randn(768, 768)
        fake_params.append((f"model.layers.{layer_idx}.self_attn.q_proj.weight", weight))
        fake_params.append((f"model.layers.{layer_idx}.self_attn.v_proj.weight", weight))
        fake_params.append((f"model.layers.{layer_idx}.mlp.gate_proj.weight", weight))
    model.named_parameters.return_value = fake_params

    return model


@pytest.fixture
def mock_tokenizer():
    """A minimal mock tokenizer with encode, decode, and apply_chat_template."""
    tokenizer = MagicMock()

    tokenizer.encode.return_value = [1, 2, 3, 4, 5]
    tokenizer.decode.return_value = "Hello, this is a decoded string."
    tokenizer.apply_chat_template.return_value = [1, 2, 3, 4, 5, 6, 7]

    tokenizer.pad_token = "<pad>"
    tokenizer.eos_token = "<eos>"

    return tokenizer


@pytest.fixture
def refusal_direction():
    """A normalized random torch tensor of shape (768,)."""
    t = torch.randn(768)
    return t / t.norm()


@pytest.fixture
def activation_pair():
    """A tuple of (harmful_activations, harmless_activations) as random tensors of shape (10, 768)."""
    harmful_activations = torch.randn(10, 768)
    harmless_activations = torch.randn(10, 768)
    return (harmful_activations, harmless_activations)


@pytest.fixture
def tmp_output_dir(tmp_path):
    """A clean temporary output directory for test artifacts."""
    output_dir = tmp_path / "test_output"
    output_dir.mkdir()
    return output_dir