from unittest.mock import patch, Mock

import pytest

from haystack.nodes.prompt.prompt_model import PromptModel
from haystack.nodes.prompt.invocation_layer import PromptModelInvocationLayer, HFLocalInvocationLayer

from .conftest import create_mock_layer_that_supports


@pytest.mark.unit
def test_constructor_with_default_model():
    mock_layer = create_mock_layer_that_supports("google/flan-t5-base")
    another_layer = create_mock_layer_that_supports("another-model")

    with patch.object(PromptModelInvocationLayer, "invocation_layer_providers", new=[mock_layer, another_layer]):
        model = PromptModel()
        mock_layer.assert_called_once()
        another_layer.assert_not_called()
        model.model_invocation_layer.model_name_or_path = "google/flan-t5-base"


@pytest.mark.unit
def test_construtor_with_custom_model():
    mock_layer = create_mock_layer_that_supports("some-model")
    another_layer = create_mock_layer_that_supports("another-model")

    with patch.object(PromptModelInvocationLayer, "invocation_layer_providers", new=[mock_layer, another_layer]):
        model = PromptModel("another-model")
        mock_layer.assert_not_called()
        another_layer.assert_called_once()
        model.model_invocation_layer.model_name_or_path = "another-model"


@pytest.mark.unit
def test_constructor_with_no_supported_model():
    with pytest.raises(ValueError, match="Model some-random-model is not supported"):
        PromptModel("some-random-model")


def create_mock_pipeline(model_name_or_path=None, max_length=100):
    return Mock(
        **{"model_name_or_path": model_name_or_path},
        return_value=Mock(**{"model_name_or_path": model_name_or_path, "tokenizer.model_max_length": max_length}),
    )


@pytest.mark.unit
def test_hf_local_invocation_layer_with_task_name():
    mock_pipeline = create_mock_pipeline()
    mock_get_task = Mock(return_value="dummy_task")

    with patch("haystack.nodes.prompt.invocation_layer.hugging_face.get_task", mock_get_task):
        with patch("haystack.nodes.prompt.invocation_layer.hugging_face.pipeline", mock_pipeline):
            PromptModel(
                model_name_or_path="local_model",
                max_length=100,
                model_kwargs={"task_name": "dummy_task"},
                invocation_layer_class=HFLocalInvocationLayer,
            )
            # checking if get_task is called when task_name is passed to HFLocalInvocationLayer constructor
            mock_get_task.assert_not_called()
            mock_pipeline.assert_called_once()