"""Unit tests for the external-checkpoint auto-conversion dispatch."""

from unittest.mock import patch

import pytest

from speculators.convert.entrypoints import maybe_convert_external_checkpoint


class TestMaybeConvertExternalCheckpoint:
    @patch("speculators.convert.entrypoints.PretrainedConfig.get_config_dict")
    def test_speculators_checkpoint_passes_through(self, mock_cfg):
        mock_cfg.return_value = ({"speculators_model_type": "dflash"}, None)
        assert maybe_convert_external_checkpoint("some/speculators-model") == (
            "some/speculators-model"
        )

    @patch("speculators.convert.entrypoints.convert_model")
    @patch("speculators.convert.entrypoints.PretrainedConfig.get_config_dict")
    def test_external_dflash_converts(self, mock_cfg, mock_convert):
        mock_cfg.return_value = ({"dflash_config": {}, "model_type": "qwen3"}, None)
        out = maybe_convert_external_checkpoint(
            "z-lab/Qwen3-8B-DFlash-b16",
            verifier="Qwen/Qwen3-8B",
            output_path="/tmp/out",
        )
        assert out == "/tmp/out"
        mock_convert.assert_called_once()
        assert mock_convert.call_args.kwargs["algorithm"] == "dflash"
        assert mock_convert.call_args.kwargs["verifier"] == "Qwen/Qwen3-8B"

    @patch("speculators.convert.entrypoints.convert_model")
    @patch("speculators.convert.entrypoints.PretrainedConfig.get_config_dict")
    def test_external_domino_converts(self, mock_cfg, mock_convert):
        mock_cfg.return_value = (
            {
                "architectures": ["DominoDraftModel"],
                "dflash_config": {"projector_type": "domino"},
            },
            None,
        )
        out = maybe_convert_external_checkpoint(
            "some/domino-model",
            verifier="Qwen/Qwen3-8B",
            output_path="/tmp/out",
        )
        assert out == "/tmp/out"
        mock_convert.assert_called_once()
        assert mock_convert.call_args.kwargs["algorithm"] == "domino"
        assert mock_convert.call_args.kwargs["verifier"] == "Qwen/Qwen3-8B"

    @patch("speculators.convert.entrypoints.PretrainedConfig.get_config_dict")
    def test_external_without_verifier_raises(self, mock_cfg):
        mock_cfg.return_value = ({"architectures": ["DFlashDraftModel"]}, None)
        with pytest.raises(ValueError, match="requires a verifier"):
            maybe_convert_external_checkpoint("z-lab/Qwen3-8B-DFlash-b16")

    @patch("speculators.convert.entrypoints.PretrainedConfig.get_config_dict")
    def test_unrecognized_format_raises(self, mock_cfg):
        mock_cfg.return_value = ({"model_type": "qwen3"}, None)
        with pytest.raises(NotImplementedError, match="unrecognized external"):
            maybe_convert_external_checkpoint("some/model", verifier="Qwen/Qwen3-8B")