from __future__ import annotations

import os
import tempfile
import unittest
import importlib.util
import sys
import types
from pathlib import Path
from unittest import mock


MODULE_PATH = Path(__file__).resolve().parents[1] / "trellis" / "utils" / "dino_hub.py"
_SPEC = importlib.util.spec_from_file_location("near_test_dino_hub", MODULE_PATH)
assert _SPEC is not None and _SPEC.loader is not None
dino_hub = importlib.util.module_from_spec(_SPEC)
_SPEC.loader.exec_module(dino_hub)


def _write_hub_repo(repo_root: Path) -> None:
    repo_root.mkdir(parents=True, exist_ok=True)
    (repo_root / "hubconf.py").write_text("def dinov2_vitl14_reg(pretrained=True): return None\n", encoding="utf-8")


class DinoHubTests(unittest.TestCase):
    def setUp(self) -> None:
        self._tmpdir = tempfile.TemporaryDirectory()
        self.tmp_path = Path(self._tmpdir.name)
        self._old_env = os.environ.copy()
        for key in (
            "NEAR_DINO_LOCAL_REPO",
            "NEAR_AUX_REPO",
            "NEAR_DINO_REPO_SUBDIR",
            "NEAR_DINO_MODEL_ID",
            "NEAR_DINO_FILENAME",
            "NEAR_DINO_TORCH_HUB_REPO",
        ):
            os.environ.pop(key, None)
        dino_hub.resolve_dinov2_repo_root.cache_clear()

    def tearDown(self) -> None:
        os.environ.clear()
        os.environ.update(self._old_env)
        dino_hub.resolve_dinov2_repo_root.cache_clear()
        self._tmpdir.cleanup()

    def test_resolve_dinov2_repo_root_prefers_local_override(self) -> None:
        repo_root = self.tmp_path / "dinov2-local"
        _write_hub_repo(repo_root)
        os.environ["NEAR_DINO_LOCAL_REPO"] = str(repo_root)

        resolved = dino_hub.resolve_dinov2_repo_root()

        self.assertEqual(resolved, str(repo_root.resolve()))

    def test_resolve_dinov2_repo_root_requires_mirror_when_no_local(self) -> None:
        with self.assertRaises(FileNotFoundError):
            dino_hub.resolve_dinov2_repo_root()

    def test_resolve_dinov2_repo_root_uses_aux_repo_subdir(self) -> None:
        aux_root = self.tmp_path / "near-assets"
        repo_root = aux_root / "dinov2"
        _write_hub_repo(repo_root)
        os.environ["NEAR_AUX_REPO"] = str(aux_root)
        os.environ["NEAR_DINO_REPO_SUBDIR"] = "dinov2"

        resolved = dino_hub.resolve_dinov2_repo_root()

        self.assertEqual(resolved, str(repo_root.resolve()))

    def test_resolve_dinov2_repo_root_validates_optional_filename(self) -> None:
        repo_root = self.tmp_path / "dinov2-local"
        _write_hub_repo(repo_root)
        os.environ["NEAR_DINO_LOCAL_REPO"] = str(repo_root)
        os.environ["NEAR_DINO_FILENAME"] = "weights/model.bin"

        with self.assertRaisesRegex(FileNotFoundError, "weights/model.bin"):
            dino_hub.resolve_dinov2_repo_root()

    def test_load_dinov2_model_uses_local_torch_hub_mirror(self) -> None:
        repo_root = self.tmp_path / "dinov2-local"
        _write_hub_repo(repo_root)
        os.environ["NEAR_DINO_LOCAL_REPO"] = str(repo_root)
        os.environ["NEAR_DINO_MODEL_ID"] = "custom_dino_entry"

        fake_torch = types.SimpleNamespace(hub=types.SimpleNamespace(load=mock.Mock(return_value=object())))
        with mock.patch.dict(sys.modules, {"torch": fake_torch}):
            loaded = dino_hub.load_dinov2_model("dinov2_vitl14_reg")

        self.assertIsNotNone(loaded)
        fake_torch.hub.load.assert_called_once_with(
            repo_or_dir=str(repo_root.resolve()),
            model="custom_dino_entry",
            source="local",
            pretrained=True,
        )

    def test_load_dinov2_model_torch_hub_github_when_no_mirror_env(self) -> None:
        fake_torch = types.SimpleNamespace(hub=types.SimpleNamespace(load=mock.Mock(return_value=object())))
        with mock.patch.dict(sys.modules, {"torch": fake_torch}):
            loaded = dino_hub.load_dinov2_model("dinov2_vitl14_reg")

        self.assertIsNotNone(loaded)
        fake_torch.hub.load.assert_called_once_with(
            "facebookresearch/dinov2",
            "dinov2_vitl14_reg",
            pretrained=True,
        )


if __name__ == "__main__":
    unittest.main()