from __future__ import annotations

import importlib.util
import json
import tempfile
import unittest
from pathlib import Path

from build123d import Box, Cylinder, Pos, export_step, import_step


SCRIPT_PATH = Path(__file__).resolve().parents[1] / "scripts" / "model_spec.py"
MODULE_SPEC = importlib.util.spec_from_file_location("cad_router_model_spec", SCRIPT_PATH)
assert MODULE_SPEC is not None and MODULE_SPEC.loader is not None
MODEL_SPEC = importlib.util.module_from_spec(MODULE_SPEC)
MODULE_SPEC.loader.exec_module(MODEL_SPEC)


class ModelSpecTests(unittest.TestCase):
    def test_affine_parameter_expression(self) -> None:
        payload = {
            "parameters": {
                "extension": {
                    "value": 2.0,
                }
            }
        }
        self.assertEqual(
            MODEL_SPEC.resolve_number(
                payload,
                {
                    "parameter": "extension",
                    "scale": 0.5,
                    "offset": 14.1,
                },
                "center[2]",
            ),
            15.1,
        )

    def test_import_step_exact_base_round_trip(self) -> None:
        with tempfile.TemporaryDirectory() as temporary:
            root = Path(temporary)
            source = root / "teacher.step"
            export_step(Box(30, 20, 10) - Pos(0, 0, -1) * Cylinder(3, 12), source)

            result = MODEL_SPEC.import_step_model(
                source,
                root / "task",
                "round_trip",
            )
            verification = MODEL_SPEC.verify_model(
                Path(result["model_spec"])
            )

            self.assertTrue(verification["valid"])
            self.assertEqual(
                verification["checks"][0]["check"],
                "exact_base_geometry_signature",
            )
            self.assertTrue((root / "task" / "round_trip.step").is_file())
            self.assertTrue((root / "task" / "round_trip.stl").is_file())

    def test_parameterized_cut_rebuilds_from_json(self) -> None:
        with tempfile.TemporaryDirectory() as temporary:
            root = Path(temporary)
            source = root / "source.step"
            export_step(Box(40, 30, 12), source)
            imported = MODEL_SPEC.import_step_model(
                source,
                root / "task",
                "parameterized_cut",
            )
            spec_path = Path(imported["model_spec"])
            payload = json.loads(spec_path.read_text(encoding="utf-8"))
            payload["parameters"] = {
                "bore_diameter": {
                    "value": 6,
                    "unit": "mm",
                    "role": "central_bore_diameter",
                },
                "bore_length": {
                    "value": 16,
                    "unit": "mm",
                    "role": "through_cut_length",
                },
            }
            payload["modifications"] = [
                {
                    "id": "central_bore",
                    "operation": "cut_cylinder",
                    "axis": "z",
                    "center": [0, 0, 0],
                    "diameter": {"parameter": "bore_diameter"},
                    "length": {"parameter": "bore_length"},
                    "enabled": True,
                }
            ]
            spec_path.write_text(
                json.dumps(payload, ensure_ascii=False, indent=2) + "\n",
                encoding="utf-8",
            )

            first = MODEL_SPEC.build_model(spec_path)
            first_volume = first["facts"]["volume_mm3"]
            MODEL_SPEC.set_parameter(spec_path, "bore_diameter", 12)
            second = MODEL_SPEC.build_model(spec_path)

            self.assertLess(second["facts"]["volume_mm3"], first_volume)
            rebuilt = import_step(second["step"])
            self.assertGreater(len(rebuilt.faces()), 0)

    def test_exact_base_rejects_changed_source(self) -> None:
        with tempfile.TemporaryDirectory() as temporary:
            root = Path(temporary)
            source = root / "source.step"
            export_step(Box(10, 10, 10), source)
            imported = MODEL_SPEC.import_step_model(
                source,
                root / "task",
                "checksum_guard",
            )
            export_step(Box(12, 10, 10), root / "task" / "source.step")

            with self.assertRaises(MODEL_SPEC.ModelSpecError):
                MODEL_SPEC.build_model(Path(imported["model_spec"]))


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