import copy
import tempfile
import unittest
from pathlib import Path
from unittest.mock import patch

import svg2gcode
from optimise import get_total_distance


class OptimisationTests(unittest.TestCase):
    def test_distance_does_not_remove_shapes(self):
        shapes = [[(0, 0), (1, 0)], [(4, 0), (5, 0)], [(5, 4)]]
        original = copy.deepcopy(shapes)
        self.assertEqual(get_total_distance(shapes), 7)
        self.assertEqual(get_total_distance(shapes), 7)
        self.assertEqual(shapes, original)

    def test_empty_and_single_shape_distance(self):
        self.assertEqual(get_total_distance([]), 0)
        self.assertEqual(get_total_distance([[(0, 0), (1, 1)]]), 0)

    def test_single_shape_conversion_retains_all_moves(self):
        with tempfile.TemporaryDirectory() as directory:
            output = Path(directory) / "drawing.gcode"
            shapes = [[(10, 20), (11, 21), (12, 22)]]
            with patch.object(svg2gcode, "get_shapes", return_value=shapes), \
                    patch.object(svg2gcode, "optimise", True):
                svg2gcode.main("drawing.svg", output)
            text = output.read_text()
            for x, y in ((10, 20), (11, 21), (12, 22)):
                self.assertIn(f"G1 X{x:.3f} Y{y:.3f}", text)
            self.assertTrue(text.endswith("G0 Z2\nG0 X0 Y0\n"))

    def test_no_shapes_is_an_explicit_error_without_output(self):
        with tempfile.TemporaryDirectory() as directory:
            output = Path(directory) / "drawing.gcode"
            with patch.object(svg2gcode, "get_shapes", return_value=[]):
                with self.assertRaisesRegex(ValueError, "no drawable SVG shapes"):
                    svg2gcode.main("empty.svg", output)
            self.assertFalse(output.exists())


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