import sys
import tempfile
import unittest
from pathlib import Path

from PIL import Image

SCRIPTS = Path(__file__).resolve().parents[1] / "scripts"
sys.path.insert(0, str(SCRIPTS))

from build_scroll_skins import build_asset, remove_chroma_background, sanitize_output_edges, stretch_safe_center


class BuildScrollSkinsTests(unittest.TestCase):
    def setUp(self):
        self.directory = tempfile.TemporaryDirectory()
        self.addCleanup(self.directory.cleanup)
        self.root = Path(self.directory.name)

    def test_chroma_background_becomes_transparent_black(self):
        image = Image.new("RGB", (4, 2), (0, 255, 0))
        image.putpixel((1, 0), (180, 30, 20))

        cleaned = remove_chroma_background(image, (0, 255, 0), tolerance=80)

        self.assertEqual((0, 0, 0, 0), cleaned.getpixel((0, 0)))
        self.assertEqual((180, 30, 20, 255), cleaned.getpixel((1, 0)))

    def test_safe_center_stretch_preserves_caps_and_exact_size(self):
        image = Image.new("RGBA", (30, 10), (150, 20, 10, 255))
        for y in range(10):
            for x in range(5):
                image.putpixel((x, y), (220, 170, 40, 255))
                image.putpixel((29 - x, y), (220, 170, 40, 255))

        output = stretch_safe_center(
            image,
            output_size=(60, 20),
            cap_width=5,
            padding=2,
        )

        self.assertEqual((60, 20), output.size)
        self.assertEqual((0, 0, 0, 0), output.getpixel((0, 0)))
        self.assertEqual((220, 170, 40, 255), output.getpixel((3, 10)))
        self.assertEqual((150, 20, 10, 255), output.getpixel((30, 10)))
        self.assertEqual((220, 170, 40, 255), output.getpixel((56, 10)))

    def test_sanitizes_only_forbidden_edge_artifacts(self):
        image = Image.new("RGBA", (3, 1), (248, 240, 220, 255))
        image.putpixel((0, 0), (0, 255, 0, 128))
        image.putpixel((1, 0), (250, 250, 250, 96))

        cleaned = sanitize_output_edges(image)

        self.assertEqual((0, 0, 0, 0), cleaned.getpixel((0, 0)))
        self.assertEqual((0, 0, 0, 0), cleaned.getpixel((1, 0)))
        self.assertEqual((248, 240, 220, 255), cleaned.getpixel((2, 0)))

    def test_build_asset_honors_declared_palette_size(self):
        source = Image.new("RGB", (32, 16), (0, 255, 0))
        for y in range(1, 15):
            for x in range(1, 31):
                source.putpixel((x, y), (120 + (x % 30) * 4, 20 + y, 10))
        source_path = self.root / "source.png"
        output_path = self.root / "output.png"
        source.save(source_path)
        asset = {
            "id": "palette-test",
            "source": "source.png",
            "output": "output.png",
            "outputPixels": {"width": 60, "height": 30},
            "alpha": {"transparentOuterPadding": 1},
            "processing": {
                "capWidth": 4,
                "keyColor": "#00FF00",
                "keyTolerance": 80,
                "paletteColors": 8,
            },
        }

        build_asset(asset, self.root)

        with Image.open(output_path) as output:
            visible_colors = {
                pixel[:3] for pixel in output.convert("RGBA").get_flattened_data() if pixel[3] > 0
            }
        self.assertLessEqual(len(visible_colors), 8)


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