import shutil
import tempfile
import unittest
from pathlib import Path

import numpy as np
from PIL import Image

from mapgen import sketch as SK
from mapgen.pipeline import StageError
from tests.helpers import make_ctx


class SampleTest(unittest.TestCase):
    def test_bilinear_centres_and_wrap(self):
        img = np.arange(32, dtype=np.float64).reshape(4, 8)
        # pixel (1, 2) centre: lon = 2.5/8*360-180 = -67.5, lat = 90-1.5/4*180 = 22.5
        self.assertAlmostEqual(SK.sample_equirect(img, np.array([22.5]), np.array([-67.5]))[0], img[1, 2])
        a = SK.sample_equirect(img, np.array([22.5]), np.array([179.999]))[0]
        b = SK.sample_equirect(img, np.array([22.5]), np.array([-179.999]))[0]
        self.assertAlmostEqual(a, b, places=2)  # wraps across the antimeridian
        self.assertAlmostEqual(SK.sample_equirect(img, np.array([90.0]), np.array([-157.5]))[0], img[0, 0])

    def test_mask_8bit_and_any_size(self):
        tmp = Path(tempfile.mkdtemp())
        try:
            Image.fromarray(np.full((19, 37), 255, np.uint8), "L").save(tmp / "a.png")
            Image.fromarray(np.full((10, 20), 32768, np.uint16)).save(tmp / "b.png")
            self.assertGreater(SK.load_mask(tmp / "a.png").min(), 0.99)
            self.assertAlmostEqual(float(np.abs(SK.load_mask(tmp / "b.png")).max()), 0.0)
        finally:
            shutil.rmtree(tmp)


class StageTest(unittest.TestCase):
    def setUp(self):
        self.tmp = Path(tempfile.mkdtemp())

    def tearDown(self):
        shutil.rmtree(self.tmp)

    def test_requires_import(self):
        ctx = make_ctx(1, root=self.tmp)
        with self.assertRaisesRegex(StageError, "new-world"):
            SK.run(ctx)

    def test_outputs(self):
        (self.tmp / "sketch").mkdir()
        land = np.zeros((100, 200), np.uint8)
        land[:, :100] = 255  # western hemisphere is land
        for n in SK.SKETCH:
            Image.fromarray(land if n == "land" else np.zeros_like(land), "L").save(self.tmp / "sketch" / f"{n}.png")
        ctx = make_ctx(2, root=self.tmp)
        out = SK.run(ctx)
        g = ctx.grid
        self.assertGreater(out["sk_land"][g.lon < -10].mean(), 0.95)
        self.assertLess(out["sk_land"][g.lon > 10].mean(), 0.05)
        for m in SK.MASKS:
            self.assertTrue(np.all(out[f"m_{m}"] == 0))


class MaskFormatsTest(unittest.TestCase):
    def setUp(self):
        self.tmp = Path(tempfile.mkdtemp())

    def tearDown(self):
        shutil.rmtree(self.tmp)

    def test_gimp_formats(self):
        Image.fromarray(np.full((8, 16), 128, np.uint8), "L").save(self.tmp / "grey.png")
        pal = Image.new("P", (16, 8), 0)
        pal.putpalette([128, 128, 128, 255, 255, 255] + [0] * 762)
        pal.save(self.tmp / "pal_grey.png")
        pal.paste(1, (0, 0, 16, 8))
        pal.save(self.tmp / "pal_white.png")
        Image.new("1", (16, 8), 1).save(self.tmp / "bit_white.png")
        Image.new("RGBA", (16, 8), (0, 0, 0, 0)).save(self.tmp / "clear.png")
        self.assertEqual(float(np.abs(SK.load_mask(self.tmp / "grey.png")).max()), 0.0)
        self.assertEqual(float(np.abs(SK.load_mask(self.tmp / "pal_grey.png")).max()), 0.0)
        self.assertAlmostEqual(float(SK.load_mask(self.tmp / "pal_white.png").min()), 1.0)
        self.assertAlmostEqual(float(SK.load_mask(self.tmp / "bit_white.png").min()), 1.0)
        self.assertEqual(float(np.abs(SK.load_mask(self.tmp / "clear.png")).max()), 0.0)

    def test_corrupt_mask_is_stage_error(self):
        (self.tmp / "bad.png").write_bytes(b"not a png")
        with self.assertRaisesRegex(StageError, "bad.png"):
            SK.load_mask(self.tmp / "bad.png")


class SketchWarpTest(unittest.TestCase):
    def setUp(self):
        self.tmp = Path(tempfile.mkdtemp())
        (self.tmp / "sketch").mkdir()
        lat = 90 - (np.arange(100) + 0.5) * 1.8
        lon = (np.arange(200) + 0.5) * 1.8 - 180
        LA, LO = np.meshgrid(lat, lon, indexing="ij")
        land = ((np.abs(LA) < 35) & (np.abs(LO) < 60)).astype(np.uint8) * 255
        for n in SK.SKETCH:
            Image.fromarray(land if n == "land" else np.zeros_like(land), "L").save(self.tmp / "sketch" / f"{n}.png")

    def tearDown(self):
        shutil.rmtree(self.tmp)

    def _land(self, **over):
        ctx = make_ctx(3, root=self.tmp, cfg={"sketch": over} if over else None)
        return SK.run(ctx)["sk_land"] > 0.5, ctx.grid

    def test_warp_off_matches_drawing(self):
        warped, g = self._land(warp_km=0.0, detail_warp_km=0.0)
        direct = SK.sample_equirect(SK.load_png01(self.tmp / "sketch" / "land.png"), g.lat, g.lon) > 0.5
        np.testing.assert_array_equal(warped, direct)

    def test_default_warp_deviates_but_keeps_continent(self):
        straight, g = self._land(warp_km=0.0, detail_warp_km=0.0)
        warped, _ = self._land()
        iou = (warped & straight).sum() / (warped | straight).sum()
        self.assertTrue(0.35 < iou < 0.85, iou)
        again, _ = self._land()
        np.testing.assert_array_equal(warped, again)


class SketchMoveTest(unittest.TestCase):
    def setUp(self):
        self.tmp = Path(tempfile.mkdtemp())
        (self.tmp / "sketch").mkdir()
        lat = 90 - (np.arange(200) + 0.5) * 0.9
        lon = (np.arange(400) + 0.5) * 0.9 - 180
        LA, LO = np.meshgrid(lat, lon, indexing="ij")
        land = (((LA - 0) ** 2 + (LO - 0) ** 2 < 15 ** 2) | ((LA + 40) ** 2 + (LO - 100) ** 2 < 10 ** 2))
        for n in SK.SKETCH:
            Image.fromarray((land * 255).astype(np.uint8) if n == "land" else np.zeros(land.shape, np.uint8), "L") \
                .save(self.tmp / "sketch" / f"{n}.png")

    def tearDown(self):
        shutil.rmtree(self.tmp)

    def _land(self, moves):
        ctx = make_ctx(4, root=self.tmp, cfg={"sketch": {"warp_km": 0.0, "detail_warp_km": 0.0, "moves": moves}})
        return SK.run(ctx)["sk_land"] > 0.5, ctx.grid

    def test_move_rotates_one_continent_and_keeps_its_area(self):
        before, g = self._land([])
        after, _ = self._land([{"at": [0.0, 0.0], "to": [30.0, 0.0]}])
        near = lambda la, lo, r: g.radius_km * np.arccos(np.clip(g.xyz @ g.xyz[g.cell_index(la, lo)], -1, 1)) < r
        self.assertTrue(before[near(0.0, 0.0, 800)].all() and not after[near(0.0, 0.0, 800)].any())
        self.assertTrue(after[near(30.0, 0.0, 800)].all())
        other = near(-40.0, 100.0, 600)
        np.testing.assert_array_equal(before[other], after[other])            # the other island stays
        a = g.area_km2
        moved_area = a[after & ~other].sum() / a[before & ~other].sum()
        self.assertAlmostEqual(moved_area, 1.0, delta=0.05)                   # rotation preserves area