import sys
import unittest

import pytest
from PIL import Image

from .helper import PillowTestCase, is_pypy


def test_get_stats():
    # Create at least one image
    Image.new("RGB", (10, 10))

    stats = Image.core.get_stats()
    assert "new_count" in stats
    assert "reused_blocks" in stats
    assert "freed_blocks" in stats
    assert "allocated_blocks" in stats
    assert "reallocated_blocks" in stats
    assert "blocks_cached" in stats


def test_reset_stats():
    Image.core.reset_stats()

    stats = Image.core.get_stats()
    assert stats["new_count"] == 0
    assert stats["reused_blocks"] == 0
    assert stats["freed_blocks"] == 0
    assert stats["allocated_blocks"] == 0
    assert stats["reallocated_blocks"] == 0
    assert stats["blocks_cached"] == 0


class TestCoreMemory(PillowTestCase):
    def tearDown(self):
        # Restore default values
        Image.core.set_alignment(1)
        Image.core.set_block_size(1024 * 1024)
        Image.core.set_blocks_max(0)
        Image.core.clear_cache()

    def test_get_alignment(self):
        alignment = Image.core.get_alignment()

        self.assertGreater(alignment, 0)

    def test_set_alignment(self):
        for i in [1, 2, 4, 8, 16, 32]:
            Image.core.set_alignment(i)
            alignment = Image.core.get_alignment()
            self.assertEqual(alignment, i)

            # Try to construct new image
            Image.new("RGB", (10, 10))

        self.assertRaises(ValueError, Image.core.set_alignment, 0)
        self.assertRaises(ValueError, Image.core.set_alignment, -1)
        self.assertRaises(ValueError, Image.core.set_alignment, 3)

    def test_get_block_size(self):
        block_size = Image.core.get_block_size()

        self.assertGreaterEqual(block_size, 4096)

    def test_set_block_size(self):
        for i in [4096, 2 * 4096, 3 * 4096]:
            Image.core.set_block_size(i)
            block_size = Image.core.get_block_size()
            self.assertEqual(block_size, i)

            # Try to construct new image
            Image.new("RGB", (10, 10))

        self.assertRaises(ValueError, Image.core.set_block_size, 0)
        self.assertRaises(ValueError, Image.core.set_block_size, -1)
        self.assertRaises(ValueError, Image.core.set_block_size, 4000)

    def test_set_block_size_stats(self):
        Image.core.reset_stats()
        Image.core.set_blocks_max(0)
        Image.core.set_block_size(4096)
        Image.new("RGB", (256, 256))

        stats = Image.core.get_stats()
        self.assertGreaterEqual(stats["new_count"], 1)
        self.assertGreaterEqual(stats["allocated_blocks"], 64)
        if not is_pypy():
            self.assertGreaterEqual(stats["freed_blocks"], 64)

    def test_get_blocks_max(self):
        blocks_max = Image.core.get_blocks_max()

        self.assertGreaterEqual(blocks_max, 0)

    def test_set_blocks_max(self):
        for i in [0, 1, 10]:
            Image.core.set_blocks_max(i)
            blocks_max = Image.core.get_blocks_max()
            self.assertEqual(blocks_max, i)

            # Try to construct new image
            Image.new("RGB", (10, 10))

        self.assertRaises(ValueError, Image.core.set_blocks_max, -1)
        if sys.maxsize < 2 ** 32:
            self.assertRaises(ValueError, Image.core.set_blocks_max, 2 ** 29)

    @unittest.skipIf(is_pypy(), "images are not collected")
    def test_set_blocks_max_stats(self):
        Image.core.reset_stats()
        Image.core.set_blocks_max(128)
        Image.core.set_block_size(4096)
        Image.new("RGB", (256, 256))
        Image.new("RGB", (256, 256))

        stats = Image.core.get_stats()
        self.assertGreaterEqual(stats["new_count"], 2)
        self.assertGreaterEqual(stats["allocated_blocks"], 64)
        self.assertGreaterEqual(stats["reused_blocks"], 64)
        self.assertEqual(stats["freed_blocks"], 0)
        self.assertEqual(stats["blocks_cached"], 64)

    @unittest.skipIf(is_pypy(), "images are not collected")
    def test_clear_cache_stats(self):
        Image.core.reset_stats()
        Image.core.clear_cache()
        Image.core.set_blocks_max(128)
        Image.core.set_block_size(4096)
        Image.new("RGB", (256, 256))
        Image.new("RGB", (256, 256))
        # Keep 16 blocks in cache
        Image.core.clear_cache(16)

        stats = Image.core.get_stats()
        self.assertGreaterEqual(stats["new_count"], 2)
        self.assertGreaterEqual(stats["allocated_blocks"], 64)
        self.assertGreaterEqual(stats["reused_blocks"], 64)
        self.assertGreaterEqual(stats["freed_blocks"], 48)
        self.assertEqual(stats["blocks_cached"], 16)

    def test_large_images(self):
        Image.core.reset_stats()
        Image.core.set_blocks_max(0)
        Image.core.set_block_size(4096)
        Image.new("RGB", (2048, 16))
        Image.core.clear_cache()

        stats = Image.core.get_stats()
        self.assertGreaterEqual(stats["new_count"], 1)
        self.assertGreaterEqual(stats["allocated_blocks"], 16)
        self.assertGreaterEqual(stats["reused_blocks"], 0)
        self.assertEqual(stats["blocks_cached"], 0)
        if not is_pypy():
            self.assertGreaterEqual(stats["freed_blocks"], 16)


class TestEnvVars(PillowTestCase):
    def tearDown(self):
        # Restore default values
        Image.core.set_alignment(1)
        Image.core.set_block_size(1024 * 1024)
        Image.core.set_blocks_max(0)
        Image.core.clear_cache()

    def test_units(self):
        Image._apply_env_variables({"PILLOW_BLOCKS_MAX": "2K"})
        self.assertEqual(Image.core.get_blocks_max(), 2 * 1024)
        Image._apply_env_variables({"PILLOW_BLOCK_SIZE": "2m"})
        self.assertEqual(Image.core.get_block_size(), 2 * 1024 * 1024)

    def test_warnings(self):
        pytest.warns(
            UserWarning, Image._apply_env_variables, {"PILLOW_ALIGNMENT": "15"}
        )
        pytest.warns(
            UserWarning, Image._apply_env_variables, {"PILLOW_BLOCK_SIZE": "1024"}
        )
        pytest.warns(
            UserWarning, Image._apply_env_variables, {"PILLOW_BLOCKS_MAX": "wat"}
        )