import math
import unittest

from cachetools import TLRUCache

from . import CacheTestMixin


class Timer:
    def __init__(self, auto=False):
        self.auto = auto
        self.time = 0

    def __call__(self):
        if self.auto:
            self.time += 1
        return self.time

    def tick(self):
        self.time += 1


class TLRUTestCache(TLRUCache):
    def default_ttu(_key, _value, _time):
        return math.inf

    def __init__(self, maxsize, ttu=default_ttu, **kwargs):
        TLRUCache.__init__(self, maxsize, ttu, timer=Timer(), **kwargs)


class TLRUCacheTest(unittest.TestCase, CacheTestMixin):
    Cache = TLRUTestCache

    def test_ttu(self):
        cache = TLRUCache(maxsize=6, ttu=lambda _, v, t: t + v + 1, timer=Timer())
        self.assertEqual(0, cache.timer())
        self.assertEqual(3, cache.ttu(None, 1, 1))

        cache[1] = 1
        self.assertEqual(1, cache[1])
        self.assertEqual(1, len(cache))
        self.assertEqual({1}, set(cache))

        cache.timer.tick()
        self.assertEqual(1, cache[1])
        self.assertEqual(1, len(cache))
        self.assertEqual({1}, set(cache))

        cache[2] = 2
        self.assertEqual(1, cache[1])
        self.assertEqual(2, cache[2])
        self.assertEqual(2, len(cache))
        self.assertEqual({1, 2}, set(cache))

        cache.timer.tick()
        self.assertNotIn(1, cache)
        self.assertEqual(2, cache[2])
        self.assertEqual(1, len(cache))
        self.assertEqual({2}, set(cache))

        cache[3] = 3
        self.assertNotIn(1, cache)
        self.assertEqual(2, cache[2])
        self.assertEqual(3, cache[3])
        self.assertEqual(2, len(cache))
        self.assertEqual({2, 3}, set(cache))

        cache.timer.tick()
        self.assertNotIn(1, cache)
        self.assertEqual(2, cache[2])
        self.assertEqual(3, cache[3])
        self.assertEqual(2, len(cache))
        self.assertEqual({2, 3}, set(cache))

        cache[1] = 1
        self.assertEqual(1, cache[1])
        self.assertEqual(2, cache[2])
        self.assertEqual(3, cache[3])
        self.assertEqual(3, len(cache))
        self.assertEqual({1, 2, 3}, set(cache))

        cache.timer.tick()
        self.assertEqual(1, cache[1])
        self.assertNotIn(2, cache)
        self.assertEqual(3, cache[3])
        self.assertEqual(2, len(cache))
        self.assertEqual({1, 3}, set(cache))

        cache.timer.tick()
        self.assertNotIn(1, cache)
        self.assertNotIn(2, cache)
        self.assertEqual(3, cache[3])
        self.assertEqual(1, len(cache))
        self.assertEqual({3}, set(cache))

        cache.timer.tick()
        self.assertNotIn(1, cache)
        self.assertNotIn(2, cache)
        self.assertNotIn(3, cache)

        with self.assertRaises(KeyError):
            del cache[1]
        with self.assertRaises(KeyError):
            cache.pop(2)
        with self.assertRaises(KeyError):
            del cache[3]

        self.assertEqual(0, len(cache))
        self.assertEqual(set(), set(cache))

    def test_ttu_lru(self):
        cache = TLRUCache(maxsize=2, ttu=lambda k, v, t: t + 1, timer=Timer())
        self.assertEqual(0, cache.timer())
        self.assertEqual(2, cache.ttu(None, None, 1))

        cache[1] = 1
        cache[2] = 2
        cache[3] = 3

        self.assertEqual(len(cache), 2)
        self.assertNotIn(1, cache)
        self.assertEqual(cache[2], 2)
        self.assertEqual(cache[3], 3)

        cache[2]
        cache[4] = 4
        self.assertEqual(len(cache), 2)
        self.assertNotIn(1, cache)
        self.assertEqual(cache[2], 2)
        self.assertNotIn(3, cache)
        self.assertEqual(cache[4], 4)

        cache[5] = 5
        self.assertEqual(len(cache), 2)
        self.assertNotIn(1, cache)
        self.assertNotIn(2, cache)
        self.assertNotIn(3, cache)
        self.assertEqual(cache[4], 4)
        self.assertEqual(cache[5], 5)

    def test_ttu_expire(self):
        cache = TLRUCache(maxsize=3, ttu=lambda k, v, t: t + 3, timer=Timer())
        with cache.timer as time:
            self.assertEqual(time, cache.timer())

        cache[1] = 1
        cache.timer.tick()
        cache[2] = 2
        cache.timer.tick()
        cache[3] = 3
        self.assertEqual(2, cache.timer())

        self.assertEqual({1, 2, 3}, set(cache))
        self.assertEqual(3, len(cache))
        self.assertEqual(1, cache[1])
        self.assertEqual(2, cache[2])
        self.assertEqual(3, cache[3])

        items = cache.expire()
        self.assertEqual(set(), set(items))
        self.assertEqual({1, 2, 3}, set(cache))
        self.assertEqual(3, len(cache))
        self.assertEqual(1, cache[1])
        self.assertEqual(2, cache[2])
        self.assertEqual(3, cache[3])

        items = cache.expire(3)
        self.assertEqual({(1, 1)}, set(items))
        self.assertEqual({2, 3}, set(cache))
        self.assertEqual(2, len(cache))
        self.assertNotIn(1, cache)
        self.assertEqual(2, cache[2])
        self.assertEqual(3, cache[3])

        items = cache.expire(4)
        self.assertEqual({(2, 2)}, set(items))
        self.assertEqual({3}, set(cache))
        self.assertEqual(1, len(cache))
        self.assertNotIn(1, cache)
        self.assertNotIn(2, cache)
        self.assertEqual(3, cache[3])

        items = cache.expire(5)
        self.assertEqual({(3, 3)}, set(items))
        self.assertEqual(set(), set(cache))
        self.assertEqual(0, len(cache))
        self.assertNotIn(1, cache)
        self.assertNotIn(2, cache)
        self.assertNotIn(3, cache)

    def test_ttu_expired(self):
        cache = TLRUCache(maxsize=1, ttu=lambda k, _, t: t + k, timer=Timer())
        cache[1] = None
        self.assertEqual(cache[1], None)
        self.assertEqual(1, len(cache))
        cache[0] = None
        self.assertNotIn(0, cache)
        self.assertEqual(cache[1], None)
        self.assertEqual(1, len(cache))
        cache[-1] = None
        self.assertNotIn(-1, cache)
        self.assertNotIn(0, cache)
        self.assertEqual(cache[1], None)
        self.assertEqual(1, len(cache))

    def test_ttu_atomic(self):
        cache = TLRUCache(maxsize=1, ttu=lambda k, v, t: t + 2, timer=Timer(auto=True))
        cache[1] = 1
        self.assertEqual(1, cache[1])
        cache[1] = 1
        self.assertEqual(1, cache.get(1))
        cache[1] = 1
        self.assertEqual(1, cache.pop(1))
        cache[1] = 1
        self.assertEqual(1, cache.setdefault(1))
        cache[1] = 1
        cache.clear()
        self.assertEqual(0, len(cache))

    def test_ttu_tuple_key(self):
        cache = TLRUCache(maxsize=1, ttu=lambda k, v, t: t + 1, timer=Timer())

        cache[(1, 2, 3)] = 42
        self.assertEqual(42, cache[(1, 2, 3)])
        cache.timer.tick()
        with self.assertRaises(KeyError):
            cache[(1, 2, 3)]
        self.assertNotIn((1, 2, 3), cache)

    def test_ttu_reverse_insert(self):
        cache = TLRUCache(maxsize=4, ttu=lambda k, v, t: t + v, timer=Timer())
        self.assertEqual(0, cache.timer())

        cache[3] = 3
        cache[2] = 2
        cache[1] = 1
        cache[0] = 0

        self.assertEqual({1, 2, 3}, set(cache))
        self.assertEqual(3, len(cache))
        self.assertNotIn(0, cache)
        self.assertEqual(1, cache[1])
        self.assertEqual(2, cache[2])
        self.assertEqual(3, cache[3])

        cache.timer.tick()

        self.assertEqual({2, 3}, set(cache))
        self.assertEqual(2, len(cache))
        self.assertNotIn(0, cache)
        self.assertNotIn(1, cache)
        self.assertEqual(2, cache[2])
        self.assertEqual(3, cache[3])

        cache.timer.tick()

        self.assertEqual({3}, set(cache))
        self.assertEqual(1, len(cache))
        self.assertNotIn(0, cache)
        self.assertNotIn(1, cache)
        self.assertNotIn(2, cache)
        self.assertEqual(3, cache[3])

        cache.timer.tick()

        self.assertEqual(set(), set(cache))
        self.assertEqual(0, len(cache))
        self.assertNotIn(0, cache)
        self.assertNotIn(1, cache)
        self.assertNotIn(2, cache)
        self.assertNotIn(3, cache)