from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import numpy as np

from ray.rllib.optimizers.segment_tree import SumSegmentTree, MinSegmentTree


def test_tree_set():
    tree = SumSegmentTree(4)

    tree[2] = 1.0
    tree[3] = 3.0

    assert np.isclose(tree.sum(), 4.0)
    assert np.isclose(tree.sum(0, 2), 0.0)
    assert np.isclose(tree.sum(0, 3), 1.0)
    assert np.isclose(tree.sum(2, 3), 1.0)
    assert np.isclose(tree.sum(2, -1), 1.0)
    assert np.isclose(tree.sum(2, 4), 4.0)


def test_tree_set_overlap():
    tree = SumSegmentTree(4)

    tree[2] = 1.0
    tree[2] = 3.0

    assert np.isclose(tree.sum(), 3.0)
    assert np.isclose(tree.sum(2, 3), 3.0)
    assert np.isclose(tree.sum(2, -1), 3.0)
    assert np.isclose(tree.sum(2, 4), 3.0)
    assert np.isclose(tree.sum(1, 2), 0.0)


def test_prefixsum_idx():
    tree = SumSegmentTree(4)

    tree[2] = 1.0
    tree[3] = 3.0

    assert tree.find_prefixsum_idx(0.0) == 2
    assert tree.find_prefixsum_idx(0.5) == 2
    assert tree.find_prefixsum_idx(0.99) == 2
    assert tree.find_prefixsum_idx(1.01) == 3
    assert tree.find_prefixsum_idx(3.00) == 3
    assert tree.find_prefixsum_idx(4.00) == 3


def test_prefixsum_idx2():
    tree = SumSegmentTree(4)

    tree[0] = 0.5
    tree[1] = 1.0
    tree[2] = 1.0
    tree[3] = 3.0

    assert tree.find_prefixsum_idx(0.00) == 0
    assert tree.find_prefixsum_idx(0.55) == 1
    assert tree.find_prefixsum_idx(0.99) == 1
    assert tree.find_prefixsum_idx(1.51) == 2
    assert tree.find_prefixsum_idx(3.00) == 3
    assert tree.find_prefixsum_idx(5.50) == 3


def test_max_interval_tree():
    tree = MinSegmentTree(4)

    tree[0] = 1.0
    tree[2] = 0.5
    tree[3] = 3.0

    assert np.isclose(tree.min(), 0.5)
    assert np.isclose(tree.min(0, 2), 1.0)
    assert np.isclose(tree.min(0, 3), 0.5)
    assert np.isclose(tree.min(0, -1), 0.5)
    assert np.isclose(tree.min(2, 4), 0.5)
    assert np.isclose(tree.min(3, 4), 3.0)

    tree[2] = 0.7

    assert np.isclose(tree.min(), 0.7)
    assert np.isclose(tree.min(0, 2), 1.0)
    assert np.isclose(tree.min(0, 3), 0.7)
    assert np.isclose(tree.min(0, -1), 0.7)
    assert np.isclose(tree.min(2, 4), 0.7)
    assert np.isclose(tree.min(3, 4), 3.0)

    tree[2] = 4.0

    assert np.isclose(tree.min(), 1.0)
    assert np.isclose(tree.min(0, 2), 1.0)
    assert np.isclose(tree.min(0, 3), 1.0)
    assert np.isclose(tree.min(0, -1), 1.0)
    assert np.isclose(tree.min(2, 4), 3.0)
    assert np.isclose(tree.min(2, 3), 4.0)
    assert np.isclose(tree.min(2, -1), 4.0)
    assert np.isclose(tree.min(3, 4), 3.0)


if __name__ == "__main__":
    test_tree_set()
    test_tree_set_overlap()
    test_prefixsum_idx()
    test_prefixsum_idx2()
    test_max_interval_tree()