// Copyright 2023 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <Common/SimpleIntrusiveNode.h>
#include <TestUtils/TiFlashTestBasic.h>

namespace DB::tests
{
namespace
{
template <typename T, typename F>
auto getElems(T * head, F && getter)
{
    std::vector<decltype(getter(head))> elems;
    elems.push_back(getter(head));
    for (auto * next = head->next; next != head; next = next->next)
        elems.push_back(getter(next));
    return elems;
}

struct IntNode : public SimpleIntrusiveNode<IntNode>
{
    int v;

    explicit IntNode(int x)
        : SimpleIntrusiveNode<IntNode>()
        , v(x)
    {}
};

int getValue(const IntNode * node)
{
    return node->v;
}

std::vector<int> vec(std::initializer_list<int> l)
{
    return l;
}

TEST(SimpleIntrusiveNode, testSingleNode)
{
    IntNode n(0);
    ASSERT_EQ(n.isSingle(), true);
    ASSERT_EQ(getElems(&n, getValue), vec({0}));
}

TEST(SimpleIntrusiveNode, testOperateOnSelf)
{
    IntNode n(0);

    n.appendTo(&n);
    ASSERT_EQ(n.isSingle(), true);
    ASSERT_EQ(getElems(&n, getValue), vec({0}));

    n.prependTo(&n);
    ASSERT_EQ(n.isSingle(), true);
    ASSERT_EQ(getElems(&n, getValue), vec({0}));

    n.detach();
    ASSERT_EQ(n.isSingle(), true);
    ASSERT_EQ(getElems(&n, getValue), vec({0}));
}

TEST(SimpleIntrusiveNode, testAppendTo)
{
    IntNode n0(0), n1(1), n2(2);
    n1.appendTo(&n0);
    n2.appendTo(&n1);

    ASSERT_EQ(getElems(&n0, getValue), vec({0, 1, 2}));
}

TEST(SimpleIntrusiveNode, testPrependTo)
{
    IntNode n0(0), n1(1), n2(2);
    n1.prependTo(&n0);
    n2.prependTo(&n1);

    ASSERT_EQ(getElems(&n0, getValue), vec({0, 2, 1}));
}
} // namespace
} // namespace DB::tests