#include <cassert>
#include <iostream>
#include <sstream>

struct Node
{
    int value { };
    Node* next { };
};

class Circular_List
{
public:
    Circular_List() = default;
    
    // TODO: Implement destructor

    void push_front(int value)
    {
        Node* head { /* TODO: Allocate node */ };
        if (tail == nullptr)
        {
            head->next = head;
            tail = head;
        }
        else
        {
            head->next = tail->next;
            tail->next = head;
        }
    }

    int pop_front()
    {
        Node* head { tail->next };
        int value { head->value };

        if (head == tail)
        {
            tail = nullptr;
        }
        else
        {
            tail->next = head->next;
        }

        /* TODO: Deallocate head */
        return value;
    }

    // TODO: Implement front()

    // TODO: Implement rotate()

    // TODO: Implement print()

private:

    Node* tail { nullptr };

};



int main()
{
    Circular_List list { };

    {
        std::ostringstream oss { };
        list.print(oss);
        assert( oss.str() == "[ ]" );
    }


    list.rotate();
    {
        std::ostringstream oss { };
        list.print(oss);
        assert( oss.str() == "[ ]" );
    }
    

    list.push_front(1);
    list.push_front(2);
    list.push_front(3);

    {
        std::ostringstream oss { };
        list.print(oss);
        assert( oss.str() == "[ 3 2 1 ]" );   
    }

    // test front
    assert( list.front() == 3 );

    // test rotate
    {
        list.rotate();

        std::ostringstream oss { };
        list.print(oss);
        assert( oss.str() == "[ 2 1 3 ]" );
	assert( list.front() == 2 );
    }

    // test rotate together with pop_front() and push_front()
    {
        list.rotate();
        list.pop_front();
        list.rotate();
        list.push_front(1);

        std::ostringstream oss { };
        list.print(oss);
        assert( oss.str() == "[ 1 2 3 ]" );
    }
}