#ifndef STACK2QUEUE_H
#define STACK2QUEUE_H

#include "LinkedStack.h"
#include "Queue.h"
#include <initializer_list>

namespace Kylin {
template <typename T>
class StackToQueue : public Queue<T> {
public:
    StackToQueue(std::initializer_list<T> init) {
        for (auto &value : init) enqueue(value);
    }
    void enqueue(const T &value) final { m_in.push(value); }

    T dequeue() final {
        if (size() <= 0) THROW_EXCEPTION(InvalidOperationException, "There is no element in the queue...");
        auto value = head();
        move();
        m_out.pop();
        return value;
    }
    T &head() final {
        if (size() <= 0) THROW_EXCEPTION(InvalidOperationException, "There is no element in the queue...");
        move();
        return m_out.top();
    }

    virtual void clear() {
        m_in.clear();
        m_out.clear();
    }

    size_t size() const noexcept override { return m_in.size() + m_out.size(); }

protected:
    void move() const {
        if (m_out.size() <= 0) {
            while (m_in.size() > 0) {
                m_out.push(m_in.top());
                m_in.pop();
            }
        }
    }

private:
    mutable LinkedStack<T> m_in;
    mutable LinkedStack<T> m_out;
};
} // namespace Kylin
#endif // STACK2QUEUE_H