#pragma once
namespace renderive {
template <typename T>
struct Circular_Linked_List_Node {
    Circular_Linked_List_Node *prev = nullptr, *next = nullptr;
    T data;
};
template <typename T>
class Circular_Linked_List {
public:
    Circular_Linked_List_Node<T>* head = nullptr;
    Circular_Linked_List_Node<T>* cur = nullptr;
    void init(const std::vector<T>& data_list) {
        head = new Circular_Linked_List_Node<T>();
        head->data = data_list.front();
        Circular_Linked_List_Node<T>* prev = head;
        int n = data_list.size();
        for (int i = 1; i < n - 1; i++) {
            auto node = new Circular_Linked_List_Node<T>();
            node->data = data_list[i];
            node->prev = prev;
            prev->next = node;
            prev = node;
        }
        auto tail = new Circular_Linked_List_Node<T>();
        tail->data = data_list.back();
        tail->prev = prev;
        prev->next = tail;
        tail->next = head;
        head->prev = tail;
        cur = head;
    }
    Circular_Linked_List_Node<T>* move(int step = 1) {
        if (step == 0)
            return nullptr;
        return step > 0 ? next(step) : prev(-step);
    }
    Circular_Linked_List_Node<T>* next(int step = 1) {
        if (step <= 0)
            return nullptr;
        for (int i = 0; i < step; i++) {
            cur = cur->next;
        }
        return cur;
    }
    Circular_Linked_List_Node<T>* prev(int step = 1) {
        if (step <= 0)
            return nullptr;
        for (int i = 0; i < step; i++) {
            cur = cur->prev;
        }
        return cur;
    }
    void insert_next(const T& t, Circular_Linked_List_Node<T>* that = nullptr) {
        if (that == nullptr)
            that = cur;
        auto node = new Circular_Linked_List_Node<T>();
        node->data = t;
        node->next = that->next;
        node->prev = that;
        that->next = node;
    }
    void insert_prev(const T& t, Circular_Linked_List_Node<T>* that = nullptr) {
        if (that == nullptr)
            that = cur;
        auto node = new Circular_Linked_List_Node<T>();
        node->data = t;
        node->prev = that->prev;
        node->next = that;
        that->prev = node;
    }
    std::vector<Circular_Linked_List_Node<T>*> to_vector() {
        if (head == nullptr)
            return {};
        std::vector<Circular_Linked_List_Node<T>*> ret;
        Circular_Linked_List_Node<T>* cur = head;
        do {
            ret.push_back(cur);
            cur = cur->next;
        }
        while (cur != head);
        return ret;
    }
    void clear() {
        if (head == nullptr)
            return;
        Circular_Linked_List_Node<T>* cur = head;
        do {
            Circular_Linked_List_Node<T>* temp = cur;
            cur = cur->next;
            delete temp;
        }
        while (cur != head);
        head = nullptr;
    }
    ~Circular_Linked_List() {
        clear();
    }
};
} // namespace renderive