#pragma once
#include <cstddef>
#include "prelude/string.hpp"

template<typename T>
struct ListNode
{
    T value;
    ListNode* prev = nullptr;
    ListNode* next = nullptr;
};

template<typename T>
class DoubleLinkedList {
public:
    DoubleLinkedList() = default;

public:
    static DoubleLinkedList<T> FromView(const View<T> &view)
    {
        auto list = DoubleLinkedList<T>();
        for (size_t i = 0; i < view.size; ++i)
        {
            list.Append(new ListNode<T>(view.data[i]));
        }
        return list;
    }

public:
    View<T> ToView()
    {
        Builder<T> b;
        for(ListNode<T>* cur = Begin(); cur != nullptr; cur = cur->next)
        {
            b.Push(cur->value);
        }
        return b.view();
    }

public:
    void Append(ListNode<T>* node)
    {
        if (IsEmpty())
        {
            node->next = nullptr;
            node->prev = nullptr;
            tail = node;
            head = node;
        } else {
            head->next = node;
            node->prev = head;
            node->next = nullptr;
            head = node;
        }
        m_size++;
    }

    void Prepend(ListNode<T>* node)
    {
        if (IsEmpty())
        {
            Append(node);
        } else {
            tail->prev = node;
            node->next = tail;
            node->prev = nullptr;
            tail = node;
            m_size++;
        }
    }

    void SpliceFront(ListNode<T>* node)
    {
        if (m_size == 1 && tail == node && head == node) return;
        assert((node->next || node->prev) && "node should be inside of the linked list");
        if (node == tail) return;
        if (node == head) {
            node->prev->next = nullptr;
            head = node->prev;
        } else {
            node->prev->next = node->next;
            node->next->prev = node->prev;
        }
        m_size--;
        Prepend(node);
    }

    bool IsEmpty() const { return m_size == 0; }

    ListNode<T>* Begin() const { return tail; }
    ListNode<T>* End() const { return head; }
private:
    ListNode<T>* head = nullptr;
    ListNode<T>* tail = nullptr;
    size_t m_size = 0;
};