#include <stdio.h>
#include <stdlib.h>
#include "function.h"

size_t sz = 0;

Node *newNode(unsigned short val) {
	Node *temp = (Node *)malloc(sizeof(Node));
	temp->val = val;
	temp->prev = temp->next = NULL;
	return temp;
}

void do_I(Node **head, size_t pos, unsigned short val) {
	++sz;
	if (head == NULL || *head == NULL || sz - 1 == 0) {
		*head = newNode(val);
		(*head)->next = (*head)->prev = *head;
		return ;
	}
	if (pos == 0) {
		Node *temp = newNode(val);
		Node *last = (*head)->prev;
		temp->prev = last;
		last->next = temp;
		temp->next = *head;
		(*head)->prev = temp;
		*head = temp;
		return ;
	}
	if (pos > sz - 1)
		pos = sz - 1;
	Node *node = *head;
	for (size_t i = 1; i < pos; i++)
		node = node->next;
	Node *temp = newNode(val);
	Node *nxt = node->next;
	temp->prev = node;
	node->next = temp;
	temp->next = nxt;
	nxt->prev = temp;
}

void do_E(Node **head, size_t begin_pos, size_t end_pos) {
	if (head == NULL || *head == NULL)
		return ;
	if (begin_pos > sz)
		begin_pos = sz;
	if (end_pos > sz)
		end_pos = sz;
	if (begin_pos >= end_pos)
		return ;
	if (begin_pos == 0 && end_pos == sz) {
		sz = 0;
		*head = NULL;
		return ;
	}
	sz -= (end_pos - begin_pos);
	if (begin_pos == 0) {
		Node *last = (*head)->prev;
		for (size_t i = 0; i < end_pos; i++)
			*head = (*head)->next;
		(*head)->prev = last;
		last->next = *head;
		return ;
	}
	Node *node = *head;
	for (size_t i = 1; i < begin_pos; i++)
		node = node->next;
	Node *node2 = *head;
	for (size_t i = 0; i < end_pos; i++)
		node2 = node2->next;
	node->next = node2;
	node2->prev = node;
}

void do_R(Node **head, unsigned short val) {
	if (head == NULL || *head == NULL)
		return ;
	Node *node = *head;
	size_t s = sz;
	for (size_t i = 0; i < s; i++) {
		if (node->val == val) {
			--sz;
			if (sz == 0) {
				*head = NULL;
				return ;
			}
			if (node == *head) {
				*head = node->next;
				Node *last = node->prev;
				(*head)->prev = last;
				last->next = *head;
			} else {
				Node *pre = node->prev;
				Node *nxt = node->next;
				pre->next = nxt;
				nxt->prev = pre;
			}
		}
		node = node->next;
	}
}

void do_P(Node *head, size_t pos) {
	if (head == NULL)
		return ;
	if (pos >= sz)
		pos = sz - 1;
	for (size_t i = 0; i < pos; i++)
		head = head->next;
	printf("%hu ", head->val);
}

void do_S(Node *head) {
	if (head == NULL)
		return ;
	for (size_t i = 0; i < sz; i++) {
		printf("%hu ", head->val);
		head = head->next;
	}
}