#include <c_LinkDQueue.h>
#include <c_Memory.h>
#include <c_Alignment.h>
#include "c_Macros.h"

C_STATIC_FORCE_INLINE
c_LinkDQueueNode_t* create_node(int obj_size, void* obj) {
    int size = sizeof(c_LinkDQueueNode_t) + obj_size;
    size = C_ALIGN_UPB(size, C_ALIGN_SIZE);

    c_LinkDQueueNode_t* new_node = (c_LinkDQueueNode_t*)C_ALLOC(size);
    if (!new_node) return NULL;
    new_node->data = new_node + 1;

    memcpy(new_node->data, obj, obj_size);
    new_node->prev = NULL;
    new_node->next = NULL;
    return new_node;
}

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

c_err_t c_LinkDQueue_Init(c_LinkDQueue_t* self, int obj_size) {
    if (!self || obj_size <= 0) return C_ERR_PARAM;
    self->head = NULL;
    self->tail = NULL;
    self->obj_size = obj_size;
    self->size = 0;
    return C_ERR_OK;
}

void c_LinkDQueue_Destroy(c_LinkDQueue_t* self) {
    if (!self) return;
    c_LinkDQueueNode_t* current = self->head;
    while (current != NULL) {
        c_LinkDQueueNode_t* next = current->next;
        C_FREE(current);
        current = next;
    }
    self->head = NULL;
    self->tail = NULL;
    self->size = 0;
}

// 前端推入 O(1)
c_err_t c_LinkDQueue_PushHead(c_LinkDQueue_t* self, void* obj) {
    if (!self || !obj) return C_ERR_PARAM;
    c_LinkDQueueNode_t* new_node = create_node(self->obj_size, obj);
    if (!new_node) return C_ERR_NOMEM;

    if (self->size == 0) {
        self->head = new_node;
        self->tail = new_node;
    } else {
        new_node->next = self->head;
        self->head->prev = new_node;
        self->head = new_node;
    }
    self->size++;
    return C_ERR_OK;
}

// 尾端推入 O(1)
c_err_t c_LinkDQueue_PushTail(c_LinkDQueue_t* self, void* obj) {
    if (!self || !obj) return C_ERR_PARAM;
    c_LinkDQueueNode_t* new_node = create_node(self->obj_size, obj);
    if (!new_node) return C_ERR_NOMEM;

    if (self->size == 0) {
        self->head = new_node;
        self->tail = new_node;
    } else {
        new_node->prev = self->tail;
        self->tail->next = new_node;
        self->tail = new_node;
    }
    self->size++;
    return C_ERR_OK;
}

// 前端彈出 O(1)
c_err_t c_LinkDQueue_PopHead(c_LinkDQueue_t* self, void* obj) {
    if (!self || !obj) return C_ERR_PARAM;
    if (self->size == 0) return C_ERR_EMPTY;

    c_LinkDQueueNode_t* to_delete = self->head;
    memcpy(obj, to_delete->data, self->obj_size);

    self->head = to_delete->next;
    if (self->head == NULL) {
        self->tail = NULL; // 變空佇列
    } else {
        self->head->prev = NULL;
    }

    C_FREE(to_delete);
    self->size--;
    return C_ERR_OK;
}

// 尾端彈出 O(1)
c_err_t c_LinkDQueue_PopTail(c_LinkDQueue_t* self, void* obj) {
    if (!self || !obj) return C_ERR_PARAM;
    if (self->size == 0) return C_ERR_EMPTY;

    c_LinkDQueueNode_t* to_delete = self->tail;
    memcpy(obj, to_delete->data, self->obj_size);

    self->tail = to_delete->prev;
    if (self->tail == NULL) {
        self->head = NULL; // 變空佇列
    } else {
        self->tail->next = NULL;
    }

    C_FREE(to_delete);
    self->size--;
    return C_ERR_OK;
}

void* c_LinkDQueue_PeekHead(c_LinkDQueue_t* self) {
    if (!self || self->size == 0) return NULL;
    return self->head->data;
}

void* c_LinkDQueue_PeekTail(c_LinkDQueue_t* self) {
    if (!self || self->size == 0) return NULL;
    return self->tail->data;
}

// 迭代器安全刪除：利用雙向指標在 O(1) 修正前後驅關係並安全維護 head/tail
void c_LinkDQueueIter_Remove(c_LinkDQueueIter_t* self) {
    if (!self || !self->dqueue || !self->node || !*(self->node)) return;

    c_LinkDQueueNode_t* to_delete = *(self->node);
    c_LinkDQueue_t* dq = self->dqueue;

    // 1. 修正前驅節點的 next 或主結構的 head
    *(self->node) = to_delete->next;

    // 2. 修正後繼節點的 prev 或主結構的 tail
    if (to_delete->next != NULL) {
        to_delete->next->prev = to_delete->prev;
    } else {
        dq->tail = to_delete->prev; // 刪除的是尾端，更新 tail
    }

    // 3. 釋放資源與修正大小
    C_FREE(to_delete);
    dq->size--;
}