#include <c_SeqSearchST.h>


c_err_t c_SeqSearchST_Init(c_SeqSearchST_t* self, c_size_t key_size, c_size_t val_size, c_SortCompare_t key_cmp, void* args, c_Allocator_t* allocator) {
    if (!self || key_size == 0 || val_size == 0 || !key_cmp) {
        return C_ERR_PARAM;
    }

    // 自适应分配器降级缺省安全播种
    if (allocator) {
        self->allocator = *allocator;
    } else {
        self->allocator = c_DefaultAllocator;
    }

    self->first = NULL;
    self->size = 0;
    self->key_size = key_size;
    self->val_size = val_size;
    self->key_cmp = key_cmp;
    self->args = args;

    return C_ERR_OK;
}

/**
 * @brief 存入键值对。若 Key 已存在则覆写更新其 Value；若不存在则使用头插法压入新节点
 */
c_err_t c_SeqSearchST_Put(c_SeqSearchST_t* self, const void* key, const void* val) {
    if (!self || !key || !val) return C_ERR_PARAM;

    // 1. 前置顺序走查：如果键值已经存在，直接更新它的值（覆写语义）
    for (c_SeqSearchSTNode* x = self->first; x != NULL; x = x->next) {
        if (self->key_cmp(key, x->key, self->args) == 0) {
            memcpy(x->val, val, self->val_size);
            return C_ERR_OK;
        }
    }

    // 2. 键值不存在，启动托管分配：开辟新节点以及键和值的独立存储块
    c_SeqSearchSTNode* new_node = (c_SeqSearchSTNode*)c_Allocator_Alloc(&self->allocator, sizeof(c_SeqSearchSTNode));
    void* new_key = c_Allocator_Alloc(&self->allocator, self->key_size);
    void* new_val = c_Allocator_Alloc(&self->allocator, self->val_size);

    if (!new_node || !new_key || !new_val) {
        // 部分失败安全回收拦截，杜绝内存泄漏
        if (new_node) c_Allocator_Free(&self->allocator, new_node);
        if (new_key)  c_Allocator_Free(&self->allocator, new_key);
        if (new_val)  c_Allocator_Free(&self->allocator, new_val);
        return C_ERR_NOMEM;
    }

    // 执行内存数据安全转储
    memcpy(new_key, key, self->key_size);
    memcpy(new_val, val, self->val_size);

    new_node->key = new_key;
    new_node->val = new_val;

    // 3. 头插法挂载新节点
    new_node->next = self->first;
    self->first = new_node;
    self->size++;

    return C_ERR_OK;
}

/**
 * @brief 根据指定的 Key 检索关联的 Value 值
 */
c_err_t c_SeqSearchST_Get(const c_SeqSearchST_t* self, const void* key, void* out_val) {
    if (!self || !key || !out_val) return C_ERR_PARAM;

    for (const c_SeqSearchSTNode* x = self->first; x != NULL; x = x->next) {
        if (self->key_cmp(key, x->key, self->args) == 0) {
            memcpy(out_val, x->val, self->val_size);
            return C_ERR_OK;
        }
    }

    return C_ERR_NOTFOUND;
}

/**
 * @brief 检查符号表内是否包含指定的 Key 键值
 */
bool c_SeqSearchST_Contains(const c_SeqSearchST_t* self, const void* key) {
    if (!self || !key) return false;
    for (const c_SeqSearchSTNode* x = self->first; x != NULL; x = x->next) {
        if (self->key_cmp(key, x->key, self->args) == 0) {
            return true;
        }
    }
    return false;
}

/**
 * @brief 根据指定 Key 彻底从符号表中移出其关联的键值对节点
 */
c_err_t c_SeqSearchST_Delete(c_SeqSearchST_t* self, const void* key) {
    if (!self || !key) return C_ERR_PARAM;
    if (self->size == 0) return C_ERR_EMPTY;

    c_SeqSearchSTNode* prev = NULL;
    c_SeqSearchSTNode* curr = self->first;

    while (curr != NULL) {
        if (self->key_cmp(key, curr->key, self->args) == 0) {
            if (prev == NULL) {
                self->first = curr->next;
            } else {
                prev->next = curr->next;
            }

            // 原路回收释放单节点下深开辟的所有子内存块
            c_Allocator_Free(&self->allocator, curr->key);
            c_Allocator_Free(&self->allocator, curr->val);
            c_Allocator_Free(&self->allocator, curr);

            self->size--;
            return C_ERR_OK;
        }
        prev = curr;
        curr = curr->next;
    }

    return C_ERR_NOTFOUND;
}

/**
 * @brief 反初始化：深度级联释放符号表内的所有节点、键和值的全部堆空间
 */
void c_SeqSearchST_Destroy(c_SeqSearchST_t* self) {
    if (!self) return;

    c_SeqSearchSTNode* curr = self->first;
    while (curr != NULL) {
        c_SeqSearchSTNode* next_tmp = curr->next;

        c_Allocator_Free(&self->allocator, curr->key);
        c_Allocator_Free(&self->allocator, curr->val);
        c_Allocator_Free(&self->allocator, curr);

        curr = next_tmp;
    }

    self->first = NULL;
    self->size = 0;
}