// ll_queue.c - Упрощенная архитектура: разделение создания элементов и работы с очередью
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include "ll_queue.h"
#include "u_async.h"
#include "debug_config.h"
#include "mem.h"

#ifdef _WIN32
    #include <windows.h>
#else
    #include <pthread.h>
#endif

// ==================== Thread safety check ====================
#ifdef QUEUE_THREAD_CHECK
static inline void queue_check_thread(struct ll_queue* q) {
    if (!q) return;
    
#ifdef _WIN32
    DWORD current = GetCurrentThreadId();
    if (q->owner_thread != current) {
        DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "Queue '%s': thread mismatch! owner=%lu current=%lu",
                    q->name ? q->name : "unknown", 
                    (unsigned long)q->owner_thread, 
                    (unsigned long)current);
        printf("ERROR: Queue '%s' accessed from wrong thread!\n", q->name ? q->name : "unknown");
        abort();
    }
#else
    pthread_t current = pthread_self();
    if (!pthread_equal(q->owner_thread, current)) {
        DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "Queue '%s': thread mismatch! owner=%lu current=%lu",
                    q->name ? q->name : "unknown", 
                    (unsigned long)q->owner_thread, 
                    (unsigned long)current);
        printf("ERROR: Queue '%s' accessed from wrong thread!\n", q->name ? q->name : "unknown");
        abort();
    }
#endif
}
#endif

// Предварительные объявления внутренних функций
static void queue_resume_timeout_cb(void* arg);
static void check_waiters(struct ll_queue* q);
static void add_to_hash(struct ll_queue* q, struct ll_entry* entry);
static void remove_from_hash(struct ll_queue* q, struct ll_entry* entry);

// ==================== Управление очередью ====================

struct ll_queue* queue_new(struct UASYNC* ua, size_t hash_size, char* name) {
    if (!ua) return NULL;
    
    struct ll_queue* q = u_calloc(1, sizeof(struct ll_queue));
    if (!q) return NULL;
    
    q->name = name;
    q->ua = ua;
    q->size_limit = -1;  // Без ограничения по умолчанию
    q->hash_size = hash_size;
    
#ifdef QUEUE_THREAD_CHECK
#ifdef _WIN32
    q->owner_thread = GetCurrentThreadId();
#else
    q->owner_thread = pthread_self();
#endif
#endif
    
    // Создать хеш-таблицу если нужно
    if (hash_size > 0) {
        q->hash_table = u_calloc(hash_size, sizeof(struct ll_entry*));
        if (!q->hash_table) {
            u_free(q);
            return NULL;
        }
    }
    
    DEBUG_DEBUG(DEBUG_CATEGORY_LL_QUEUE, "queue_new: created queue %p, hash_size=%zu", q, hash_size);
    
    return q;
}

struct ll_entry* ll_alloc_lldgram(uint16_t len) {
    struct ll_entry* entry = queue_entry_new(0);
    if (!entry) return NULL;

    entry->len=0;
    entry->memlen=len;
    entry->dgram = u_malloc(len);
//    entry->dgram_pool = NULL; - уже null (memset)
//    entry->dgram_free_fn = NULL;
    if (!entry->dgram) {
        queue_entry_free(entry);
        return NULL;
    }

    return entry;
}

void queue_free(struct ll_queue* q) {
    if (!q) return;
    
    DEBUG_DEBUG(DEBUG_CATEGORY_LL_QUEUE, "queue_free: freeing queue %p, head=%p, tail=%p, count=%d", 
                q, q->head, q->tail, q->count);
    
    // ВАЖНО: Не освобождаем элементы в очереди - они должны быть извлечены отдельно
    // Это упрощает архитектуру и предотвращает double-u_free
    
    // Освободить хеш-таблицу
    if (q->hash_table) {
        u_free(q->hash_table);
    }
    
    // Отменить отложенное возобновление
    if (q->resume_timeout_id) {
        uasync_call_soon_cancel(q->ua, q->resume_timeout_id);
        q->resume_timeout_id = NULL;
    }
    
    u_free(q);
}

// ==================== Конфигурация очереди ====================

void queue_set_callback(struct ll_queue* q, queue_callback_fn cbk_fn, void* arg) {
    if (!q) return;
    q->callback = cbk_fn;
    q->callback_arg = arg;
}

static void queue_resume_timeout_cb(void* arg) {
    struct ll_queue* q = (struct ll_queue*)arg;
    if (!q) return;
    
    q->resume_timeout_id = NULL;
    
    // Вызвать коллбэк если есть элементы и коллбэки разрешены
    if (q->head && !q->callback_suspended && q->callback) {
        q->callback(q, q->callback_arg);
    }
}

void queue_resume_callback(struct ll_queue* q) {
    if (!q) return;
    
    q->callback_suspended = 0;
    
    // Если есть элементы, запланировать вызов коллбэка
    if (q->head && q->callback && !q->resume_timeout_id) {
        q->resume_timeout_id = uasync_call_soon(q->ua, q, queue_resume_timeout_cb);
    }
}

void queue_set_size_limit(struct ll_queue* q, int lim) {
    if (!q) return;
    q->size_limit = lim;
}

// ==================== Управление элементами ====================

struct ll_entry* queue_entry_new(size_t data_size) {
    struct ll_entry* entry = u_malloc(sizeof(struct ll_entry) + data_size);
    if (!entry) return NULL;
    
    memset(entry, 0, sizeof(struct ll_entry) + data_size);
    entry->size = data_size;
    entry->len = 0;
    entry->pool = NULL;   // Выделено через u_malloc
    
//    DEBUG_DEBUG(DEBUG_CATEGORY_LL_QUEUE, "queue_entry_new: created entry %p, size=%zu", entry, data_size);
    
    return entry;
}

struct ll_entry* queue_entry_new_from_pool(struct memory_pool* pool) {
    if (!pool) return NULL;
    
    struct ll_entry* entry = memory_pool_alloc(pool);
    if (!entry) return NULL;
    
    memset(entry, 0, pool->object_size);
    entry->size = pool->object_size - sizeof(struct ll_entry);
    entry->len = 0;
    entry->pool = pool;   // Выделено из пула
    
//    DEBUG_DEBUG(DEBUG_CATEGORY_LL_QUEUE, "queue_entry_new_from_pool: created entry %p from pool %p", entry, pool);
    
    return entry;
}

//void ll_u_free_dgram(struct ll_entry* entry) {
void queue_dgram_free(struct ll_entry* entry) {
    if (!entry) return;

    if (entry->dgram) {
        if (entry->dgram_free_fn) {
            entry->dgram_free_fn(entry->dgram);  // arg=NULL, если не задан
        } else if (entry->dgram_pool) {
            memory_pool_free(entry->dgram_pool, entry->dgram);
        } else {
            u_free(entry->dgram);
        }
        entry->dgram = NULL;
        entry->len = 0;  // Опционально сброс len
    }
}

void queue_entry_free(struct ll_entry* entry) {
    if (!entry) return;
    
    if (entry->pool) {
        memory_pool_free(entry->pool, entry);
    } else {
        u_free(entry);
    }
}

// ==================== Операции с очередью ====================

// Внутренняя функция добавления в хеш-таблицу
static void add_to_hash(struct ll_queue* q, struct ll_entry* entry) {
    if (!q || !entry) return;

    if (q->hash_size == 0 || entry->index_size == 0) {
        DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "[%s] Empty hash_size=%d or index_size=%d",q->name, q->hash_size, entry->index_size);
        return;
    }

    uint32_t slot = entry->index_hash % q->hash_size;
    entry->hash_next = q->hash_table[slot];
    q->hash_table[slot] = entry;
}

static void remove_from_hash(struct ll_queue* q, struct ll_entry* entry) {
    if (!q || q->hash_size == 0 || !entry) return;

    uint32_t slot = entry->index_hash % q->hash_size;  // теперь используем index_hash
    struct ll_entry** ptr = &q->hash_table[slot];
    while (*ptr) {
        if (*ptr == entry) {
            *ptr = entry->hash_next;
            entry->hash_next = NULL;
            return;
        }
        ptr = &(*ptr)->hash_next;
    }
}

static uint32_t make_hash(const void* data, uint16_t len) {// алгоритм FNV-1a
    if (len == 0 || data == NULL) return 0;

    const uint8_t* p = (const uint8_t*)data;
    uint32_t hash = 0x811C9DC5u;           // FNV-1a offset basis (32-bit)

    for (uint16_t i = 0; i < len; ++i) {
        hash ^= (uint32_t)p[i];             // XOR с байтом
        hash *= 0x01000193u;                // FNV-1a prime
    }

    return hash;
}

// Проверить и запустить ожидающие коллбэки
static void check_waiters(struct ll_queue* q) {
    if (!q) return;
    
//    DEBUG_DEBUG(DEBUG_CATEGORY_LL_QUEUE, "check_waiters: checking waiters, count=%d, bytes=%zu", q->count, q->total_bytes);
    
    struct queue_waiter* waiter = &q->waiter;
    
    if (waiter->callback) {
        // Проверить условие: не больше max_packets и не больше max_bytes
        // max_bytes = 0 означает "не проверять байты"
        if (q->count <= waiter->max_packets && (waiter->max_bytes == 0 || q->total_bytes <= waiter->max_bytes)) {
            DEBUG_DEBUG(DEBUG_CATEGORY_LL_QUEUE, "check_waiters: condition met, calling callback, count=%d<=%d, bytes=%zu<=%zu (max_bytes_check=%s)",
                        q->count, waiter->max_packets, q->total_bytes, waiter->max_bytes,
                        waiter->max_bytes == 0 ? "disabled" : "enabled");
            waiter->callback(q, waiter->callback_arg);
            memset(waiter, 0, sizeof(*waiter));
        }
    }
}

int queue_data_put(struct ll_queue* q, struct ll_entry* entry) {
    if (!q || !entry) return -1;
#ifdef QUEUE_THREAD_CHECK
    queue_check_thread(q);
#endif

    entry->index_offset = 0;
    entry->index_size = 0;
    entry->index_hash = 0;

    if (q->hash_size > 0) {
        DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "[%s] Put no-hash data to hash queue",q->name);
        queue_dgram_free(entry);
        queue_entry_free(entry);
        return -1;
    }

    if (q->size_limit >= 0 && q->count >= q->size_limit) {
        queue_dgram_free(entry);
        queue_entry_free(entry);
        return -1;
    }

    // Добавляем в конец
    entry->next = NULL;
    entry->prev = q->tail;
    if (q->tail) q->tail->next = entry; else q->head = entry;
    q->tail = entry;

    q->count++;
    entry->int_len = entry->len;
    q->total_bytes += entry->int_len;

    // НЕ вызываем add_to_hash

    if (q->count == 1 && !q->callback_suspended && q->callback) {
        q->callback(q, q->callback_arg);
    }

#ifdef QUEUE_DEBUG
    queue_check_consistency(q);
#endif
    return 0;
}

int queue_data_put_with_index(struct ll_queue* q, struct ll_entry* entry, uint16_t index_offset, uint16_t index_size) {
    if (!q || !entry) return -1;
#ifdef QUEUE_THREAD_CHECK
    queue_check_thread(q);
#endif

    if (index_size == 0 || (size_t)index_offset + index_size > (size_t)entry->size) {
        DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "[%s] invalid index: offset=%u size=%u (data_size=%u)",q->name, index_offset, index_size, entry->size);
        queue_dgram_free(entry);
        queue_entry_free(entry);
        return -1;
    }

    entry->index_offset = index_offset;
    entry->index_size = index_size;

    entry->index_hash = make_hash(entry->data + index_offset, index_size);

    if (q->size_limit >= 0 && q->count >= q->size_limit) {
        queue_dgram_free(entry);
        queue_entry_free(entry);
        return -1;
    }

    // Добавляем в конец
    entry->next = NULL;
    entry->prev = q->tail;
    if (q->tail) q->tail->next = entry; else q->head = entry;
    q->tail = entry;

    q->count++;
    entry->int_len = entry->len;
    q->total_bytes += entry->int_len;

    add_to_hash(q, entry);

    if (q->count == 1 && !q->callback_suspended && q->callback) {
        q->callback(q, q->callback_arg);
    }

#ifdef QUEUE_DEBUG
    queue_check_consistency(q);
#endif
    return 0;
}

int queue_data_put_first(struct ll_queue* q, struct ll_entry* entry) {
    if (!q || !entry) return -1;
#ifdef QUEUE_THREAD_CHECK
    queue_check_thread(q);
#endif

    entry->index_offset = 0;
    entry->index_size = 0;
    entry->index_hash = 0;

    if (q->hash_size > 0) {
        DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "[%s] Put no-hash data to hash queue",q->name);
        queue_dgram_free(entry);
        queue_entry_free(entry);
        return -1;
    }

    if (q->size_limit >= 0 && q->count >= q->size_limit) {
        queue_dgram_free(entry);
        queue_entry_free(entry);   // как было в оригинале
        return -1;
    }

    entry->next = q->head;
    entry->prev = NULL;
    if (q->head) q->head->prev = entry; else q->tail = entry;
    q->head = entry;

    q->count++;
    entry->int_len = entry->len;
    q->total_bytes += entry->int_len;

    if (q->count == 1 && !q->callback_suspended && q->callback) {
        q->callback(q, q->callback_arg);
    }

#ifdef QUEUE_DEBUG
    queue_check_consistency(q);
#endif
    return 0;
}

// С хешем для put_first
int queue_data_put_first_with_index(struct ll_queue* q, struct ll_entry* entry, uint16_t index_offset, uint16_t index_size) {
    if (!q || !entry) return -1;
#ifdef QUEUE_THREAD_CHECK
    queue_check_thread(q);
#endif

    if (index_size == 0 || (size_t)index_offset + index_size > (size_t)entry->size) {
        DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "[%s] invalid index: offset=%u size=%u (data_size=%u)",q->name, index_offset, index_size, entry->size);
        queue_dgram_free(entry);
        queue_entry_free(entry);
        return -1;
    }

    entry->index_offset = index_offset;
    entry->index_size = index_size;
    entry->index_hash = make_hash(entry->data + index_offset, index_size);

    if (q->size_limit >= 0 && q->count >= q->size_limit) {
        queue_dgram_free(entry);
        queue_entry_free(entry);
        return -1;
    }

    entry->next = q->head;
    entry->prev = NULL;
    if (q->head) q->head->prev = entry; else q->tail = entry;
    q->head = entry;

    q->count++;
    entry->int_len = entry->len;
    q->total_bytes += entry->int_len;

    add_to_hash(q, entry);

    if (q->count == 1 && !q->callback_suspended && q->callback) {
        q->callback(q, q->callback_arg);
    }

#ifdef QUEUE_DEBUG
    queue_check_consistency(q);
#endif
    return 0;
}


struct ll_entry* queue_data_get(struct ll_queue* q) {
    if (!q || !q->head) return NULL;

#ifdef QUEUE_THREAD_CHECK
    queue_check_thread(q);
#endif

    struct ll_entry* entry = q->head;
    
    q->head = entry->next;
    if (q->head) q->head->prev = NULL;
    if (!q->head) q->tail = NULL;
    
    q->count--;
    q->total_bytes -= entry->int_len;
    
    entry->next = NULL;
    entry->prev = NULL;
    
    remove_from_hash(q, entry);
    
//    DEBUG_DEBUG(DEBUG_CATEGORY_LL_QUEUE, "queue_data_get: got entry %p (id=%u), count=%d", entry, entry->id, q->count);
    
    // Приостановить коллбэки для предотвращения рекурсии
    q->callback_suspended = 1;
    
    // Проверить ожидающие коллбэки
    check_waiters(q);
    
#ifdef QUEUE_DEBUG
    queue_check_consistency(q);// !!!! for debug
#endif
    return entry;
}

int queue_entry_count(struct ll_queue* q) {
    return q ? q->count : 0;
}

// Функция проверки консистентности count и total_bytes
// Возвращает 0 если ok, -1 если есть несоответствия
int queue_check_consistency(struct ll_queue* q) {
    if (!q) return -1; // Недопустимая очередь
    
    // Проверка: если count > 0, то head не должен быть NULL
    if (q->count > 0 && !q->head) {
        DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "Queue '%s': count=%d but head is NULL!",
                    q->name ? q->name : "unknown", q->count);
        return -1;
    }
    
    int actual_count = 0;
    size_t actual_bytes = 0;
    struct ll_entry* current = q->head;
    
    while (current) {
        actual_count++;
        actual_bytes += current->int_len;
        if (current->next) {
            if (current->next->prev != current) {
                // Несоответствие в связях prev/next
                DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "Queue '%s': prev/next error at entry %p != %p entries: %d!=%d bytes: %zu!=%zu",
                          q->name ? q->name : "unknown", (void*)current, (void*)current->next->prev, actual_count, q->count, actual_bytes, q->total_bytes);
                return -1;
            }
        }
        current = current->next;
    }
    
    // Проверить хвост
    if (q->tail && q->tail->next != NULL) {
        DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "Queue '%s': tail error", q->name ? q->name : "unknown");
        return -1; // Хвост должен иметь next == NULL
    }
    
    // Сравнить с сохранёнными значениями
    if (actual_count != q->count || actual_bytes != q->total_bytes) {
        DEBUG_ERROR(DEBUG_CATEGORY_LL_QUEUE, "Queue '%s': count error entries: %d!=%d or bytes: %zu!=%zu",
                    q->name ? q->name : "unknown", actual_count, q->count, actual_bytes, q->total_bytes);
        return -1;
    }
    
    return 0;
}

// ==================== Асинхронное ожидание ====================

struct queue_waiter* queue_wait_threshold(struct ll_queue* q, int max_packets, size_t max_bytes,
                                     queue_threshold_callback_fn callback, void* arg) {
    if (!q || !callback) return NULL;
    
    struct queue_waiter* waiter = &q->waiter;
    
    // Проверить условие немедленно
    if (q->count <= max_packets && (max_bytes == 0 || q->total_bytes <= max_bytes)) {
        // Условие уже выполнено - вызвать коллбэк немедленно
        callback(q, arg);
        return NULL;
    }
    
    // Установить waiter для отложенного вызова
    waiter->max_packets = max_packets;
    waiter->max_bytes = max_bytes;
    waiter->callback = callback;
    waiter->callback_arg = arg;
    
    return waiter;
}

void queue_cancel_wait(struct ll_queue* q, struct queue_waiter* waiter) {
    if (!q || !waiter || waiter != &q->waiter) return;
    
    memset(waiter, 0, sizeof(*waiter));
}

// ==================== Поиск и удаление по ID ====================

struct ll_entry* queue_find_data_by_index(struct ll_queue* q, const void* index_key, uint16_t index_size) {
    if (!q || q->hash_size == 0 || !q->hash_table || index_size == 0 || !index_key) return NULL;

    uint32_t hash_val = make_hash(index_key, index_size);

    uint32_t slot = hash_val % q->hash_size;
    struct ll_entry* entry = q->hash_table[slot];

    while (entry) {
        if (entry->index_size == index_size &&
            (size_t)entry->index_offset + index_size <= (size_t)entry->size &&
            memcmp(entry->data + entry->index_offset, index_key, index_size) == 0) {
            return entry;
        }
        entry = entry->hash_next;
    }
    return NULL;
}

int queue_remove_data(struct ll_queue* q, struct ll_entry* entry) {
    if (!q || !entry) return -1;
    
#ifdef QUEUE_THREAD_CHECK
    queue_check_thread(q);
#endif
    
    // Удалить из двусвязного списка
    if (entry->prev) {
        entry->prev->next = entry->next;
    } else {
        q->head = entry->next;
    }
    
    if (entry->next) {
        entry->next->prev = entry->prev;
    } else {
        q->tail = entry->prev;
    }
    
    q->count--;
    q->total_bytes -= entry->int_len;
    
    entry->next = NULL;
    entry->prev = NULL;
    
    remove_from_hash(q, entry);
    
//    DEBUG_DEBUG(DEBUG_CATEGORY_LL_QUEUE, "queue_remove_data: removed entry %p (id=%u), count=%d", entry, entry->id, q->count);
#ifdef QUEUE_DEBUG
    queue_check_consistency(q);// !!!! for debug
#endif    
    check_waiters(q);
    return 0;
}