/*
 * This program source code file is part of SystemK, a library in the KTag project.
 *
 * 🛡️ <https://ktag.clubk.club> 🃞
 *
 * Copyright © 2016-2025 Joseph P. Kearney and the KTag developers.
 *
 * This program is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Affero General Public License as published by the Free
 * Software Foundation, either version 3 of the License, or (at your option) any
 * later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more
 * details.
 *
 * There should be a copy of the GNU Affero General Public License in the LICENSE
 * file in the root of this repository.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdbool.h>
#include <string.h>
#include "SystemK.h"
#include "BLE_Packets.h"
#include "BLE_Packet_Tracker.h"

#define MAX_REMEMBERED_PACKETS 10

typedef struct
{
    uint8_t sender_BD_ADDR[BD_ADDR_SIZE];
    BLE_PacketType_T packet_type;
    uint8_t event_number;
} TrackedPacket_T;

typedef struct
{
    TrackedPacket_T packets[MAX_REMEMBERED_PACKETS];
    // Number of unique packets we've seen so far.  This value saturates at MAX_REMEMBERED_PACKETS.
    uint8_t count;
    // Index of the oldest packet.
    uint8_t head;
} PacketTracker_T;

static PacketTracker_T Tracker =
    {
        .count = 0,
        .head = 0,
    };

// A packet is _new_ if the combination of BLE address, type, and event number have not been seen recently.
bool BLE_IsPacketNew(const uint8_t *sender_BD_ADDR,
                     BLE_PacketType_T packet_type,
                     uint8_t event_number)
{
    //esp_log_level_set("BLE", ESP_LOG_DEBUG);   
    //KLOG_DEBUG("BLE", "Packet from %s", BLE_ADDR_To_Str(sender_BD_ADDR));

    // Check if the packet already exists in the tracker.
    for (int i = 0; i < Tracker.count; i++)
    {
        int index = (Tracker.head + i) % MAX_REMEMBERED_PACKETS;
        if ((memcmp(Tracker.packets[index].sender_BD_ADDR, sender_BD_ADDR, BD_ADDR_SIZE) == 0) &&
            (Tracker.packets[index].packet_type == packet_type) &&
            (Tracker.packets[index].event_number == event_number))
        {
            // We've already seen this packet.
            return false;
        }
    }

    // The packet is new--find the location to store it.
    int new_index;
    if (Tracker.count < MAX_REMEMBERED_PACKETS)
    {
        // There's space, so just add the new packet at the end.
        new_index = (Tracker.head + Tracker.count) % MAX_REMEMBERED_PACKETS;
        Tracker.count++;
    }
    else
    {
        // No space, so overwrite the oldest packet.
        new_index = Tracker.head;
        Tracker.head = (Tracker.head + 1) % MAX_REMEMBERED_PACKETS;
    }

    // Add the new packet to the tracker.
    memcpy(Tracker.packets[new_index].sender_BD_ADDR, sender_BD_ADDR, BD_ADDR_SIZE);
    Tracker.packets[new_index].packet_type = packet_type;
    Tracker.packets[new_index].event_number = event_number;

    return true;
}

// Initialize the MessageTracker
void BLE_ClearPacketTracker(void)
{
    Tracker.count = 0;
    Tracker.head = 0;
}