//
// Created by epagris on 2023.01.16..
//

#include <memory.h>
#include <stdbool.h>
#include "tcp_window.h"
#include "etherlib/dynmem.h"

TcpWindow *tcpw_create(uint32_t size) {
    uint32_t allocSize = sizeof(TcpWindow) + size; // calculate full allocation size
    TcpWindow * win = (TcpWindow *) dynmem_alloc(allocSize); // allocate data block at the end
    mp_init(win->data, size); // initialize memory pool

    return win;
}

#define TCP_WINDOW_MAX_WINSIZE_PADDING (16) // keep-out zone, this way allocated blocks will not block registry table growth TODO: not the best solution

uint32_t tcpw_get_max_window_size(TcpWindow * tcpw) {
    return mp_largest_free_block_size(&tcpw->pool) - sizeof(TcpWindowSegment) - TCP_WINDOW_MAX_WINSIZE_PADDING;
}

TcpWindowSegment * tcpw_store_segment(TcpWindow * tcpw, const uint8_t * data, uint32_t size, uint32_t seqNum) {
    TcpWindowSegment * seg = (TcpWindowSegment *) mp_alloc(&tcpw->pool, sizeof(TcpWindowSegment) + size);
    if (seg == NULL) { // could not store...
        return NULL;
    }

    // store segment descriptor
    seg->size = size;
    seg->seqNum = seqNum;

    // store segment
    memcpy(seg->data, data, size);

    return seg;
}

static void tcpw_segment_search(MP *mp, const MPAllocRecord * rec, void * userData) {
    TcpWindow * tcpw = (TcpWindow *) userData;

}

uint32_t tcpw_get_acknowledge(TcpWindow * tcpw) {
    mp_foreach_block(&tcpw->pool, tcpw_segment_search, tcpw, false);
    return 0;
}

void tcpw_set_sequence_number(TcpWindow * tcpw, uint32_t seqNum) {
    tcpw->seqNum = seqNum;
}