//=-------------------------------------------------------------------------=//
//  Arrows management module                                                 //
//                                                                           //
//  Copyright © 2021 Libre en Communs (contact@a-lec.org)                    //
//  Copyright © 2021 Adrien Bourmault (neox@a-lec.org)                       //
//                                                                           //
//  This file is part of gem-graph.                                          //
//                                                                           //
//  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.                      //
//                                                                           //
//  You should have received a copy of the GNU Affero General Public License //
//  along with this program.  If not, see <https://www.gnu.org/licenses/>.   //
//=-------------------------------------------------------------------------=//

#include "../include/base.h"
#include "../include/arrows.h"

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


static inline int location(Space_t *space, int x, int y, int z) {
    return x + y * (space->xMax+1) + z * (space->xMax+1) * (space->zMax+1);
}

Arrow_t *ArrowAdd(Scheduler_t *scheduler, int x, int y, int z, int siteId,
                  int weight) {

    ArrowArray_t *arrowArray = scheduler->arrowArray;
    Space_t *drawingSpace = scheduler->globalDrawingSpace;
    Site_t *currentSite = &drawingSpace->space[
                                                location(drawingSpace, x, y, z)
                                              ].sites[siteId];
    Arrow_t *curArrow;

    // Check if there is a free slot to store the a new arrow
    if (arrowArray->freeSlotCount == 0) {
        // Realloc array to create free slot
        arrowArray->array = realloc(arrowArray->array, arrowArray->size + 1);
        curArrow = &arrowArray->array[arrowArray->size + 1];
        arrowArray->size++;
    } else {
        // Reuse an unused free slot
        curArrow = arrowArray->freeSlots[0];

        // Delete the free slot reference (it's our *PROPERTY* now !)
        if (!(memmove(&arrowArray->freeSlots[0],
                &arrowArray->freeSlots[0] + sizeof(arrowArray->freeSlots[0]),
                arrowArray->freeSlotCount - 1
                )))
            return NULL;
        arrowArray->freeSlotCount--;
    }

    // Assign values to the new arrow
    curArrow->x = x;
    curArrow->y = y;
    curArrow->z = z;
    curArrow->siteId = siteId;

    // Store a reference of this new arrow in space (to find it quickly later)
    currentSite->arrowsPtr = curArrow;
    currentSite->nArrow++;

    return curArrow;
}

bool ArrowRemove(Scheduler_t *scheduler, int x, int y, int z, int siteId,
                 int weight) {

    ArrowArray_t *arrowArray = scheduler->arrowArray;
    Space_t *drawingSpace = scheduler->globalDrawingSpace;
    Site_t *currentSite = &drawingSpace->space[
                                                location(drawingSpace, x, y, z)
                                              ].sites[siteId];
    Arrow_t *curArrow;

    // Look for a corresponding arrow in that site
    if (currentSite->nArrow) {
        // Get an arrow from space unit at siteId
        curArrow = currentSite->arrowsPtr;

        // Mark arrow for deletion
        arrowArray->freeSlots =
            realloc(arrowArray->freeSlots, arrowArray->freeSlotCount + 1);
        if (!arrowArray->freeSlots)
            return false;
        arrowArray->freeSlots[arrowArray->freeSlotCount] = curArrow;
        arrowArray->freeSlotCount++;

        currentSite->arrowsPtr = NULL;

        currentSite->nArrow--;
    }

    return false;
}