// Constants
integer LINK_ROOT = 0;
string  SOUND_NAME = llGetInventoryName(INVENTORY_SOUND, 0);
integer MAX_TEXTURES = 12;
float HIGHLIGHT_GLOW = 0.2;
float NORMAL_GLOW = 0.0;
float SOUND_VOLUME = 1.0;
float SELECTION_DELAY = 0.5;

// Global variables
list gTextures;
integer gSelectedCard1 = -1;
integer gSelectedCard2 = -1;

setTexture(integer linkNumber, string textureUUID) {
    llSetLinkPrimitiveParamsFast(linkNumber, [PRIM_TEXTURE, ALL_SIDES, textureUUID, <1.0, 1.0, 1.0>, ZERO_VECTOR, 0.0]);
}

setGlow(integer linkNumber, float glowIntensity) {
    llSetLinkPrimitiveParamsFast(linkNumber, [PRIM_GLOW, ALL_SIDES, glowIntensity]);
}

default {
    state_entry() {

        integer i;
        for (i = 0; i < MAX_TEXTURES; ++i) {
            string textureName = llGetInventoryName(INVENTORY_TEXTURE, i);
            if (textureName != "") {
                gTextures += [textureName];
            }
        }
        gTextures = llListRandomize(gTextures, 1);

        for (i = 2; i <= llGetNumberOfPrims(); ++i) {
            string texture = llList2String(gTextures, i - 2);
            setTexture(i, texture);
            setGlow(i, NORMAL_GLOW);
        }
    }

    touch_start(integer total_number) {
        integer i;
        for (i = 0; i < total_number; ++i) {
            integer linkNum = llDetectedLinkNumber(i);

            if (linkNum > 1 && linkNum <= (MAX_TEXTURES + 1)) {
                if (gSelectedCard1 == -1) {
                    gSelectedCard1 = linkNum;
                    setGlow(linkNum, HIGHLIGHT_GLOW);
                } else if (gSelectedCard2 == -1 && linkNum != gSelectedCard1) {
                    gSelectedCard2 = linkNum;
                    setGlow(linkNum, HIGHLIGHT_GLOW);

                    swapTextures();
                    resetSelection();
                }

                if (SOUND_NAME != "") {
                    llPlaySound(SOUND_NAME, SOUND_VOLUME);
                }
            }
        }
    }
}

swapTextures() {
    string texture1 = llList2String(gTextures, gSelectedCard1 - 2);
    string texture2 = llList2String(gTextures, gSelectedCard2 - 2);
    setTexture(gSelectedCard1, texture2);
    setTexture(gSelectedCard2, texture1);
    gTextures = llListReplaceList(gTextures, [texture2], gSelectedCard1 - 2, gSelectedCard1 - 2);
    gTextures = llListReplaceList(gTextures, [texture1], gSelectedCard2 - 2, gSelectedCard2 - 2);
}

resetSelection() {
    llSleep(SELECTION_DELAY);
    setGlow(gSelectedCard1, NORMAL_GLOW);
    setGlow(gSelectedCard2, NORMAL_GLOW);
    gSelectedCard1 = -1;
    gSelectedCard2 = -1;
}