// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Five-cell diffusion lab
// Not compiled or tested in-world
// Setup: Enter step, or heat to add one unit at center. Owner-touch initializes; enter reset to restart. Text input closes after90seconds.
// Stop / restore: Close or ignore the text box, or remove the script. It changes no world objects, avatar state or inventory.
// Notes: Original bounded, manually stepped educational toy. Not a calibrated simulator, real-world control system, or live scientific measurement. Illustrates diffusion with a stable fixed coefficient; units are arbitrary. Floating-point rounding may cause small conservation errors.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Not compiled or tested in-world.
integer channel;
integer handle;
list values;
integer steps;
close()
{
    if(handle)llListenRemove(handle);
    handle=0;
    llSetTimerEvent(0.0);
}
start()
{
    values=[0.0,0.0,10.0,0.0,0.0];
    steps=0;
}
string view()
{
    return "Step "+(string)steps+": "+llList2CSV(values);
}
show()
{
    llOwnerSay(view());
    if(!handle)
    {
        channel=-1000-(integer)llFrand(1000000.0);
        handle=llListen(channel,"",llGetOwner(),"");
    }
    llTextBox(llGetOwner(),"Enter step, or heat to add one unit at center. Type reset to restart.",channel);
    llSetTimerEvent(90.0);
}
default
{
    touch_start(integer n)
    {
        if(llDetectedKey(0)!=llGetOwner())return;
        close();
        start();
        show();
    }
    listen(integer incomingChannel,string name,key id,string s)
    {
        if(!handle||incomingChannel!=channel||id!=llGetOwner())return;
        s=llToLower(llStringTrim(s,STRING_TRIM));
        if(s=="reset")start();
        else
        {
            if(s=="heat")
            {
                float center=llList2Float(values,2);
                if(center<100.0)values=llListReplaceList(values,[center+1.0],2,2);
            }
            else if(s=="step")
            {
                list next=[];
                integer i;
                for(i=0;i<5;++i)
                {
                    float here=llList2Float(values,i);
                    float left=here;
                    float right=here;
                    if(i>0)left=llList2Float(values,i-1);
                    if(i<4)right=llList2Float(values,i+1);
                    next+=[here+0.25*(left+right-2.0*here)];
                }
                values=next;
                ++steps;
            }
        }
        show();
    }
    timer()
    {
        close();
    }
}