// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Chess-square color trainer
// Not compiled or tested in-world
// Setup: Owner-touch. Answer LIGHT or DARK for a random square such as c5.
// Stop / restore: Stop responding and the listener closes after 90 seconds, or remove/disable the script. Owner-touch restarts the exercise.
// Notes: Owner-only local exercise; no prizes, visitor records, network service, or persistent scores. Uses the standard convention that a1 is dark. It teaches the board pattern, not chess moves or rules.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Not compiled or tested in-world.
integer channel;
integer handle;
close()
{
    if(handle)llListenRemove(handle);
    handle=0;
    llSetTimerEvent(0.0);
}
ask(string prompt)
{
    if(!handle)
    {
        channel=-1000-(integer)llFrand(1000000.0);
        handle=llListen(channel,"",llGetOwner(),"");
    }
    llTextBox(llGetOwner(),prompt,channel);
    llSetTimerEvent(90.0);
}
integer file;
integer rank;
string square;
start()
{
    file=(integer)llFrand(8.0);
    rank=1+(integer)llFrand(8.0);
    square=llGetSubString("abcdefgh",file,file)+(string)rank;
    ask("Is "+square+" LIGHT or DARK? a1 is dark.");
}
answer(string s)
{
    s=llToLower(s);
    if(s!="light"&&s!="dark")
    {
        ask("Enter LIGHT or DARK.");
        return;
    }
    string correct="dark";
    if((file+rank)%2==0)correct="light";
    close();
    if(s==correct)llOwnerSay("Correct: "+square+" is "+correct);
    else llOwnerSay(square+" is "+correct);
}
default
{
    touch_start(integer count)
    {
        if(llDetectedKey(0)!=llGetOwner())return;
        close();
        start();
    }
    listen(integer ch,string name,key id,string message)
    {
        if(!handle||ch!=channel||id!=llGetOwner())return;
        answer(llStringTrim(message,STRING_TRIM));
    }
    timer()
    {
        close();
        llOwnerSay("Exercise paused. Touch to restart.");
    }
    changed(integer change)
    {
        if(change&CHANGED_OWNER)llResetScript();
    }
}