// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Five-by-five knight tour
// Not compiled or tested in-world
// Setup: Enter coordinates a1 through e5. Start a1; no square may be revisited. Owner-touch starts a fresh game; type reset to restart. Input times out after 90 seconds.
// Stop / restore: Let the input timeout expire or remove the script. No world geometry, avatar or inventory is changed.
// Notes: Original compact educational game. Owner-only local input; no scores or avatar identities are sent to a service. Output is short ASCII text. Not a competition authority.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Not compiled or tested in-world.
integer channel;
integer handle;
integer x;
integer y;
list visited;
close()
{
    if(handle)llListenRemove(handle);
    handle=0;
    llSetTimerEvent(0.0);
}
start()
{
    x=0;
    y=0;
    visited=[0];
}
string board()
{
    return "Current "+llGetSubString("abcde",x,x)+(string)(y+1)+" | visited "+(string)llGetListLength(visited)+"/25";
}
show()
{
    llOwnerSay(board());
    if(!handle)
    {
        channel=-1000-(integer)llFrand(1000000.0);
        handle=llListen(channel,"",llGetOwner(),"");
    }
    llTextBox(llGetOwner(),"Enter coordinates a1 through e5. Start a1; no square may be revisited. 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 input)
    {
        if(!handle||incomingChannel!=channel||id!=llGetOwner())return;
        input=llToLower(llStringTrim(input,STRING_TRIM));
        if(input=="reset")start();
        else
        {
            if(llStringLength(input)==2)
            {
                integer nx=llSubStringIndex("abcde",llGetSubString(input,0,0));
                integer ny=llSubStringIndex("12345",llGetSubString(input,1,1));
                integer dx=llAbs(nx-x);
                integer dy=llAbs(ny-y);
                integer square=ny*5+nx;
                if(nx>=0&&ny>=0&&((dx==1&&dy==2)||(dx==2&&dy==1))&&llListFindList(visited,[square])<0)
                {
                    x=nx;
                    y=ny;
                    visited+=[square];
                    if(llGetListLength(visited)==25)llOwnerSay("Tour complete!");
                }
                else llOwnerSay("Not a fresh knight move.");
            }
        }
        show();
    }
    timer()
    {
        close();
    }
}