// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Four-digit codebreaker
// Not compiled or tested in-world
// Setup: Owner-touch. Enter exactly four digits from 1–6; repeated digits are allowed.
// 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. Counts each matching symbol once, including repeated symbols. This is a puzzle, not an access lock or security mechanism.
// 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 digit(string text,integer min,integer max)
{
    if(llStringLength(text)!=1)return -1;
    integer n=llSubStringIndex("0123456789",text);
    if(n<min||n>max)return -1;
    return n;
}
string secret;
start()
{
    secret="";
    integer i;
    for(i=0;i<4;++i)secret+=(string)(1+(integer)llFrand(6.0));
    ask("Guess four digits 1-6. Repeats allowed.");
}
answer(string s)
{
    if(llStringLength(s)!=4)
    {
        ask("Enter exactly four digits 1-6.");
        return;
    }
    integer i;
    integer exact;
    list a;
    list b;
    for(i=0;i<4;++i)
    {
        string x=llGetSubString(s,i,i);
        if(digit(x,1,6)<0)
        {
            ask("Use only digits 1-6.");
            return;
        }
        string y=llGetSubString(secret,i,i);
        if(x==y)++exact;
        else
        {
            a+=[x];
            b+=[y];
        }
    }
    integer misplaced;
    for(i=0;i<llGetListLength(a);++i)
    {
        integer p=llListFindList(b,[llList2String(a,i)]);
        if(p>=0)
        {
            ++misplaced;
            b=llDeleteSubList(b,p,p);
        }
    }
    if(exact==4)
    {
        close();
        llOwnerSay("Code solved: "+secret);
    }
    else ask((string)exact+" exact; "+(string)misplaced+" correct digit, wrong place.\nGuess again.");
}
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();
    }
}