// SPDX-License-Identifier: MIT
// Copyright (c) 2026 Incoprea
// Replace faces sharing one diffuse asset
// Not compiled or tested in-world
// Setup: Put inside a test prim with at most32 faces. Add a texture named replacement with permissions that allow reuse. Owner-touch a face; next touch restores.
// Stop / restore: Owner-touch again to restore before removing, resetting, relinking or transferring. Snapshots are memory-only; deletion/reset does not undo changes. Keep an untouched backup.
// Notes: Only this prim is edited. Preserves each face’s repeats, offsets and rotation. Does not touch normal, specular or PBR assets.
// License: see LICENSE in this distribution.
// Original Incoprea. MIT. Test on a spare copy first.
list saved;
integer active;
default
{
    touch_start(integer n)
    {
        if(llDetectedKey(0)!=llGetOwner())return;
        integer i;
        if(active)
        {
            for(i=0;i<llGetListLength(saved);i+=5)llSetLinkPrimitiveParamsFast(LINK_THIS,[PRIM_TEXTURE,llList2Integer(saved,i)]+llList2List(saved,i+1,i+4));
            saved=[];
            active=FALSE;
            return;
        }
        integer face=llDetectedTouchFace(0);
        if(face<0||llDetectedLinkNumber(0)!=llGetLinkNumber()||llGetNumberOfSides()>32)return;
        if(llGetInventoryType("replacement")!=INVENTORY_TEXTURE)
        {
            llOwnerSay("Add replacement texture.");
            return;
        }
        string asset=llList2String(llGetLinkPrimitiveParams(LINK_THIS,[PRIM_TEXTURE,face]),0);
        if((key)asset==NULL_KEY)
        {
            llOwnerSay("Selected texture key is not readable.");
            return;
        }
        for(i=0;i<llGetNumberOfSides();++i)
        {
            list data=llGetLinkPrimitiveParams(LINK_THIS,[PRIM_TEXTURE,i]);
            if(llList2String(data,0)==asset)
            {
                saved += [i]+data;
                llSetLinkPrimitiveParamsFast(LINK_THIS,[PRIM_TEXTURE,i,"replacement"]+llList2List(data,1,3));
            }
        }
        active=TRUE;
        llOwnerSay("Replaced matching faces="+(string)(llGetListLength(saved)/5));
    }
    changed(integer flags)
    {
        if(flags&CHANGED_OWNER)llResetScript();
    }
}