Bartender

Bartender! v1.0.0

Bartender to serve drinks.. and other things.
Drop this script in your bartender prim.
Drop a bunch of 'drink' objects into your bartender prim.
Touch the bartender prim and select a drink.
Some debugging info is transmitted on llOwnerSay, but spam is minimal. Edit the script variable to adjust this.
This script differs from others in that:
It opens a single random negative channel, it does not activate an llListen *every time* someone clicks it.
IF the random channel is being used by something else, and this causes the bartender to get a bunch of garbage inputs, it will automatically change to a new random channel, and optionally inform the owner.
Evidently this script can be used as a kind of object freebie vendor too.
NOTES:
It's been a while since I wrote it, and it was never really extensively tested, so i expect there is some stupid in it. But AFAIK it's fine.
It features a primitive kind of double-touch prevention that i don't use anymore, so I guess the touch functions have been improved.. yeah.. that was it.. i think.. yeah. So there are some redundant bits.

//
// BETLOG Hax
// for Aley Arai AEST: 20080328 0645 [SLT:  20080327 1345]
// Written to allow easier use - just dump drink objects into inv and you are done.
// No more editing script drink lists.
//=========================================================================
// ---LICENCE START---
// http://creativecommons.org/licenses/by-sa/3.0/
// ie: Attribution licence:
//   Give me credit by leaving it in the script I created.
//   Supply my original script with your modified version.
//   Refer to the wiki URL from which you copied this script.
//      https://wiki.secondlife.com/wiki/Bartender
// ---LICENCE END---
//=========================================================================

//----------------------------------
// SHARED CONFIGURATION
//----------------------------------
// CONFIGURATION
//
//OPTIONAL debug feedback - 0=off, 1=Channel & Noise info, 2=all debug
integer gDebug              = 
                                //0;
                                1;
                                //2;
//
//number of invalid messages received before re-randomizing channel
integer gChannelNoiseMax    = 5; 
//
// message that appears on the dialog
string  gDlgMessage         = "\n\t\n\t\n\t\t\tMay I offer you a drink?";
//
// Optional chat responses
// leave BOTH of these fields blank ( ""; ) to NOT speak a message
// leave one OR the other blank to alter the form of the message
//recipient name is auto-inserted between these two
string  gMsgResponseA       = "Thanks";
// target name ends up here
string  gMsgResponseB       = ", enjoy your drink. :)";
//----------------------------------
// CORE CODE
integer gListenHandle       = 0;
integer gDlgLimiter         = 0;
integer gDlgChannel         = -5746547; //failsafe only
list    gDrinksList         = [];
integer gDrinksCount        = 0;
integer gChannelNoise       = 0;
//----------------------------------
f_dialogMenu(key id, list dlgButtons)
{   llDialog(id, gDlgMessage, dlgButtons, gDlgChannel);
    if (gDebug > 1)
    {   llOwnerSay("***OFFERING DIALOG:***"
            +"\nname: "+llKey2Name(id)
            +"\nid: "+(string)id
            +"\ngDlgMessage: "+gDlgMessage
            +"\ndlgButtons: "+llList2CSV(dlgButtons)
            +"\ngDlgChannel: "+(string)gDlgChannel
            +"\n***************"
        );
    }
}
//-----------------------
f_dialogNullify()
{   gDlgLimiter = 0;    
}
//-----------------------
f_randomChannel()
{   
//a static channel is more reliable where many people may request a drink while another is still considering the choices
//gChannelNoise will trigger auto-re-randomization of this static channel if too much invalid message activity is detected
    if (gListenHandle)
        llListenRemove(gListenHandle);
    gDlgChannel = (integer)(llFrand(-0x7FFFFFFF)-1);
    gListenHandle = llListen(gDlgChannel, "", "", ""); 
    if (gDebug)
        llOwnerSay("gDlgChannel: "+(string)gDlgChannel);
}
//-----------------------
f_assessInventory()
{   integer    i;
    integer    n = llGetInventoryNumber(INVENTORY_OBJECT);
    gDrinksList = [];
    for(i=0; i<n; i++ )
        gDrinksList += [ llGetInventoryName(INVENTORY_OBJECT, i) ];
    gDrinksCount = llGetListLength(gDrinksList);
    if (gDebug > 1)
        llOwnerSay("gDrinksCount: "+(string)gDrinksCount+" - gDrinksList: "+llList2CSV(gDrinksList));        
}
//-----------------------
default
{   on_rez(integer start_param)
    {   llResetScript();
    }
    changed(integer change)
    {   if (change & CHANGED_INVENTORY)
        {   llSetText("RE-EVALUATING\ninventory.", <0.0, 1.0, 0.0>,1.0);            
            //so its not being called too much and slowing down inv changes            
            llSetTimerEvent(8.0);
        }
        if (change & CHANGED_OWNER)
            llResetScript();
    }
    timer()
    {   llSetTimerEvent(0.0);
        llSetText("", <1.0, 1.0, 1.0>,1.0);
        f_assessInventory();        
    }
    state_entry()
    {   f_randomChannel();
        f_assessInventory();
    }
    touch_end(integer num_detected)
    {   gDlgLimiter += 1;
        if (gDlgLimiter == 1)
        {   key av = llDetectedKey(0);
            f_dialogMenu(av, gDrinksList);            
        }
        else if (gDlgLimiter >= 2) //3)
            f_dialogNullify();
    }
    listen(integer channel, string name, key id, string message)
    {   integer index = llListFindList(gDrinksList, [message]);
        if (index == -1)
        {   gChannelNoise++;
            if (gDebug)
                llOwnerSay("FYI - INVALID MESSAGE DETECTED ON THIS CHANNEL:\ngDlgChannel: "+(string)gDlgChannel+"\ngChannelNoise/gChannelNoiseMax = "+(string)gChannelNoise+"/"+(string)gChannelNoiseMax+"\nFrom: "+name+" [key: "+(string)id+"]");
            if (gChannelNoise >= gChannelNoiseMax)
                f_randomChannel();
            return;
        }
        string drink = llGetInventoryName(INVENTORY_OBJECT, index);
        if (drink != "")
        {   f_dialogNullify();            
            if ( (gMsgResponseA != "") || (gMsgResponseB != "") )
                llSay(0, gMsgResponseA+" "+name+" "+gMsgResponseB);
            llGiveInventory(id, drink);
            if (gDebug > 1)
                llOwnerSay("drink: "+drink+" was given to: "+name+" [key: "+(string)id+"]");
        }
        else
        {   // SHOULD never happen
            llOwnerSay("ERROR: The bar has no drinks!!!..or somthing else bad happened..");
        }
    }
}