Editing WoW:ItemString (section)

== Details ==
Used to pass between clients and to pass item information from the client to the user interface.

=== Enchant Ids and Suffix Ids ===
Adding of enchant, jewel, and bonus stat information to the tooltip appear to be handled on the client side with out any kind of validation.  By altering the item string in an item hyperlink you can add any enchant or any bonus stats to any item and still pass it to clients via chat, or display a tooltip for it. The Item name must match that of the itemId combined with the suffix or you will be disconnected if you try to link the item to others. suffixIDs can be negative (see Scaled Random Suffixes below).

'''NOTE:''' Even though the EnchantId page lists shaman weapon buffs, player generated Shaman Buffs do not appear in the link when using GetInventoryItemLink().

=== Unique Ids ===
UniqueId contains information on the maker of a crafted item, number of charges or uses if applicable, or other information exclusive to one particular manifestation of an item. Items received from quests frequently have a UniqueId value, and occasionally dropped items have one as well. The numbers don't appear to hold any information in and of themselves, and are not consistent in any way across servers like EnchantIds and SecondaryIds.  The value appears to be a link to a database entry on the server or client that contains the unique information such as who made an item, which quest it came from, when the quest was delivered, who sold the item on the Auction House, etc. GMs would then be able to track an item should a petition about one be made. UniqueID can have negative values (see Scaled Random Suffixes below).

'''Addendum:''' In-game testing indicates that the UniqueId can change from the first loot to successive loots on the same item. To observe this behavior, Master Looter method was used, an item meeting the loot threshold found, and then the loot window closed without giving the item to a raid member. On re-opening the corpse, the value had changed. For example, on the first loot of Shimmering Trousers of the Eagle, the UniqueId value was 0x00009182. On successive loot attempts it was 0x40679182. Note that the low order bytes were maintained. In at least a few observations, negative UniqueId values did not change in successive looting attempts.

'''On negative UniqueID's:''' I do not believe that a UniqueID being negative is special in any way. It seems to me that the high 16 bits are simply "random", i.e. 0x0000-0xffff. If this value is >0x8000, it will translate to a negative decimal value (signed 32-bit).  --[[User:Mikk|<span style="border-bottom: 1px dotted; cursor: help;" title="Mikk is a WoWWiki Admin">Mikk</span>]] <small>([[User talk:Mikk|T]])</small> 09:55, 7 August 2009 (UTC)

=== Scaled Random Suffixes ===
Since WoW 2.0, both the SuffixIds and the UniqueIds have the ability to be negative. This indicates a different way of calculating the stats bonuses is being used. Previous to WoW 2.0, every time a new stats bonus was added to a new item, the [[SuffixId]] list needed to be updated via a client patch. This limited Blizzard's ability to arbitrarily add new items to the game, since the new data would need to be accompanied by a client patch if it's stats bonus did not already exist.

Post 2.0, a new system of stats bonuses has been implemented via the [[ItemRandomSuffix]] table. If the suffixId is negative, it indicates that the suffix of the item is instead one of the new RandomSuffixes, and that the uniqueId will contain an embedded suffixFactor, which can be extracted via the following algorithm.

  local suffixFactor = 0
  local linkType, itemId, enchantId,
        jewelId1, jewelId2, jewelId3, jewelId4,
        suffixId, uniqueId = strsplit(":", '''itemString''')
  suffixId = tonumber(suffixId) or 0
  uniqueId = tonumber(uniqueId) or 0
  if (linkType == 'item') then
      if (suffixId < 0) then
          suffixFactor = bit.band(uniqueId, 65535)
      end
  end

To see how this suffixFactor gets applied to get the final stat bonuses, see the [[ItemRandomSuffix]] table.

==== 3.2 wotlk randomstat items changing their suffix factors ====
In 3.2, wotlk randomstat items got upgraded, i.e. their scaling factors changed.

This means that the high 16 bits of the uniqueid remained the same, but the low 16 bits changed.

If this was a one-time thing, we could have lived with item databases etc becoming slightly wobbly. But that's not the whole story. '''As soon as you place an item in mail, or AH, or a guild bank, it gets downgraded again'''. So the uniqueIDs are no longer constant.

'''Update:''' It seems that this only happens with items that were actually looted/spawned/crafted before 3.2. --[[User:Mikk|<span style="border-bottom: 1px dotted; cursor: help;" title="Mikk is a WoWWiki Admin">Mikk</span>]] <small>([[User talk:Mikk|T]])</small> 22:51, 11 August 2009 (UTC)

Examples:
<nowiki> </nowiki><nowiki>|cff1eff00|</nowiki>Hitem:36050:0:0:0:0:0:-8:-2052980689:76:0:0|h[Crystalsong Bracelets of the Whale]|h|r<nowiki>
 |cff1eff00|</nowiki>Hitem:36050:0:0:0:0:0:-8:-2052980680:76:0:0|h[Crystalsong Bracelets of the Whale]|h|r<nowiki></nowiki>
 0x85A2002F vs
 0x85A20038
 Difference: 9
 
 |cff1eff00|Hitem:36156:0:0:0:0:0:-18:1209139262:76:0:0:0:0|h[Wendigo Boots of Agility]|h|r
 |cff1eff00|Hitem:36156:0:0:0:0:0:-18:1209139275:76:0:0:0:0|h[Wendigo Boots of Agility]|h|r
 0x4812003E vs
 0x4812004B
 Difference: 13
 
 |cff0070dd|Hitem:44741:0:0:0:0:0:-26:77201509:76:0:0:0:0|h[Mechanized Snow Goggles of Spell Power]|h|r
 |cff0070dd|Hitem:44741:0:0:0:0:0:-26:77201534:76:0:0:0:0|h[Mechanized Snow Goggles of Spell Power]|h|r
 0x049A0065 vs
 0x049A007E
 Difference: 25
 
 |cff0070dd|Hitem:44732:0:0:0:0:0:-36:1867317349:76:0:0:0:0|h[Azure Dragonleather Helm of the Sorcerer]|h|r
 |cff0070dd|Hitem:44732:0:0:0:0:0:-36:1867317374:76:0:0:0:0|h[Azure Dragonleather Helm of the Sorcerer]|h|r
 0x6F4D0065
 0x6F4D007E
 Difference: 25
 
 |cff1eff00|Hitem:36675:0:0:0:0:0:-44:-1664483297:76:0:0:0:0|h[Sockeye Dagger of the Elder]|h|r
 |cff1eff00|Hitem:36675:0:0:0:0:0:-44:-1664483292:76:0:0:0:0|h[Sockeye Dagger of the Elder]|h|r
 0x9CCA001F
 0x9CCA0024
 Difference: 5

For added humor, note that GetItemCount() and PickupItem() will work on both the downgraded and upgraded itemStrings (tested for items in bags), but a SecureActionButton using the "target-item" attribute will only work if given the upgraded itemString.