WoWInterface - Getting spellId from CombatLogGetCurrentEventInfo in WoW Classic

Hello fellow developers!

I've been working on an addon for WoW Classic and currently hit a little bump.

I'm using the COMBAT_LOG_EVENT_UNFILTERED event to get information regarding spells being cast by certain players, their target and so on. I researched that the API requires you to use the CombatLogGetCurrentEventInfo() method to retrieve the event info like so:

Lua Code:

local timestamp, eventType, _, sourceGUID, sourceName, _, _, destGUID, destName, _, _, spellId, spellName, spellSchool = CombatLogGetCurrentEventInfo()

But in Classic I don't get the spellId (Correction: I do get a spellId but it's always 0). However, I get every other combat log detail. The code works like intended on the retail version of WoW (See the full code below), but not in the Classic release. I know theres been changes to the WoW API to restrict certain methods and functionality. However, I've been unable to find any documentation regarding changing how the COMBAT_LOG_EVENT_UNFILTERED event and CombatLogGetCurrentEventInfo method functions. So I must be doing something wrong regarding how the API works with Classic? (Compared to retail)

Here's the full code:

Lua Code:

local spells = {
    SPELL_AURA_APPLIED = {
        [19742] = 300, -- Rank 1 Blessing of Wisdom
        [19850] = 300, -- Rank 2 Blessing of Wisdom
        [19852] = 300, -- Rank 3 Blessing of Wisdom
        [19853] = 300, -- Rank 4 Blessing of Wisdom
        [19854] = 300, -- Rank 5 Blessing of Wisdom
        [25290] = 300, -- Rank 6 Blessing of Wisdom
        [19740] = 300, -- Rank 1 Blessing of Might
        [19834] = 300, -- Rank 2 Blessing of Might 
        [19835] = 300, -- Rank 3 Blessing of Might 
        [19836] = 300, -- Rank 4 Blessing of Might 
        [19837] = 300, -- Rank 5 Blessing of Might
        [19838] = 300, -- Rank 6 Blessing of Might  
        [25291] = 300, -- Rank 7 Blessing of Might  
    },
}
 
local function eventHandler(self, event, ...)
    if event == 'COMBAT_LOG_EVENT_UNFILTERED' then
        local timestamp, eventType, _, sourceGUID, sourceName, _, _, destGUID, destName, _, _, spellId, spellName, spellSchool = CombatLogGetCurrentEventInfo()
        -- Debug the combat log event
        print('Player ' .. sourceName .. ' casted ' .. spellName .. ' (id: ' .. spellId .. ', school: ' .. spellSchool .. ') on ' .. destName .. ' triggered by ' .. eventType)
        
        if spells[eventType] and spells[eventType][spellId] and sourceGUID == UnitGUID('player') then
            print('Success!')
            -- Handle Aura buff
        end
    end
end
 
local eventFrame = CreateFrame('Frame')
 
eventFrame:RegisterEvent('COMBAT_LOG_EVENT_UNFILTERED')
 
eventFrame:SetScript('OnEvent', eventHandler)

So if anyone could help me out with my mistakes or point me in the direction of some useful documentation or examples, I would be really grateful!

- SnaBe