WowAce

!stats and !ostats are working very well and are very handy. Can also get the same functionality by open the interface menu and click the button, but that takes time and many clicks. So writing !ostats is more convenient.

But what about !reset? It doesn't exist. Have to go all the way into the interface menu and click it there.

(Hmm, while I'm writing this I start to think: Why can't it also react to "/efreset" or "/ef reset"? That way it's easier to to access these functions from other addons and macros.)

What I have done and will show you is how it could be done by adding some lines in EnsidiaFails.lua:
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EnsidiaFails.lua

Changes to make it reset stats and ostats with chat commands.

Row 441:
--------

Insert the following to allow for /ef reset and /ef oreset.

"
        self:RegisterChatCommand("ef reset", "reset")
        self:RegisterChatCommand("ef oreset", "oreset")
"

Row 497:
--------

Insert the following in row 495 or after:
"
elseif msg:find("!ostats") then
"

"
        elseif msg:find("!reset") then
            target = event:sub(10)
            local Time = GetTime()
            if not LastTime then
                LastTime = Time
                addon:reset(target,channelnum)
            elseif LastTime+10.000 < Time then
                addon:reset(target,channelnum)
                LastTime=nil
            end
        elseif msg:find("!oreset") then
            target = event:sub(10)
            local Time = GetTime()
            if not LastTime then
                LastTime = Time
                addon:oreset(target,channelnum)
            elseif LastTime+10.000 < Time then
                addon:oreset(target,channelnum)
                LastTime=nil
            end
"




Row 894 (when !reset and !oreset are added):
--------------------------------------------
Switch out the whole function "function addon:reset" with:

"
function addon:reset(target,channelnum)
    EnsidiaFails_FailCount = {}
    if not channelnum then
        DEFAULT_CHAT_FRAME:AddMessage(L["Fails are reseted."]);
    else
        addon:SendChatMessage("Fails are reseted.", target, channelnum)
    end
end
"

Row 903 (when all previous is added):
-------------------------------------
Switch out the whole function "function addon:oreset" with:

"
function addon:oreset(target,channelnum)
    EnsidiaFails_FailCount = {}
    EnsidiaFails_OFailCount = {}
    if not target or channelnum then
        DEFAULT_CHAT_FRAME:AddMessage(L["All and overall fails are reseted."]);
    else
        addon:SendChatMessage("All and overall fails are reseted.", target, channelnum)
    end
end
"

Just changed the chat output so it's more clear which addon and which function they are related to.

if not target or channelnum then

is used to give the feedback as Print() instead of the addon:SendChatMessage tells it as /say when no target/channel is predefined.

Also better to give some kind of feedback of what happened than nothing at all if that is the other solution than /say.