WoWInterface/Interface/AddOns/BtWTodo/Sync.lua

local ADDON_NAME, Internal = ...
local External = _G[ADDON_NAME]
local L = Internal.L

local PREFIX = ADDON_NAME

C_ChatInfo.RegisterAddonMessagePrefix(PREFIX)

-- First character of sent messages decribe what the message is about
local ControlCharacters = {
    RequestAccess = '\1', -- Request access to character data
    RequestAccessResponse = '\2', -- Response for access request

    AuthorityNotification = '\3', -- Notify someone that you are an authority for a character

    RegisterCharacterEventsMultiple = '\4', -- Register for character data events, more parts to follow
    RegisterCharacterEventsLast = '\5', -- Register for character data events, last or only part

    CharacterDataMultiple = '\6', -- Character data, more parts to follow
    CharacterDataLast = '\7', -- Character data, last or only part

    Ping = '\8', -- Check if a player is still online
    Pong = '\9', -- Respond to ping

    RequestSharedData = '\10',
    SendSharedData = '\11',
}

local LibSerialize = LibStub("LibSerialize")
local LibDeflate = LibStub("LibDeflate")

local sharedDataLastSeen = {}

function Internal.RequestAccessToCharacter(name, realm)
    ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, ControlCharacters.RequestAccess, "WHISPER", name .. "-" .. realm);
end
local MAX_LENGTH = 253
function Internal.RegisterRemoteCharacterEvents(slug, ...)
    --@TODO get a character to request this data from instead of always from the target

    local compressed = LibDeflate:CompressDeflate(slug .. " " .. table.concat({...}, " "))
    local encoded = LibDeflate:EncodeForWoWAddonChannel(compressed)

    for i=1,#encoded,MAX_LENGTH do
        local data = strsub(encoded, i, math.min(i + MAX_LENGTH,#encoded))
        if i + MAX_LENGTH >= #encoded then
            ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, ControlCharacters.RegisterCharacterEventsLast .. data, "WHISPER", slug);
        else
            ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, ControlCharacters.RegisterCharacterEventsMultiple .. data, "WHISPER", slug);
        end
    end
end

local eventsToRegister = {}
local registerFrame = CreateFrame("Frame")
registerFrame:SetScript("OnUpdate", function (self)
    local tbl = {}
    for character,events in pairs(eventsToRegister) do
        wipe(tbl)
        for event in pairs(events) do
            tbl[#tbl+1] = event
        end

        Internal.RegisterRemoteCharacterEvents(character, unpack(tbl))
    end
    wipe(eventsToRegister)
    self:Hide()
end)
function Internal.RegisterRemoteCharacterEvent(slug, event)
    local tbl = eventsToRegister[slug]
    if not tbl then
        tbl = {}
        eventsToRegister[slug] = tbl
    end

    tbl[event] = true
    registerFrame:Show()
end
do
    -- local
    function Internal.SendRemoteCharacterDataTable(slug, key, ...)

    end
end

-- This is here because I thought a ping/pong might be useful
local PingTimers = {}
function Internal.PingCharacter(name, realm)
    local slug = realm and (name .. "-" .. realm) or name

    if PingTimers[slug] ~= false then
        PingTimers[slug] = false
        ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, ControlCharacters.Ping, "WHISPER", slug);

        -- If we dont get a response in 10 minutes wipe the value and allow for more pings
        C_Timer.After(10, function ()
            if PingTimers[slug] == false then
                PingTimers[slug] = nil
            end
        end)
    end
end

local function ADDON_LOADED(event, name)
    if name == ADDON_NAME then
        if BtWTodoAuthorization == nil then
            BtWTodoAuthorization = {} -- Characters that are authorized to view data
        end

        -- for character in pairs(BtWTodoAuthorization) do
        --     Internal.PingCharacter(character)
        -- end

        Internal.UnregisterEvent("ADDON_LOADED", ADDON_LOADED)
    end
end
Internal.RegisterEvent("ADDON_LOADED", ADDON_LOADED)

Internal.RegisterEvent("PING", function (event, character)
    print(character)
end)

-- Used to store multipart messages
local CharacterEventsStore = {}
local CharacterDataStore = {}
Internal.RegisterEvent("CHAT_MSG_ADDON", function (event, prefix, text, channel, sender, target, zoneChannelID, localID, name, instanceID)
    local name, realm = UnitFullName("player")
    if prefix ~= PREFIX or sender == name .. "-" .. realm then
        return
    end

    local control = strsub(text, 1, 1)

    if control == ControlCharacters.RequestAccess then
        External.TriggerEvent("REQUEST_ACCESS", sender)
    elseif control == ControlCharacters.RequestAccessResponse then
        External.TriggerEvent("REQUEST_ACCESS_RESPONSE", strsub(text, 2, 2) == 1)
    elseif control == ControlCharacters.AuthorityNotification then
        External.TriggerEvent("AUTHORITY_NOTIFICATION", strsub(text, 2), sender)
    elseif control == ControlCharacters.RegisterCharacterEventsMultiple or control == ControlCharacters.RegisterCharacterEventsLast then
        local tbl = CharacterEventsStore[sender]
        if not tbl then
            tbl = {}
            CharacterEventsStore[sender] = tbl
        end

        tbl[#tbl+1] = strsub(text, 2)

        if control == ControlCharacters.RegisterCharacterEventsLast then
            local compressed = LibDeflate:DecodeForWoWAddonChannel(table.concat(tbl, ""))
            local data = LibDeflate:DecompressDeflate(compressed)

            -- print(sender, strsplit(" ", data))
            External.TriggerEvent("REGISTER_CHARACTER_EVENT", sender, strsplit(" ", data))

            CharacterEventsStore[sender] = nil
        end
    elseif control == ControlCharacters.OnCharacterEvent then
        local compressed = LibDeflate:DecodeForWoWAddonChannel(strsub(text, 2))
        local data = LibDeflate:DecompressDeflate(compressed)

        External.TriggerEvent("ON_CHARACTER_EVENT", sender, strsplit(" ", data))
    elseif control == ControlCharacters.CharacterDataMultiple or control == ControlCharacters.CharacterDataLast then
        local tbl = CharacterDataStore[sender]
        if not tbl then
            tbl = {}
            CharacterDataStore[sender] = tbl
        end

        tbl[#tbl+1] = strsub(text, 2)

        if control == ControlCharacters.CharacterDataLast then
            local compressed = LibDeflate:DecodeForWoWAddonChannel(table.concat(tbl, ""))
            local data = LibDeflate:DecompressDeflate(compressed)
            External.TriggerEvent("CHARACTER_DATA", sender, LibSerialize:Deserialize(data))

            CharacterDataStore[sender] = nil
        end
    elseif control == ControlCharacters.Ping or control == ControlCharacters.Pong then
        PingTimers[sender] = GetTime()

        if control == ControlCharacters.Ping then
            ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, ControlCharacters.Pong, "WHISPER", sender);
        end

        External.TriggerEvent("PING", sender)
    elseif control == ControlCharacters.RequestSharedData then
        local id = strsub(text, 2)

        --[==[@debug@
        print("[BtWTodo] Request Shared Data " .. id)
        --@end-debug@]==]

        -- Super hacky cheat to prevent everyone from sending the same data when requested,
        -- first person to send it will trigger the SendSharedData below, that'll update the last seen value
        -- so when the timer runs out and tries to send it it'll not send it to the same place it got it from
        C_Timer.After(math.random() * 5, function()
            Internal.SendSharedData(id, BtWTodoCache[id])
        end)
    elseif control == ControlCharacters.SendSharedData then
        local encoded = strsub(text, 2)
        local compressed = LibDeflate:DecodeForWoWAddonChannel(encoded)
        local full = LibDeflate:DecompressDeflate(compressed)
        local id, serialized = strsplit(" ", full, 2)
        local success, data = LibSerialize:Deserialize(serialized)
        if not success or not Internal.ValidateSharedData(id, data) then
            return
        end

        --[==[@debug@
        print("[BtWTodo] Received Shared Data " .. id)
        --@end-debug@]==]

        BtWTodoCache[id] = data
        sharedDataLastSeen[channel .. ":" .. id] = GetTime()

        External.TriggerEvent("SHARED_DATA:" .. id, data)
    end
end)

-- Shared data is anything that can be shared to other players, like which are the available korthia dailies, which quests for the current assault
local lastRequested = {}
local sharedDataValidators = {}
function Internal.RegisterSharedData(id, validator)
    if type(id) ~= "string" then
        error("External.RegisterSharedData(id, validator): id must be string")
    elseif id:match("[^%w-_]") then
        error(L["External.RegisterSharedData(id, validator): id must contain only word characters, dashes, and underscores"])
    elseif sharedDataValidators[id] then
        error("External.RegisterSharedData(id, validator): " .. id .. " is already registered")
    elseif type(validator) ~= "function" then
        error("External.RegisterSharedData(id, validator): validator must be a function")
    end
    sharedDataValidators[id] = validator
end
function Internal.ValidateSharedData(id, data)
    if not sharedDataValidators[id] then
        return true
    end

    return sharedDataValidators[id](id, data)
end
function Internal.GetSharedData(id)
    if type(id) ~= "string" or id:match("[^%w-_]") then
        error(L["Shared data id must be a string containing only word characters, dashes, and underscores"])
    end

    local data = BtWTodoCache[id]

    if not data and (lastRequested[id] == nil or lastRequested[id] < GetTime() - 60) then
        lastRequested[id] = GetTime()
        if IsInGuild() then
            ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, ControlCharacters.RequestSharedData .. id, "GUILD")
        end
        if IsInGroup(LE_PARTY_CATEGORY_HOME) then
            if IsInRaid() then
                ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, ControlCharacters.RequestSharedData .. id, "RAID")
            else
                ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, ControlCharacters.RequestSharedData .. id, "PARTY")
            end
        end
        if IsInGroup(LE_PARTY_CATEGORY_INSTANCE) then
            ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, ControlCharacters.RequestSharedData .. id, "INSTANCE_CHAT")
        end
    end

    return data and CopyTable(data)
end
function External.GetSharedData(id)
    return Internal.GetSharedData(id)
end
function Internal.SaveSharedData(id, data, dontSend)
    local isDifferent = (type(BtWTodoCache[id]) ~= type(data) or data == nil or not tCompare(data, BtWTodoCache[id], 10))
    local send = (dontSend == nil or dontSend) and isDifferent

    --[==[@debug@
    if isDifferent then
        print("[" .. ADDON_NAME .. "] Save Shared Data " .. id, type(BtWTodoCache[id]), type(data), data == nil, type(data) == "table" and type(BtWTodoCache[id]) == "table" and not tCompare(data, BtWTodoCache[id], 10))
    end
    --@end-debug@]==]

    BtWTodoCache[id] = data
    if send then
        Internal.SendSharedData(id, data)
    end
end
function External.SaveSharedData(id, data, dontSend)
    return Internal.SaveSharedData(id, data, dontSend)
end
function Internal.WipeSharedData(id)
    Internal.SaveSharedData(id, nil)
end
function External.WipeSharedData(id)
    return Internal.WipeSharedData(id)
end
function Internal.SendSharedData(id, data)
    if data == nil or not Internal.ValidateSharedData(id, data) then
        return
    end

    local serialized = LibSerialize:Serialize(data)
    local compressed = LibDeflate:CompressDeflate(id .. " " .. serialized)
    local encoded = ControlCharacters.SendSharedData .. LibDeflate:EncodeForWoWAddonChannel(compressed)

    if #encoded > 254 then -- We dont chunk shared data, just keep it smaller
        error("Shared data for " .. id .. " is too large")
        return
    end

    --[==[@debug@
    print("[BtWTodo] Send Shared Data " .. id)
    --@end-debug@]==]

    if IsInGuild() and (sharedDataLastSeen["GUILD:" .. id] == nil or sharedDataLastSeen["GUILD:" .. id] < GetTime() - 60) then
        sharedDataLastSeen["GUILD:" .. id] = GetTime()
        ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, encoded, "GUILD")
    end
    if IsInGroup(LE_PARTY_CATEGORY_HOME) then
        if IsInRaid() and (sharedDataLastSeen["RAID:" .. id] == nil or sharedDataLastSeen["RAID:" .. id] < GetTime() - 60) then
            sharedDataLastSeen["RAID:" .. id] = GetTime()
            ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, encoded, "RAID")
        end
        if not IsInRaid() and (sharedDataLastSeen["PARTY:" .. id] == nil or sharedDataLastSeen["PARTY:" .. id] < GetTime() - 60) then
            sharedDataLastSeen["PARTY:" .. id] = GetTime()
            ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, encoded, "PARTY")
        end
    end
    if IsInGroup(LE_PARTY_CATEGORY_INSTANCE) and (sharedDataLastSeen["INSTANCE_CHAT:" .. id] == nil or sharedDataLastSeen["INSTANCE_CHAT:" .. id] < GetTime() - 60) then
        sharedDataLastSeen["INSTANCE_CHAT:" .. id] = GetTime()
        ChatThrottleLib:SendAddonMessage("NORMAL", PREFIX, encoded, "INSTANCE_CHAT")
    end
end