local CHOICE_TABLE = {
    -- TYPES:
    --      1: Spell
    --      2: Item
    -- [level] = { { type, ID, chance }, ... }
    [2] = {
        {1, 90008, 100},
        {2, 23368, 100},
        {2, 26029, 100}
    },
    [3] = {
        {2, 50055, 100},
        {2, 23368, 100},
        {2, 26029, 100}
    },
    [4] = {
        {1, 90010, 100},
        {2, 23368, 100},
        {2, 26029, 100}
    },
    [5] = {
        {1, 90000, 100},
        {2, 50055, 100},
        {2, 23368, 100}
    },
    [6] = {
        {1, 90011, 100},
        {1, 90009, 100},
        {2, 23368, 33},
        {2, 50055, 33},
        {2, 26029, 33}
    }
}

local function PLAYER_EVENT_ON_LEVEL_CHANGE(event, player, oldLevel)
    local t = CHOICE_TABLE[oldLevel + 1]
    if not t then
        return
    end
    local results = {}
    local position = 1
    for i=1,3 do
        local inserted = false
        while not inserted do
            local row = t[position]
            if not row then
                position = 1
            else
                local valid = true
                local _type = row[1]
                local id = row[2]
                local chance = row[3]
                for _,v in pairs(results) do
                    if v[1] == _type and v[2] == id then
                        valid = false
                        break
                    end
                    if v[1] == 1 and player:HasSpell(v[2]) then
                        valid = false
                        break
                    end
                end
                if valid and math.random(1, 100) <= chance then
                    table.insert(results, {_type, id})
                    inserted = true
                end
            end
        end
    end

    local query = "INSERT INTO `spellselectionsystem` (guid, `level`, type1, option1, type2, option2, type3, option3) VALUES "
        .. "('" .. player:GetGUIDLow() .. "', '" .. (oldLevel + 1) .. "'"
    local message = "LEVELUP-" .. string.format("%02d", oldLevel + 1)
    for i=1,3 do
        query = query .. ", '" .. results[i][1] .. "'"
        message = message .. "-" ..  string.format("%01d", results[i][1])
        query = query .. ", '" .. results[i][2] .. "'"
        message = message .. "-" ..  string.format("%06d", results[i][2])
    end

    CharDBQuery(query .. ")")

    sendAddonMessage(player, message, 1)
end

RegisterPlayerEvent(13, PLAYER_EVENT_ON_LEVEL_CHANGE)

-----------
----------- receiving
-----------
local _DEBUG = false

-- Prototypes
local functionLookup

-- Handle addon messages
local function onReceiveAddonMsg(event, plr, Type, prefix, msg, receiver)
    if receiver ~= plr then return end
    if not msg or not prefix or not plr then return end
    if _DEBUG then print("[GOT] " .. prefix .. " | " .. msg) end
    local func = functionLookup[prefix]
    if func then
        func(plr, msg)
    end
end

RegisterServerEvent(30, onReceiveAddonMsg)

function SelectLevelReward(plr, msg)
    local option = tonumber(msg)
    if not option or option < 1 or option > 3 then
        return
    end
    local level = plr:GetLevel()
    local result = CharDBQuery("SELECT * FROM `spellselectionsystem` WHERE `guid` = '"..plr:GetGUIDLow().."' AND `level` = '"..level.."'")
    if result then
        local t = result:GetRow()
        if t["selected"] then
            return
        end
        local optionVal = t["option"..tostring(option)]
        local optionType = t["type"..tostring(option)]
        if (optionType == 1) then
            plr:LearnSpell(optionVal)
        elseif (optionType == 2) then
            plr:AddItem(optionVal, 1)
        end
        CharDBQuery("UPDATE `spellselectionsystem` SET `selectedType` = '"..tostring(optionType).."', `selected` = '"..tostring(optionVal).."' WHERE `guid` = '"..plr:GetGUIDLow().."' AND `level` = '"..level.."'")
    end
end

-- function lookup
functionLookup = {
    ["SELECT"] = SelectLevelReward
}

--- on delete character

local function PLAYER_EVENT_ON_CHARACTER_DELETE(event, guid)
    if guid then
        CharDBQuery("DELETE FROM `spellselectionsystem` WHERE `guid` = '"..guid.."'")
    end
end

RegisterPlayerEvent(2, PLAYER_EVENT_ON_CHARACTER_DELETE)

---- on first login

local function PLAYER_EVENT_ON_FIRST_LOGIN(event, plr)
    if plr then
        for _,t in pairs(CHOICE_TABLE) do
            for _,r in pairs(t) do
                if r[1] == 2 then
                    plr:ForceItemDownPlayersThroat(r[2])
                end
            end
        end
    end
end

RegisterPlayerEvent(30, PLAYER_EVENT_ON_FIRST_LOGIN)