local msg = include("sca_msg.lua")
local isRunning = false
local summerTime = nil

local function sca_setup_timezone()
    local time = os.time()
    local daysPastUnixYear = math.floor(time / 86400) // Unix began on 01.01.1970
    local year = 1970
    local month = 0
    local day = 0
    local weekDay = daysPastUnixYear % 7 // 0 = thursday, 1 = friday, 2 = saturday, 3 = sunday, 4 = monday, 5 = tuesday, 6 = wensday. 01.01.1970 was on thursday

    local daysPerMonth = {
        [0] = 31, // January
        [1] = 28, // February
        [2] = 31, // March
        [3] = 30, // April
        [4] = 31, // May
        [5] = 30, // June
        [6] = 31, // July
        [7] = 31, // August
        [8] = 30, // September
        [9] = 31, // Ocotober
        [10] = 30, // Novmeber
        [11] = 31 // December
    }

    while (daysPastUnixYear > 364) do
        if (year % 4 == 0 && (year % 400 == 0 && year % 100 != 0)) then
            daysPastUnixYear = daysPastUnixYear - 366
        else
            daysPastUnixYear = daysPastUnixYear - 365 
        end
        year = year + 1
    end

    for i = 0, 11, 1 do
       if (daysPastUnixYear - daysPerMonth[i] >= daysPerMonth[i]) then
            if (i == 2 && (year % 4 == 0 && (year % 400 == 0 && year % 100 != 0))) then
                daysPastUnixYear = daysPastUnixYear - (daysPerMonth[i] + 1)
            else
                daysPastUnixYear = daysPastUnixYear - daysPerMonth[i]
            end
            month = month + 1
        else
            day = daysPastUnixYear - 1
            break
        end
    end
    
    local hourInSeconds = time % 86400
    
    if (month > 2 && month < 9) then  
        summerTime = true 
    elseif (month == 2) then
        // If its less than 6 days until end of the month (aka last Weekday in the month) and its sunday and its 3 am or later....
        if ((daysPerMonth[month] - day <= 6) && weekDay == 3 && hoursInSeconds >= 10800) then
            summerTime = true
        else
            summerTime = false
        end
    elseif (month == 9) then
        // The same action again but for winter time
        if ((daysPerMonth[month] - day <= 6) && weekDay == 3 && hoursInSeconds >= 10800) then
            summerTime = false
        else
            summerTime = true
        end
    else
        summerTime = false
    end
end

// Odd... Windows returns timezoned os.time, hmmm.... Need to check it on Linux
local function sca_msg_to_player(time)
    if (msg[time] != nil) then
        for k, v in ipairs(player.GetHumans()) do
            v:SendLua('chat.AddText(' .. msg[time] .. ')')
        end 
    end
end

local function sca_timer_loop()
    // If timezone has been setup then...
    if summerTime != nil then
        local time = os.time()

        // Germany timezone in summer is UTC+1, in winter is UTC+2
        if summerTime then
            time = time + 3600
        else
            time = time + 7200
        end

        local timeModulo = time % 60
        if timeModulo == 0 then
            if !isRunning then
                // 86400 seconds are 24 hours. We will get time between 00:00 - 23:59 (current time) in seconds from that modulo operation. 0 = 00:00, 86340 = 23:59
                sca_msg_to_player(time % 86400)
                isRunning = true
            end
        else
            if isRunning then
                isRunning = false
            end
        end 
    end
end

hook.Add("Tick", "sca_timer_loop", sca_timer_loop)
hook.Add("Initialize", "sca_setup_timezone", sca_setup_timezone)