local DRAIN_THRESHOLD = 0.1
local DRAIN_RATE = 0.02

local drainEvents = {
    {time = 48000, duration = 7000},
    {time = 99000, duration = 5000},
    {time = 147400, duration = 9000}
}

local currentDrainingEvent = nil
local drainStartTime = 0

function drainHealth(amount)
    local health = getProperty('health')
    if health > DRAIN_THRESHOLD then
        setProperty('health', math.max(health - amount, DRAIN_THRESHOLD))
    end
end

function onUpdate(elapsedTime)
    local currentTime = getSongPosition()

    if currentDrainingEvent then
        local elapsedDrainTime = currentTime - drainStartTime
        if elapsedDrainTime < currentDrainingEvent.duration then
            local amountToDrain = (DRAIN_RATE * elapsedTime * 1000) / (currentDrainingEvent.duration / 1000)
            drainHealth(amountToDrain)
        else
            currentDrainingEvent = nil
        end
    else
        for _, event in ipairs(drainEvents) do
            if currentTime >= event.time and currentTime < event.time + event.duration then
                currentDrainingEvent = event
                drainStartTime = currentTime
                break
            end
        end
    end
end