stopwatch

--------
-- Stopwatch Timing Class, v1.2.1
--
-- by Kyle Coburn
-- 10 April 2012
----
-- For the latest updates, release notes, and support/feedback:
-- http://developer.anscamobile.com/code/stopwatch-timing-class
----
-- Usage:
-- local stopwatch = require "stopwatch"
--
-- stopwatch.new() --Counts up indefinitely
-- stopwatch.new( 60 ) --Counts down from 60 seconds
--------

local stopwatch = {}
local stopwatch_mt = { __index = stopwatch }

local floor, getTime = math.floor, system.getTimer


local function timeFormat(secs)
        if (secs < 1) then
                return "00:00"
        end
        local mins = "00"
        if (secs > 59) then
                mins = floor(secs / 60)
                if (mins < 10) then
                        mins = "0"..mins
                end
                secs = secs % 60
        end
        if (secs < 10) then
                secs = "0"..secs
        end
        return mins..":"..secs
end


-- Time check
function stopwatch:getElapsed()
        if (self._pauseStart) then
                return self._pauseStart - self._startTime
        end
        return getTime() - self._startTime
end

function stopwatch:getElapsedSeconds()
        return floor(self:getElapsed() / 1000)
end

function stopwatch:getRemaining()
        if (self._pauseStart) then
                return self._endTime - self._pauseStart
        end
        return self._endTime - getTime()
end

function stopwatch:getRemainingSeconds()
        return floor(self:getRemaining() / 1000)
end

function stopwatch:isElapsed()
        if (self._endTime) then
                return self:getRemaining() <= 0
        end
end


-- Modify
function stopwatch:addTime(seconds)
        if (self._endTime) then
                self._endTime = self._endTime + seconds * 1000
        else
                self._startTime = self._startTime - seconds * 1000
        end
end


-- Pause
function stopwatch:isPaused()
        return self._pauseStart ~= nil
end

function stopwatch:pause()
        if (not self:isPaused()) then
                self._pauseStart = getTime()
        end
end

function stopwatch:resume()
        if (self:isPaused()) then
                if (self._endTime) then
                        self._endTime = self._endTime + (getTime() - self._pauseStart)
                else
                        self._startTime = self._startTime + (getTime() - self._pauseStart)
                end
                self._pauseStart = nil
        end
end


-- Formatting
function stopwatch:toElapsedString()
        return timeFormat(self:getElapsedSeconds())
end

function stopwatch:toRemainingString()
        if (not self._endTime) then
                return "99:99"
        end
        return timeFormat(self:getRemainingSeconds())
end


-- Object creation
function stopwatch.new(countdown)
        local newTimer = {}
        local startTime = getTime()

        if (countdown) then
                newTimer._endTime = startTime + countdown * 1000
        end
        newTimer._startTime = startTime

        return setmetatable(newTimer, stopwatch_mt)
end

stopwatch.format = timeFormat


return stopwatch