---------------------------------------------------------------------------
-- @author Uli Schlachter
-- @copyright 2014 Uli Schlachter
-- @release @AWESOME_VERSION@
---------------------------------------------------------------------------

local setmetatable = setmetatable
local pairs = pairs
local tonumber = tonumber
local traceback = debug.traceback
local glib = require("lgi").GLib
local object = require("gears.object")

--- Timer objects. This type of object is useful when triggering events repeatedly.
-- The timer will emit the "timeout" signal every N seconds, N being the timeout
-- value.
-- @field timeout Interval in seconds to emit the timeout signal. Can be any
-- value, including floating point ones (i.e. 1.5 seconds).
-- @field started Read-only boolean field indicating if the timer has been
-- started.
-- @class table
-- @name timer

local timer = { mt = {} }

--- Start the timer.
function timer:start()
    if self.data.source_id ~= nil then
        print(traceback("timer already started"))
        return
    end
    self.data.source_id = glib.timeout_add(glib.PRIORITY_DEFAULT, self.data.timeout * 1000, function()
        local success, message = pcall(function()
            self:emit_signal("timeout")
        end)
        assert(success, message)
        return true
    end)
end

--- Stop the timer.
function timer:stop()
    if self.data.source_id == nil then
        print(traceback("timer not started"))
        return
    end
    glib.source_remove(self.data.source_id)
    self.data.source_id = nil
end

--- Restart the timer.
function timer:again()
    if self.data.source_id ~= nil then
        self:stop()
    end
    self:start()
end

local timer_instance_mt = {
    __index = function(self, property)
        if property == "timeout" then
            return self.data.timeout
        elseif property == "started" then
            return self.data.source_id ~= nil
        end

        return timer[property]
    end,

    __newindex = function(self, property, value)
        if property == "timeout" then
            self.data.timeout = tonumber(value)
            self:emit_signal("property::timeout")
        end
    end
}

local function new(args)
    local ret = object()

    ret:add_signal("property::timeout")
    ret:add_signal("timeout")

    ret.data = { timeout = 0 }
    setmetatable(ret, timer_instance_mt)

    for k, v in pairs(args) do
        ret[k] = v
    end

    return ret
end

function timer.mt:__call(...)
    return new(...)
end

return setmetatable(timer, timer.mt)

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