#!/usr/bin/env lua

local json = require 'cjson'
local arrr = require 'arrr'
local inspect = require "inspect"

local function zulu_offset()
	local current = os.date("*t")
	current.isdst = false
	local zulu = os.date("!*t")
	return os.difftime(os.time(current), os.time(zulu))
end

local params do
	local parse = arrr {
		{ "Time or something", "--time", "-t", "time" };
	}

	local function validate(args)
		return args
	end

	params = validate(parse(arg))
end

local done = {}

while true do
	local data = json.decode(io.popen("task export"):read("*a"))
	for _, task in ipairs(data) do
		if task.status == "pending" and task.due then
			local due do
				local d = {}
				d.year, d.month, d.day, d.hour, d.min, d.sec
				= task.due:match("(%d%d%d%d)(%d%d)(%d%d)T(%d%d)(%d%d)(%d%d)Z")
				d.sec = d.sec + zulu_offset()
				due = os.time(d)
			end

			if os.difftime(due, os.time()) < 3600*params.time then
				if not done[task.uuid] then
					done[task.uuid] = task
					print("Notifying:", task.uuid, task.description)
					os.execute("notify-send 'Task due soon' '"..task.description:gsub([[']], [['"'"']]).."'")
				end
			end
		end
	end

	if not os.execute("sleep 3") then
		os.exit()
	end
end