local Luan = require "luan:Luan.luan"
local error = Luan.error
local ipairs = Luan.ipairs or error()
local pairs = Luan.pairs or error()
local stringify = Luan.stringify or error()
local Time = require "luan:Time.luan"
local time_now = Time.now or error()
local Thread = require "luan:Thread.luan"
local Http = require "luan:http/Http.luan"
local Chat = require "site:/lib/Chat.luan"
local User = require "site:/lib/User.luan"
local get_user_by_id = User.get_by_id or error()
local Db = require "site:/lib/Db.luan"
local run_in_transaction = Db.run_in_transaction or error()
local Shared = require "site:/lib/Shared.luan"
local send_mail = Shared.send_mail or error()
local Utils = require "site:/lib/Utils.luan"
local shallow_copy = Utils.shallow_copy or error()
local Logging = require "luan:logging/Logging.luan"
local logger = Logging.logger "Notify"


local Notify = {}

local base_url = Http.domain and "https://"..Http.domain or "http://localhost:8080"

local wait = Time.period{seconds=10}

local function set_notified(user,was_notified)
	run_in_transaction( function()
		user = user.reload()
		user.was_notified = was_notified
		user.save()
	end )
end

local function init()
	local users = {}
	local fns = {}

	function fns.add(user_ids)
		local now = time_now()
		for _, user_id in ipairs(user_ids) do
			local user = get_user_by_id(user_id)
			if users[user_id] == nil and user.notify_email ~= nil and (user.multi_notify or not user.was_notified) then
				users[user_id] = now
				-- logger.info("add "..user_id)
			end
		end
	end

	function fns.remove(user_id)
		users[user_id] = nil
		-- logger.info("remove "..user_id)
	end

	function fns.notify()
		-- logger.info("notify")
		local now = time_now()
		for user_id, when in pairs(shallow_copy(users)) do
			if now - when > wait then
				local user = get_user_by_id(user_id)
				-- logger.info("notify "..user.notify_email.." "..user_id)
				send_mail {
					To = user.notify_email
					Subject = "New Messages"
					body = `%>
You have received new messages.

<%= base_url %>/

To unsubscribe:
<%= base_url %>/unsubscribe.html?user=<%=user_id%>&password=<%=user.password%>
<%					`
				}
				users[user_id] = nil
				set_notified(user,true)
			end
		end
	end

	return fns
end

local glob = Thread.global_callable("notify",init)

function Notify.add(chat)
	Thread.run(function()
		glob.add(chat.user_ids)
	end)
end

function Notify.remove(user)
	Thread.run(function()
		glob.remove(user.id)
		if user.was_notified then
			set_notified(user,false)
		end
	end)
end

Thread.schedule( glob.notify, { repeating_delay=Time.period{seconds=10} } )

return Notify