local mt = require"util.multitable";

local datetime = require"util.datetime";

local jid_split = require"util.jid".split;

local nodeprep = require"util.encodings".stringprep.nodeprep;

local it = require"util.iterators";

local url = require"socket.url";

local os_time, os_date = os.time, os.date;

local httplib = require "util.http";

local render = require"util.interpolation".new("%b{}", require"util.stanza".xml_escape);

local archive = module:open_store("muc_log", "archive");

-- Support both old and new MUC code

local mod_muc = module:depends"muc";

local rooms = rawget(mod_muc, "rooms");

local each_room = rawget(mod_muc, "each_room") or function() return it.values(rooms); end;

local new_muc = not rooms;

if new_muc then

	rooms = module:shared"muc/rooms";

end

local get_room_from_jid = rawget(mod_muc, "get_room_from_jid") or

	function (jid)

		return rooms[jid];

	end

local function get_room(name)

	local jid = name .. '@' .. module.host;

	return get_room_from_jid(jid);

end

module:depends"http";

local template;

do

	local template_filename = module:get_option_string(module.name .. "_template", module.name .. ".html");

	local template_file, err = module:load_resource(template_filename);

	if template_file then

		template, err = template_file:read("*a");

		template_file:close();

	end

	if not template then

		module:log("error", "Error loading template: %s", err);

		template = render("<h1>mod_{module} could not read the template</h1>\

		<p>Tried to open <b>{filename}</b></p>\

		<pre>{error}</pre>",

			{ module = module.name, filename = template_filename, error = err });

	end

end

-- local base_url = module:http_url() .. '/'; -- TODO: Generate links in a smart way

local get_link do

	local link, path = { path = '/' }, { "", "", is_directory = true };

	function get_link(room, date)

		path[1], path[2] = room, date;

		path.is_directory = not date;

		link.path = url.build_path(path);

		return url.build(link);

	end

end

-- Whether room can be joined by anyone

local function open_room(room) -- : boolean

	if type(room) == "string" then

		room = get_room(room);

		-- assumed to be a room object otherwise

	end

	if not room then

		return nil;

	end

	if (room.get_members_only or room.is_members_only)(room) then

		return false;

	end

	if room:get_password() then

		return false;

	end

	return true;

end

module:hook("muc-disco#info", function (event)

	local room = event.room;

	if open_room(room) then

		table.insert(event.form, { name = "muc#roominfo_logs", type="text-single" });

		event.formdata["muc#roominfo_logs"] = module:http_url() .. "/" .. get_link(jid_split(event.room.jid), nil);

	end

end);

local function sort_Y(a,b) return a.year > b.year end

local function sort_m(a,b) return a.n > b.n end

-- Time zone hack?

local t_diff = os_time(os_date("*t")) - os_time(os_date("!*t"));

local function time(t)

	return os_time(t) + t_diff;

end

local function date_floor(t)

	return t - t % 86400;

end

-- Fetch one item

local function find_once(room, query, retval)

	if query then query.limit = 1; else query = { limit = 1 }; end

	local iter, err = archive:find(room, query);

	if not iter then return iter, err; end

	if retval then

		return select(retval, iter());

	end

	return iter();

end

local lazy = module:get_option_boolean(module.name .. "_lazy_calendar", true);

local function hide_presence(request)

	if request.url.query then

		local data = httplib.formdecode(request.url.query);

		if data then

			return data.p == "h"

		end

	end

	return false;

end

-- Produce the calendar view

local function years_page(event, path)

	local request, response = event.request, event.response;

	local room = nodeprep(path:match("^(.*)/$"));

	local is_open = open_room(room);

	if is_open == nil then

		return -- implicit 404

	elseif is_open == false then

		return 403;

	end

	-- Collect each date that has messages

	-- convert it to a year / month / day tree

	local date_list = archive.dates and archive:dates(room);

	local dates = mt.new();

	if date_list then

		for _, date in ipairs(date_list) do

			local when = datetime.parse(date.."T00:00:00Z");

			local t = os_date("!*t", when);

			dates:set(t.year, t.month, t.day, when);

		end

	elseif lazy then

		-- Lazy with many false positives

		local first_day = find_once(room, nil, 3);

		local last_day = find_once(room, { reverse = true }, 3);

		if first_day and last_day then

			first_day = date_floor(first_day);

			last_day = date_floor(last_day);

			for when = first_day, last_day, 86400 do

				local t = os_date("!*t", when);

				dates:set(t.year, t.month, t.day, when);

			end

		else

			return; -- 404

		end

	else

		-- Collect date the hard way

		module:log("debug", "Find all dates with messages");

		local next_day;

		repeat

			local when = find_once(room, { start = next_day; }, 3);

			if not when then break; end

			local t = os_date("!*t", when);

			dates:set(t.year, t.month, t.day, when );

			next_day = date_floor(when) + 86400;

		until not next_day;

	end

	local years = {};

	-- Wrangle Y/m/d tree into year / month / week / day tree for calendar view

	for current_year, months_t in pairs(dates.data) do

		local t = { year = current_year, month = 1, day = 1 };

		local months = { };

		local year = { year = current_year, months = months };

		years[#years+1] = year;

		for current_month, days_t in pairs(months_t) do

			t.day = 1;

			t.month = current_month;

			local tmp = os_date("!*t", time(t));

			local days = {};

			local week = { days = days }

			local weeks = { week };

			local month = { year = year.year, month = os_date("!%B", time(t)), n = current_month, weeks = weeks };

			months[#months+1] = month;

			local current_day = 1;

			for _=1, (tmp.wday+5)%7 do

				days[current_day], current_day = {}, current_day+1;

			end

			for i = 1, 31 do

				t.day = i;

				tmp = os_date("!*t", time(t));

				if tmp.month ~= current_month then break end

				if i > 1 and tmp.wday == 2 then

					days = {};

					weeks[#weeks+1] = { days = days };

					current_day = 1;

				end

				days[current_day] = {

					wday = tmp.wday, day = i, href = days_t[i] and datetime.date(days_t[i])

				};

				current_day = current_day+1;

			end

		end

		table.sort(year, sort_m);

	end

	table.sort(years, sort_Y);

	-- Phew, all wrangled, all that's left is rendering it with the template

	response.headers.content_type = "text/html; charset=utf-8";

	return render(template, {

		title = get_room(room):get_name();

		jid = get_room(room).jid;

		hide_presence = hide_presence(request);

		years = years;

		links = {

			{ href = "../", rel = "up", text = "Room list" },

		};

	});

end