local datamanager = require"core.storagemanager".olddm;

local xml_parse = require"util.xml".parse;

local data_load, data_store = datamanager.load, datamanager.store;

local datastore = "muc_log";

local datetime = require"util.datetime"

local lfs = require"lfs";

local noop = function () end;

local os_date = os.date;

local timef, datef = "!%X", "!%y%m%d";

local host = module.host;

local driver = {};

local driver_mt = { __index = driver };

do

	-- Sanity check

	-- Fun fact: 09:00 and 21:00 en_HK are both "09:00:00 UTC"

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

	t.hour = 9;

	local am = os_date(timef, os.time(t));

	t.hour = 21;

	local pm = os_date(timef, os.time(t));

	if am == pm then

		module:log("warn", "Timestamps in AM and PM are identical in your locale, expect timestamps to be wrong");

	end

end

local function parse_silly(date, time)

	local year, month, day = date:match("^(%d%d)(%d%d)(%d%d)");

	year = "20"..year;

	-- year = (year < "70" and "20" or "19") .. year;

	local hour, min, sec = time:match("(%d%d)%D+(%d%d)%D+(%d%d)");

	if hour == "12" and time:find("[Aa][Mm]") then

		hour = "00";

	elseif hour < "12" and time:find("[Pp][Mm]") then

		hour = tostring(tonumber(hour) % 12 + 12);

	end

	return datetime.parse(("%s-%s-%sT%s:%s:%sZ"):format(year, month, day, hour or "00", min or "00", sec or "00"));

end

local function st_with(tag)

	local with = tag.attr.type;

	return with and tag.name .. "<" .. with or tag.name;

end

function driver:append(node, key, when, with, stanza)

	local today = os_date(datef, when);

	local now = os_date(timef, when);

	local data = data_load(node, host, datastore .. "/" .. today) or {};

	data[#data + 1] = "<stanza time=\"".. now .. "\">" .. tostring(stanza) .. "</stanza>\n";

	datamanager.getpath(node, host, datastore, nil, true); -- create the datastore dir

	local ok, err = data_store(node, host, datastore .. "/" .. today, data);

	if not ok then

		return ok, err;

	end

	return today .. "_" .. #data;

end

function driver:find(node, query)

	local path = datamanager.getpath(node, host, datastore):match("(.*)/");

	local ok, iter, state, var = pcall(lfs.dir, path);

	if not ok then

		module:log("warn", iter);

		return nil, iter;

	end

	local dates, i = {}, 1;

	for dir in iter, state, var do

		if lfs.attributes(datamanager.getpath(node, host, datastore .. "/" .. dir), "mode") == "file" then

			dates[i], i = dir, i+1;

		end

	end

	if dates[1] == nil then return noop, 0; end

	table.sort(dates);

	return coroutine.wrap(function ()

		local query = query;

		local dates = dates;

		local start_date = query and query.start and os_date(datef, query.start) or dates[1];

		local end_date = query and query["end"] and os_date(datef, query["end"]) or dates[#dates];

		local start_time = query and query.start and os_date(timef, query.start) or dates[1];

		local end_time = query and query["end"] and os_date(timef, query["end"]) or dates[#dates];

		local query_with = query and query.with;

		local query_limit = query and query.limit;

		local seek_once = query and query.after;

		local today, time, data, err, item;

		local inner_start, inner_stop, inner_step;

		local outer_start, outer_stop, outer_step = 1, #dates, 1;

		if query and query.reverse then 

			outer_start, outer_stop, outer_step = outer_stop, outer_start, -outer_step;

			seek_once = query.before;

			if seek_once then

				end_date = seek_once:match"^(%d+)_%d";

			end

		elseif seek_once then

			start_date = seek_once:match"^(%d+)_%d";

		end

		local matches = 0;

		for i = outer_start, outer_stop, outer_step do

			today = dates[i];

			if today >= start_date and today <= end_date then

				data, err = data_load(node, host, datastore .. "/" .. today);

				if data then

					inner_start, inner_stop, inner_step = 1, #data, 1;

					if query and query.reverse then 

						inner_start, inner_stop, inner_step = inner_stop, inner_start, -inner_step;

					end

					if seek_once then

						inner_start = tonumber(seek_once:match("_(%d+)$"));

						inner_start = inner_start + (query and query.reverse and -1 or 1);

						seek_once = nil;

					end

					for i = inner_start, inner_stop, inner_step do

						item, err = data[i];

						if item then

							item, err = xml_parse(item);

						end

						if item then

							time = item.attr.time;

							item = item.tags[1];

							if (today >= start_date or time >= start_time) and

								(today <= end_date or time <= end_time) and

								(not query_with or query_with == st_with(item)) and

								item:get_child_text("alreadyJoined") ~= "true" then

								matches = matches + 1;

								coroutine.yield(today.."_"..i, item, parse_silly(today, time));

								if query_limit and matches >= query_limit then

									return;

								end

							end

						elseif err then

							module:log("warn", err);

						end

					end

				elseif err then

					module:log("warn", err);

				end

			end

		end

	end);

end

function open(_, store, typ)

	if typ ~= "archive" then

		return nil, "unsupported-store";

	end

	return setmetatable({ store = store, type = typ }, driver_mt);

end

module:provides "storage";