-- luacheck: ignore 212/self

local uuid = require "util.uuid".generate;

local store = module:shared("archive");

local archive_store = { _provided_by = "mam"; name = "fallback"; };

function archive_store:append(username, key, value, when, with)

	local archive = store[username];

	if not archive then

		archive = { [0] = 0 };

		store[username] = archive;

	end

	local index = (archive[0] or #archive)+1;

	local item = { key = key, when = when, with = with, value = value };

	if not key or archive[key] then

		key = uuid();

		item.key = key;

	end

	archive[index] = item;

	archive[key] = index;

	archive[0] = index;

	return key;

end

function archive_store:find(username, query)

	local archive = store[username] or {};

	local start, stop, step = 1, archive[0] or #archive, 1;

	local qstart, qend, qwith = -math.huge, math.huge;

	local limit;

	if query then

		if query.reverse then

			start, stop, step = stop, start, -1;

			if query.before and archive[query.before] then

				start = archive[query.before] - 1;

			end

		elseif query.after and archive[query.after] then

			start = archive[query.after] + 1;

		end

		qwith = query.with;

		limit = query.limit;

		qstart = query.start or qstart;

		qend = query["end"] or qend;

	end

	return function ()

		if limit and limit <= 0 then return end

		for i = start, stop, step do

			local item = archive[i];

			if (not qwith or qwith == item.with) and item.when >= qstart and item.when <= qend then

				if limit then limit = limit - 1; end

				start = i + step; -- Start on next item

				return item.key, item.value, item.when, item.with;

			end

		end

	end

end

function archive_store:delete(username, query)

	if not query or next(query) == nil then

		-- no specifics, delete everything

		store[username] = nil;

		return true;

	end

	local archive = store[username];

	if not archive then return true; end -- no messages, nothing to delete

	local start, stop, step = 1, archive[0] or #archive, 1;

	local qstart = query.start or -math.huge;

	local qend = query["end"] or math.huge;

	local qwith = query.with;

	store[username] = nil;

	for i = 1, #archive do

		local item = archive[i];

		local when, with = item.when, item.when;

		-- Add things that don't match the query

		if not ((not qwith or qwith == item.with) and item.when >= qstart and item.when <= qend) then

			self:append(username, item.key, item.value, when, with);

		end

	end

	return true;

end

return archive_store;