-- mod_storage_xmlarchive

-- Copyright (C) 2015-2017 Kim Alvefur

--

-- This file is MIT/X11 licensed.

--

-- luacheck: ignore unused self

local lfs = require "lfs";

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

local hmac_sha256 = require"util.hashes".hmac_sha256;

local st = require"util.stanza";

local dt = require"util.datetime";

local new_stream = require "util.xmppstream".new;

local empty = {};

if not dm.append_raw then

	module:require"datamanager_append_raw";

end

local archive = {};

local archive_mt = { __index = archive };

local is_stanza = st.is_stanza or function (s)

	return getmetatable(s) == st.stanza_mt;

end

function archive:append(username, _, data, when, with)

	if type(when) ~= "number" then

		when, with, data = data, when, with;

	end

	if not is_stanza(data) then

		module:log("error", "Attempt to store non-stanza object, traceback: %s", debug.traceback());

		return nil, "unsupported-datatype";

	end

	username = username or "@";

	data = tostring(data) .. "\n";

	local day = dt.date(when);

	local ok, err = dm.append_raw(username.."@"..day, module.host, self.store, "xml", data);

	if not ok then

		return nil, err;

	end

	-- If the day-file is missing then we need to add it to the list of days

	local first_of_day = not lfs.attributes(dm.getpath(username .. "@" .. day, module.host, self.store, "list"));

	local offset = ok and err or 0;

	local id = day .. "-" .. hmac_sha256(username.."@"..day.."+"..offset, data, true):sub(-16);

	ok, err = dm.list_append(username.."@"..day, module.host, self.store,

		{ id = id, when = dt.datetime(when), with = with, offset = offset, length = #data });

	if ok and first_of_day then

		ok, err = dm.list_append(username, module.host, self.store, day);

	end

	if not ok then

		return nil, err;

	end

	return id;

end

function archive:_get_idx(username, id, dates)

	dates = dates or self:dates(username) or empty;

	local date = id:sub(1, 10);

	for d = 1, #dates do

		if date == dates[d] then

			module:log("debug", "Loading items from %s", dates[d]);

			local items = dm.list_load(username .. "@" .. dates[d], module.host, self.store) or empty;

			for i = 1, #items do

				if items[i].id == id then

					return d, i, items;

				end

			end

			return; -- Assuming no duplicates

		elseif date < dates[d] then

			return; -- List is assumed to be sorted

		end

	end

end

function archive:find(username, query)

	username = username or "@";

	query = query or empty;

	local result;

	local function cb(_, stanza)

		assert(not result, "Multiple items in chunk");

		result = stanza;

	end

	local stream_session = { notopen = true };

	local stream_callbacks = { handlestanza = cb, stream_ns = "jabber:client", default_ns = "jabber:client" };

	local stream = new_stream(stream_session, stream_callbacks);

	local dates = dm.list_load(username, module.host, self.store) or empty;

	local function reset_stream()

		stream:reset();

		stream_session.notopen = true;

		stream:feed(st.stanza("stream", { xmlns = "jabber:client" }):top_tag());

		stream_session.notopen = nil;

	end

	reset_stream();

	local limit = query.limit;

	local start_day, step, last_day = 1, 1, #dates;

	local count = 0;

	local rev = query.reverse;

	if query.start then

		local d = dt.date(query.start);

		for i = 1, #dates do

			if dates[i] == d then

				start_day = i; break;

			end

		end

	end

	if query["end"] then

		local d = dt.date(query["end"]);

		for i = #dates, 1, -1 do

			if dates[i] == d then

				last_day = i; break;

			end

		end

	end

	local items;

	local first_item, last_item;

	if rev then

		start_day, step, last_day = last_day, -step, start_day;

		if query.before then

			local before_day, before_item, items_ = self:_get_idx(username, query.before, dates);

			if before_day and before_day <= start_day then

				if before_item then

					first_item = before_item - 1;

				else

					first_item = #items_;

				end

				last_item = 1;

				start_day = before_day;

				items = items_;

			end

		end

	elseif query.after then

		local after_day, after_item, items_ = self:_get_idx(username, query.after, dates);

		if after_day and after_day >= start_day then

			if after_item then

				first_item = after_item + 1;

			else

				first_item = 1;

			end

			last_item = #items_;

			start_day = after_day;

			items = items_;

		end

	end

	local date_open, xmlfile;

	local function read_xml(date, offset, length)

		if xmlfile and date ~= date_open then

			xmlfile:close();

			xmlfile = nil;

		end

		if not xmlfile then

			date_open = date;

			local filename = dm.getpath(username .. "@" .. date, module.host, self.store, "xml");

			local ferr;

			xmlfile, ferr = io.open(filename);

			if not xmlfile then

				module:log("error", "Error: %s", ferr);

				return nil, ferr;

			end

		end

		local pos, err = xmlfile:seek("set", offset);

		if pos ~= offset then

			return nil, err or "seek-failed";

		end

		return xmlfile:read(length);

	end

	return function ()

		if limit and count >= limit then if xmlfile then xmlfile:close() end return; end

		for d = start_day, last_day, step do

			local date = dates[d];

			if not items then

				module:log("debug", "Loading items from %s", date);

				start_day = d;

				items = dm.list_load(username .. "@" .. date, module.host, self.store) or empty;

				if not rev then

					first_item, last_item = 1, #items;

				else

					first_item, last_item = #items, 1;

				end

			end

			local q_with, q_start, q_end = query.with, query.start, query["end"];

			for i = first_item, last_item, step do

				local item = items[i];

				if not item then

					module:log("warn", "data[%q][%d] is nil", date, i);

					break;

				end

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

				if type(i_when) == "string" then

					i_when = dt.parse(i_when);

				end

				if type(i_when) ~= "number" then

					module:log("warn", "data[%q][%d].when is invalid", date, i);

					break;

				end

				if  (not q_with or i_with == q_with)

				and (not q_start or i_when >= q_start)

				and (not q_end or i_when <= q_end) then

					count = count + 1;

					first_item = i + step;

					local data = read_xml(date, item.offset, item.length);

					if not data then return end

					local ok, err = stream:feed(data);

					if not ok then

						module:log("warn", "Parse error in %s@%s/%s/%q[%d]: %s", username, module.host, self.store, i, err);

						reset_stream();

					end

					if result then

						local stanza = result;

						result = nil;

						return item.id, stanza, i_when, i_with;

					end

				end

			end

			items = nil;

			if xmlfile then

				xmlfile:close();

				xmlfile = nil;

			end

		end

	end

end

function archive:delete(username, query)

	username = username or "@";

	query = query or empty;

	if query.with or query.start or query.after then

		return nil, "not-implemented"; -- Only trimming the oldest messages

	end

	local before = query.before or query["end"] or "9999-12-31";

	if type(before) == "number" then before = dt.date(before); else before = before:sub(1, 10); end

	local dates, err = dm.list_load(username, module.host, self.store);

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

		if not err then return true end -- already empty

		return dates, err;

	end

	if dates[1] > before then return true; end -- Nothing to delete

	local remaining_dates = {};

	for d = 1, #dates do

		if dates[d] >= before then

			table.insert(remaining_dates, dates[d]);

		end

	end

	table.sort(remaining_dates);

	local ok, err = dm.list_store(username, module.host, self.store, remaining_dates);

	if not ok then return ok, err; end

	for d = 1, #dates do

		if dates[d] < before then

			os.remove(dm.getpath(username .. "@" .. dates[d], module.host, self.store, "list"));

			os.remove(dm.getpath(username .. "@" .. dates[d], module.host, self.store, "xml"));

		end

	end

	return true;

end

function archive:dates(username)

	return dm.list_load(username, module.host, self.store);

end

local provider = {};

function provider:open(store, typ)

	if typ ~= "archive" then return nil, "unsupported-store"; end

	return setmetatable({ store = store }, archive_mt);

end

function provider:purge(username)

	for store in dm.stores(username, module.host) do

		local dates = dm.list_load(username, module.host, store) or empty;

		if dates[1] and type(dates[1]) == "string" and dates[1]:match("^%d%d%d%d%-%d%d%-%d%d$") then

			module:log("info", "Store %s looks like an archive store, emptying it...", store);

			provider:open(store, "archive"):delete(username);

		end

	end

	return true;

end

module:provides("storage", provider);