local st = require "util.stanza";

module:depends("http");

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

local os_time = os.time;

local t_remove = table.remove;

local add_task = require "util.timer".add_task;

local jid_bare = require "util.jid".bare;

local function get_room_from_jid() end;

local is_component = module:get_host_type() == "component";

if is_component then

	local mod_muc = module:depends "muc";

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

	get_room_from_jid = rawget(mod_muc, "get_room_from_jid") or

		function (jid)

			return muc_rooms[jid];

		end

end

local utf8_pattern = "[\194-\244][\128-\191]*$";

local function drop_invalid_utf8(seq)

	local start = seq:byte();

	module:log("debug", "utf8: %d, %d", start, #seq);

	if (start <= 223 and #seq < 2)

	or (start >= 224 and start <= 239 and #seq < 3)

	or (start >= 240 and start <= 244 and #seq < 4)

	or (start > 244) then

		return "";

	end

	return seq;

end

local function utf8_length(str)

	local _, count = string.gsub(str, "[^\128-\193]", "");

	return count;

end

local pastebin_private_messages = module:get_option_boolean("pastebin_private_messages", not is_component);

local length_threshold = module:get_option_number("pastebin_threshold", 500);

local line_threshold = module:get_option_number("pastebin_line_threshold", 4);

local max_summary_length = module:get_option_number("pastebin_summary_length", 150);

local html_preview = module:get_option_boolean("pastebin_html_preview", true);

local base_url = module:get_option_string("pastebin_url", module:http_url()):gsub("/$", "").."/";

-- Seconds a paste should live for in seconds (config is in hours), default 24 hours

local expire_after = math.floor(module:get_option_number("pastebin_expire_after", 24) * 3600);

local trigger_string = module:get_option_string("pastebin_trigger");

trigger_string = (trigger_string and trigger_string .. " ");

local pastes = {};

local xmlns_xhtmlim = "http://jabber.org/protocol/xhtml-im";

local xmlns_xhtml = "http://www.w3.org/1999/xhtml";

function pastebin_text(text)

	local uuid = uuid_new();

	pastes[uuid] = { body = text, time = os_time(), };

	pastes[#pastes+1] = uuid;

	if not pastes[2] then -- No other pastes, give the timer a kick

		add_task(expire_after, expire_pastes);

	end

	return base_url..uuid;

end

function handle_request(event, pasteid)

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

	if not pasteid then

		return "Invalid paste id, perhaps it expired?";

	end

	--module:log("debug", "Received request, replying: %s", pastes[pasteid].text);

	local paste = pastes[pasteid];

	if not paste then

		return "Invalid paste id, perhaps it expired?";

	end

	return paste.body;

end

local function replace_tag(s, replacement)

	local once = false;

	s:maptags(function (tag)

		if tag.name == replacement.name and tag.attr.xmlns == replacement.attr.xmlns then

			if not once then

				once = true;

				return replacement;

			else

				return nil;

			end

		end

		return tag;

	end);

	if not once then

		s:add_child(replacement);

	end

end

local line_count_pattern = string.rep("[^\n]*\n", line_threshold + 1):sub(1,-2);

function check_message(data)

	local stanza = data.stanza;

	-- Only check for MUC presence when loaded on a component.

	if is_component then

		local room = get_room_from_jid(jid_bare(stanza.attr.to));

		if not room then return; end

		local nick = room._jid_nick[stanza.attr.from];

		if not nick then return; end

	end

	local body = stanza:get_child_text("body");

	if not body then return; end

	--module:log("debug", "Body(%s) length: %d", type(body), #(body or ""));

	if ( #body > length_threshold and utf8_length(body) > length_threshold ) or

		(trigger_string and body:find(trigger_string, 1, true) == 1) or

		body:find(line_count_pattern) then

		if trigger_string and body:sub(1, #trigger_string) == trigger_string then

			body = body:sub(#trigger_string+1);

		end

		local url = pastebin_text(body);

		module:log("debug", "Pasted message as %s", url);

		--module:log("debug", " stanza[bodyindex] = %q", tostring( stanza[bodyindex]));

		local summary = (body:sub(1, max_summary_length):gsub(utf8_pattern, drop_invalid_utf8) or ""):match("[^\n]+") or "";

		summary = summary:match("^%s*(.-)%s*$");

		local summary_prefixed = summary:match("[,:]$");

		replace_tag(stanza, st.stanza("body"):text(summary .. "\n" .. url));

		stanza:add_child(st.stanza("query", { xmlns = "jabber:iq:oob" }):tag("url"):text(url));

		if html_preview then

			local line_count = select(2, body:gsub("\n", "%0")) + 1;

			local link_text = ("[view %spaste (%d line%s)]"):format(summary_prefixed and "" or "rest of ", line_count, line_count == 1 and "" or "s");

			local html = st.stanza("html", { xmlns = xmlns_xhtmlim }):tag("body", { xmlns = xmlns_xhtml });

			html:tag("p"):text(summary.." "):up();

			html:tag("a", { href = url }):text(link_text):up();

			replace_tag(stanza, html);

		end

	end

end

module:hook("message/bare", check_message);

if pastebin_private_messages then

	module:hook("message/full", check_message);

end

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

	local reply, form, formdata = event.reply, event.form, event.formdata;

	reply:tag("feature", { var = "https://modules.prosody.im/mod_pastebin" }):up();

	table.insert(form, { name = "{https://modules.prosody.im/mod_pastebin}max_lines", datatype = "xs:integer" });

	table.insert(form, { name = "{https://modules.prosody.im/mod_pastebin}max_characters", datatype = "xs:integer" });

	formdata["{https://modules.prosody.im/mod_pastebin}max_lines"] = tostring(line_threshold);

	formdata["{https://modules.prosody.im/mod_pastebin}max_characters"] = tostring(length_threshold);

end);

function expire_pastes(time)

	time = time or os_time(); -- COMPAT with 0.5

	if pastes[1] then

		pastes[pastes[1]] = nil;

		t_remove(pastes, 1);

		if pastes[1] then

			return (expire_after - (time - pastes[pastes[1]].time)) + 1;

		end

	end

end

module:provides("http", {

	route = {

		["GET /*"] = handle_request;

	};

});

local function set_pastes_metatable()

	-- luacheck: ignore 212/pastes 431/pastes

	if expire_after == 0 then

		local dm = require "util.datamanager";

		setmetatable(pastes, {

			__index = function (pastes, id)

				if type(id) == "string" then

					return dm.load(id, module.host, "pastebin");

				end

			end;

			__newindex = function (pastes, id, data)

				if type(id) == "string" then

					dm.store(id, module.host, "pastebin", data);

				end

			end;

		});

	else

		setmetatable(pastes, nil);

	end

end

module.load = set_pastes_metatable;

function module.save()

	return { pastes = pastes };

end

function module.restore(data)

	pastes = data.pastes or pastes;

	set_pastes_metatable();

end