-- Copyright (C) 2008-2009 Matthew Wild

-- Copyright (C) 2008-2009 Waqas Hussain

-- 

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local plugin_dir = CFG_PLUGINDIR or "./plugins/";

local logger = require "util.logger";

local log = logger.init("modulemanager");

local addDiscoInfoHandler = require "core.discomanager".addDiscoInfoHandler;

local eventmanager = require "core.eventmanager";

local config = require "core.configmanager";

local multitable_new = require "util.multitable".new;

local register_actions = require "core.actions".register;

local hosts = hosts;

local loadfile, pcall = loadfile, pcall;

local setmetatable, setfenv, getfenv = setmetatable, setfenv, getfenv;

local pairs, ipairs = pairs, ipairs;

local t_insert, t_concat = table.insert, table.concat;

local type = type;

local next = next;

local rawget = rawget;

local tostring, print = tostring, print;

-- We need this to let modules access the real global namespace

local _G = _G;

module "modulemanager"

local api = {}; -- Module API container

local modulemap = { ["*"] = {} };

local stanza_handlers = multitable_new();

local handler_info = {};

local modulehelpers = setmetatable({}, { __index = _G });

local features_table = multitable_new();

local handler_table = multitable_new();

local hooked = multitable_new();

local event_hooks = multitable_new();

local NULL = {};

-- Load modules when a host is activated

function load_modules_for_host(host)

	-- Load modules from global section

	local modules_enabled = config.get("*", "core", "modules_enabled");

	local modules_disabled = config.get(host, "core", "modules_disabled");

	local disabled_set = {};

	if modules_enabled then

		if modules_disabled then

			for _, module in ipairs(modules_disabled) do

				disabled_set[module] = true;

			end

		end

		for _, module in ipairs(modules_enabled) do

			if not disabled_set[module] then

				load(host, module);

			end

		end

	end

	-- Load modules from just this host

	local modules_enabled = config.get(host, "core", "modules_enabled");

	if modules_enabled then

		for _, module in pairs(modules_enabled) do

			if not is_loaded(host, module) then

				load(host, module);

			end

		end

	end

end

eventmanager.add_event_hook("host-activated", load_modules_for_host);

--

function load(host, module_name, config)

	if not (host and module_name) then

		return nil, "insufficient-parameters";

	end

	if not modulemap[host] then

		modulemap[host] = {};

	end

	if modulemap[host][module_name] then

		log("warn", "%s is already loaded for %s, so not loading again", module_name, host);

		return nil, "module-already-loaded";

	elseif modulemap["*"][module_name] then

		return nil, "global-module-already-loaded";

	end

	local mod, err = loadfile(get_module_filename(module_name));

	if not mod then

		log("error", "Unable to load module '%s': %s", module_name or "nil", err or "nil");

		return nil, err;

	end

	local _log = logger.init(host..":"..module_name);

	local api_instance = setmetatable({ name = module_name, host = host, config = config,  _log = _log, log = function (self, ...) return _log(...); end }, { __index = api });

	local pluginenv = setmetatable({ module = api_instance }, { __index = _G });

	setfenv(mod, pluginenv);

	if not hosts[host] then hosts[host] = { type = "component", host = host, connected = false, s2sout = {} }; end

	local success, ret = pcall(mod);

	if not success then

		log("error", "Error initialising module '%s': %s", name or "nil", ret or "nil");

		return nil, ret;

	end

	-- Use modified host, if the module set one

	modulemap[api_instance.host][module_name] = pluginenv;

	return true;

end

function get_module(host, name)

	return modulemap[host] and modulemap[host][name];

end

function is_loaded(host, name)

	return modulemap[host] and modulemap[host][name] and true;

end

function unload(host, name, ...)

	local mod = get_module(host, name); 

	if not mod then return nil, "module-not-loaded"; end

	if module_has_method(mod, "unload") then

		local ok, err = call_module_method(mod, "unload");

		if (not ok) and err then

			log("warn", "Non-fatal error unloading module '%s' on '%s': %s", name, host, err);

		end

	end

	modulemap[host][name] = nil;

	features_table:remove(host, name);

	local params = handler_table:get(host, name); -- , {module.host, origin_type, tag, xmlns}

	for _, param in pairs(params or NULL) do

		local handlers = stanza_handlers:get(param[1], param[2], param[3], param[4]);

		if handlers then

			handler_info[handlers[1]] = nil;

			stanza_handlers:remove(param[1], param[2], param[3], param[4]);

		end

	end

	event_hooks:remove(host, name);

	return true;

end

function reload(host, name, ...)

	local mod = get_module(host, name);

	if not mod then return nil, "module-not-loaded"; end

	local _mod, err = loadfile(get_module_filename(name)); -- checking for syntax errors

	if not _mod then

		log("error", "Unable to load module '%s': %s", module_name or "nil", err or "nil");

		return nil, err;

	end

	local saved;

	if module_has_method(mod, "save") then

		local ok, ret, err = call_module_method(mod, "save");

		if ok then

			saved = ret;

		else

			log("warn", "Error saving module '%s:%s' state: %s", host, module, ret);

			if not config.get(host, "core", "force_module_reload") then

				log("warn", "Aborting reload due to error, set force_module_reload to ignore this");

				return nil, "save-state-failed";

			else

				log("warn", "Continuing with reload (using the force)");

			end

		end

	end

	unload(host, name, ...);

	local ok, err = load(host, name, ...);

	if ok then

		mod = get_module(host, name);

		if module_has_method(mod, "restore") then

			local ok, err = call_module_method(mod, "restore", saved or {})

			if (not ok) and err then

				log("warn", "Error restoring module '%s' from '%s': %s", name, host, err);

			end

		end

		return true;

	end

	return ok, err;

end

function handle_stanza(host, origin, stanza)

	local name, xmlns, origin_type = stanza.name, stanza.attr.xmlns, origin.type;

	if name == "iq" and xmlns == "jabber:client" then

		if stanza.attr.type == "get" or stanza.attr.type == "set" then

			xmlns = stanza.tags[1].attr.xmlns;

			log("debug", "Stanza of type %s from %s has xmlns: %s", name, origin_type, xmlns);

		else

			log("debug", "Discarding %s from %s of type: %s", name, origin_type, stanza.attr.type);

			return true;

		end

	end

	local handlers = stanza_handlers:get(host, origin_type, name, xmlns);

	if not handlers then handlers = stanza_handlers:get("*", origin_type, name, xmlns); end

	if handlers then

		log("debug", "Passing stanza to mod_%s", handler_info[handlers[1]].name);

		(handlers[1])(origin, stanza);

		return true;

	else

		log("debug", "Stanza unhandled by any modules, xmlns: %s", stanza.attr.xmlns); -- we didn't handle it

	end

end

function module_has_method(module, method)

	return type(module.module[method]) == "function";

end

function call_module_method(module, method, ...)

	if module_has_method(module, method) then	

		local f = module.module[method];

		return pcall(f, ...);

	else

		return false, "no-such-method";

	end

end

local _modulepath = { plugin_dir, "mod_", nil, ".lua"};

function get_module_filename(name)

	_modulepath[3] = name;

	return t_concat(_modulepath);

end

----- API functions exposed to modules -----------

-- Must all be in api.* 

-- Returns the name of the current module

function api:get_name()

	return self.name;

end

-- Returns the host that the current module is serving

function api:get_host()

	return self.host;

end

function api:get_host_type()

	return hosts[self.host].type;

end

function api:set_global()

	self.host = "*";

end

local function _add_handler(module, origin_type, tag, xmlns, handler)

	local handlers = stanza_handlers:get(module.host, origin_type, tag, xmlns);

	local msg = (tag == "iq") and "namespace" or "payload namespace";

	if not handlers then

		stanza_handlers:add(module.host, origin_type, tag, xmlns, handler);

		handler_info[handler] = module;

		handler_table:add(module.host, module.name, {module.host, origin_type, tag, xmlns});

		--module:log("debug", "I now handle tag '%s' [%s] with %s '%s'", tag, origin_type, msg, xmlns);

	else

		module:log("warn", "I wanted to handle tag '%s' [%s] with %s '%s' but mod_%s already handles that", tag, origin_type, msg, xmlns, handler_info[handlers[1]].module.name);

	end

end

function api:add_handler(origin_type, tag, xmlns, handler)

	if not (origin_type and tag and xmlns and handler) then return false; end

	if type(origin_type) == "table" then

		for _, origin_type in ipairs(origin_type) do

			_add_handler(self, origin_type, tag, xmlns, handler);

		end

	else

		_add_handler(self, origin_type, tag, xmlns, handler);

	end

end

function api:add_iq_handler(origin_type, xmlns, handler)

	self:add_handler(origin_type, "iq", xmlns, handler);

end

addDiscoInfoHandler("*host", function(reply, to, from, node)

	if #node == 0 then

		local done = {};

		for module, features in pairs(features_table:get(to) or NULL) do -- for each module

			for feature in pairs(features) do

				if not done[feature] then

					reply:tag("feature", {var = feature}):up(); -- TODO cache

					done[feature] = true;

				end

			end

		end

		for module, features in pairs(features_table:get("*") or NULL) do -- for each module

			for feature in pairs(features) do

				if not done[feature] then

					reply:tag("feature", {var = feature}):up(); -- TODO cache

					done[feature] = true;

				end

			end

		end

		return next(done) ~= nil;

	end

end);

function api:add_feature(xmlns)

	features_table:set(self.host, self.name, xmlns, true);

end

local event_hook = function(host, mod_name, event_name, ...)

	if type((...)) == "table" and (...).host and (...).host ~= host then return; end

	for handler in pairs(event_hooks:get(host, mod_name, event_name) or NULL) do

		handler(...);

	end

end;

function api:add_event_hook(name, handler)

	if not hooked:get(self.host, self.name, name) then

		eventmanager.add_event_hook(name, function(...) event_hook(self.host, self.name, name, ...); end);

		hooked:set(self.host, self.name, name, true);

	end

	event_hooks:set(self.host, self.name, name, handler, true);

end

--------------------------------------------------------------------

local actions = {};

function actions.load(params)

	--return true, "Module loaded ("..params.module.." on "..params.host..")";

	return load(params.host, params.module);

end

function actions.unload(params)

	return unload(params.host, params.module);

end

register_actions("/modules", actions);

return _M;