local logger = require "util.logger";

local log = logger.init("modulemanager")

local loadfile, pcall = loadfile, pcall;

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

local pairs, ipairs = pairs, ipairs;

local t_insert = table.insert;

local type = type;

local tostring, print = tostring, print;

local _G = _G;

module "modulemanager"

local api = {}; -- Module API container

local modulemap = {};

local handler_info = {};

local stanza_handlers = {};

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

function load(host, module_name, config)

	if not (host and module_name) then

		return nil, "insufficient-parameters";

	end

	if not mod then

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

		return nil, err;

	end

	if not modulemap[host] then

		modulemap[host] = {};

		stanza_handlers[host] = {};

	elseif 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";

	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);

	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

	modulemap[host][module_name] = mod;

	return true;

end

function is_loaded(host, name)

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

end

function unload(host, name, ...)

	local mod = modulemap[host] and modulemap[host][name];

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

	if type(mod.unload) == "function" then

		local ok, err = pcall(mod.unload, ...)

		if (not ok) and err then

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

		end

	end

end

function handle_stanza(host, origin, stanza)

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

	local handlers = stanza_handlers[host];

	if not handlers then

		log("warn", "No handlers for %s", host);

		return false;

	end

	if name == "iq" and xmlns == "jabber:client" and handlers[origin_type] then

		local child = stanza.tags[1];

		if child then

			local xmlns = child.attr.xmlns or xmlns;

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

			local handler = handlers[origin_type][name] and handlers[origin_type][name][xmlns];

			if handler then

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

				return handler(origin, stanza) or true;

			end

		end

	elseif handlers[origin_type] then

		local handler = handlers[origin_type][name];

		if  handler then

			handler = handler[xmlns];

			if handler then

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

				return handler(origin, stanza) or true;

			end

		end

	end

	log("debug", "Stanza unhandled by any modules, xmlns: %s", stanza.attr.xmlns);

	return false; -- we didn't handle it

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

local function _add_iq_handler(module, origin_type, xmlns, handler)

	local handlers = stanza_handlers[module.host];

	handlers[origin_type] = handlers[origin_type] or {};

	handlers[origin_type].iq = handlers[origin_type].iq or {};

	if not handlers[origin_type].iq[xmlns] then

		handlers[origin_type].iq[xmlns]= handler;

		handler_info[handler] = module;

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

	else

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

	end

end

function api:add_iq_handler(origin_type, xmlns, handler)

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

	if type(origin_type) == "table" then

		for _, origin_type in ipairs(origin_type) do

			_add_iq_handler(self, origin_type, xmlns, handler);

		end

		return;

	end

	_add_iq_handler(self, origin_type, xmlns, handler);

end

do

	local event_handlers = {};

	function api:add_event_hook(name, handler)

		if not event_handlers[name] then

			event_handlers[name] = {};

		end

		t_insert(event_handlers[name] , handler);

		self:log("debug", "Subscribed to %s", name);

	end

	function fire_event(name, ...)

		local event_handlers = event_handlers[name];

		if event_handlers then

			for name, handler in ipairs(event_handlers) do

				handler(...);

			end

		end

	end

end

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

	local handlers = stanza_handlers[module.host];

	handlers[origin_type] = handlers[origin_type] or {};

	if not handlers[origin_type][tag] then

		handlers[origin_type][tag] = handlers[origin_type][tag] or {};

		handlers[origin_type][tag][xmlns]= handler;

		handler_info[handler] = module;

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

	elseif handler_info[handlers[origin_type][tag]] then

		log("warning", "I wanted to handle tag '%s' [%s] but mod_%s already handles that", tag, origin_type, handler_info[handlers[origin_type][tag]].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

		return;

	end

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

end

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

return _M;