-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

-- 

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

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

--

local logger = require "util.logger";

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

local config = require "core.configmanager";

local pluginloader = require "util.pluginloader";

local set = require "util.set";

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

local hosts = hosts;

local prosody = prosody;

local pcall, xpcall = pcall, xpcall;

local setmetatable, rawget = setmetatable, rawget;

local ipairs, pairs, type, tostring, t_insert = ipairs, pairs, type, tostring, table.insert;

local debug_traceback = debug.traceback;

local unpack, select = unpack, select;

pcall = function(f, ...)

	local n = select("#", ...);

	local params = {...};

	return xpcall(function() return f(unpack(params, 1, n)) end, function(e) return tostring(e).."\n"..debug_traceback(); end);

end

local autoload_modules = {"presence", "message", "iq", "offline", "c2s", "s2s"};

local component_inheritable_modules = {"tls", "dialback", "iq", "s2s"};

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

local _G = _G;

module "modulemanager"

local api = _G.require "core.moduleapi"; -- Module API container

-- [host] = { [module] = module_env }

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

-- Load modules when a host is activated

function load_modules_for_host(host)

	local component = config.get(host, "component_module");

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

	local global_modules_disabled = config.get("*", "modules_disabled");

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

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

	if host_modules_enabled == global_modules_enabled then host_modules_enabled = nil; end

	if host_modules_disabled == global_modules_disabled then host_modules_disabled = nil; end

	local global_modules = set.new(autoload_modules) + set.new(global_modules_enabled) - set.new(global_modules_disabled);

	if component then

		global_modules = set.intersection(set.new(component_inheritable_modules), global_modules);

	end

	local modules = (global_modules + set.new(host_modules_enabled)) - set.new(host_modules_disabled);

	-- COMPAT w/ pre 0.8

	if modules:contains("console") then

		log("error", "The mod_console plugin has been renamed to mod_admin_telnet. Please update your config.");

		modules:remove("console");

		modules:add("admin_telnet");

	end

	if component then

		load(host, component);

	end

	for module in modules do

		load(host, module);

	end

end

prosody.events.add_handler("host-activated", load_modules_for_host);

prosody.events.add_handler("host-deactivated", function (host)

	modulemap[host] = nil;

end);

--- Private helpers ---

local function do_unload_module(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

	for object, event, handler in mod.module.event_handlers:iter(nil, nil, nil) do

		object.remove_handler(event, handler);

	end

	if mod.module.items then -- remove items

		local events = (host == "*" and prosody.events) or hosts[host].events;

		for key,t in pairs(mod.module.items) do

			for i = #t,1,-1 do

				local value = t[i];

				t[i] = nil;

				events.fire_event("item-removed/"..key, {source = mod.module, item = value});

			end

		end

	end

	mod.module.loaded = false;

	modulemap[host][name] = nil;

	return true;

end

local function do_load_module(host, module_name, state)

	if not (host and module_name) then

		return nil, "insufficient-parameters";

	elseif not hosts[host] and host ~= "*"then

		return nil, "unknown-host";

	end

	if not modulemap[host] then

		modulemap[host] = hosts[host].modules;

	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

		local mod = modulemap["*"][module_name];

		if module_has_method(mod, "add_host") then

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

			local host_module_api = setmetatable({

				host = host, event_handlers = new_multitable(), items = {};

				_log = _log, log = function (self, ...) return _log(...); end;

			},{

				__index = modulemap["*"][module_name].module;

			});

			local host_module = setmetatable({ module = host_module_api }, { __index = mod });

			host_module_api.environment = host_module;

			modulemap[host][module_name] = host_module;

			local ok, result, module_err = call_module_method(mod, "add_host", host_module_api);

			if not ok or result == false then

				modulemap[host][module_name] = nil;

				return nil, ok and module_err or result;

			end

			return host_module;

		end

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

	end

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

	local api_instance = setmetatable({ name = module_name, host = host,

		_log = _log, log = function (self, ...) return _log(...); end, event_handlers = new_multitable(),

		reloading = not not state, saved_state = state~=true and state or nil }

		, { __index = api });

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

	api_instance.environment = pluginenv;

	local mod, err = pluginloader.load_code(module_name, nil, pluginenv);

	if not mod then

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

		return nil, err;

	end

	api_instance.path = err;

	modulemap[host][module_name] = pluginenv;

	local ok, err = pcall(mod);

	if ok then

		-- Call module's "load"

		if module_has_method(pluginenv, "load") then

			ok, err = call_module_method(pluginenv, "load");

			if not ok then

				log("warn", "Error loading module '%s' on '%s': %s", module_name, host, err or "nil");

			end

		end

		api_instance.reloading, api_instance.saved_state = nil, nil;

		if api_instance.host == "*" then

			if not api_instance.global then -- COMPAT w/pre-0.9

				if host ~= "*" then

					log("warn", "mod_%s: Setting module.host = '*' deprecated, call module:set_global() instead", module_name);

				end

				api_instance:set_global();

			end

			modulemap[host][module_name] = nil;

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

			if host ~= api_instance.host and module_has_method(pluginenv, "add_host") then

				-- Now load the module again onto the host it was originally being loaded on

				ok, err = do_load_module(host, module_name);

			end

		end

	end

	if not ok then

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

		log("error", "Error initializing module '%s' on '%s': %s", module_name, host, err or "nil");

	end

	return ok and pluginenv, err;

end

local function do_reload_module(host, name)

	local mod = get_module(host, name);

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

	local _mod, err = pluginloader.load_code(name); -- checking for syntax errors

	if not _mod then

		log("error", "Unable to load module '%s': %s", 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, name, ret);

			if not config.get(host, "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

	mod.module.reloading = true;

	do_unload_module(host, name);

	local ok, err = do_load_module(host, name, saved or true);

	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

	end

	return ok and mod, err;

end

--- Public API ---

-- Load a module and fire module-loaded event

function load(host, name)

	local mod, err = do_load_module(host, name);

	if mod then

		(hosts[mod.module.host] or prosody).events.fire_event("module-loaded", { module = name, host = mod.module.host });

	end

	return mod, err;

end

-- Unload a module and fire module-unloaded

function unload(host, name)

	local ok, err = do_unload_module(host, name);

	if ok then

		(hosts[host] or prosody).events.fire_event("module-unloaded", { module = name, host = host });

	end

	return ok, err;

end

function reload(host, name)

	local mod, err = do_reload_module(host, name);

	if mod then

		modulemap[host][name].module.reloading = true;

		(hosts[host] or prosody).events.fire_event("module-reloaded", { module = name, host = host });

		mod.module.reloading = nil;

	elseif not is_loaded(host, name) then

		(hosts[host] or prosody).events.fire_event("module-unloaded", { module = name, host = host });

	end

	return mod, err;

end

function get_module(host, name)

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

end

function get_items(key, host)

	local result = {};

	local modules = modulemap[host];

	if not key or not host or not modules then return nil; end

	for _, module in pairs(modules) do

		local mod = module.module;

		if mod.items and mod.items[key] then

			for _, value in ipairs(mod.items[key]) do

				t_insert(result, value);

			end

		end

	end

	return result;

end

function get_modules(host)

	return modulemap[host];

end

function is_loaded(host, name)

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

end

function module_has_method(module, method)

	return type(rawget(module.module, method)) == "function";

end

function call_module_method(module, method, ...)

	local f = rawget(module.module, method);

	if type(f) == "function" then

		return pcall(f, ...);

	else

		return false, "no-such-method";

	end

end

return _M;