-- 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 debug = require "prosody.util.debug";

-- Helper functions for debugging

local log = require "prosody.util.logger".init("util.debug");

local function log_events(events, name, logger)
	local f = events.fire_event;
	if not f then
		error("Object does not appear to be a util.events object");
	end
	logger = logger or log;
	name = name or tostring(events);
	function events.fire_event(event, ...)
		logger("debug", "%s firing event: %s", name, event);
		return f(event, ...);
	end

	local function event_handler_hook(handler, event_name, event_data)
		logger("debug", "calling handler for %s: %s", event_name, handler);
		local ok, ret = pcall(handler, event_data);
		if not ok then
			logger("error", "error in event handler %s: %s", handler, ret);
			error(ret);
		end
		if ret ~= nil then
			logger("debug", "event chain ended for %s by %s with result: %s", event_name, handler, ret);
		end
		return ret;
	end
	events.set_debug_hook(event_handler_hook);
	events[events.fire_event] = f;
	return events;
end

local function revert_log_events(events)
	events.fire_event, events[events.fire_event] = events[events.fire_event], nil; -- :))
	events.set_debug_hook(nil);
end

local function log_host_events(host)
	return log_events(prosody.hosts[host].events, host);
end

local function revert_log_host_events(host)
	return revert_log_events(prosody.hosts[host].events);
end

local function show_events(events, specific_event)
	local event_handlers = events._handlers;
	local events_array = {};
	local event_handler_arrays = {};
	for event, priorities in pairs(events._event_map) do
		local handlers = event_handlers[event];
		if handlers and (event == specific_event or not specific_event) then
			table.insert(events_array, event);
			local handler_strings = {};
			for i, handler in ipairs(handlers) do
				local upvals = debug.string_from_var_table(debug.get_upvalues_table(handler));
				handler_strings[i] = "  "..(priorities[handler] or "?")..": "..tostring(handler)..(upvals and ("\n        "..upvals) or "");
			end
			event_handler_arrays[event] = handler_strings;
		end
	end
	table.sort(events_array);
	local i = 1;
	while i <= #events_array do
		local handlers = event_handler_arrays[events_array[i]];
		for j=#handlers, 1, -1 do
			table.insert(events_array, i+1, handlers[j]);
		end
		if i > 1 then events_array[i] = "\n"..events_array[i]; end
		i = i + #handlers + 1
	end
	return table.concat(events_array, "\n");
end

local function get_upvalue(f, get_name)
	local i, name, value = 0;
	repeat
		i = i + 1;
		name, value = debug.getupvalue(f, i);
	until name == get_name or name == nil;
	return value;
end

return {
	log_host_events = log_host_events;
	revert_log_host_events = revert_log_host_events;
	log_events = log_events;
	revert_log_events = revert_log_events;
	show_events = show_events;
	get_upvalue = get_upvalue;
};