-------------------
-- Session class --
-------------------

do Session = class()
    -- Static
    local sessions = {}
    
    function Session.getSessions()
        return sessions
    end
    
    function Session.updateSessions()
	for session,_ in pairs(sessions) do
	    session:tick()
	end
    end
    
    function Session.addSession(session)
	sessions[session] = true
    end
        
    function Session.removeSession(session)
	sessions[session] = nil
    end
    
    
    -- Object
    function Session:init(console, func, callback, commandTable)
	self.thread    = coroutine.create(func)
	self.console   = console
	self.callback  = callback
	
	self.commandTable = commandTable or {}
	
	self.started   = false
	self.suspended = true
	
	self.nextTick  = timer.getMilliSecCounter()
    end
    
    function Session:checkSession(state, ...)
	local co = self.thread
	if coroutine.status(co) == "dead" then	    
	    if self.callback then
		self:callback(tuple(state, ...))
		return
	    end
	    
	    if not state then
		self.console:print("----- TRACEBACK -----")
		self.console:print("[" .. tostring(co) .. "] terminated unsuccesfully")
		self.console:print(tostring(...))
		self.console:print("")
	    else
		self.console:print("[" .. tostring(co) .. "] terminated succesfully")
	    end
	    
	    -- remove session from sessions table
	    sessions[self] = nil
    	end
    end
    
    function Session:start(run)
	assert(not self.started, "Cannot start an already started session!")
	
	self.started   = true
	self.suspended = false
	
	if not run then
	    self:checkSession(coroutine.resume(self.thread, self))
	end
    end
    
    function Session:suspend()
	self.suspended = true
	self:interrupt()
    end
   
    function Session:interrupt()
	coroutine.yield(self.thread)
    end
    
    function Session:triggerResume()
	self.suspended = false
    end
    
    function Session:sleep(n)
	self.nextTick = timer.getMilliSecCounter() + 1000 * n
	self:interrupt()
    end

    function Session:tick(forceTick)
	local time = timer.getMilliSecCounter()
	
	if (not self.suspended and self.nextTick <= time) or forceTick then
	    self:checkSession(coroutine.resume(self.thread))
	end
    end
    
    -- NOT thread safe! Bugged sessions *could* crash the script. Will be improved in future versions
    function Session:sendCommand(command, ...)
	local c = self.commandTable[command]
	if c then
	    c(...)
	end
    end
    
    -- Links to console --
    
    function Session:print(...)
	self.console:print(...)
    end
    
    function Session:write(str)
	self.console:write(str)
    end
    
    function Session:read()
	return self.console:read(self)
    end
    
    function Session:readLine(str)
	return self.console:readLine(self, str)
    end
end