Modular Computer Multitasking + Fixes

- Modular computers now support multitasking.
- New hardware type added. Basic CPUs may be obtained when purchasing a laptop or tablet, Photonic CPUs can be printed at research at imprinter. This hardware piece determines how many programs can be on background.
- Programs can now have an icon that is rendered in main UI's header (along with the power icons, etc.) when the program is on background. As an example, these icons have been added to NTNRC client (Dark icon when no messages have been received, blinking when new message is waiting), Alarm monitor (Blinking red when an alarm is active, green otherwise) and downloader program (Animated arrow when downloading, stationary when finished.)
- Adds missing crew monitor icon to tablets. Fixes #11937

code/modules/modular_computers/computers/item/modular_computer.dm

@@ -28,6 +28,7 @@
 
 
 	// Important hardware (must be installed for computer to work)
+	var/obj/item/weapon/computer_hardware/processor_unit/processor_unit				// CPU. Without it the computer won't run. Better CPUs can run more programs at once.
 	var/obj/item/weapon/computer_hardware/network_card/network_card					// Network Card component of this computer. Allows connection to NTNet
 	var/obj/item/weapon/computer_hardware/hard_drive/hard_drive						// Hard Drive component of this computer. Stores programs and files.
 	var/obj/item/weapon/computer_hardware/battery_module/battery_module				// An internal power source for this computer. Can be recharged.
@@ -36,6 +37,8 @@
 	var/obj/item/weapon/computer_hardware/nano_printer/nano_printer					// Nano Printer component of this computer, for your everyday paperwork needs.
 	var/obj/item/weapon/computer_hardware/hard_drive/portable/portable_drive		// Portable data storage
 
+	var/list/idle_threads = list()							// Idle programs on background. They still receive process calls but can't be interacted with.
+
 
 // Eject ID card from computer, if it has ID slot with card inside.
 /obj/item/modular_computer/verb/eject_id()
@@ -164,7 +167,7 @@
 
 /obj/item/modular_computer/proc/turn_on(var/mob/user)
 	var/issynth = issilicon(user) // Robots and AIs get different activation messages.
-	if((battery_module && battery_module.battery.charge) || check_power_override()) // Battery-run and charged or non-battery but powered by APC.
+	if(processor_unit && ((battery_module && battery_module.battery.charge) || check_power_override())) // Battery-run and charged or non-battery but powered by APC.
 		if(issynth)
 			user << "You send an activation signal to \the [src], turning it on"
 		else
@@ -188,11 +191,22 @@
 		kill_program(1)
 		visible_message("<span class='danger'>\The [src]'s screen briefly freezes and then shows \"NETWORK ERROR - NTNet connection lost. Please retry. If problem persists contact your system administrator.\" error.</span>")
 
+	for(var/datum/computer_file/program/P in idle_threads)
+		if(P.requires_ntnet && !get_ntnet_status(P.requires_ntnet_feature))
+			P.kill_program(1)
+			idle_threads.Remove(P)
+			visible_message("<span class='danger'>\The [src] screen displays an \"Process [P.filename].[P.filetype] (PID [rand(100,999)]) terminated - Network Error\" error</span>")
+
 	if(active_program)
 		active_program.process_tick()
 		active_program.ntnet_status = get_ntnet_status()
 		active_program.computer_emagged = computer_emagged
 
+	for(var/datum/computer_file/program/P in idle_threads)
+		P.process_tick()
+		P.ntnet_status = get_ntnet_status()
+		P.computer_emagged = computer_emagged
+
 	handle_power() // Handles all computer power interaction
 
 // Function used by NanoUI's to obtain data for header. All relevant entries begin with "PC_"
@@ -230,6 +244,17 @@
 		if(3)
 			data["PC_ntneticon"] = "sig_lan.gif"
 
+	if(idle_threads.len)
+		var/list/program_headers = list()
+		for(var/datum/computer_file/program/P in idle_threads)
+			if(!P.ui_header)
+				continue
+			program_headers.Add(list(list(
+				"icon" = P.ui_header
+			)))
+
+		data["PC_programheaders"] = program_headers
+
 	data["PC_stationtime"] = worldtime2text()
 	data["PC_hasheader"] = 1
 	data["PC_showexitprogram"] = active_program ? 1 : 0 // Hides "Exit Program" button on mainscreen
@@ -257,9 +282,13 @@
 		return 0
 	return ntnet_global.add_log(text, network_card)
 
-/obj/item/modular_computer/proc/shutdown_computer()
+/obj/item/modular_computer/proc/shutdown_computer(var/loud = 1)
 	kill_program(1)
-	visible_message("\The [src] shuts down.")
+	for(var/datum/computer_file/program/P in idle_threads)
+		P.kill_program(1)
+		idle_threads.Remove(P)
+	if(loud)
+		visible_message("\The [src] shuts down.")
 	enabled = 0
 	update_icon()
 	return
@@ -284,6 +313,23 @@
 	if( href_list["PC_shutdown"] )
 		shutdown_computer()
 		return
+	if( href_list["PC_minimize"] )
+		var/mob/user = usr
+		if(!active_program || !processor_unit)
+			return
+
+		if(idle_threads.len >= processor_unit.max_idle_programs)
+			user << "<span class='notice'>\The [src] displays a \"Maximal CPU load reached. Unable to minimize another program.\" error</span>"
+			return
+
+		idle_threads.Add(active_program)
+		active_program.running = 0 // Should close any existing UIs
+		nanomanager.close_uis(active_program.NM ? active_program.NM : active_program)
+		active_program = null
+		update_icon()
+		if(user && istype(user))
+			ui_interact(user) // Re-open the UI on this computer. It should show the main screen now.
+
 	if( href_list["PC_runprogram"] )
 		var/prog = href_list["PC_runprogram"]
 		var/datum/computer_file/program/P = null
@@ -299,6 +345,14 @@
 		if(!P.is_supported_by_hardware(hardware_flag, 1, user))
 			return
 
+		// The program is already running. Resume it.
+		if(P in idle_threads)
+			P.running = 1
+			active_program = P
+			idle_threads.Remove(P)
+			update_icon()
+			return
+
 		if(P.requires_ntnet && !get_ntnet_status(P.requires_ntnet_feature)) // The program requires NTNet connection, but we are not connected to NTNet.
 			user << "<span class='danger'>\The [src]'s screen shows \"NETWORK ERROR - Unable to connect to NTNet. Please retry. If problem persists contact your system administrator.\" warning.</span>"
 			return
@@ -311,9 +365,7 @@
 /obj/item/modular_computer/proc/power_failure()
 	if(enabled) // Shut down the computer
 		visible_message("<span class='danger'>\The [src]'s screen flickers \"BATTERY CRITICAL\" warning as it shuts down unexpectedly.</span>")
-		kill_program(1)
-		enabled = 0
-		update_icon()
+		shutdown_computer(0)
 
 // Handles power-related things, such as battery interaction, recharging, shutdown when it's discharged
 /obj/item/modular_computer/proc/handle_power()
@@ -322,11 +374,10 @@
 		return 0
 
 	var/power_usage = screen_on ? base_active_power_usage : base_idle_power_usage
-	if(network_card && network_card.enabled)
-		power_usage += network_card.power_usage
 
-	if(hard_drive && hard_drive.enabled)
-		power_usage += hard_drive.power_usage
+	for(var/obj/item/weapon/computer_hardware/H in get_all_components())
+		if(H.enabled)
+			power_usage += H.power_usage
 
 	if(battery_module)
 		battery_module.battery.use(power_usage * CELLRATE)
@@ -440,6 +491,12 @@
 			return
 		found = 1
 		battery_module = H
+	else if(istype(H, /obj/item/weapon/computer_hardware/processor_unit))
+		if(processor_unit)
+			user << "This computer's processor slot is already occupied by \the [processor_unit]."
+			return
+		found = 1
+		processor_unit = H
 	if(found)
 		user << "You install \the [H] into \the [src]"
 		H.holder2 = src
@@ -467,11 +524,15 @@
 	if(battery_module == H)
 		battery_module = null
 		found = 1
+	if(processor_unit == H)
+		processor_unit = null
+		found = 1
+		critical = 1
 	if(found)
 		user << "You remove \the [H] from \the [src]."
 		H.forceMove(get_turf(src))
 		H.holder2 = null
-	if(critical)
+	if(critical && enabled)
 		user << "<span class='danger'>\The [src]'s screen freezes for few seconds and then displays an \"HARDWARE ERROR: Critical component disconnected. Please verify component connection and reboot the device. If the problem persists contact technical support for assistance.\" warning.</span>"
 		kill_program(1)
 		enabled = 0
@@ -492,6 +553,8 @@
 		return card_slot
 	if(battery_module && (battery_module.name == name))
 		return battery_module
+	if(processor_unit && (processor_unit.name == name))
+		return processor_unit
 	return null
 
 // Returns list of all components
@@ -509,4 +572,6 @@
 		all_components.Add(card_slot)
 	if(battery_module)
 		all_components.Add(battery_module)
+	if(processor_unit)
+		all_components.Add(processor_unit)
 	return all_components

code/modules/modular_computers/computers/item/processor.dm

@@ -78,9 +78,7 @@
 /obj/item/modular_computer/processor/shutdown_computer()
 	if(!machinery_computer)
 		return
-	kill_program(1)
-	visible_message("\The [machinery_computer] shuts down.")
-	enabled = 0
+	..()
 	machinery_computer.update_icon()
 	return
 

code/modules/modular_computers/computers/machinery/console_presets.dm

@@ -8,6 +8,7 @@
 	. = ..()
 	if(!cpu)
 		return
+	cpu.processor_unit = new/obj/item/weapon/computer_hardware/processor_unit(cpu)
 	if(_has_id_slot)
 		cpu.card_slot = new/obj/item/weapon/computer_hardware/card_slot(cpu)
 	if(_has_printer)

code/modules/modular_computers/computers/machinery/modular_computer.dm

@@ -81,8 +81,7 @@
 	if(cpu && cpu.enabled) // Shut down the computer
 		visible_message("<span class='danger'>\The [src]'s screen flickers [cpu.battery_module ? "\"BATTERY CRITICAL\"" : "\"EXTERNAL POWER LOSS\""] warning as it shuts down unexpectedly.</span>")
 		if(cpu)
-			cpu.kill_program(1)
-			cpu.enabled = 0
+			cpu.shutdown_computer(0)
 		battery_powered = 0
 		update_icon()
 	stat |= NOPOWER