// /program/ files are executable programs that do things.
/datum/computer_file/program
	filetype = "PRG"
	/// File name. FILE NAME MUST BE UNIQUE IF YOU WANT THE PROGRAM TO BE DOWNLOADABLE FROM NTNET!
	filename = "UnknownProgram"
	/// List of required accesses to *run* the program.
	var/required_access = null
	/// List of required access to download or file host the program
	var/transfer_access = null
	/// PROGRAM_STATE_KILLED or PROGRAM_STATE_BACKGROUND or PROGRAM_STATE_ACTIVE - specifies whether this program is running.
	var/program_state = PROGRAM_STATE_KILLED
	/// Device that runs this program.
	var/obj/item/modular_computer/computer
	/// User-friendly name of this program.
	var/filedesc = "Unknown Program"
	/// Short description of this program's function.
	var/extended_desc = "N/A"
	/// Program-specific screen icon state
	var/program_icon_state = null
	/// Set to 1 for program to require nonstop NTNet connection to run. If NTNet connection is lost program crashes.
	var/requires_ntnet = FALSE
	/// Optional, if above is set to 1 checks for specific function of NTNet (currently NTNET_SOFTWAREDOWNLOAD, NTNET_PEERTOPEER, NTNET_SYSTEMCONTROL and NTNET_COMMUNICATION)
	var/requires_ntnet_feature = 0
	/// NTNet status, updated every tick by computer running this program. Don't use this for checks if NTNet works, computers do that. Use this for calculations, etc.
	var/ntnet_status = 1
	/// Bitflags (PROGRAM_CONSOLE, PROGRAM_LAPTOP, PROGRAM_TABLET combination) or PROGRAM_ALL
	var/usage_flags = PROGRAM_ALL
	/// Whether the program can be downloaded from NTNet. Set to 0 to disable.
	var/available_on_ntnet = 1
	/// Whether the program can be downloaded from SyndiNet (accessible via emagging the computer). Set to 1 to enable.
	var/available_on_syndinet = 0
	/// Name of the tgui interface
	var/tgui_id
	/// Example: "something.gif" - a header image that will be rendered in computer's UI when this program is running at background. Images are taken from /icons/program_icons. Be careful not to use too large images!
	var/ui_header = null

/datum/computer_file/program/New(obj/item/modular_computer/comp = null)
	..()
	if(comp && istype(comp))
		computer = comp

/datum/computer_file/program/Destroy()
	computer = null
	. = ..()

/datum/computer_file/program/clone()
	var/datum/computer_file/program/temp = ..()
	temp.required_access = required_access
	temp.filedesc = filedesc
	temp.program_icon_state = program_icon_state
	temp.requires_ntnet = requires_ntnet
	temp.requires_ntnet_feature = requires_ntnet_feature
	temp.usage_flags = usage_flags
	return temp

// Relays icon update to the computer.
/datum/computer_file/program/proc/update_computer_icon()
	if(computer)
		computer.update_icon()

// Attempts to create a log in global ntnet datum. Returns 1 on success, 0 on fail.
/datum/computer_file/program/proc/generate_network_log(text)
	if(computer)
		return computer.add_log(text)
	return 0

/datum/computer_file/program/proc/is_supported_by_hardware(hardware_flag = 0, loud = 0, mob/user = null)
	if(!(hardware_flag & usage_flags))
		if(loud && computer && user)
			to_chat(user, "<span class='danger'>\The [computer] flashes a \"Hardware Error - Incompatible software\" warning.</span>")
		return 0
	return 1

/datum/computer_file/program/proc/get_signal(specific_action = 0)
	if(computer)
		return computer.get_ntnet_status(specific_action)
	return 0

// Called by Process() on device that runs us, once every tick.
/datum/computer_file/program/proc/process_tick()
	return 1

/**
  *Check if the user can run program. Only humans can operate computer. Automatically called in run_program()
  *ID must be inserted into a card slot to be read. If the program is not currently installed (as is the case when
  *NT Software Hub is checking available software), a list can be given to be used instead.
  *Arguments:
  *user is a ref of the mob using the device.
  *loud is a bool deciding if this proc should use to_chats
  *access_to_check is an access level that will be checked against the ID
  *transfer, if TRUE and access_to_check is null, will tell this proc to use the program's transfer_access in place of access_to_check
  *access can contain a list of access numbers to check against. If access is not empty, it will be used istead of checking any inserted ID.
*/
/datum/computer_file/program/proc/can_run(mob/user, loud = FALSE, access_to_check, transfer = FALSE, var/list/access)
	// Defaults to required_access
	if(!access_to_check)
		if(transfer && transfer_access)
			access_to_check = transfer_access
		else
			access_to_check = required_access
	if(!access_to_check) // No required_access, allow it.
		return TRUE

	if(!transfer && computer && (computer.obj_flags & EMAGGED))	//emags can bypass the execution locks but not the download ones.
		return TRUE

	if(IsAdminGhost(user))
		return TRUE

	if(issilicon(user))
		return TRUE

	if(!length(access))
		var/obj/item/card/id/D
		var/obj/item/computer_hardware/card_slot/card_slot
		if(computer)
			card_slot = computer.all_components[MC_CARD]
			D = card_slot?.GetID()

		if(!D)
			if(loud)
				to_chat(user, "<span class='danger'>\The [computer] flashes an \"RFID Error - Unable to scan ID\" warning.</span>")
			return FALSE
		access = D.GetAccess()

	if(access_to_check in access)
		return TRUE
	if(loud)
		to_chat(user, "<span class='danger'>\The [computer] flashes an \"Access Denied\" warning.</span>")
	return FALSE

// This attempts to retrieve header data for UIs. If implementing completely new device of different type than existing ones
// always include the device here in this proc. This proc basically relays the request to whatever is running the program.
/datum/computer_file/program/proc/get_header_data()
	if(computer)
		return computer.get_header_data()
	return list()

// This is performed on program startup. May be overridden to add extra logic. Remember to include ..() call. Return 1 on success, 0 on failure.
// When implementing new program based device, use this to run the program.
/datum/computer_file/program/proc/run_program(mob/living/user)
	if(can_run(user, 1))
		if(requires_ntnet)
			var/obj/item/card/id/ID
			var/obj/item/computer_hardware/card_slot/card_holder = computer.all_components[MC_CARD]
			if(card_holder)
				ID = card_holder.GetID()
			generate_network_log("Connection opened -- Program ID: [filename] User:[ID?"[ID.registered_name]":"None"]")
		program_state = PROGRAM_STATE_ACTIVE
		return 1
	return 0

/**
  *
  *Called by the device when it is emagged.
  *
  *Emagging the device allows certain programs to unlock new functions. However, the program will
  *need to be downloaded first, and then handle the unlock on their own in their run_emag() proc.
  *The device will allow an emag to be run multiple times, so the user can re-emag to run the
  *override again, should they download something new. The run_emag() proc should return TRUE if
  *the emagging affected anything, and FALSE if no change was made (already emagged, or has no
  *emag functions).
**/
/datum/computer_file/program/proc/run_emag()
	return FALSE

// Use this proc to kill the program. Designed to be implemented by each program if it requires on-quit logic, such as the NTNRC client.
/datum/computer_file/program/proc/kill_program(forced = FALSE)
	program_state = PROGRAM_STATE_KILLED
	if(requires_ntnet)
		var/obj/item/card/id/ID
		var/obj/item/computer_hardware/card_slot/card_holder = computer.all_components[MC_CARD]
		if(card_holder)
			ID = card_holder.GetID()
		generate_network_log("Connection closed -- Program ID: [filename] User:[ID?"[ID.registered_name]":"None"]")
	return 1

/datum/computer_file/program/ui_interact(mob/user, datum/tgui/ui)
	ui = SStgui.try_update_ui(user, src, ui)
	if(!ui && tgui_id)
		ui = new(user, src, tgui_id, filedesc)
		ui.open()
		ui.send_asset(get_asset_datum(/datum/asset/simple/headers))

// CONVENTIONS, READ THIS WHEN CREATING NEW PROGRAM AND OVERRIDING THIS PROC:
// Topic calls are automagically forwarded from NanoModule this program contains.
// Calls beginning with "PRG_" are reserved for programs handling.
// Calls beginning with "PC_" are reserved for computer handling (by whatever runs the program)
// ALWAYS INCLUDE PARENT CALL ..() OR DIE IN FIRE.
/datum/computer_file/program/ui_act(action,list/params,datum/tgui/ui)
	if(..())
		return 1
	if(computer)
		switch(action)
			if("PC_exit")
				computer.kill_program()
				ui.close()
				return 1
			if("PC_shutdown")
				computer.shutdown_computer()
				ui.close()
				return 1
			if("PC_minimize")
				var/mob/user = usr
				if(!computer.active_program || !computer.all_components[MC_CPU])
					return

				computer.idle_threads.Add(computer.active_program)
				program_state = PROGRAM_STATE_BACKGROUND // Should close any existing UIs

				computer.active_program = null
				computer.update_icon()
				ui.close()

				if(user && istype(user))
					computer.ui_interact(user) // Re-open the UI on this computer. It should show the main screen now.


/datum/computer_file/program/ui_host()
	if(computer.physical)
		return computer.physical
	else
		return computer

/datum/computer_file/program/ui_status(mob/user)
	if(program_state != PROGRAM_STATE_ACTIVE) // Our program was closed. Close the ui if it exists.
		return UI_CLOSE
	return ..()