Bubberstation/code/datums/components/rot.dm

#define REAGENT_BLOCKER (1<<0)
#define TEMPERATURE_BLOCKER (1<<1)
#define HUSK_BLOCKER (1<<2)

///Makes a thing rotting, carries with it a start delay and some things that can halt the rot, along with infection logic
/datum/component/rot
	///The time we were created, allows for cheese smell
	var/start_time = 0
	///The delay in ticks between the start of rot and effects kicking in
	var/start_delay = 0
	///The time in ticks before a rot component reaches its full effectiveness
	var/scaling_delay = 0
	///How strong is the rot? used for scaling different aspects of the component. Between 0 and 1
	var/strength = 0
	///Is the component active right now?
	var/active = FALSE
	///Bitfield of sources preventing the component from rotting
	var/blockers = NONE

	var/static/list/loc_connections = list(
		COMSIG_ATOM_ENTERED = .proc/on_entered,
	)

/datum/component/rot/Initialize(delay, scaling, severity)
	if(!isatom(parent))
		return COMPONENT_INCOMPATIBLE
	if(isliving(parent))
		var/mob/living/living_parent = parent
		//I think this can break in cases where someone becomes a robot post death, but I uh, I don't know how to account for that
		if(!(living_parent.mob_biotypes & (MOB_ORGANIC|MOB_UNDEAD)))
			return COMPONENT_INCOMPATIBLE

	start_delay = delay
	scaling_delay = scaling
	strength = severity

	RegisterSignal(parent, list(COMSIG_ATOM_HULK_ATTACK, COMSIG_ATOM_ATTACK_ANIMAL, COMSIG_ATOM_ATTACK_HAND), .proc/rot_react_touch)
	RegisterSignal(parent, COMSIG_PARENT_ATTACKBY, .proc/rot_hit_react)
	if(ismovable(parent))
		AddElement(/datum/element/connect_loc_behalf, parent, loc_connections)
		RegisterSignal(parent, COMSIG_MOVABLE_BUMP, .proc/rot_react)
	if(isliving(parent))
		RegisterSignal(parent, COMSIG_LIVING_REVIVE, .proc/react_to_revive) //mobs stop this when they come to life
		RegisterSignal(parent, COMSIG_LIVING_GET_PULLED, .proc/rot_react_touch)
	if(iscarbon(parent))
		var/mob/living/carbon/carbon_parent = parent
		RegisterSignal(carbon_parent.reagents, list(COMSIG_REAGENTS_ADD_REAGENT,
			COMSIG_REAGENTS_REM_REAGENT,
			COMSIG_REAGENTS_DEL_REAGENT), .proc/check_reagent)
		RegisterSignal(parent, list(SIGNAL_ADDTRAIT(TRAIT_HUSK), SIGNAL_REMOVETRAIT(TRAIT_HUSK)), .proc/check_husk_trait)
		check_reagent(carbon_parent.reagents, null)
		check_husk_trait(null)
	if(ishuman(parent))
		var/mob/living/carbon/human/human_parent = parent
		RegisterSignal(parent, COMSIG_HUMAN_CORETEMP_CHANGE, .proc/check_for_temperature)
		check_for_temperature(null, 0, human_parent.coretemperature)

	start_up(NONE) //If nothing's blocking it, start

/datum/component/rot/UnregisterFromParent()
	. = ..()
	if(ismovable(parent))
		RemoveElement(/datum/element/connect_loc_behalf, parent, loc_connections)

///One of two procs that modifies blockers, this one handles removing a blocker and potentially restarting the rot
/datum/component/rot/proc/start_up(blocker_type)
	blockers &= ~blocker_type //Yeet the type
	if(blockers || active)  //If it's not empty
		return
	start_time = world.time
	active = TRUE

///One of two procs that modifies blockers, this one handles adding a blocker and potentially ending the rot
/datum/component/rot/proc/rest(blocker_type)
	var/old_blockers = blockers
	blockers |= blocker_type
	if(old_blockers || !active) //If it had anything before this
		return
	start_delay = max((start_time + start_delay) - world.time, 0) //Account for the time spent rotting
	active = FALSE

/datum/component/rot/proc/react_to_revive()
	SIGNAL_HANDLER
	qdel(src)

/datum/component/rot/proc/check_reagent(datum/reagents/source, datum/reagent/modified)
	SIGNAL_HANDLER
	if(modified && !istype(modified, /datum/reagent/toxin/formaldehyde) && !istype(modified, /datum/reagent/cryostylane))
		return
	if(source.has_reagent(/datum/reagent/toxin/formaldehyde, 15) || source.has_reagent(/datum/reagent/cryostylane))
		rest(REAGENT_BLOCKER)
		return
	start_up(REAGENT_BLOCKER)

/datum/component/rot/proc/check_for_temperature(datum/source, old_temp, new_temp)
	if(new_temp <= T0C-10)
		rest(TEMPERATURE_BLOCKER)
		return
	start_up(TEMPERATURE_BLOCKER)

/datum/component/rot/proc/check_husk_trait()
	SIGNAL_HANDLER
	if(HAS_TRAIT(parent, TRAIT_HUSK))
		rest(HUSK_BLOCKER)
		return
	start_up(HUSK_BLOCKER)

/datum/component/rot/proc/rot_hit_react(datum/source, obj/item/hit_with, mob/living/attacker, params)
	SIGNAL_HANDLER
	rot_react_touch(source, attacker)

/datum/component/rot/proc/rot_react_touch(datum/source, mob/living/react_to)
	SIGNAL_HANDLER
	rot_react(source, react_to, pick(BODY_ZONE_L_ARM, BODY_ZONE_R_ARM))

/// Triggered when something enters the component's parent.
/datum/component/rot/proc/on_entered(datum/source, atom/movable/arrived, direction)
	SIGNAL_HANDLER
	rot_react(source, arrived)

///The main bit of logic for the rot component, does a temperature check and has a chance to infect react_to
/datum/component/rot/proc/rot_react(source, mob/living/react_to, target_zone = null)
	SIGNAL_HANDLER
	if(!isliving(react_to))
		return

	// Don't infect if you're chilled (I'd like to link this with the signals, but I can't come up with a good way to pull it off)
	var/atom/atom_parent = parent
	var/datum/gas_mixture/our_mix = atom_parent.return_air()
	if(our_mix?.temperature <= T0C-10)
		return

	if(!active)
		return

	var/time_delta = world.time - start_time
	// Wait a bit before decaying
	if(time_delta < start_delay)
		return

	var/time_scaling = min((time_delta - start_delay) / scaling_delay, 1)

	if(!prob(strength * 1 * time_scaling))
		return

	//We're running just under the "worst disease", since we don't want these to be too strong
	var/datum/disease/advance/random/rand_disease = new(rand(4 * strength * time_scaling), rand(strength * 5 * time_scaling))
	rand_disease.name = "Unknown"
	react_to.ContactContractDisease(rand_disease, target_zone)

#undef REAGENT_BLOCKER
#undef TEMPERATURE_BLOCKER
#undef HUSK_BLOCKER