#define NON_CONTAGIOUS -1
#define SPECIAL 0
#define CONTACT_GENERAL 1
#define CONTACT_HANDS 2
#define CONTACT_FEET 3
#define AIRBORNE 4
#define BLOOD 5

#define SCANNER 1
#define PANDEMIC 2

/*

IMPORTANT NOTE: Please delete the diseases by using cure() proc or del() instruction.
Diseases are referenced in a global list, so simply setting mob or obj vars
to null does not delete the object itself. Thank you.

*/


/datum/disease
	var/form = "Virus" //During medscans, what the disease is referred to as
	var/name = "No disease"
	var/stage = 1 //all diseases start at stage 1
	var/max_stages = 0.0
	var/cure = null
	var/cure_id = null// reagent.id or list containing them
	var/cure_list = null // allows for multiple possible cure combinations
	var/cure_chance = 8//chance for the cure to do its job
	var/spread = null //spread type description
	var/spread_type = AIRBORNE
	var/contagious_period = 0//the disease stage when it can be spread
	var/list/affected_species = list()
	var/mob/living/carbon/affected_mob = null //the mob which is affected by disease.
	var/holder = null //the atom containing the disease (mob or obj)
	var/carrier = 0.0 //there will be a small chance that the person will be a carrier
	var/curable = 0 //can this disease be cured? (By itself...)
	var/list/strain_data = list() //This is passed on to infectees
	var/stage_prob = 4		// probability of advancing to next stage, default 4% per check
	var/agent = "some microbes"//name of the disease agent
	var/permeability_mod = 1//permeability modifier coefficient.
	var/desc = null//description. Leave it null and this disease won't show in med records.
	var/severity = null//severity descr
	var/longevity = 250//time in "ticks" the virus stays in inanimate object (blood stains, corpses, etc). In syringes, bottles and beakers it stays infinitely.
	var/list/hidden = list(0, 0)
	// if hidden[1] is true, then virus is hidden from medical scanners
	// if hidden[2] is true, then virus is hidden from PANDEMIC machine


/datum/disease/proc/stage_act()
	var/cure_present = has_cure()
	//world << "[cure_present]"

	if(carrier&&!cure_present)
		//world << "[affected_mob] is carrier"
		return

	spread = (cure_present?"Remissive":initial(spread))

	if(stage > max_stages)
		stage = max_stages
	if(stage_prob != 0 && prob(stage_prob) && stage != max_stages && !cure_present) //now the disease shouldn't get back up to stage 4 in no time
		stage++
	if(stage != 1 && (prob(1) || (cure_present && prob(cure_chance))))
		stage--
	else if(stage <= 1 && ((prob(1) && curable) || (cure_present && prob(cure_chance))))
//		world << "Cured as stage act"
		cure()
		return
	return

/datum/disease/proc/has_cure()//check if affected_mob has required reagents.
	if(!cure_id) return 0
	var/result = 1
	if(cure_list == list(cure_id))
		if(istype(cure_id, /list))
			for(var/C_id in cure_id)
				if(!affected_mob.reagents.has_reagent(C_id))
					result = 0
		else if(!affected_mob.reagents.has_reagent(cure_id))
			result = 0
	else
		for(var/C_list in cure_list)
			if(istype(C_list, /list))
				for(var/C_id in cure_id)
					if(!affected_mob.reagents.has_reagent(C_id))
						result = 0
			else if(!affected_mob.reagents.has_reagent(C_list))
				result = 0

	return result


/datum/disease/proc/spread(var/atom/source=null)
	//world << "Disease [src] proc spread was called from holder [source]"

	if(spread_type == SPECIAL || spread_type == NON_CONTAGIOUS)//does not spread
		return

	if(stage < contagious_period) //the disease is not contagious at this stage
		return

	if(!source)//no holder specified
		if(affected_mob)//no mob affected holder
			source = affected_mob
		else //no source and no mob affected. Rogue disease. Break
			return


	var/check_range = AIRBORNE//defaults to airborne - range 4

	if(spread_type != AIRBORNE && spread_type != SPECIAL)
		check_range = 0 // everything else, like infect-on-contact things, only infect things on top of it

	for(var/mob/living/carbon/M in oviewers(check_range, source))
		M.contract_disease(src)

	return


/datum/disease/proc/process()
	if(!holder) return
	if(prob(65))
		spread(holder)

	if(affected_mob)
		for(var/datum/disease/D in affected_mob.viruses)
			if(D != src)
				if(istype(src, D.type))
					del(D) // if there are somehow two viruses of the same kind in the system, delete the other one

	if(holder == affected_mob)
		if(affected_mob.stat < 2) //he's alive
			stage_act()
		else //he's dead.
			if(spread_type!=SPECIAL)
				spread_type = CONTACT_GENERAL
			affected_mob = null
	if(!affected_mob) //the virus is in inanimate obj
//		world << "[src] longevity = [longevity]"

		if(prob(70))
			if(--longevity<=0)
				cure(0)
	return

/datum/disease/proc/cure(var/resistance=1)//if resistance = 0, the mob won't develop resistance to disease
	if(resistance && affected_mob && !(type in affected_mob.resistances))
//		world << "Setting res to [src]"
		var/saved_type = "[type]"//copy the value, not create the reference to it, so when the object is deleted, the value remains.
		affected_mob.resistances += text2path(saved_type)
	if((affected_mob) && (istype(src, /datum/disease/alien_embryo)))//Get rid of the flag.
		affected_mob.alien_egg_flag = 0
//	world << "Removing [src]"
	spawn(0)
		del(src)
	return


/datum/disease/New(var/process=1)//process = 1 - adding the object to global list. List is processed by master controller.
	cure_list = list(cure_id) // to add more cures, add more vars to this list in the actual disease's New()
	if(process)					 // Viruses in list are considered active.
		active_diseases += src

/*
/datum/disease/Del()
	active_diseases.Remove(src)
*/