Fix negative eHP and NaN Max hit values for some builds (#9772)

Some builds could show up having negative eHP values or nan max hit when they have single digit life values
numHits could become negative which would make eHP show up as negative too
Enemy damage conversion could also result in max hit becoming 0 in one part of the code and that would then display as NaN after it tries to divide by 0

Co-authored-by: LocalIdentity <localidentity2@gmail.com>

Author: LocalIdentity

src/Modules/CalcDefence.lua

@@ -2701,7 +2701,10 @@ function calcs.buildDefenceEstimations(env, actor)
 		if poolTable.Life >= 0 and damageTotal >= maxDamage then -- If still living and the amount of damage exceeds maximum threshold we survived infinite number of hits.
 			return m_huge
 		end
-		return numHits
+		if numHits ~= numHits then
+			return 0
+		end
+		return m_max(numHits, 0)
 	end
 
 	if damageCategoryConfig ~= "DamageOverTime" then
@@ -3161,9 +3164,12 @@ function calcs.buildDefenceEstimations(env, actor)
 					local damageConvertedMulti = convertPercent / 100
 					local totalHitPool = output[damageConvertedType.."TotalHitPool"]
 					local totalTakenMulti = output[damageConvertedType.."AfterReductionTakenHitMulti"] * (1 - output["VaalArcticArmourMitigation"])
-
-					if effectiveAppliedArmour == 0 and convertPercent == 100 then	-- use a simpler calculation for no armour DR
-						local drMulti = output[damageConvertedType.."ResistTakenHitMulti"] * (1 - output[damageConvertedType.."DamageReduction"] / 100)
+					if damageConvertedMulti <= 0 then
+						local takenWithoutIncoming = m_max(takenFlat, 0) * totalTakenMulti
+						hitTaken = takenWithoutIncoming >= totalHitPool and 0 or m_huge
+					elseif effectiveAppliedArmour == 0 and convertPercent == 100 then -- use a simpler calculation for no armour DR
+						local totalResistMult = output[damageConvertedType.."ResistTakenHitMulti"]
+						local drMulti = totalResistMult * (1 - output[damageConvertedType.."DamageReduction"] / 100)
 						hitTaken = m_max(totalHitPool / damageConvertedMulti / drMulti - takenFlat, 0) / totalTakenMulti
 					else
 						-- get relevant raw reductions and reduction modifiers
@@ -3194,7 +3200,7 @@ function calcs.buildDefenceEstimations(env, actor)
 						local b = ((enemyOverwhelmPercent / 100 - flatDR) * effectiveAppliedArmour * totalTakenMulti - 5 * (totalHitPool - takenFlat * totalTakenMulti)) * resistXConvert
 						local c = -effectiveAppliedArmour * (totalHitPool - takenFlat * totalTakenMulti)
 
-						local RAW = (m_sqrt(b * b - 4 * a * c) - b) / (2 * a)
+						local RAW = a ~= 0 and (m_sqrt(m_max(b * b - 4 * a * c, 0)) - b) / (2 * a) or m_huge
 
 						-- tack on some caps
 						local noDRMaxHit = totalHitPool / damageConvertedMulti / totalResistMult / totalTakenMulti * (1 - takenFlat * totalTakenMulti / totalHitPool)
@@ -3220,9 +3226,18 @@ function calcs.buildDefenceEstimations(env, actor)
 					local passOverkill = passPools.OverkillDamage - passPools.hitPoolRemaining
 					local passRatio = 0
 					for partType, _ in pairs(passDamages) do
-						passRatio = m_max(passRatio, (passOverkill + output[partType.."TotalHitPool"]) / output[partType.."TotalHitPool"])
+						local partPool = output[partType.."TotalHitPool"] or 0
+						if partPool > 0 then
+							passRatio = m_max(passRatio, (passOverkill + partPool) / partPool)
+						end
+					end
+					if passRatio <= 0 then
+						passRatio = 1
+					end
+					local stepSize = 1
+					if n > 1 and previousOverkill and previousOverkill ~= 0 and previousOverkill == previousOverkill then
+						stepSize = m_min(m_abs((passOverkill - previousOverkill) / previousOverkill), 2)
 					end
-					local stepSize = n > 1 and m_min(m_abs((passOverkill - previousOverkill) / previousOverkill), 2) or 1
 					local stepAdjust = stepSize > 1 and -passOverkill / stepSize or n > 1 and -passOverkill * stepSize or 0
 					previousOverkill = passOverkill
 					passIncomingDamage = (passIncomingDamage + stepAdjust) / m_sqrt(passRatio)