coa-elvui/ElvUI/Modules/UnitFrames/Elements/Range.lua

local E, L, V, P, G = unpack(select(2, ...)); --Import: Engine, Locales, PrivateDB, ProfileDB, GlobalDB
local UF = E:GetModule("UnitFrames")
local SpellRange = E.Libs.SpellRange

--Lua functions
local pairs, ipairs = pairs, ipairs
local find = string.find
--WoW API / Variables
local CheckInteractDistance = CheckInteractDistance
local UnitCanAttack = UnitCanAttack
local UnitInParty = UnitInParty
local UnitInRaid = UnitInRaid
local UnitInRange = UnitInRange
local UnitIsConnected = UnitIsConnected
local UnitIsDeadOrGhost = UnitIsDeadOrGhost
local UnitIsUnit = UnitIsUnit

local SRT = {}
local function AddTable(tbl)
	SRT[E.myclass][tbl] = {}
end

local function AddSpell(tbl, spellID)
	SRT[E.myclass][tbl][#SRT[E.myclass][tbl] + 1] = spellID
end

function UF:UpdateRangeCheckSpells()
	if not SRT[E.myclass] then SRT[E.myclass] = {} end

	for tbl, spells in pairs(E.global.unitframe.spellRangeCheck[E.myclass]) do
		AddTable(tbl) --Create the table holding spells, even if it ends up being an empty table
		for spellID in pairs(spells) do
			local enabled = spells[spellID]
			if enabled then --We will allow value to be false to disable this spell from being used
				AddSpell(tbl, spellID, enabled)
			end
		end
	end
end

local function getUnit(unit)
	if not find(unit, "party") or not find(unit, "raid") then
		for i = 1, 4 do
			if UnitIsUnit(unit, "party"..i) then
				return "party"..i
			end
		end

		for i = 1, 40 do
			if UnitIsUnit(unit, "raid"..i) then
				return "raid"..i
			end
		end
	else
		return unit
	end
end

local function friendlyIsInRange(unit)
	if (not UnitIsUnit(unit, "player")) and (UnitInParty(unit) or UnitInRaid(unit)) then
		unit = getUnit(unit) -- swap the unit with `raid#` or `party#` when its NOT `player`, UnitIsUnit is true, and its not using `raid#` or `party#` already
	end

	local inRange, checkedRange = UnitInRange(unit)
	if checkedRange and not inRange then
		return false -- blizz checked and said the unit is out of range
	end

	if CheckInteractDistance(unit, 1) then
		return true -- within 28 yards (arg2 as 1 is Compare Achievements distance)
	end

	if SRT[E.myclass] then
		if SRT[E.myclass].resSpells and UnitIsDeadOrGhost(unit) and (#SRT[E.myclass].resSpells > 0) then -- dead with rez spells
			for _, spellID in ipairs(SRT[E.myclass].resSpells) do
				if SpellRange.IsSpellInRange(spellID, unit) == 1 then
					return true -- within rez range
				end
			end

			return false -- dead but no spells are in range
		end

		if SRT[E.myclass].friendlySpells and (#SRT[E.myclass].friendlySpells > 0) then -- you have some healy spell
			for _, spellID in ipairs(SRT[E.myclass].friendlySpells) do
				if SpellRange.IsSpellInRange(spellID, unit) == 1 then
					return true -- within healy spell range
				end
			end
		end
	end

	return false -- not within 28 yards and no spells in range
end

local function petIsInRange(unit)
	if CheckInteractDistance(unit, 2) then
		return true -- within 8 yards (arg2 as 2 is Trade distance)
	end

	if SRT[E.myclass] then
		if SRT[E.myclass].friendlySpells and (#SRT[E.myclass].friendlySpells > 0) then -- you have some healy spell
			for _, spellID in ipairs(SRT[E.myclass].friendlySpells) do
				if SpellRange.IsSpellInRange(spellID, unit) == 1 then
					return true
				end
			end
		end

		if SRT[E.myclass].petSpells and (#SRT[E.myclass].petSpells > 0) then -- you have some pet spell
			for _, spellID in ipairs(SRT[E.myclass].petSpells) do
				if SpellRange.IsSpellInRange(spellID, unit) == 1 then
					return true
				end
			end
		end
	end

	return false -- not within 8 yards and no spells in range
end

local function enemyIsInRange(unit)
	if CheckInteractDistance(unit, 2) then
		return true -- within 8 yards (arg2 as 2 is Trade distance)
	end

	if SRT[E.myclass] then
		if SRT[E.myclass].enemySpells and (#SRT[E.myclass].enemySpells > 0) then -- you have some damage spell
			for _, spellID in ipairs(SRT[E.myclass].enemySpells) do
				if SpellRange.IsSpellInRange(spellID, unit) == 1 then
					return true
				end
			end
		end
	end

	return false -- not within 8 yards and no spells in range
end

local function enemyIsInLongRange(unit)
	if SRT[E.myclass] then
		if SRT[E.myclass].longEnemySpells and (#SRT[E.myclass].longEnemySpells > 0) then -- you have some 30+ range damage spell
			for _, spellID in ipairs(SRT[E.myclass].longEnemySpells) do
				if SpellRange.IsSpellInRange(spellID, unit) == 1 then
					return true
				end
			end
		end
	end

	return false
end

function UF:UpdateRange(unit)
	if not self.Fader then return end
	local alpha

	unit = unit or self.unit

	if self.forceInRange or unit == "player" then
		alpha = self.Fader.MaxAlpha
	elseif self.forceNotInRange then
		alpha = self.Fader.MinAlpha
	elseif unit then
		if UnitCanAttack("player", unit) then
			alpha = ((enemyIsInRange(unit) or enemyIsInLongRange(unit)) and self.Fader.MaxAlpha) or self.Fader.MinAlpha
		elseif UnitIsUnit(unit, "pet") then
			alpha = (petIsInRange(unit) and self.Fader.MaxAlpha) or self.Fader.MinAlpha
		else
			alpha = (UnitIsConnected(unit) and friendlyIsInRange(unit) and self.Fader.MaxAlpha) or self.Fader.MinAlpha
		end
	else
		alpha = self.Fader.MaxAlpha
	end

	self.Fader.RangeAlpha = alpha
end