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

local pairs, ipairs = pairs, ipairs
local CheckInteractDistance = CheckInteractDistance
local UnitCanAttack = UnitCanAttack
local UnitInParty = UnitInParty
local UnitInRaid = UnitInRaid
local UnitInRange = UnitInRange
local UnitIsConnected = UnitIsConnected
local UnitIsDeadOrGhost = UnitIsDeadOrGhost
local UnitPhaseReason = UnitPhaseReason
local UnitIsPlayer = UnitIsPlayer
local UnitIsUnit = UnitIsUnit

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

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

function UF:UpdateRangeCheckSpells()
	if not SR[E.myclass] then SR[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 unit:find('party') or not unit:find('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

	if UnitIsPlayer(unit) and UnitPhaseReason(unit) then
		return false -- is not in same phase
	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

	local object = SR[E.myclass]
	if object then
		if object.resSpells and (#object.resSpells > 0) and UnitIsDeadOrGhost(unit) then -- dead with rez spells
			for _, spellID in ipairs(object.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 object.friendlySpells and (#object.friendlySpells > 0) then -- you have some healy spell
			for _, spellID in ipairs(object.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

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

		if object.petSpells and (#object.petSpells > 0) then -- you have some pet spell
			for _, spellID in ipairs(object.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

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

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

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