-- functions

function stopAllAnimations()
	local oldAnim = currentAnim

	-- return to idle if finishing an emote
	if (emoteNames[oldAnim] ~= nil and emoteNames[oldAnim] == false) then
		oldAnim = "idle"
	end

	if currentlyPlayingEmote then
		oldAnim = "idle"
		currentlyPlayingEmote = false
	end

	currentAnim = ""
	currentAnimInstance = nil
	if (currentAnimKeyframeHandler ~= nil) then
		currentAnimKeyframeHandler:disconnect()
	end

	if (currentAnimTrack ~= nil) then
		currentAnimTrack:Stop()
		currentAnimTrack:Destroy()
		currentAnimTrack = nil
	end

	-- clean up walk if there is one
	if (runAnimKeyframeHandler ~= nil) then
		runAnimKeyframeHandler:disconnect()
	end

	if (runAnimTrack ~= nil) then
		runAnimTrack:Stop()
		runAnimTrack:Destroy()
		runAnimTrack = nil
	end

	return oldAnim
end

function getHeightScale()
	if Humanoid then
		if not Humanoid.AutomaticScalingEnabled then
			-- When auto scaling is not enabled, the rig scale stands in for
			-- a computed scale.
			return getRigScale()
		end

		local scale = Humanoid.HipHeight / HumanoidHipHeight
		if AnimationSpeedDampeningObject == nil then
			AnimationSpeedDampeningObject = script:FindFirstChild("ScaleDampeningPercent")
		end
		if AnimationSpeedDampeningObject ~= nil then
			scale = 1 + (Humanoid.HipHeight - HumanoidHipHeight) * AnimationSpeedDampeningObject.Value / HumanoidHipHeight
		end
		return scale
	end	
	return getRigScale()
end

local function rootMotionCompensation(speed)
	local speedScaled = speed * 1.25
	local heightScale = getHeightScale()
	local runSpeed = speedScaled / heightScale
	return runSpeed
end

local smallButNotZero = 0.0001
local function setRunSpeed(speed)
	local normalizedWalkSpeed = 0.5 -- established empirically using current `913402848` walk animation
	local normalizedRunSpeed  = 1
	local runSpeed = rootMotionCompensation(speed)

	local walkAnimationWeight = smallButNotZero
	local runAnimationWeight = smallButNotZero
	local walkAnimationTimewarp = runSpeed/normalizedWalkSpeed
	local runAnimationTimerwarp = runSpeed/normalizedRunSpeed

	if runSpeed <= normalizedWalkSpeed then
		walkAnimationWeight = 1
	elseif runSpeed < normalizedRunSpeed then
		local fadeInRun = (runSpeed - normalizedWalkSpeed)/(normalizedRunSpeed - normalizedWalkSpeed)
		walkAnimationWeight = 1 - fadeInRun
		runAnimationWeight  = fadeInRun
		walkAnimationTimewarp = 1
		runAnimationTimerwarp = 1
	else
		runAnimationWeight = 1
	end
	currentAnimTrack:AdjustWeight(walkAnimationWeight)
	runAnimTrack:AdjustWeight(runAnimationWeight)
	currentAnimTrack:AdjustSpeed(walkAnimationTimewarp)
	runAnimTrack:AdjustSpeed(runAnimationTimerwarp)
end

function setAnimationSpeed(speed)
	if currentAnim == "walk" then
		setRunSpeed(speed)
	else
		if speed ~= currentAnimSpeed then
			currentAnimSpeed = speed
			currentAnimTrack:AdjustSpeed(currentAnimSpeed)
		end
	end
end

function keyFrameReachedFunc(frameName)
	if (frameName == "End") then
		if currentAnim == "walk" then
			if userNoUpdateOnLoop == true then
				if runAnimTrack.Looped ~= true then
					runAnimTrack.TimePosition = 0.0
				end
				if currentAnimTrack.Looped ~= true then
					currentAnimTrack.TimePosition = 0.0
				end
			else
				runAnimTrack.TimePosition = 0.0
				currentAnimTrack.TimePosition = 0.0
			end
		else
			local repeatAnim = currentAnim
			-- return to idle if finishing an emote
			if (emoteNames[repeatAnim] ~= nil and emoteNames[repeatAnim] == false) then
				repeatAnim = "idle"
			end

			if currentlyPlayingEmote then
				if currentAnimTrack.Looped then
					-- Allow the emote to loop
					return
				end

				repeatAnim = "idle"
				currentlyPlayingEmote = false
			end

			local animSpeed = currentAnimSpeed
			playAnimation(repeatAnim, 0.15, Humanoid)
			setAnimationSpeed(animSpeed)
		end
	end
end

function rollAnimation(animName)
	local roll = math.random(1, animTable[animName].totalWeight) 
	local origRoll = roll
	local idx = 1
	while (roll > animTable[animName][idx].weight) do
		roll = roll - animTable[animName][idx].weight
		idx = idx + 1
	end
	return idx
end

local function switchToAnim(anim, animName, transitionTime, humanoid)
	-- switch animation		
	if (anim ~= currentAnimInstance) then

		if (currentAnimTrack ~= nil) then
			currentAnimTrack:Stop(transitionTime)
			currentAnimTrack:Destroy()
		end

		if (runAnimTrack ~= nil) then
			runAnimTrack:Stop(transitionTime)
			runAnimTrack:Destroy()
			if userNoUpdateOnLoop == true then
				runAnimTrack = nil
			end
		end

		currentAnimSpeed = 1.0

		-- load it to the humanoid; get AnimationTrack
		currentAnimTrack = humanoid:LoadAnimation(anim)
		currentAnimTrack.Priority = Enum.AnimationPriority.Core

		-- play the animation
		currentAnimTrack:Play(transitionTime)
		currentAnim = animName
		currentAnimInstance = anim

		-- set up keyframe name triggers
		if (currentAnimKeyframeHandler ~= nil) then
			currentAnimKeyframeHandler:disconnect()
		end
		currentAnimKeyframeHandler = currentAnimTrack.KeyframeReached:connect(keyFrameReachedFunc)

		-- check to see if we need to blend a walk/run animation
		if animName == "walk" then
			local runAnimName = "run"
			local runIdx = rollAnimation(runAnimName)

			runAnimTrack = humanoid:LoadAnimation(animTable[runAnimName][runIdx].anim)
			runAnimTrack.Priority = Enum.AnimationPriority.Core
			runAnimTrack:Play(transitionTime)		

			if (runAnimKeyframeHandler ~= nil) then
				runAnimKeyframeHandler:disconnect()
			end
			runAnimKeyframeHandler = runAnimTrack.KeyframeReached:connect(keyFrameReachedFunc)	
		end
	end
end

function playAnimation(animName, transitionTime, humanoid) 	
	local idx = rollAnimation(animName)
	local anim = animTable[animName][idx].anim

	switchToAnim(anim, animName, transitionTime, humanoid)
	currentlyPlayingEmote = false
end

function playEmote(emoteAnim, transitionTime, humanoid)
	switchToAnim(emoteAnim, emoteAnim.Name, transitionTime, humanoid)
	currentlyPlayingEmote = true
end