--SFX ID to Sound object
local Sounds = {}

do
	local Figure = script.Parent.Parent
	Head = Figure:WaitForChild("Head")
	while not Humanoid do
		for _,NewHumanoid in pairs(Figure:GetChildren()) do
			if NewHumanoid:IsA("Humanoid") then
				Humanoid = NewHumanoid
				break
			end
		end
		Figure.ChildAdded:wait()
	end
	
	Sounds[SFX.Died] = 			Head:WaitForChild("Died")
	Sounds[SFX.Running] = 		Head:WaitForChild("Running")
	Sounds[SFX.Swimming] = 	Head:WaitForChild("Swimming")
	Sounds[SFX.Climbing] = 	Head:WaitForChild("Climbing")
	Sounds[SFX.Jumping] = 		Head:WaitForChild("Jumping")
	Sounds[SFX.GettingUp] = 	Head:WaitForChild("GettingUp")
	Sounds[SFX.FreeFalling] = 	Head:WaitForChild("FreeFalling")
	Sounds[SFX.Landing] = 		Head:WaitForChild("Landing")
	Sounds[SFX.Splash] = 		Head:WaitForChild("Splash")
end

local Util
Util = {
	
	--Define linear relationship between (pt1x,pt2x) and (pt2x,pt2y). Evaluate this at x.
	YForLineGivenXAndTwoPts = function(x,pt1x,pt1y,pt2x,pt2y)
		--(y - y1)/(x - x1) = m
		local m = (pt1y - pt2y) / (pt1x - pt2x)
		--float b = pt1.y - m * pt1.x;
		local b = (pt1y - m * pt1x)
		return m * x + b
	end;
	
	--Clamps the value of "val" between the "min" and "max"
	Clamp = function(val,min,max)
		return math.min(max,math.max(min,val))	
	end;
	
	--Gets the horizontal (x,z) velocity magnitude of the given part
	HorizontalSpeed = function(Head)
		local hVel = Head.Velocity + Vector3.new(0,-Head.Velocity.Y,0)
		return hVel.magnitude	
	end;
	
	--Gets the vertical (y) velocity magnitude of the given part
	VerticalSpeed = function(Head)
		return math.abs(Head.Velocity.Y)
	end;
	
	--Setting Playing/TimePosition values directly result in less network traffic than Play/Pause/Resume/Stop
	--If these properties are enabled, use them.
	Play = function(sound)		
		if sound.TimePosition ~= 0 then
			sound.TimePosition = 0
		end
		if not sound.IsPlaying then
			sound.Playing = true
		end
	end;
	Pause = function(sound)
		if sound.IsPlaying then
			sound.Playing = false
		end
	end;
	Resume = function(sound)
		if not sound.IsPlaying then
			sound.Playing = true
		end
	end;
	Stop = function(sound)
		if sound.IsPlaying then
			sound.Playing = false
		end
		if sound.TimePosition ~= 0 then
			sound.TimePosition = 0
		end
	end;
}

do
	-- List of all active Looped sounds
	local playingLoopedSounds = {}
	
	-- Last seen Enum.HumanoidStateType
	local activeState = nil
	
	-- Verify and set that "sound" is in "playingLoopedSounds".
	function setSoundInPlayingLoopedSounds(sound)
		for i=1, #playingLoopedSounds do
			if playingLoopedSounds[i] == sound then
				return
			end
		end	
		table.insert(playingLoopedSounds,sound)
	end
	
	-- Stop all active looped sounds except parameter "except". If "except" is not passed, all looped sounds will be stopped.
	function stopPlayingLoopedSoundsExcept(except)
		for i=#playingLoopedSounds,1,-1 do
			if playingLoopedSounds[i] ~= except then
				Util.Pause(playingLoopedSounds[i])			
				table.remove(playingLoopedSounds,i)	
			end
		end
	end
	
	-- Table of Enum.HumanoidStateType to handling function
	local stateUpdateHandler = {
		[Enum.HumanoidStateType.Dead] = function()
			stopPlayingLoopedSoundsExcept()
			local sound = Sounds[SFX.Died]
			Util.Play(sound)
		end;
		
		[Enum.HumanoidStateType.RunningNoPhysics] = function()
			stateUpdated(Enum.HumanoidStateType.Running)
		end;
		
		[Enum.HumanoidStateType.Running] = function()	
			local sound = Sounds[SFX.Running]
			stopPlayingLoopedSoundsExcept(sound)
			
			if Util.HorizontalSpeed(Head) > 0.5 then
				Util.Resume(sound)
				setSoundInPlayingLoopedSounds(sound)
			else
				stopPlayingLoopedSoundsExcept()
			end
		end;
		
		[Enum.HumanoidStateType.Swimming] = function()
			if activeState ~= Enum.HumanoidStateType.Swimming and Util.VerticalSpeed(Head) > 0.1 then
				local splashSound = Sounds[SFX.Splash]
				splashSound.Volume = Util.Clamp(
					Util.YForLineGivenXAndTwoPts(
						Util.VerticalSpeed(Head), 
						100, 0.28, 
						350, 1),
					0,1)
				Util.Play(splashSound)
			end
			
			do
				local sound = Sounds[SFX.Swimming]
				stopPlayingLoopedSoundsExcept(sound)
				Util.Resume(sound)
				setSoundInPlayingLoopedSounds(sound)
			end
		end;
		
		[Enum.HumanoidStateType.Climbing] = function()
			local sound = Sounds[SFX.Climbing]
			if Util.VerticalSpeed(Head) > 0.1 then
				Util.Resume(sound)
				stopPlayingLoopedSoundsExcept(sound)
			else
				stopPlayingLoopedSoundsExcept()
			end		
			setSoundInPlayingLoopedSounds(sound)
		end;
		
		[Enum.HumanoidStateType.Jumping] = function()
			if activeState == Enum.HumanoidStateType.Jumping then
				return
			end		
			stopPlayingLoopedSoundsExcept()
			local sound = Sounds[SFX.Jumping]
			Util.Play(sound)
		end;
		
		[Enum.HumanoidStateType.GettingUp] = function()
			stopPlayingLoopedSoundsExcept()
			local sound = Sounds[SFX.GettingUp]
			Util.Play(sound)
		end;
		
		[Enum.HumanoidStateType.Freefall] = function()
			if activeState == Enum.HumanoidStateType.Freefall then
				return
			end
			local sound = Sounds[SFX.FreeFalling]
			sound.Volume = 0
			stopPlayingLoopedSoundsExcept()
		end;
		
		[Enum.HumanoidStateType.FallingDown] = function()
			stopPlayingLoopedSoundsExcept()
		end;
		
		[Enum.HumanoidStateType.Landed] = function()
			stopPlayingLoopedSoundsExcept()
			if Util.VerticalSpeed(Head) > 75 then
				local landingSound = Sounds[SFX.Landing]
				landingSound.Volume = Util.Clamp(
					Util.YForLineGivenXAndTwoPts(
						Util.VerticalSpeed(Head), 
						50, 0, 
						100, 1),
					0,1)
				Util.Play(landingSound)			
			end
		end
	}
	
	-- Handle state event fired or OnChange fired
	function stateUpdated(state)
		if stateUpdateHandler[state] ~= nil then
			stateUpdateHandler[state]()
		end
		activeState = state
	end
	
	Humanoid.Died:connect(			function() stateUpdated(Enum.HumanoidStateType.Dead) 			end)
	Humanoid.Running:connect(		function() stateUpdated(Enum.HumanoidStateType.Running) 		end)
	Humanoid.Swimming:connect(		function() stateUpdated(Enum.HumanoidStateType.Swimming) 		end)
	Humanoid.Climbing:connect(		function() stateUpdated(Enum.HumanoidStateType.Climbing) 		end)
	Humanoid.Jumping:connect(		function() stateUpdated(Enum.HumanoidStateType.Jumping) 		end)
	Humanoid.GettingUp:connect(		function() stateUpdated(Enum.HumanoidStateType.GettingUp) 		end)
	Humanoid.FreeFalling:connect(		function() stateUpdated(Enum.HumanoidStateType.Freefall) 		end)
	Humanoid.FallingDown:connect(		function() stateUpdated(Enum.HumanoidStateType.FallingDown) 	end)
	
	-- required for proper handling of Landed event
	Humanoid.StateChanged:connect(function(old, new)
		stateUpdated(new)
	end)
	
	
	function onUpdate(stepDeltaSeconds, tickSpeedSeconds)
		local stepScale = stepDeltaSeconds / tickSpeedSeconds
		do
			local sound = Sounds[SFX.FreeFalling]
			if activeState == Enum.HumanoidStateType.Freefall then
				if Head.Velocity.Y < 0 and Util.VerticalSpeed(Head) > 75 then
					Util.Resume(sound)
					
					--Volume takes 1.1 seconds to go from volume 0 to 1
					local ANIMATION_LENGTH_SECONDS = 1.1
					
					local normalizedIncrement = tickSpeedSeconds / ANIMATION_LENGTH_SECONDS									
					sound.Volume = Util.Clamp(sound.Volume + normalizedIncrement * stepScale, 0, 1)
				else
					sound.Volume = 0
				end			
			else
				Util.Pause(sound)
			end
		end
		
		do
			local sound = Sounds[SFX.Running]
			if activeState == Enum.HumanoidStateType.Running then
				if Util.HorizontalSpeed(Head) < 0.5 then
					Util.Pause(sound)
				end
			end
		end		
	end
	
	local lastTick = tick()
	local TICK_SPEED_SECONDS = 0.25
	while true do
		onUpdate(tick() - lastTick,TICK_SPEED_SECONDS)
		lastTick = tick()
		wait(TICK_SPEED_SECONDS)
	end
end