-- modernized 14/09/2020

-- Coolio module stuff
local handler = {}
local fpsMT = { __index = handler }

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local TweenService = game:GetService("TweenService")
local UserInputService = game:GetService("UserInputService")
local Debris = game:GetService("Debris")
local Players = game:GetService("Players")

ReplicatedStorage:WaitForChild("modules")
ReplicatedStorage.modules:WaitForChild("fastCastHandler")
ReplicatedStorage.modules:WaitForChild("spring")

local fastcastHandler = require(ReplicatedStorage.modules.fastCastHandler)
local spring = require(ReplicatedStorage.modules.spring)

-- Functions i like using and you will probably too.
-- Bobbing!

local function getBobbing(addition, speed, modifier)
	return math.sin(tick() * addition * speed) * modifier
end

function handler.new(weapons)
	local self = {}

	self.loadedAnimations = {}
	self.springs = {}
	self.lerpValues = {}
	self.ammo = {} -- per weapon

	self.lerpValues.aim = Instance.new("NumberValue")
	self.lerpValues.equip = Instance.new("NumberValue")
	self.lerpValues.equip.Value = 1

	self.springs.walkCycle = spring.create()
	self.springs.sway = spring.create()
	self.springs.fire = spring.create()

	self.canFire = true

	return setmetatable(self, fpsMT)
end

function handler:equip(wepName)
	-- Explained how this works earlier. we can store variables too!
	-- if the weapon is disabled, or equipped, remove it instead
	if self.disabled then
		return
	end
	if self.equipped then
		self:remove()
	end
	if self.reloading then
		return
	end
	-- get weapon from storage
	local weapon = ReplicatedStorage.weapons:FindFirstChild(wepName) -- do not cloen
	if not weapon then
		return
	end -- if the weapon exists, clone it, else, stop
	weapon = weapon:Clone()

	--[[
	 	Make a viewmodel (easily accessible with weapon.viewmodel too!) 
		and throw everything in the weapon straight inside of it. This makes animation hierarchy work.
	--]]

	self.viewmodel = ReplicatedStorage.viewmodel:Clone()
	for _, v in pairs(weapon:GetChildren()) do
		v.Parent = self.viewmodel
		if v:IsA("BasePart") then
			v.CanCollide = false
			v.CastShadow = false
		end
	end

	-- Time for automatic rigging and some basic properties
	self.camera = workspace.CurrentCamera
	self.character = Players.LocalPlayer.Character

	-- Throw the viewmodel under the map. It will go back to the camera the next render frame once we get to moving it.
	self.viewmodel.rootPart.CFrame = CFrame.new(0, -100, 0)
	-- We're making the gun bound to the viewmodel's rootpart, and making the arms move along with the viewmodel using hierarchy.
	self.viewmodel.rootPart.weapon.Part1 = self.viewmodel.weaponRootPart
	self.viewmodel.left.leftHand.Part0 = self.viewmodel.weaponRootPart
	self.viewmodel.right.rightHand.Part0 = self.viewmodel.weaponRootPart
	-- I legit forgot to do this in the first code revision.
	self.viewmodel.Parent = workspace.Camera

	self.settings = require(self.viewmodel.settings)
	self.loadedAnimations.idle = self.viewmodel.AnimationController:LoadAnimation(
		self.settings.animations.viewmodel.idle
	)
	self.loadedAnimations.reload = self.viewmodel.AnimationController:LoadAnimation(
		self.settings.animations.viewmodel.reload
	)
	self.loadedAnimations.fire = self.viewmodel.AnimationController:LoadAnimation(
		self.settings.animations.viewmodel.fire
	)
	self.loadedAnimations.idle:Play()

	-- set ammo, either current or default filled
	self.wepName = wepName
	self.ammo[wepName] = self.ammo[wepName] or (self.settings.firing.magCapacity + 1)

	local tweeningInformation = TweenInfo.new(0.5, Enum.EasingStyle.Quart, Enum.EasingDirection.Out)
	TweenService:Create(self.lerpValues.equip, tweeningInformation, { Value = 0 }):Play()

	--[[
		Real life example:
			
		self.loadedAnimations.idle = self.viewmodel.AnimationController:LoadAnimation(self.settings.anims.viewmodel.idle)
		self.loadedAnimations.idle:Play()
	
		self.tweenLerp("equip","In")
		self.playSound("draw")
		
	--]]

	-- spawned because server requests are far from instant
	task.spawn(function()
		-- if server say no, then so does the client
		local pass = ReplicatedStorage.weaponRemotes.equip:InvokeServer(wepName)
		if not pass then
			self:remove()
		end
	end)

	self.curWeapon = wepName
	self.equipped = true -- Yay! our gun is ready.
end

function handler:remove()
	if self.reloading then
		return
	end
	if self.firing then
		self:fire(false)
	end
	if self.aiming then
		self:aim(false)
	end

	local tweeningInformation = TweenInfo.new(0.6, Enum.EasingStyle.Quart, Enum.EasingDirection.Out)
	TweenService:Create(self.lerpValues.equip, tweeningInformation, { Value = 1 }):Play()

	self.equipped = false -- Nay! We can't do anything with the gun now.
	self.disabled = true
	self.curWeapon = nil

	task.spawn(function()
		-- cough
		ReplicatedStorage.weaponRemotes.unequip:InvokeServer()
	end)

	task.wait(0.6) --task.wait until the tween finished so the gun lowers itself smoothly
	if self.viewmodel then
		self.viewmodel:Destroy()
		self.viewmodel = nil
	end
	self.disabled = false
end

function handler:reload()
	if self.firing then
		self:fire(false)
	end
	if self.aiming then
		self:aim(false)
	end
	if self.reloading then
		return
	end

	self.reloading = true
	self.ammo[self.wepName] = 0
	self.loadedAnimations.reload:Play()

	-- we can use keyframe reached here, i will use length instead. waiting for the animation to finish will yield infinitely
	if not self.equipped then
		return
	end
	task.wait(self.loadedAnimations.reload.Length)

	self.ammo[self.wepName] = self.settings.firing.magCapacity
	self.reloading = false
end

function handler:fire(tofire)
	if self.reloading then
		return
	end
	if self.disabled then
		return
	end
	if not self.equipped then
		return
	end
	if tofire and self.ammo[self.wepName] <= 0 then
		self:reload()
		return
	end
	if self.firing and tofire then
		return
	end
	if not self.canFire and tofire then
		return
	end

	-- this makes the loop stop running when set to false
	self.firing = tofire
	if not tofire then
		return
	end

	-- while lmb held down do
	local function fire()
		if self.ammo[self.wepName] <= 0 then
			return
		end

		-- It's better to replicate the change to other clients and play it there with the same code as here instead of using SoundService.RespectFilteringEnabled = false
		local sound = self.viewmodel.receiver.pewpew:Clone()
		sound.Parent = self.viewmodel.receiver
		sound:Play()

		-- replace? i've heard bad things about debris service
		Debris:AddItem(sound, 5)
		self.loadedAnimations.fire:Play()
		self.ammo[self.wepName] = self.ammo[self.wepName] - 1

		-- addition of deltatime here is a poor attempt at fixing the recoil being framerate based
		-- this doesn't happen in my own game, dunno why
		self.springs.fire:shove(Vector3.new(0.03, 0, 0) * self.deltaTime * 60)
		task.delay(0.15, function()
			self.springs.fire:shove(Vector3.new(-0.03, 0, 0) * self.deltaTime * 60)
		end)

		-- Muzzle flash
		for _, v in pairs(self.viewmodel.receiver.barrel:GetChildren()) do
			if v:IsA("ParticleEmitter") then
				v:Emit(v.Rate)
			end
		end

		-- origin, direction
		-- barrel because realism, camera.CFrame because uh accuracy and arcadeying
		-- make sure the barrel is facing where the gun fires
		-- aaand make sure the gun is actually facing towards the cursor properly, players don't like offsets

		local origin = self.viewmodel.receiver.barrel.WorldPosition
		local direction = self.viewmodel.receiver.barrel.WorldCFrame

		-- inconsistent :(
		fastcastHandler:fire(origin, direction, self.settings)

		task.wait(60 / self.settings.firing.rpm)
	end

	repeat
		self.canFire = false
		fire()
		self.canFire = true
	until self.ammo[self.wepName] <= 0 or not self.firing

	if self.ammo[self.wepName] <= 0 then
		self.firing = false
	end
end

function handler:aim(toaim)
	-- we'll be using this soon
	-- We used it! ha!

	-- add a TweenService variable at the top that references TweenService yourself, thanks

	if self.disabled then
		return
	end
	if not self.equipped then
		return
	end

	self.aiming = toaim
	UserInputService.MouseIconEnabled = not toaim --do this wherever you want
	ReplicatedStorage.weaponRemotes.aim:FireServer(toaim)

	-- This is an easy to make approach

	if toaim then
		-- customize speed at will.

		local tweeningInformation = TweenInfo.new(1, Enum.EasingStyle.Quart, Enum.EasingDirection.Out)
		TweenService:Create(self.lerpValues.aim, tweeningInformation, { Value = 1 }):Play()
	else
		local tweeningInformation = TweenInfo.new(0.5, Enum.EasingStyle.Quart, Enum.EasingDirection.Out)
		TweenService:Create(self.lerpValues.aim, tweeningInformation, { Value = 0 }):Play()
	end
end

function handler:update(deltaTime)
	self.deltaTime = deltaTime

	-- IF we have a gun right now. We're checking the viewmodel instead for "reasons".
	if self.viewmodel then
		-- for animations
		-- breaks for some people? idk
		local animatorCFrameDifference = self.lastReceiverRelativity
			or CFrame.new() * self.viewmodel.camera.CFrame:ToObjectSpace(self.viewmodel.rootPart.CFrame):Inverse()
		local x, y, z = animatorCFrameDifference:ToOrientation()
		workspace.Camera.CFrame = workspace.Camera.CFrame * CFrame.Angles(x, y, z)
		self.lastReceiverRelativity = self.viewmodel.camera.CFrame:ToObjectSpace(self.viewmodel.rootPart.CFrame)

		-- get velocity for walkCycle
		local velocity = self.character.HumanoidRootPart.Velocity

		-- you can add priorities here! for example, equip offset for procedural equipping would be below aimOffset to overwrite it when removing the gun.
		-- here, aim overwrites idle.
		local idleOffset = self.viewmodel.offsets.idle.Value
		local aimOffset = idleOffset:lerp(self.viewmodel.offsets.aim.Value, self.lerpValues.aim.Value)
		local equipOffset = aimOffset:lerp(self.viewmodel.offsets.equip.Value, self.lerpValues.equip.Value)

		-- it'll be final for a reason. You saw!
		local finalOffset = equipOffset

		-- Let's get some mouse movement!
		local mouseDelta = UserInputService:GetMouseDelta()
		if self.aiming then
			mouseDelta *= 0.1
		end
		self.springs.sway:shove(Vector3.new(mouseDelta.X / 200, mouseDelta.Y / 200)) --not sure if this needs deltaTime filtering

		-- speed can be dependent on a value changed when you're running, or standing still, or aiming, etc.
		-- this makes the bobble faster.
		local speed = 1
		-- modifier can be dependent on a value changed when you're aiming, or standing still, etc.
		-- this makes the bobble do more. or something.
		local modifier = 0.1

		if self.aiming then
			modifier = 0.01
		end

		-- See? Bobbing! contruct a vector3 with getBobbing.
		local movementSway = Vector3.new(
			getBobbing(10, speed, modifier),
			getBobbing(5, speed, modifier),
			getBobbing(5, speed, modifier)
		)

		-- if velocity is 0, then so will the walk cycle
		self.springs.walkCycle:shove((movementSway / 25) * deltaTime * 60 * velocity.Magnitude)

		-- Sway! Yay!
		local sway = self.springs.sway:update(deltaTime)
		local walkCycle = self.springs.walkCycle:update(deltaTime)
		local recoil = self.springs.fire:update(deltaTime)

		-- RecoillllL!!!!!
		self.camera.CFrame = self.camera.CFrame * CFrame.Angles(recoil.x, recoil.y, recoil.z)

		--ToWorldSpace basically means rootpart.CFrame = camera CFrame but offset by xxx while taking rotation into account. I don't know. You'll see how it works soon enough.
		self.viewmodel.rootPart.CFrame = self.camera.CFrame:ToWorldSpace(finalOffset)
		self.viewmodel.rootPart.CFrame = self.viewmodel.rootPart.CFrame:ToWorldSpace(
			CFrame.new(walkCycle.x / 4, walkCycle.y / 2, 0)
		)

		-- Rotate our rootpart based on sway
		self.viewmodel.rootPart.CFrame = self.viewmodel.rootPart.CFrame * CFrame.Angles(0, -sway.x, sway.y)
		self.viewmodel.rootPart.CFrame = self.viewmodel.rootPart.CFrame
			* CFrame.Angles(0, walkCycle.y / 2, walkCycle.x / 5)
	end
end

return handler