Damage Numbers

local Players = game:GetService("Players")
local ServerStorage = game:GetService("ServerStorage")
local Settings = require(game.ReplicatedStorage.Settings)

local remotes = game.ReplicatedStorage.Remotes
local lastSwing = {} -- player -> when they last swung
local combo = {} -- player -> { hits in a row, when the last one landed }

-- Roblox's own sword animations
local slash = Instance.new("Animation")
slash.AnimationId = "rbxassetid://522635514"
local lunge = Instance.new("Animation")
lunge.AnimationId = "rbxassetid://522638767"

print("Swords deal " .. Settings.SwordDamage .. " damage")

-- Every hit in the game goes through here
local function hurt(humanoid, amount)
	if humanoid.Health <= 0 then
		return
	end
	local character = humanoid.Parent
	-- a block takes most of the hit
	if character:GetAttribute("Blocking") then
		amount *= Settings.BlockMultiplier
	end
	humanoid:TakeDamage(amount)
end

-- A stun freezes someone for a moment
local function stun(humanoid)
	local character = humanoid.Parent
	if character:GetAttribute("Stunned") then
		return
	end
	character:SetAttribute("Stunned", true)
	local speed = humanoid.WalkSpeed
	humanoid.WalkSpeed = 0
	task.delay(Settings.StunTime, function()
		if character.Parent then
			humanoid.WalkSpeed = speed
			character:SetAttribute("Stunned", nil)
		end
	end)
end

-- A swing: the animation, then everyone in the box in front of you is hit
local function swing(player)
	local character = player.Character
	local root = character and character:FindFirstChild("HumanoidRootPart")
	if not root or character.Humanoid.Health <= 0 then
		return
	end
	local now = time()
	if lastSwing[player] and now - lastSwing[player] < Settings.SwingCooldown then
		return
	end
	lastSwing[player] = now
	-- three swings in a row make a combo; the third is a lunge
	local c = combo[player]
	if c and now - c.last <= Settings.ComboWindow then
		c.count = c.count % 3 + 1
	else
		c = { count = 1 }
		combo[player] = c
	end
	c.last = now
	local finisher = c.count == 3
	character.Humanoid.Animator:LoadAnimation(finisher and lunge or slash):Play()
	-- the box in front of you, never your own body
	local params = OverlapParams.new()
	params.FilterDescendantsInstances = { character }
	local box = root.CFrame * CFrame.new(0, 0, -3)
	local hit = {} -- each humanoid once per swing
	for _, part in workspace:GetPartBoundsInBox(box, Settings.HitboxSize, params) do
		local humanoid = part.Parent:FindFirstChildOfClass("Humanoid")
		if humanoid and not hit[humanoid] then
			hit[humanoid] = true
			hurt(humanoid, Settings.ComboDamage[c.count])
			if finisher then
				stun(humanoid)
			end
		end
	end
end

-- The abilities, by name: what each one does
local abilities = {}

function abilities.Dash(player, character, root)
	root.AssemblyLinearVelocity = root.CFrame.LookVector * Settings.DashSpeed + Vector3.new(0, 15, 0)
end

-- everyone around you is hit and thrown away from you
function abilities.Slam(player, character, root)
	local params = OverlapParams.new()
	params.FilterDescendantsInstances = { character }
	local hit = {}
	for _, part in workspace:GetPartBoundsInRadius(root.Position, Settings.SlamRadius, params) do
		local humanoid = part.Parent:FindFirstChildOfClass("Humanoid")
		local theirRoot = part.Parent:FindFirstChild("HumanoidRootPart")
		if humanoid and theirRoot and not hit[humanoid] then
			hit[humanoid] = true
			hurt(humanoid, Settings.SlamDamage)
			local away = (theirRoot.Position - root.Position) * Vector3.new(1, 0, 1)
			if away.Magnitude > 0 then
				away = away.Unit
			end
			theirRoot:ApplyImpulse((away * Settings.SlamKnockback + Vector3.new(0, 40, 0)) * theirRoot.AssemblyMass)
		end
	end
end

function abilities.Block(player, character)
	character:SetAttribute("Blocking", true)
	task.delay(Settings.BlockTime, function()
		if character.Parent then
			character:SetAttribute("Blocking", nil)
		end
	end)
end

-- The client asks for an ability by name. The server checks it: a real
-- ability, a living player, and its cooldown over. When it is ready again
-- is an attribute of the player, so their screen can show it.
remotes.Ability.OnServerEvent:Connect(function(player, name)
	if typeof(name) ~= "string" or not abilities[name] then
		return
	end
	local character = player.Character
	local root = character and character:FindFirstChild("HumanoidRootPart")
	if not root or character.Humanoid.Health <= 0 then
		return
	end
	local now = workspace:GetServerTimeNow()
	if now < (player:GetAttribute(name .. "ReadyAt") or 0) then
		return
	end
	player:SetAttribute(name .. "ReadyAt", now + Settings.Cooldowns[name])
	abilities[name](player, character, root)
end)

-- Every player gets Kills on the leaderboard, and a sword every life
Players.PlayerAdded:Connect(function(player)
	local leaderstats = Instance.new("Folder")
	leaderstats.Name = "leaderstats"
	leaderstats.Parent = player

	local kills = Instance.new("IntValue")
	kills.Name = "Kills"
	kills.Parent = leaderstats

	player.CharacterAdded:Connect(function()
		local sword = ServerStorage.Sword:Clone()
		sword.Parent = player.Backpack
		sword.Activated:Connect(function()
			swing(player)
		end)
	end)
end)

-- The training dummy: its health bar follows its health, and a beaten
-- dummy comes back after a moment, a fresh copy in the same place
local function setupDummy(dummy)
	local humanoid = dummy.Humanoid
	humanoid.HealthChanged:Connect(function(health)
		dummy.HealthBar.Back.Fill.Size = UDim2.fromScale(health / humanoid.MaxHealth, 1)
	end)
	humanoid.Died:Connect(function()
		local spot = dummy:GetPivot()
		task.wait(0.5)
		dummy:Destroy()
		task.wait(Settings.DummyRespawn)
		local fresh = ServerStorage.Dummy:Clone()
		fresh:PivotTo(spot)
		fresh.Parent = workspace
		setupDummy(fresh)
	end)
end
setupDummy(workspace.Dummy)