-- RivetStrider AI (attachment-aware aim + stable yaw/pitch + 180° guard)
-- Paste into the RivetStrider root model (replaces prior AI).
-- This version:
--  - prefers attachments (TurretAttachment, GunBaseAttachment, GunAttachment, Muzzle)
--  - picks the sign (forward vs -forward) that produces the smallest yaw change (prevents 180° flip)
--  - clamps barrel pitch to sensible range to avoid wild/flip behaviour
--  - uses CFrame:Lerp for smooth rotation (dt-based)
-- Keeps HeliCoins reward on death (uses _G.HeliCoinsReward if present).

local Workspace = game:GetService("Workspace")
local Debris = game:GetService("Debris")
local RunService = game:GetService("RunService")
local Players = game:GetService("Players")

local enemy = script.Parent

-- WAIT for required parts
local hum = enemy:WaitForChild("Humanoid")
local hrp = enemy:WaitForChild("HumanoidRootPart")

-- Submodels (non-fatal fallbacks)
local Hull = enemy:FindFirstChild("Hull") or enemy
local TurretModel = Hull and (Hull:FindFirstChild("Turret") or Hull:FindFirstChildWhichIsA("Model"))
local BarrelModel = TurretModel and (TurretModel:FindFirstChild("Barrel") or TurretModel:FindFirstChildWhichIsA("Model"))

-- helper to find attachments/parts by many possible names
local function findAny(root, names)
	if not root then return nil end
	for _,n in ipairs(names) do
		local f = root:FindFirstChild(n, true)
		if f then return f end
	end
	for _,d in ipairs(root:GetDescendants()) do
		if d:IsA("Attachment") or d:IsA("BasePart") then
			-- stop at first attachment/part if nothing matched, but prefer attachments above
			-- we'll still prefer direct finds above
		end
	end
	return nil
end

-- Common part/attachment lookups (use provided names)
local turretPart = nil
if TurretModel then
	turretPart = TurretModel:FindFirstChild("TurretPart", true) or TurretModel:FindFirstChildWhichIsA("BasePart", true)
end
-- Barrel part primary fallback
local barrelPart = nil
if BarrelModel then
	barrelPart = BarrelModel:FindFirstChild("BarrelPart", true) or BarrelModel:FindFirstChildWhichIsA("BasePart", true)
end

-- Attachments (preferred)
local turretAttachment = nil
if TurretModel then
	turretAttachment = TurretModel:FindFirstChild("TurretAttachment", true) or TurretModel:FindFirstChild("GunBaseAttachment", true)
end
local gunAttachment = nil
if BarrelModel then
	gunAttachment = BarrelModel:FindFirstChild("GunAttachment", true)
end
local muzzleAttachment = nil
if BarrelModel then
	muzzleAttachment = BarrelModel:FindFirstChild("Muzzle", true)
	-- fallback to any attachment on barrelPart
	if (not muzzleAttachment) and barrelPart then
		for _,c in ipairs(barrelPart:GetChildren()) do
			if c:IsA("Attachment") then muzzleAttachment = c; break end
		end
	end
end

local function dbg(...)
	print("[RivetAI]", ...)
end

dbg("Starting RivetStrider AI for:", enemy.Name)
dbg("turretPart:", turretPart and turretPart:GetFullName() or "nil")
dbg("barrelPart:", barrelPart and barrelPart:GetFullName() or "nil")
dbg("turretAttachment:", turretAttachment and turretAttachment:GetFullName() or "nil")
dbg("gunAttachment:", gunAttachment and gunAttachment:GetFullName() or "nil")
dbg("muzzleAttachment:", muzzleAttachment and muzzleAttachment:GetFullName() or "nil")

-- Animations (StriderIdle / StriderWalk)
local function findAnimation(root, fragment)
	fragment = (fragment or ""):lower()
	for _, v in ipairs(root:GetDescendants()) do
		if v:IsA("Animation") and v.Name:lower():find(fragment) then return v end
	end
	for _, v in ipairs(root:GetChildren()) do
		if v:IsA("Animation") and v.Name:lower():find(fragment) then return v end
	end
	return nil
end
local idleAnimObj = findAnimation(enemy, "strideridle") or findAnimation(enemy, "idle")
local walkAnimObj = findAnimation(enemy, "striderwalk") or findAnimation(enemy, "walk")
local idleTrack, walkTrack
pcall(function() if idleAnimObj then idleTrack = hum:LoadAnimation(idleAnimObj); idleTrack.Looped = true end end)
pcall(function() if walkAnimObj then walkTrack = hum:LoadAnimation(walkAnimObj); walkTrack.Looped = true end end)

local EnemyBullet = game:GetService("ReplicatedStorage"):FindFirstChild("StriderBullet")
if not EnemyBullet then dbg("WARNING: StriderBullet missing in ReplicatedStorage") end

-- ATTRIBUTES
local RANGE = tonumber(enemy:GetAttribute("RangeAttackDistance")) or 90
local DAMAGE = tonumber(enemy:GetAttribute("Damage")) or 12
local RELOAD = tonumber(enemy:GetAttribute("Reload")) or 1.2
local MAIN_DIST = tonumber(enemy:GetAttribute("MainDistance")) or 14
local TURN_SPEED = tonumber(enemy:GetAttribute("TurnSpeedDeg")) or 140
local PITCH_SPEED = tonumber(enemy:GetAttribute("PitchSpeedDeg")) or 90
local BULLET_SPEED = tonumber(enemy:GetAttribute("BulletSpeed")) or 160
local BULLET_LIFE = tonumber(enemy:GetAttribute("BulletLife")) or 4
local PITCH_MIN_DEG = tonumber(enemy:GetAttribute("MinPitchDeg")) or -25  -- clamp down
local PITCH_MAX_DEG = tonumber(enemy:GetAttribute("MaxPitchDeg")) or 45   -- clamp up

dbg(("ATTRIBUTES: RANGE=%s DAMAGE=%s RELOAD=%s MAIN_DIST=%s"):format(RANGE, DAMAGE, RELOAD, MAIN_DIST))

local AlliancesFolder = Workspace:WaitForChild("Alliances")

-- ensure humanoid sensible
if hum.PlatformStand then hum.PlatformStand = false end
if not hum.WalkSpeed or hum.WalkSpeed <= 0 then
	hum.WalkSpeed = tonumber(enemy:GetAttribute("DefaultWalkSpeed")) or 16
end

local function playIdle()
	if walkTrack and walkTrack.IsPlaying then pcall(function() walkTrack:Stop() end) end
	if idleTrack and not idleTrack.IsPlaying then pcall(function() idleTrack:Play() end) end
end
local function playWalk()
	if idleTrack and idleTrack.IsPlaying then pcall(function() idleTrack:Stop() end) end
	if walkTrack and not walkTrack.IsPlaying then pcall(function() walkTrack:Play() end) end
end

-- target selection (players first then Alliances)
local function getClosestTank()
	local closest, closestDist = nil, math.huge
	for _, p in ipairs(Players:GetPlayers()) do
		local ch = p.Character
		if ch and ch ~= enemy then
			local r = ch:FindFirstChild("HumanoidRootPart")
			if r then
				local d = (hrp.Position - r.Position).Magnitude
				if d < closestDist then closestDist, closest = d, ch end
			end
		end
	end
	for _, t in ipairs(AlliancesFolder:GetChildren()) do
		if t and t ~= enemy then
			local r = t:FindFirstChild("HumanoidRootPart")
			if r then
				local d = (hrp.Position - r.Position).Magnitude
				if d < closestDist then closestDist, closest = d, t end
			end
		end
	end
	return closest, closestDist
end

local function angleDeg(aVec, bVec)
	local a = aVec.Unit; local b = bVec.Unit
	local dot = math.clamp(a:Dot(b), -1, 1)
	return math.deg(math.acos(dot))
end

-- Obtain "pivot pos" for turret yaw (prefer attachment world position)
local function getTurretPivotPos()
	if turretAttachment and turretAttachment.WorldPosition then
		return turretAttachment.WorldPosition
	elseif turretPart then
		return turretPart.Position
	elseif TurretModel and TurretModel.PrimaryPart then
		return TurretModel.PrimaryPart.Position
	else
		return (TurretModel and TurretModel:GetModelCFrame().p) or hrp.Position
	end
end

-- Obtain turret "current forward" horizontal vector
local function getTurretCurrentForward()
	if turretPart then
		local fv = turretPart.CFrame.LookVector
		local horiz = Vector3.new(fv.X, 0, fv.Z)
		if horiz.Magnitude < 1e-6 then return Vector3.new(0,0,1) end
		return horiz.Unit
	elseif TurretModel and TurretModel.PrimaryPart then
		local fv = TurretModel.PrimaryPart.CFrame.LookVector
		local horiz = Vector3.new(fv.X, 0, fv.Z)
		if horiz.Magnitude < 1e-6 then return Vector3.new(0,0,1) end
		return horiz.Unit
	elseif turretAttachment and turretAttachment.WorldCFrame then
		local fv = turretAttachment.WorldCFrame.LookVector
		local horiz = Vector3.new(fv.X, 0, fv.Z)
		if horiz.Magnitude < 1e-6 then return Vector3.new(0,0,1) end
		return horiz.Unit
	else
		return Vector3.new(0,0,1)
	end
end

-- Aim function: smooth turret yaw + barrel pitch. Returns yawRemDeg, pitchRemDeg
local function aimAt(targetPos, dt)
	-- require turret/barrel available
	if not (turretPart or TurretModel) or not (barrelPart or BarrelModel) then return 999, 999 end

	local turretPos = getTurretPivotPos()
	local dir = targetPos - turretPos
	local horiz = Vector3.new(dir.X, 0, dir.Z)
	if horiz.Magnitude < 1e-6 then return 999, 999 end
	local desiredLook = horiz.Unit

	-- stable 180 handling: pick desiredLook or -desiredLook whichever is closer to current forward
	local currentForward = getTurretCurrentForward()
	-- compute angles
	local a1 = angleDeg(currentForward, desiredLook)
	local a2 = angleDeg(currentForward, -desiredLook)
	if a2 < a1 then
		desiredLook = -desiredLook
	end

	-- build desired turret CFrame (flat)
	local desiredTurretCf = CFrame.new(turretPos, turretPos + Vector3.new(desiredLook.X, 0, desiredLook.Z))

	-- compute frac from TURN_SPEED and angle
	local currentFlat = Vector3.new((turretPart and turretPart.CFrame.LookVector or (TurretModel and TurretModel.PrimaryPart and TurretModel.PrimaryPart.CFrame.LookVector)).X, 0,
		(turretPart and turretPart.CFrame.LookVector or (TurretModel and TurretModel.PrimaryPart and TurretModel.PrimaryPart.CFrame.LookVector)).Z)
	if currentFlat.Magnitude < 1e-6 then currentFlat = Vector3.new(0,0,1) end
	local angleBetween = angleDeg(currentFlat, Vector3.new(desiredLook.X,0,desiredLook.Z))
	local maxYawStep = math.rad(TURN_SPEED) * dt
	local frac = (angleBetween <= 0.5) and 1 or math.clamp((maxYawStep * 180 / math.pi) / math.max(angleBetween, 0.0001), 0, 1)

	-- lerp turret orientation
	local newTurretCf = (turretPart and turretPart.CFrame or (TurretModel and TurretModel.PrimaryPart and TurretModel.PrimaryPart.CFrame)) :Lerp(desiredTurretCf, frac)
	pcall(function()
		if TurretModel and TurretModel.PrimaryPart then
			local pos = TurretModel.PrimaryPart.Position
			local look = Vector3.new(newTurretCf.LookVector.X, 0, newTurretCf.LookVector.Z)
			if look.Magnitude < 1e-6 then look = TurretModel.PrimaryPart.CFrame.LookVector end
			TurretModel:SetPrimaryPartCFrame(CFrame.new(pos, pos + look))
		elseif turretPart then
			local pos = turretPart.Position
			local look = Vector3.new(newTurretCf.LookVector.X, 0, newTurretCf.LookVector.Z)
			if look.Magnitude < 1e-6 then look = turretPart.CFrame.LookVector end
			turretPart.CFrame = CFrame.new(pos, pos + look)
		end
	end)

	-- barrel pitch: aim from muzzle (preferred) else from barrelPart center
	local muzzlePos = nil
	if muzzleAttachment and muzzleAttachment.WorldPosition then muzzlePos = muzzleAttachment.WorldPosition
	elseif gunAttachment and gunAttachment.WorldPosition then muzzlePos = gunAttachment.WorldPosition
	elseif barrelPart then muzzlePos = barrelPart.Position
	elseif BarrelModel and BarrelModel.PrimaryPart then muzzlePos = BarrelModel.PrimaryPart.Position
	else muzzlePos = turretPos end

	local aimDir = targetPos - muzzlePos
	if aimDir.Magnitude < 1e-6 then aimDir = (barrelPart and barrelPart.CFrame.LookVector) or Vector3.new(0,0,1) end

	-- desired pitch angle (radians)
	local horizDist = Vector3.new(aimDir.X, 0, aimDir.Z).Magnitude
	local desiredPitch = 0
	if horizDist > 1e-6 or math.abs(aimDir.Y) > 1e-6 then
		desiredPitch = math.atan2(aimDir.Y, math.max(0.0001, horizDist))
	end
	-- clamp pitch to configured deg range
	local minP = math.rad(PITCH_MIN_DEG)
	local maxP = math.rad(PITCH_MAX_DEG)
	desiredPitch = math.clamp(desiredPitch, minP, maxP)

	-- derive turret horizontal forward after yaw step
	local turretForward = (TurretModel and TurretModel.PrimaryPart and TurretModel.PrimaryPart.CFrame.LookVector) or (turretPart and turretPart.CFrame.LookVector) or Vector3.new(0,0,1)
	local forward2D = Vector3.new(turretForward.X, 0, turretForward.Z)
	if forward2D.Magnitude < 1e-6 then forward2D = Vector3.new(0,0,1) end
	forward2D = forward2D.Unit

	-- build new look vector using desiredPitch (relative to turret forward)
	local cosP = math.cos(desiredPitch)
	local lookVec = Vector3.new(forward2D.X * cosP, math.sin(desiredPitch), forward2D.Z * cosP)
	if lookVec.Magnitude < 1e-6 then lookVec = turretForward end

	-- create desired barrel CFrame and LERP based on pitch speed
	local desiredBarrelCf = CFrame.new((barrelPart and barrelPart.Position) or (BarrelModel and BarrelModel.PrimaryPart and BarrelModel.PrimaryPart.Position) or muzzlePos,
		((barrelPart and barrelPart.Position) or muzzlePos) + lookVec)
	local pitchRemainAngle = angleDeg((barrelPart and barrelPart.CFrame.LookVector) or (BarrelModel and BarrelModel.PrimaryPart and BarrelModel.PrimaryPart.CFrame.LookVector) or Vector3.new(0,0,1), lookVec)
	local maxPitchStep = math.rad(PITCH_SPEED) * dt
	local fracP = (pitchRemainAngle <= 0.5) and 1 or math.clamp((maxPitchStep * 180 / math.pi) / math.max(pitchRemainAngle, 0.0001), 0, 1)
	local currentBarrelCf = (barrelPart and barrelPart.CFrame) or (BarrelModel and BarrelModel.PrimaryPart and BarrelModel.PrimaryPart.CFrame) or CFrame.new(muzzlePos)
	local newBarrelCf = currentBarrelCf:Lerp(desiredBarrelCf, fracP)

	pcall(function()
		if BarrelModel and BarrelModel.PrimaryPart then
			BarrelModel:SetPrimaryPartCFrame(newBarrelCf)
		elseif barrelPart then
			barrelPart.CFrame = newBarrelCf
		end
	end)

	-- compute remaining angles
	local curYawRem = angleDeg(Vector3.new((TurretModel and TurretModel.PrimaryPart and TurretModel.PrimaryPart.CFrame.LookVector or turretPart.CFrame.LookVector).X,0,
		(TurretModel and TurretModel.PrimaryPart and TurretModel.PrimaryPart.CFrame.LookVector or turretPart.CFrame.LookVector).Z), Vector3.new(desiredLook.X,0,desiredLook.Z))
	local curPitchRem = angleDeg((BarrelModel and BarrelModel.PrimaryPart and BarrelModel.PrimaryPart.CFrame.LookVector or barrelPart.CFrame.LookVector), lookVec)
	return curYawRem, curPitchRem
end

-- spawn bullet from muzzle toward targetHRP
local function spawnBulletAt(targetHRP)
	if not muzzleAttachment or not EnemyBullet then return end
	local muzzleCf = muzzleAttachment.WorldCFrame
	local targetPos = (targetHRP and targetHRP.Position) or (muzzleCf.Position + muzzleCf.LookVector * 100)
	local dir = targetPos - muzzleCf.Position
	if dir.Magnitude <= 1e-6 then dir = muzzleCf.LookVector end
	dir = dir.Unit

	local bullet = EnemyBullet:Clone()
	local bp = bullet:IsA("BasePart") and bullet or (bullet.PrimaryPart or bullet:FindFirstChildWhichIsA("BasePart", true))
	if not bp then
		bullet.Parent = Workspace
		Debris:AddItem(bullet, 2)
		return
	end

	bullet.Parent = Workspace
	if bullet:IsA("BasePart") then
		bullet.CFrame = muzzleCf
	else
		bullet:SetPrimaryPartCFrame(muzzleCf)
	end

	-- use BodyVelocity for consistent motion
	local topPart = bp
	local bv = topPart:FindFirstChildOfClass("BodyVelocity")
	if not bv then
		bv = Instance.new("BodyVelocity")
		bv.MaxForce = Vector3.new(1e5,1e5,1e5)
		bv.P = 3000
		bv.Parent = topPart
	end
	bv.Velocity = dir * BULLET_SPEED

	-- touch handler
	local conn
	conn = topPart.Touched:Connect(function(hit)
		if not hit or not hit.Parent then return end
		local targetModel = hit:FindFirstAncestorWhichIsA("Model")
		if targetModel and targetModel.Parent == AlliancesFolder and targetModel ~= enemy then
			local h = targetModel:FindFirstChildOfClass("Humanoid")
			if h then pcall(function() h:TakeDamage(DAMAGE) end) end
			if conn then conn:Disconnect() end
			if topPart and topPart.Parent then topPart:Destroy() end
			return
		end
		local pl = Players:GetPlayerFromCharacter(hit.Parent)
		if pl and pl.Character then
			local h = pl.Character:FindFirstChildOfClass("Humanoid")
			if h then pcall(function() h:TakeDamage(DAMAGE) end) end
			if conn then conn:Disconnect() end
			if topPart and topPart.Parent then topPart:Destroy() end
			return
		end
	end)

	Debris:AddItem(bullet, BULLET_LIFE)
end

-- MAIN LOOP
local running = true
local lastFire = 0

spawn(function()
	playIdle()
	while running and hum.Health > 0 do
		hum.AutoRotate = true

		local target, dist = getClosestTank()
		if not target then
			playIdle()
			task.wait(0.25)
			continue
		end

		local targetHRP = target:FindFirstChild("HumanoidRootPart")
		if not targetHRP then task.wait(0.12); continue end

		-- approach until MAIN_DIST
		if dist > MAIN_DIST then
			playWalk()
			local ok, err = pcall(function() hum:MoveTo(targetHRP.Position) end)
			if not ok then dbg("MoveTo failed:", err) end
		else
			-- stop and idle
			pcall(function() hum:MoveTo(hrp.Position) end)
			playIdle()
		end

		-- aim & fire if within RANGE
		if dist <= RANGE and (turretPart or TurretModel) and (barrelPart or BarrelModel) and muzzleAttachment and EnemyBullet then
			local yawRem, pitchRem = aimAt(targetHRP.Position, 0.06)
			if yawRem <= 8 and pitchRem <= 12 and (tick() - lastFire) >= RELOAD then
				lastFire = tick()
				spawn(function() spawnBulletAt(targetHRP) end)
			end
		end

		task.wait(0.06)
	end
end)

-- Cleanup on death
hum.Died:Connect(function()
	running = false
	dbg("💀 Enemy "..enemy.Name.." destroyed.")
	for _, p in ipairs(enemy:GetDescendants()) do
		if p:IsA("BasePart") then
			p.Anchored = false
			p.CanCollide = true
		end
	end
	local explosion = Instance.new("Explosion")
	explosion.Position = enemy:GetPivot().Position
	explosion.BlastRadius = 0
	explosion.BlastPressure = 0
	explosion.Parent = workspace
	Debris:AddItem(enemy, 2)
end)

-- HeliCoins reward hook
local humanoid = enemy:WaitForChild("Humanoid")
humanoid.Died:Connect(function()
	local reward = tonumber(enemy:GetAttribute("HeliCoins")) or 75
	if _G and type(_G.HeliCoinsReward) == "function" then
		pcall(function() _G.HeliCoinsReward(enemy, reward) end)
	end
end)