local thirdperson = CreateConVar("3rdperson", "0", FCVAR_USERINFO)

local m_yaw = GetConVar("m_yaw"):GetFloat()
local m_pitch = GetConVar("m_pitch"):GetFloat()
local view_angle, view_origin = EyeAngles(), EyePos()

hook.Add("CalcView", "Cool 3rd Person", function(ply, origin, angles)
	if not thirdperson:GetBool() then return end

	-- Use a hull trace to prevent the camera clipping through the world
	view_origin = util.TraceHull({
		start = origin,
		endpos = origin - view_angle:Forward() * 100 + view_angle:Right() * 15,
		filter = ply,
		mask = MASK_SHOT,
		mins = Vector(-5, -5, -5),
		maxs = Vector(5, 5, 5),
	}).HitPos

	return {
		angles = view_angle, -- Set the camera view to the calculated angle
		origin = view_origin, -- Set the origin to be thirdperson
		drawviewer = true,
	}
end)

hook.Add("StartCommand", "Cool 3rd Person", function(ply, cmd)
	if not thirdperson:GetBool() then return end

	-- We need to calculate mouse movement ourselves since we need to set the view angles
	view_angle = view_angle + Angle(cmd:GetMouseY() * m_pitch, cmd:GetMouseX() * -m_yaw, 0)
	view_angle[1] = math.Clamp(view_angle[1], -89, 89)
	view_angle[2] = math.NormalizeAngle(view_angle[2])

	-- Movement will get wonky in any other MOVETYPE
	if ply:GetMoveType() == MOVETYPE_WALK then
		-- Run a trace from the 3rd person camera
		local view_trace = util.TraceLine({
			start = view_origin,
			endpos = view_origin + view_angle:Forward() * 1e4,
			filter = ply,
			mask = MASK_SHOT,
		}).HitPos

		-- Update view angles so we're facing where the camera trace hit
		cmd:SetViewAngles((view_trace - ply:GetShootPos()):Angle())

		-- Because we've meddled with the view angle we need to update the movement so it works as expected
		local move_fix = Vector(cmd:GetForwardMove(), cmd:GetSideMove(), 0)
		move_fix = (move_fix:Angle() + (cmd:GetViewAngles() - view_angle)):Forward() * move_fix:Length()

		cmd:SetForwardMove(move_fix[1])
		cmd:SetSideMove(move_fix[2])
	else
		cmd:SetViewAngles(view_angle)
	end
end)