-- LUA Script - precede every function and global member with lowercase name of script + '_main'
local U = require "scriptbank\\utillib"
local Q = require "scriptbank\\quatlib"

local rad = math.rad
local deg = math.deg

local loco_list = {}

function loco_init( e )
	Include( "utillib.lua" )
	loco_list[ e ] = nil
end

-- 0.2 degree up rotate 
local rotQuat = Q.FromEuler( 0, rad( 0.2 ), 0 )

function loco_main( e )
	local de = loco_list[ e ] 
	local Ent = g_Entity[e]
	
	if de == nil then
		loco_list[ e ] = { state = 'init', timer = math.huge, smokeOn = false,
						   quat = Q.FromEuler( rad( Ent.anglex ), rad( Ent.angley ), rad( Ent.anglez ) ) }
		return
	end
	
	if de.state == 'init' then
		-- register for dynamic entities
		if DE_Register == nil then return end
		
		-- four dust puff decals for 'smoke'
		DE_Register( e, 'Dust Puff' )
		DE_Register( e, 'Dust Puff' )
		DE_Register( e, 'Dust Puff' )
		DE_Register( e, 'Dust Puff' )

		de.state = 'show'
		
		-- wait 5 seconds
		de.timer = g_Time + 5000
		return
	end
	
	if de.state == 'show' then 
		DE_Show( e, 'Dust Puff' )
		
		de.state = 'idle'
	
	end
	
		
	local nx, ny, nz = Ent.x, Ent.y, Ent.z

	if de.state == 'idle' and g_Time > de.timer then
	
		if not de.smokeOn then 
			StartParticleEmitter( DE_GetEnts( e, 'Dust Puff' )[ 1 ] )
			de.smokeOn = true
		end
		
		-- apply rotation
		de.quat = Q.Mul( de.quat, rotQuat )
		
		-- get new Euler angles
		local xa, ya, za = Q.ToEuler( de.quat )
		
		-- move forward by 2 units (train is 'backwards so we use -ve value)
		local XO, YO, ZO = U.Rotate3D( 0, 0, -2, xa, ya, za )
		nx, ny, nz = nx + XO, ny + YO, nz + ZO
		
		-- reposition loco
		CollisionOff( e )
		ResetRotation( e, deg( xa ), deg( ya ), deg( za ) )
		ResetPosition( e, nx, ny, nz )
		CollisionOn( e )

	end

	-- update 'attached' decals
	DE_Update( e, nx, ny, nz, de.quat ) 
	
end