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-- PZB 2000Hz Speed Warning Inductor
-- (goes next to Hp Signal)
-- Modified from Default KUJU PZB Script to make compatible with Default & vR Stock
-- SSD 5 Aug 2012
-- Also modified by HRQ 18 Aug 2012
-- Rev 1.0
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-- GLOBAL DEFINITIONS

-- Enable/Disable Script Debug Messages
DEBUG 				= false

-- Signal States
CLEAR 				= 0
WARNING 			= 1
BLOCKED 			= 2

-- Signal Messages
SIGNAL_BLOCKED  	= 12;
SIGNAL_CLEARED 		= 13;
SIGNAL_WARNING 		= 14;
SIGNAL_WARNING2 	= 15;

-- Consist Messages

-- Default Stock
MSG_DF_PZB1000		= "1000"
MSG_DF_PZB2000		= "2000"

-- vR Expert Line Stock
CUSTOM_MESSAGE 		= 15;
MSG_VR_PZB1000 		= "PZB1000";
MSG_VR_PZB500		= "PZB500";
MSG_VR_PZB2000 		= "PZB2000";


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-- INITIALISE
--
function Initialise ()
	DebugPrint( ("DEBUG: Initialise") )
	trainPassedSignal = false
	nextSignalMessageState = false
end

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-- ON CONSIST PASS
--
function OnConsistPass ( prevFrontDist, prevBackDist, frontDist, backDist, linkIndex )

	-- if the consist is crossing the inductor now
	if ( frontDist > 0 and backDist < 0 ) or ( frontDist < 0 and backDist > 0 ) then

		DebugPrint( ("DEBUG: PZB 2000Hz OnConsistPass ( pfd " .. prevFrontDist .. ", pbd " .. prevBackDist .. ", fd " .. frontDist .. ", bd " .. backDist .. ", li " .. linkIndex .. ")" ))
		-- if the consist was previously before siganl then the crossing has just started
		if (prevFrontDist > 0 and prevBackDist > 0) then

			if ( trainPassedSignal ~= true ) then

				trainPassedSignal = true

				if ( nextSignalMessageState == false ) then

					-- Request state of next signal
					local nextSignalState = Call( "GetNextSignalState", "", 1, 1, 0 )
					local nextDistantState = Call( "GetNextDistantState", "", 1, 1, 0 )
					DebugPrint( ("DEBUG: PZB 2000Hz OnConsistPass: Crossing started, next signal anim is " .. nextSignalState) )
					DebugPrint( ("DEBUG: PZB 2000Hz OnConsistPass: Crossing started, next distant anim is " .. nextDistantState) )

					-- If the signal ahead isn't clear...
					if ( nextSignalState == BLOCKED ) then
						--Call( "SendConsistMessage", CUSTOM_MESSAGE, MSG_VR_PZB2000 )
						Call( "SendConsistMessage", CUSTOM_MESSAGE, MSG_DF_PZB2000 )
					elseif ( nextDistantState ~= CLEAR ) then
						--Call( "SendConsistMessage", CUSTOM_MESSAGE, MSG_VR_PZB1000 )
						Call( "SendConsistMessage", CUSTOM_MESSAGE, MSG_DF_PZB1000 )
					end
				else
					if ( nextSignalMessageState == SIGNAL_BLOCKED ) then
						--Call( "SendConsistMessage", CUSTOM_MESSAGE, MSG_VR_PZB1000 )
						Call( "SendConsistMessage", CUSTOM_MESSAGE, MSG_DF_PZB1000 )
					end
				end
			end
		end
	else
		-- Reset once train has passed
		if ( trainPassedSignal ~= false ) then
			DebugPrint( ("DEBUG: PZB 2000Hz OnConsistPass: Crossing finished") )
			trainPassedSignal = false
		end
	end
end

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-- ON SIGNAL MESSAGE
--
function OnSignalMessage( message, parameter, direction, linkIndex )

	-- Forward every message unchanged, unless it's from a train straddling our link
	if ( parameter ~= "DoNotForward" ) then
		Call( "SendSignalMessage", message, parameter, -direction, 1, linkIndex )
	end
end

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-- JUNCTION STATE CHANGE
-- Left blank - PZB inductors only have one link
--
function OnJunctionStateChange( junction_state, parameter, direction, linkIndex )

end

function DebugPrint( message )
	if (DEBUG) then
		Print( message )
	end
end