--===============================================================
-- Top-Speed Horus widget. Displays fastest speed during the
-- current flight. The 'SH' momentary switch will call-out 
-- the current top speed.
-- 
-- Defaults to Imperial (MPH). If you want to change to metric
-- (KPH) changed the Units variable on line 28. To change the
-- switch that is used for the call-out, change line 69
-- 
-- T3chDad® August-2018     ****NON-COMMERCIAL USE ONLY****
--===============================================================

local defaultOptions = {
}

local function getTelemetryId(name)
    field = getFieldInfo(name)
    if field then
      return field.id
    else
      return -1
    end
end

local TopSpeed = 0
--==================================
-- Units: use either "mph" or "kph"
local Units = "mph"
--==================================
local block = 0
local function createWidget(zone, options)
	TopSpeed = 0
	return { zone=zone, options=options }
end

local function updateWidget(widgetToUpdate, newOptions)
	widgetToUpdate.options = newOptions
	updateSpeed(widgetToUpdate)
end

local function backgroundProcessWidget(widgetToProcessInBackground)
	updateSpeed(widgetToProcessInBackground)
end

local function round(num, numDecimalPlaces)
	local mult = 10^(numDecimalPlaces or 0)
	return math.floor(num * mult + 0.5) / mult
end

function updateSpeed(widget)
    local TelID = getTelemetryId("GSpd")
	x = widget.zone.x
	y = widget.zone.y
	if TelID == -1 then
		lcd.drawText(x, y, "No Speed Sensor",MIDSIZE)
	else
		local spd = getValue(TelID)
		--conversion from KNOTS to MPH
		if Units == "mph" then 
			spd = round(spd * 1.150, 1)
		else
		--conversion from KNOTS to KPH	
			spd = round(spd * 1.852, 1)
		end
		if spd > TopSpeed then
			TopSpeed = spd
		end
		-- Change the 'sh' on the next line to change the switch used for call-out
		if getValue('sh') > 800 then
			if getTime() > block + 300 then
				block = getTime()
				if Units == "mph" then
					playNumber(TopSpeed * 10, UNIT_MPH, PREC1)
				else
					playNumber(TopSpeed * 10, UNIT_KMH, PREC1)
				end
			end
		end	
		lcd.drawText(x,y,"Top Speed", SMLSIZE)
		lcd.drawText(x,y+13,TopSpeed..Units,MIDSIZE)		
	end
end

local function refreshWidget(widgetToRefresh)
	updateSpeed(widgetToRefresh)
end

return { name="Top-Speed", options=defaultOptions, create=createWidget, update=updateWidget, refresh=refreshWidget, background=backgroundProcessWidget }