collectgarbage()
 
local model = " "
local sensor_label_rows
local measure = false
local measure_switch = 0
local integral_switch = 0;
local app_name = "Eigensinken"
local sensorId, vario_param, altitude_param
local timestamp, diff_time
local vario_value, min_vario_value, max_vario_value, vario_integral_value = 0.0, 0.0, 0.0, 0.0
local altitude_start, altitude_end = 0, 0
local flight = {}
local flight_num, flight_index = 0, 0
local last_integral_time = 0
local vario_value_list = {}

local function Page1(width, height)
		
    if( system.getTime() % 2 == 0 and measure ) then
		lcd.drawText(1, 1, " Flugnr.    Zeit     MinVar    MaxVar   ØSteigen", FONT_BOLD|FONT_REVERSED )
	else
		lcd.drawText(1, 1, " Flugnr.    Zeit     MinVar    MaxVar   ØSteigen", FONT_BOLD )
	end	
	
	if ( #flight ) then

		for i = 1, #flight do
			
			lcd.drawText (40 - lcd.getTextWidth (FONT_NORMAL, string.format("%3d", flight[i]["num"] )), flight[i]["line_offs"],
			         string.format("%3d",flight[i]["num"]), FONT_NORMAL )
					 
			lcd.drawText (105 - lcd.getTextWidth (FONT_NORMAL, string.format("%4.2f", flight[i]["time"] )), flight[i]["line_offs"],
			         string.format("%4.2f",flight[i]["time"]), FONT_NORMAL )
			
		    lcd.drawText (170 - lcd.getTextWidth (FONT_NORMAL, string.format("%3.2f", flight[i]["min"] )), flight[i]["line_offs"],
			         string.format("%3.2f",flight[i]["min"]), FONT_NORMAL )
				
			lcd.drawText (235 - lcd.getTextWidth (FONT_NORMAL, string.format("%3.2f", flight[i]["max"] )), flight[i]["line_offs"],
			         string.format("%3.2f",flight[i]["max"]), FONT_NORMAL )

			lcd.drawText (300 - lcd.getTextWidth (FONT_NORMAL, string.format("%3.2f", flight[i]["average"] )), flight[i]["line_offs"],
			         string.format("%3.2f",flight[i]["average"]), FONT_NORMAL )
		end
	end
end

local function sensorChanged(value)
	sensorId  = sensor_label_rows[value].id
	system.pSave("sensorId", sensorId)
	vario_param = 1     -- prevent error if previous index was higher than possible in this new sensor
	altitude_param = 1  -- prevent error if previous index was higher than possible in this new sensor
	form.reinit()
end

local function paramVarioChanged(value)
	vario_param = value
	system.pSave("vario_param", vario_param)
end

local function paramAltitudeChanged(value)
	altitude_param = value
	system.pSave("altitude_param", altitude_param)
end	

local function measure_switchChanged(value)
	measure_switch = value
	system.pSave("measure_switch", measure_switch)
end

local function integral_switchChanged(value)
	integral_switch = value
	system.pSave("integral_switch", integral_switch)
end

local function setupForm(formID)
    
	local sensor_label_list = {}
	local sensorIndex=-1
	local sensor_parm_lists = {}
	
	local all_sensor_rows = system.getSensors()
	
	sensor_label_rows = {}  -- scope: this script
		
	for index,sensor in ipairs(all_sensor_rows) do
		
		if ( not ( sensor.type == 5 or sensor.type == 9 ) ) then         -- no GPS no Date Time used
			if ( sensor.param == 0) then
				
				sensor_label_list[#sensor_label_list + 1] = sensor.label -- list presented in select box
				sensor_label_rows[#sensor_label_rows + 1] = sensor       -- to get id from this header table, it has same index as list
				
				if(sensor.id==sensorId ) then                            -- mem index of  
					sensorIndex=#sensor_label_rows                       -- already selected entry for preselect in selectbox
				end
			
				sensor_parm_lists[#sensor_parm_lists + 1] = {}           -- start new param list only containing label and unit as string
			else                                                         -- subscript is number of param for current multisensor
				sensor_parm_lists[#sensor_parm_lists][sensor.param] = sensor.label .. "  " .. sensor.unit -- list presented in select box
			end
		end
	end

    form.setTitle("Telemetrieeinstellungen")
	
	form.addRow(1)
    form.addLabel({label="Sensor- und Parameterwahl",font=FONT_BOLD})
	    
    form.addRow(2)
    form.addLabel({label = "Sensor", width=200})
    form.addSelectbox(sensor_label_list, sensorIndex, true, sensorChanged)
	
	if ( sensor_label_rows and sensorIndex > 0 ) then

		form.addRow(2)
		form.addLabel({label = "Parameter Vario", width=200})
		form.addSelectbox(sensor_parm_lists[sensorIndex], vario_param, true, paramVarioChanged)
		
		form.addRow(2)
		form.addLabel({label = "Parameter Höhe", width=200})
		form.addSelectbox(sensor_parm_lists[sensorIndex], altitude_param, true, paramAltitudeChanged)
	end	
	
	form.addSpacer(318,7)
	
	form.addRow(1)
	form.addLabel({label="Schalterwahl",font=FONT_BOLD})
	
	form.addRow(2)
	form.addLabel({label="Messung An", width=220})
	form.addInputbox(measure_switch,true,measure_switchChanged)
	
	form.addRow(2)
	form.addLabel({label="Min/Max 1 Sek. integriert An", width=220})
	form.addInputbox(integral_switch,true,integral_switchChanged)
	
	form.addSpacer(318,7)
	
	form.addRow(1)
	form.addLabel({label="Eigensinken " .. Version .. " ", font=FONT_MINI, visible=true, alignRight=true})
	
	collectgarbage()
end


function average(value) -- integral vario helper
    
	local sum_vario_values = 0
	local vario
	local i
	
	if ( #vario_value_list == 100 ) then
		table.remove(vario_value_list, 1)
	end    
	
	vario_value_list[#vario_value_list + 1] = value
	
	for i,vario_value in ipairs(vario_value_list) do
		sum_vario_values = sum_vario_values + vario_value
	end
	
	collectgarbage()
	return sum_vario_values / #vario_value_list
end    

 
local function loop()
	
	local sensor
	local avr_timestamp
	
	if ( 1 == system.getInputsVal(measure_switch) ) then

		-- transition to measure state
		if ( measure == false ) then
			measure = true
			timestamp = system.getTimeCounter()
			
			sensor = system.getSensorValueByID(sensorId, altitude_param)
			if ( sensor and sensor.valid ) then
			--if ( sensor ) then                                                        --fake valid sensor
				altitude_start = sensor.value
				--altitude_start = system.getInputs ("P6") * 100 + 100                  --fake altitude
			else
				altitude_start = 0.0
		    end		
			
			min_vario_value = 100
			max_vario_value = -100
			vario_value_list = {}
			
			system.playBeep( 0, 1200, 500 )
	    end
		
		sensor = system.getSensorValueByID(sensorId, vario_param)
		if ( sensor and sensor.valid ) then
		--if ( sensor) then                                                             --fake valid sensor
			vario_value = sensor.value
			--vario_value = system.getInputs ("P8") * 10                                --fake vario
 
			if ( 1 == system.getInputsVal(integral_switch) ) then
				avr_timestamp = system.getTimeCounter()
				if avr_timestamp >= (last_integral_time + 10) then  -- one 1/100 second period
					vario_integral_value = average(vario_value)     -- average integral vario over 100 samples with 1/100 sencond period ( ie. 1 Sec )
					last_integral_time = avr_timestamp
				end

				if (vario_integral_value > max_vario_value ) then max_vario_value = vario_integral_value end
				if (vario_integral_value < min_vario_value ) then min_vario_value = vario_integral_value end
			else
				if (vario_value > max_vario_value ) then max_vario_value = vario_value end
				if (vario_value < min_vario_value ) then min_vario_value = vario_value end
			end	
		else
			vario = 0.0
		end
		
	else
		-- transition to non measure state
		if ( measure == true ) then
			measure = false
			
			diff_time = system.getTimeCounter() - timestamp

			sensor = system.getSensorValueByID(sensorId, altitude_param)
			if ( sensor and sensor.valid) then
			--if ( sensor ) then                                                        --fake valid sensor
				altitude_stop = sensor.value
				--altitude_stop = system.getInputs ("P6") * 100 + 100                   --fake altitude
			else
				altitude_stop = 0.0
			end	

			average_vario_value =  (altitude_stop - altitude_start) / ( diff_time / 1000 )
			
			if ( flight_index == 8 ) then
				flight_index = 0
			end
			
			flight_num = flight_num + 1
			flight_index = flight_index + 1
			
			flight[flight_index] = {}
			flight[flight_index]["num"] = flight_num
			flight[flight_index]["line_offs"] = flight_index * 17 + 4
			flight[flight_index]["time"] = diff_time / 1000
			flight[flight_index]["min"] = min_vario_value
			flight[flight_index]["max"] = max_vario_value
			flight[flight_index]["average"] = average_vario_value
			
			system.playBeep( 1, 1200, 500 )
		end
	end
	               
	collectgarbage()
end

 
 local function init(code1)
	model = system.getProperty("Model") 
	measure_switch = system.pLoad("measure_switch")
	integral_switch = system.pLoad("integral_switch")
	vario_param = system.pLoad("vario_param", 2)
	altitude_param = system.pLoad("altitude_param", 2)
	sensorId = system.pLoad("sensorId")
	system.registerForm(1, MENU_APPS, app_name, setupForm)
	system.registerTelemetry(1, app_name .. "   " .. model, 4, Page1)

	collectgarbage()
end

Version = "1.2"
collectgarbage()
return {init=init, loop=loop, author="nichtgedacht", version=Version, name=app_name}