--json = require "json"
json = require "JSON"

tibber_rates  = 'tibber_rates_20230318.json'
power_profile = 'bosch_program_1.power_profile'


function fmt( t )

 res = ''

 if t >= 24
  then
   t = t - 24
   res = '+'
  end

 return res .. t

end -- function fmt


function to_eur( x )

 return math.floor( x * 100 + 0.5 ) / 100

end -- function fmt


file = io.open(  tibber_rates, 'rb' )
txt = file:read '*a'

--res = json.decode( txt )
res = json:decode( txt )

prices = {}

for x, y in pairs( res["data"]["viewer"]["homes"][1]["currentSubscription"]["priceInfo"][ "today" ] )
 do
  prices[ x - 1 ] = y[ "total" ]
end

for x, y in pairs( res["data"]["viewer"]["homes"][1]["currentSubscription"]["priceInfo"][ "tomorrow" ] )
 do
  prices[ x - 1 + 24 ] = y[ "total" ]
 end

min_start = math.huge
min_price = math.huge

max_start = -math.huge
max_price = -math.huge

for h = os.date("*t").hour * 10, 460 -- search from now, interval: 1/10 h = 6 min
 do

  i=0

  cost = 0

  last_p = 0
  last_t = 0

  for l in io.lines( power_profile )
   do

    if i > 2 -- skip header
     then

      t =  tonumber( string.sub( l,  1, 10 ) )
      p =  tonumber( string.sub( l, 60, 99 ) )

      if i == 3 then profile_start_time = t end -- shift power_profile to t = 0

      t = t - profile_start_time + h / 10 * 3600

	  if last_t ~= 0
	   then

	    h_temp = math.floor( t / 3600 )

        cost = cost + ( p + last_p ) / 2 * ( t - last_t ) *  prices[ math.floor( t / 3600 ) ] / 1000 / 3600

       end

      last_p = p
	  last_t = t

     end

    i = i +1

   end -- for l in io.lines

  if cost < min_price
   then

    min_price = cost
    min_start = h

   end

  if cost > max_price
   then

    max_price = cost
    max_start = h

   end

 end -- for h

print( '', 'hour', 'total cost' )

print( 'max: ', fmt( max_start/10 ), to_eur( max_price ) )
print( 'min: ', fmt( min_start/10 ), to_eur( min_price ) )

print ( 'max-min: ', to_eur( max_price - min_price ) )