feat: add weather forecasting

lib/weather.rb

@@ -0,0 +1,64 @@
+class Weather
+  def self.get_weather(zone, hash = hash(get_seed))
+    total = 0
+    APP_DATA[zone][:weather].each do |arr|
+      name, rate = arr
+      if (total += rate) > hash
+        return name
+      end
+    end
+  end
+
+  def self.forecast(zone, seed = get_seed, count = 10)
+    res = []
+    prev_hash = hash(seed - 1)
+    prev_weather = get_weather(zone, prev_hash)
+    count.times do |_|
+      curr_hash = hash(seed)
+      curr_weather = get_weather(zone, curr_hash)
+      res.push({ zone: zone, prev_weather: prev_weather, curr_weather: curr_weather, weather_name: get_weather_name(curr_weather), seed: seed, time: Time.at(seed * 1400000.0 / 1000) })
+      prev_hash = curr_hash
+      prev_weather = curr_weather
+      seed += 1
+    end
+    res
+  end
+
+  def self.round_to_last_weather_time(time)
+    last_hour = time.hour / 8 * 8
+    time.change(hour: last_hour)
+  end
+
+  def self.get_weather_name(name)
+    case name
+    when "fair" then "Fair Skies"
+    when "showers" then "Showers"
+    when "gales" then "Gales"
+    when "blizzards" then "Blizzards"
+    when "heat" then "Heat"
+    when "thunder" then "Thunderstorms"
+    when "gloom" then "Gloom"
+    when "snow" then "Snow"
+    when "fog" then "Fog"
+    when "umbral_wind" then "Umbral Wind"
+    else "Unknown Weather"
+    end
+  end
+
+
+  def self.get_seed
+    (Time.now.utc.to_i * 1000 / 1400000.0).floor
+  end
+
+  def self.hash(seed = get_seed)
+    base = (seed / 3).floor * 100 + ((seed + 1) % 3) * 8
+    # Ruby has no other convenient way to convert a signed integer into an unsigned one
+    step1 = [ ((base << 11) ^ base) ].pack("L").unpack("L").first
+    step2 = [ (([ (step1 >> 8) ].pack("L").unpack("L").first.to_i ^ step1)) ].pack("L").unpack("L").first.to_i
+    step2 % 100
+  end
+
+  def self.unsigned_right(input, by)
+    input << by & 0xFF00 | input >> by & 0xFF
+  end
+end