Air Quality Index (AQI)

# @name    AQI Air Quality
# @desc    AQI Value from aqicn.org (WAQI API)
# @author  zap21 / claude
# @version 1.2
# @config  station text   "Station Code"     default="germany/hamburg/flughafen"
# @config  token   text   "API Token"        default="YOUR_TOKEN" maxlen=64
# @config  every   number "Request Interval" default=10 min=1 max=1440 unit=min
# @config  ic      text   "Icon ID"          default="74824"

# get TOKEN from https://aqicn.org/api/
# get Station Code (or name) from https://aqicn.org/

class Waqi
  var url, period
  var aqi                  # last known AQI value, nil until first successful request
  var label, tint
  var ic
  var ticks, in_flight
  var last_status          # last HTTP error code

  def duration()
    return 3000            # linger for 3 s (durationMS)
  end

  def init()
    self.url = "http://api.waqi.info/feed/" + store.get("station") +
               "/?token=" + store.get("token")
    self.period = store.get("every") * 60
    self.ic = store.get("ic")
    #self.aqi = store.get("aqi")
    self.tint = self.aqi == nil ? 0xFFFFFF : self.color_for(self.aqi)
    self.label = self.aqi == nil ? nil : "qi:" + str(self.aqi)
    self.ticks = 0
    self.in_flight = false
    self.last_status = 0
  end

  def color_for(v)
    if   v < 0    return 0xFFFFFF
    elif v <= 50  return 0x009966
    elif v <= 100 return 0xFFDE33
    elif v <= 150 return 0xFF9933
    elif v <= 200 return 0xCC0033
    elif v <= 300 return 0x660099
    else          return 0x7E0023
    end
  end

  def on_body(body, status)
    self.in_flight = false
    self.last_status = status
    if body == nil return end                   # no success, show old value
    var m = re.search("\"aqi\":([0-9]+)", body) # "aqi":6,... -> 6
    if m == nil return end
    var v = int(num(m[1]))
    self.aqi = v
    self.tint = self.color_for(v)
    self.label = "qi:" + str(v)
    #store.set("aqi", v)                         # store if valid
  end

  def loop()
    if self.ticks <= 0
      self.ticks = self.period
      if !self.in_flight
        self.in_flight = true
        http.get(self.url, / b, st -> self.on_body(b, st),
                 {'find': "\"aqi\":", 'keep': 16})
      end
    end
    self.ticks -= 1
  end

  def draw()
    clear()
    if self.label == nil
      if self.last_status != 0
        text(1, 6, "e:" + str(self.last_status), 0xFF0000)   # show error code
      else
        text(1, 6, "...", 0x666666)                          # no value yet
      end
      return
    end
    if !icon(self.ic, 0, 0)
      rect_fill(0, 0, 8, 8, 0x222222)                        # fallback if icon is missing
    end
    var area = width() - 9                                   # width minus icon size
    var x = 9 + (area - text_ink_width(self.label)) / 2      # centered text
    if x < 9 x = 9 end                                       # stay away from the icon
    text(x, 6, self.label, self.tint)
  end

  def on_button(btn)
    if btn == "select" self.ticks = 0 end                    # force refresh
  end
end

return Waqi()