(function() {
  let medianPressure;
  let threeHourAvrPressure;
  let currentPressures = [];

  const LOG_FILE = "widbaroalarm.log.json";
  const SETTINGS_FILE = "widbaroalarm.json";
  const storage = require('Storage');

  let settings;

  function loadSettings() {
    settings = Object.assign(
      storage.readJSON("widbaroalarm.default.json", true) || {},
      storage.readJSON(SETTINGS_FILE, true) || {}
    );
  }

  loadSettings();


  function setting(key) {
    return settings[key];
  }

  function saveSetting(key, value) {
    settings[key] = value;
    storage.write(SETTINGS_FILE, settings);
  }

  const interval = setting("interval");

  let history3 = storage.readJSON(LOG_FILE, true) || []; // history of recent 3 hours

  function showAlarm(body, title) {
    if (body == undefined) return;

    require("notify").show({
      title: title || "Pressure",
      body: body,
      icon: require("heatshrink").decompress(atob("jEY4cA///gH4/++mkK30kiWC4H8x3BGDmSGgYDCgmSoEAg3bsAIDpAIFkmSpMAm3btgIFDQwIGNQpTYkAIJwAHEgMoCA0JgMEyBnBCAW3KoQQDhu3oAIH5JnDBAW24IIBEYm2EYwACBCIACA"))
    });

    if (setting("buzz") &&
      !(storage.readJSON('setting.json', 1) || {}).quiet) {
      Bangle.buzz();
    }
  }


  function didWeAlreadyWarn(key) {
    return setting(key) == undefined || setting(key) > 0;
  }

  function checkForAlarms(pressure) {
    if (pressure == undefined || pressure <= 0) return;

    let alreadyWarned = false;

    const ts = Math.round(Date.now() / 1000); // seconds
    const d = {
      "ts": ts,
      "p": pressure
    };

    // delete entries older than 3h
    for (let i = 0; i < history3.length; i++) {
      if (history3[i]["ts"] < ts - (3 * 60 * 60)) {
        history3.shift();
      }
    }
    // delete oldest entries until we have max 50
    while (history3.length > 50) {
      history3.shift();
    }

    if (setting("lowalarm")) {
      // Is below the alarm threshold?
      if (pressure <= setting("min")) {
        if (!didWeAlreadyWarn("lastLowWarningTs")) {
          showAlarm("Pressure low: " + Math.round(pressure) + " hPa");
          saveSetting("lastLowWarningTs", ts);
          alreadyWarned = true;
        }
      } else {
        saveSetting("lastLowWarningTs", 0);
      }
    } else {
      saveSetting("lastLowWarningTs", 0);
    }

    if (setting("highalarm")) {
      // Is above the alarm threshold?
      if (pressure >= setting("max")) {
        if (!didWeAlreadyWarn("lastHighWarningTs")) {
          showAlarm("Pressure high: " + Math.round(pressure) + " hPa");
          saveSetting("lastHighWarningTs", ts);
          alreadyWarned = true;
        }
      } else {
        saveSetting("lastHighWarningTs", 0);
      }
    } else {
      saveSetting("lastHighWarningTs", 0);
    }

    if (history3.length > 0 && !alreadyWarned) {
      // 3h change detection
      const drop3halarm = setting("drop3halarm");
      const raise3halarm = setting("raise3halarm");
      if (drop3halarm > 0 || raise3halarm > 0) {
        // we need at least 30min of data for reliable detection
        if (history3[0]["ts"] > ts - (30 * 60)) {
          return;
        }

        // Get oldest entry:
        const oldestPressure = history3[0]["p"];
        if (oldestPressure != undefined && oldestPressure > 0) {
          const diff = oldestPressure - pressure;

          // drop alarm
          if (drop3halarm > 0 && oldestPressure > pressure) {
            if (Math.abs(diff) > drop3halarm) {
              if (!didWeAlreadyWarn("lastDropWarningTs")) {
                showAlarm((Math.round(Math.abs(diff) * 10) / 10) + " hPa/3h from " +
                  Math.round(oldestPressure) + " to " + Math.round(pressure) + " hPa", "Pressure drop");
                saveSetting("lastDropWarningTs", ts);
              }
            } else {
              saveSetting("lastDropWarningTs", 0);
            }
          } else {
            saveSetting("lastDropWarningTs", 0);
          }

          // raise alarm
          if (raise3halarm > 0 && oldestPressure < pressure) {
            if (Math.abs(diff) > raise3halarm) {
              if (!didWeAlreadyWarn("lastRaiseWarningTs")) {
                showAlarm((Math.round(Math.abs(diff) * 10) / 10) + " hPa/3h from " +
                  Math.round(oldestPressure) + " to " + Math.round(pressure) + " hPa", "Pressure raise");
                saveSetting("lastRaiseWarningTs", ts);
              }
            } else {
              saveSetting("lastRaiseWarningTs", 0);
            }
          } else {
            saveSetting("lastRaiseWarningTs", 0);
          }
        }
      }
    }

    history3.push(d);
    // write data to storage
    storage.writeJSON(LOG_FILE, history3);

    // calculate 3h average for widget
    let sum = 0;
    for (let i = 0; i < history3.length; i++) {
      sum += history3[i]["p"];
    }
    threeHourAvrPressure = sum / history3.length;
  }



  function baroHandler(data) {
    if (data) {
      const pressure = Math.round(data.pressure);
      if (pressure == undefined || pressure <= 0) return;
      currentPressures.push(pressure);
    }
  }

  /*
   turn on barometer power
   take 5 measurements
   sort the results
   take the middle one (median)
   turn off barometer power
  */
  function check() {
    Bangle.setBarometerPower(true, "widbaroalarm");
    setTimeout(function() {
      currentPressures = [];

      Bangle.getPressure().then(baroHandler);
      Bangle.getPressure().then(baroHandler);
      Bangle.getPressure().then(baroHandler);
      Bangle.getPressure().then(baroHandler);
      Bangle.getPressure().then(baroHandler);

      setTimeout(function() {
        Bangle.setBarometerPower(false, "widbaroalarm");

        currentPressures.sort();

        // take median value
        medianPressure = currentPressures[3];
        checkForAlarms(medianPressure);
      }, 1000);
    }, 500);
  }

  function reload() {
    check();
  }

  function draw() {
    if (global.WIDGETS != undefined && typeof WIDGETS === "object") {
      WIDGETS["baroalarm"] = {
        width: setting("show") ? 24 : 0,
        reload: reload,
        area: "tr",
        draw: draw
      };
    }

    g.reset();
    if (setting("show") && medianPressure != undefined) {
      g.setFont("6x8", 1).setFontAlign(1, 0);
      g.drawString(Math.round(medianPressure), this.x + 24, this.y + 6);
      if (threeHourAvrPressure != undefined && threeHourAvrPressure > 0) {
        g.drawString(Math.round(threeHourAvrPressure), this.x + 24, this.y + 6 + 10);
      }
    }
  }

  // Let's delay the first check a bit
  setTimeout(function() {
    check();
    if (interval > 0) {
      setInterval(check, interval * 60000);
    }
  }, 1000);

})();