1 files changed, 141 insertions, 0 deletions
diff --git a/src/ew.js b/src/ew.js
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index 0000000..3519be1
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+++ b/src/ew.js
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+import { aWeather, paWeather, pyWeather, hWeather } from "./stores";
+
+const WEATHER = {
+  FAIR: 0,
+  SHOWERS: 1,
+  GALES: 2,
+  BLIZZARDS: 3,
+  HEAT: 4,
+  THUNDER: 5,
+  GLOOM: 6,
+  SNOW: 7,
+  FOG: 8,
+  UMBRAL_WIND: 9,
+};
+
+// Anemos: 30/Fair, 30/Gales, 30/Showers, 10/Snowy
+const ANEMOS_WEATHER = [
+  [WEATHER.FAIR, 30],
+  [WEATHER.GALES, 30],
+  [WEATHER.SHOWERS, 30],
+  [WEATHER.SNOW, 10],
+];
+
+// Pagos: 10/Fair, 18/Fog, 18/Heat, 18/Snow, 18/Thunder, 18/Blizzards
+const PAGOS_WEATHER = [
+  [WEATHER.FAIR, 10],
+  [WEATHER.FOG, 18],
+  [WEATHER.HEAT, 18],
+  [WEATHER.SNOW, 18],
+  [WEATHER.THUNDER, 18],
+  [WEATHER.BLIZZARDS, 18],
+];
+
+// Pyros: 10/Fair, 18/Heat, 18/Thunder, 18/Blizzards, 18/Umbral Wind, 18/Snow
+const PYROS_WEATHER = [
+  [WEATHER.FAIR, 10],
+  [WEATHER.HEAT, 18],
+  [WEATHER.THUNDER, 18],
+  [WEATHER.BLIZZARDS, 18],
+  [WEATHER.UMBRAL_WIND, 18],
+  [WEATHER.SNOW, 18],
+];
+
+// Hydatos: 12/Fair, 22/Showers, 22/Gloom, 22/Thunder, 22/Snow
+const HYDATOS_WEATHER = [
+  [WEATHER.FAIR, 12],
+  [WEATHER.SHOWERS, 22],
+  [WEATHER.GLOOM, 22],
+  [WEATHER.THUNDER, 22],
+  [WEATHER.SNOW, 22],
+];
+
+function getWeatherName(weather) {
+  switch (weather) {
+    case 0:
+      return "Fair";
+    case 1:
+      return "Showers";
+    case 2:
+      return "Gales";
+    case 3:
+      return "Blizzards";
+    case 4:
+      return "Heat";
+    case 5:
+      return "Thunder";
+    case 6:
+      return "Gloom";
+    case 7:
+      return "Snow";
+    case 8:
+      return "Fog";
+    case 9:
+      return "Umbral Wind";
+    default:
+      return "Unknown";
+  }
+}
+
+function getSeed(date = new Date()) {
+  return Math.floor(date.getTime() / 1400000);
+}
+
+function hash(seed = getSeed()) {
+  const base = Math.floor(seed / 3) * 100 + ((seed + 1) % 3) * 8;
+  const step1 = ((base << 11) ^ base) >>> 0;
+  const step2 = ((step1 >>> 8) ^ step1) >>> 0;
+  return step2 % 100;
+}
+
+function hashSeq(seed = getSeed(), count = 10) {
+  const hashes = [];
+  for (let i = 0; i < count; ++i) {
+    hashes.push(hash(seed + i));
+  }
+  return hashes;
+}
+
+function getWeather(rates, hash = hashSeed()) {
+  let total = 0;
+  for (const [weather, chance] of rates) {
+    if ((total += chance) > hash) {
+      return weather;
+    }
+  }
+  return WEATHER.FAIR;
+}
+
+function forecast(rates, seed = getSeed(), count = 10) {
+  const res = [];
+  let prevHash = hash(seed - 1);
+  let prevWeather = getWeather(rates, prevHash);
+
+  for (let i = 0; res.length < count && i < 100000; ++i) {
+    const currHash = hash(seed);
+    const currWeather = getWeather(rates, currHash);
+    res.push({
+      prevWeather,
+      currWeather,
+      weatherName: getWeatherName(currWeather),
+      seed,
+      date: new Date(seed * 1400000),
+    });
+    prevHash = currHash;
+    prevWeather = currWeather;
+    ++seed;
+  }
+
+  return res;
+}
+
+export default {
+  WEATHER,
+  ANEMOS_WEATHER,
+  PAGOS_WEATHER,
+  PYROS_WEATHER,
+  HYDATOS_WEATHER,
+  getWeather,
+  forecast,
+  getWeatherName,
+};