Calculations of lucky levels (#1179)

src/Disp/HelperFunctions/CalculateLuckyLevels.js

@@ -0,0 +1,104 @@
+const SPECIAL_DIGIT = 7;
+
+/**
+ * Count the number of 7s in any number
+ * @param	{number}	number	The number to count sevens for
+ * @returns	{number}	The number of 7s in the provided number
+ */
+export function CountSevens(number) {
+  return String(number).split(String(SPECIAL_DIGIT)).length - 1;
+}
+
+/**
+ * Calculate the delta for the next number where the given digit is a 7
+ * @param	{number}	number			The starting number to calculate the delta for
+ * @param	{number}	digitPlace	1 for ones place, 10 for tens place, 100 for hundreds place, etc
+ * @returns	{number}	The calculated delta
+ */
+export function CalculateSevenDelta(number, digitPlace) {
+  const target = SPECIAL_DIGIT * digitPlace;
+  const modulus = digitPlace * 10;
+
+  let delta = target - (number % modulus) + (number % digitPlace);
+  if (delta < 0) delta += modulus;
+
+  return delta;
+}
+
+/**
+ * This function calculates each of the next "lucky" prestige levels
+ * @param	{number}	currentLevel	The user's prestige level, including levels earned since the last ascension
+ * @returns	{{number}, {number}, {number}}	luckyDigit, luckyNumber, luckyPayout	The next eligible level for each upgrade
+ */
+export default function CalculateLuckyLevels(currentLevel) {
+  const result = {};
+  let sevenCount = CountSevens(currentLevel);
+  const numberOfDigits = String(currentLevel).length;
+
+  if (sevenCount >= 1) {
+    result.luckyDigit = currentLevel;
+    if (sevenCount >= 2) {
+      result.luckyNumber = currentLevel;
+      if (sevenCount >= 4) {
+        result.luckyPayout = currentLevel;
+        return result;
+      }
+    }
+  }
+
+  // Consider only top 15 digits if it is big number
+  let localLevel;
+  if (numberOfDigits >= 16) {
+    localLevel = Math.ceil(currentLevel / 10 ** (numberOfDigits - 15));
+  } else {
+    localLevel = currentLevel;
+  }
+  sevenCount = CountSevens(localLevel);
+
+  if (result.luckyDigit === undefined) {
+    if (sevenCount < 1) {
+      const delta = CalculateSevenDelta(localLevel, 1);
+
+      localLevel += delta;
+      sevenCount = CountSevens(localLevel);
+    }
+
+    result.luckyDigit = localLevel;
+    if (numberOfDigits >= 16) {
+      result.luckyDigit *= 10 ** Number(numberOfDigits - 15);
+    }
+  }
+
+  if (result.luckyNumber === undefined) {
+    while (sevenCount < 2) {
+      let delta = CalculateSevenDelta(localLevel, 1);
+      if (delta === 0) delta = CalculateSevenDelta(localLevel, 10);
+
+      localLevel += delta;
+      sevenCount = CountSevens(localLevel);
+    }
+
+    result.luckyNumber = localLevel;
+    if (numberOfDigits >= 16) {
+      result.luckyNumber *= 10 ** Number(numberOfDigits - 15);
+    }
+  }
+
+  let digitPlace = 1;
+  while (sevenCount < 4) {
+    const delta = CalculateSevenDelta(localLevel, digitPlace);
+    if (delta === 0) {
+      digitPlace *= 10;
+    } else {
+      localLevel += delta;
+      sevenCount = CountSevens(localLevel);
+    }
+  }
+
+  result.luckyPayout = localLevel;
+  if (numberOfDigits >= 16) {
+    result.luckyPayout *= 10 ** Number(numberOfDigits - 15);
+  }
+
+  return result;
+}