adds more tests for period predictions, moves getcycleslength into cycle module

lib/cycle.js

@@ -1,5 +1,5 @@
 import * as joda from 'js-joda'
-import {getCycleLengthStats, getCycleLength} from './cycle-length'
+import {getCycleLengthStats} from './cycle-length'
 const LocalDate = joda.LocalDate
 const DAYS = joda.ChronoUnit.DAYS
 
@@ -7,6 +7,8 @@ export default function config(opts) {
   let bleedingDaysSortedByDate
   let cycleDaysSortedByDate
   let maxBreakInBleeding
+  let maxCycleLength
+  let minCyclesForPrediction
 
   if (!opts) {
     // we only want to require (and run) the db module
@@ -14,10 +16,14 @@ export default function config(opts) {
     bleedingDaysSortedByDate = require('../db').bleedingDaysSortedByDate
     cycleDaysSortedByDate = require('../db').cycleDaysSortedByDate
     maxBreakInBleeding = 1
+    maxCycleLength = 99
+    minCyclesForPrediction = 3
   } else {
     bleedingDaysSortedByDate = opts.bleedingDaysSortedByDate || []
     cycleDaysSortedByDate = opts.cycleDaysSortedByDate || []
     maxBreakInBleeding = opts.maxBreakInBleeding || 1
+    maxCycleLength = opts.maxCycleLength || 99
+    minCyclesForPrediction = opts.minCyclesForPrediction || 3
   }
 
   function getLastMensesStart(targetDateString) {
@@ -144,22 +150,37 @@ export default function config(opts) {
     }
   }
 
-  function getPredictedMenses(maxCycleLength, minCyclesForPrediction) {
-    maxCycleLength = maxCycleLength || 99
-    minCyclesForPrediction = minCyclesForPrediction || 3
+  function getCycleLength(cycleStartDates) {
+    const cycleLengths = []
+    for (let i = 0; i < cycleStartDates.length - 1; i++) {
+      const nextCycleStart = LocalDate.parse(cycleStartDates[i])
+      const cycleStart = LocalDate.parse(cycleStartDates[i + 1])
+      const cycleLength = cycleStart.until(nextCycleStart, DAYS)
+      if (cycleLength <= maxCycleLength) { cycleLengths.push(cycleLength) }
+    }
+    return cycleLengths
+  }
+
+  function getPredictedMenses() {
     const allMensesStarts = getAllMensesStarts()
 
     const atLeastOneCycle = allMensesStarts.length > 1
     if (!atLeastOneCycle ||
-      allMensesStarts.length < minCyclesForPrediction ||
-      getCycleDayNumber(LocalDate.now().toString()) > maxCycleLength
+      allMensesStarts.length < minCyclesForPrediction
     ) {
       return {}
     }
     const cycleLengths = getCycleLength(allMensesStarts)
     const cycleInfo = getCycleLengthStats(cycleLengths)
     const periodDistance = Math.round(cycleInfo.mean)
-    const periodStartVariation = (cycleInfo.stdDeviation < 1.5) ? 1 : 2 // threshold is choosen a little arbitrarily
+    let periodStartVariation
+    if (cycleInfo.stdDeviation === null) {
+      periodStartVariation = 2
+    } else if (cycleInfo.stdDeviation < 1.5) { // threshold is choosen a little arbitrarily
+      periodStartVariation = 1
+    } else {
+      periodStartVariation = 2
+    }
     var lastStart = allMensesStarts[0]
     const predictedMenses = []
     for (let i = 0; i < 3; i++) {
@@ -179,6 +200,7 @@ export default function config(opts) {
     getPreviousCycle,
     getCyclesBefore,
     getAllMensesStarts,
+    getCycleLength,
     getPredictedMenses
   }
 }