Implement 5-day-rule

lib/sympto/index.js

@@ -1,5 +1,7 @@
 import getTemperatureShift from './temperature'
 import getMucusShift from './mucus'
+import getPreOvulatoryPhase from './pre-ovulatory'
+import { LocalDate } from 'js-joda'
 
 export default function ({ cycle, previousCycle }) {
   // TODO check for basic stuff, throw if nonexistent
@@ -8,8 +10,7 @@ export default function ({ cycle, previousCycle }) {
     phases: {
       periOvulatory: {
         start: {
-          date: null,
-          time: '00:00'
+          date: null
         },
         cycleDays: null
       }
@@ -18,13 +19,19 @@ export default function ({ cycle, previousCycle }) {
 
   // if there was no first higher measurement in the previous cycle,
   // no infertile preovulatory phase may be assumed
+  if (getTemperatureShift(previousCycle).detected && !cycle[0].mucus) {
+    status.phases.preOvulatory = getPreOvulatoryPhase(cycle)
+  }
 
-  if (getTemperatureShift(previousCycle).detected) {
-    // add preOvulatory phase
+  const periPhase = status.phases.periOvulatory
+  if (status.phases.preOvulatory) {
+    const prePhase = status.phases.preOvulatory
+    periPhase.start.date = LocalDate.parse(prePhase.end.date).plusDays(1).toString()
+    const lastPreDay = prePhase.cycleDays[prePhase.cycleDays.length - 1]
+    periPhase.cycleDays = cycle.slice(cycle.indexOf(lastPreDay) + 1)
   } else {
-    const first = cycle[0]
-    status.phases.periOvulatory.start.date = first.date
-    status.phases.periOvulatory.cycleDays = [...cycle]
+    periPhase.start.date = cycle[0].date
+    periPhase.cycleDays = [...cycle]
   }
 
   const temperatureShift = getTemperatureShift(cycle)

lib/sympto/pre-ovulatory.js

@@ -0,0 +1,21 @@
+export default function(cycle) {
+  const fiveDayRuleDays = cycle.slice(0, 5)
+  const preOvulatoryDays = getDaysUntilFertileMucus(fiveDayRuleDays)
+  return {
+    cycleDays: preOvulatoryDays,
+    start: {
+      date: preOvulatoryDays[0].date
+    },
+    end: {
+      date: preOvulatoryDays[preOvulatoryDays.length - 1].date,
+    }
+  }
+}
+
+function getDaysUntilFertileMucus(days) {
+  const firstFertileMucusDayIndex = days.findIndex(day => day.mucus && day.mucus.value > 1)
+  if (firstFertileMucusDayIndex > -1) {
+    return days.slice(0, firstFertileMucusDayIndex)
+  }
+  return days
+}