Np mj sort items soon integers

src/lib/estimates.js

@@ -0,0 +1,24 @@
+/**
+ * Calculate a weighted estimate for the interval until the next purchase
+ * Current purchase a tiny bit less weight than all previous purchases
+ * @param {Number} lastEstimate The last stored purchase interval estimate
+ * @param {Number} latestInterval The interval between the most recent and previous purchases
+ * @param {Number} numberOfPurchases Total number of purchases for the item
+ */
+const calculateEstimate = (lastEstimate, latestInterval, numberOfPurchases) => {
+  if (isNaN(lastEstimate)) {
+    lastEstimate = 14;
+  }
+
+  // fake interval to see if variable is added to database - need to store prev and current buy day to calculate difference
+  if (isNaN(latestInterval)) {
+    latestInterval = 10;
+  }
+  // FIXME algorithm doesn't work when there's only 1 purchase in the database
+  let previousFactor = lastEstimate * numberOfPurchases;
+  let latestFactor = latestInterval * (numberOfPurchases - 1);
+  let totalDivisor = numberOfPurchases * 2 - 1;
+  return (previousFactor + latestFactor) / totalDivisor;
+};
+
+export default calculateEstimate;

src/listContext.js

@@ -75,8 +75,14 @@ const ListContextProvider = props => {
   };
 
   //we use .set to add the time the item was purchased to an already existing document we search for the item.id
-  const addDatePurchased = (item, lastDatePurchased) => {
-    itemsRef.doc(item.id).set({ ...item, lastDatePurchased });
+  const addDatePurchased = (item, lastDatePurchased, numberOfPurchases) => {
+    itemsRef
+      .doc(item.id)
+      .set({ ...item, lastDatePurchased, numberOfPurchases });
+  };
+
+  const addCalculatedEstimate = (item, calculatedEstimate) => {
+    itemsRef.doc(item.id).set({ ...item, calculatedEstimate });
   };
 
   return (
@@ -85,6 +91,7 @@ const ListContextProvider = props => {
         validToken,
         shoppingList,
         setShoppingList,
+        addCalculatedEstimate,
         fetchList,
         isDuplicate,
         addItem,

src/pages/AddItem.js

@@ -87,3 +87,5 @@ const AddItem = () => {
 };
 
 export default AddItem;
+
+//MJ: testing to make sure that I pulled the branch correctly.

src/pages/List.js

@@ -1,33 +1,64 @@
 import React, { useContext } from 'react';
 import NavTabs from '../components/NavTabs';
-import Loading from '../components/Loading';
-// import ErrorMessage from '../components/ErrorMessage';
-import useListToken, { getCurrentToken } from '../useListToken';
-import { FirestoreCollection } from 'react-firestore';
 import { ListContext } from '../listContext';
+import useListToken from '../useListToken';
+import { FirestoreCollection } from 'react-firestore';
+import Loading from '../components/Loading';
+import ErrorMessage from '../components/ErrorMessage';
+import HomePageButton from '../components/HomePageButton';
+import calculateEstimate from '../lib/estimates.js';
+import latestInterval from '../lib/estimates.js';
 import dayjs from 'dayjs';
 import './List.css';
 
+const today = dayjs();
+
+function isLessThan24hrs(datePurchased) {
+  let purchaseDateCalc = dayjs(datePurchased);
+  return today.diff(purchaseDateCalc, 'hour') <= 24;
+}
+
 const List = props => {
-  const { shoppingList, setShoppingList, addDatePurchased } = useContext(
-    ListContext,
-  );
-  const { token } = useListToken;
-  const today = dayjs();
+  const {
+    shoppingList,
+    setShoppingList,
+    addDatePurchased,
+    addCalculatedEstimate,
+  } = useContext(ListContext);
+  const { token } = useListToken();
 
-  function isLessThan24hrs(datePurchased) {
-    let purchaseDateCalc = dayjs(datePurchased);
-    return today.diff(purchaseDateCalc, 'hour') <= 24;
-  }
-  //when an item has been created but not yet purchased.
+  //we are checking if the last date it was purchased is less than 24hrs using isLessThan24hrs function
   function isChecked(lastDatePurchased) {
     return !!lastDatePurchased && isLessThan24hrs(lastDatePurchased);
   }
-
+  // let count = 1;
   //we are adding the item.id as well as the date purchased when clicking on the checkbox
   function handlePurchasedChange(item) {
     const datePurchased = item.lastDatePurchased ? null : Date.now();
-    addDatePurchased(item, datePurchased);
+    const numberOfPurchases = item.numberOfPurchases
+      ? item.numberOfPurchases + 1
+      : 1;
+    console.log('Item before:', item);
+    addDatePurchased(item, datePurchased, numberOfPurchases);
+
+    let lastEstimate = item.nextExpectedPurchase
+      ? item.nextExpectedPurchase
+      : 14;
+
+    let prevDate = item.lastDatePurchased ? item.lastDatePurchased : null;
+
+    console.log('prevDate:', prevDate);
+    console.log('currentDate:', datePurchased);
+    console.log('lastEstimate:', lastEstimate);
+
+    const calculatedEstimate = calculateEstimate(
+      lastEstimate,
+      latestInterval,
+      numberOfPurchases,
+    );
+    console.log('the calculateEstimate ran:', calculatedEstimate);
+    addCalculatedEstimate(item, calculatedEstimate);
+    console.log('Item after:', item);
   }
 
   return (
@@ -38,19 +69,20 @@ const List = props => {
         // Sort the data
         sort="name"
         // Only fetch the items associated with the token saved in localStorage
-        filter={['token', '==', token || getCurrentToken() || 'no token set']}
+        filter={['token', '==', token]}
         // isLoading = is a Boolean that represents the loading status for the firebase query. true until an initial payload from Firestore is received.
         // data = an Array containing all of the documents in the collection. Each item will contain an id along with the other data contained in the document.
         render={({ isLoading, data }) => {
-          // if (!isLoading && data.length === 0) {
-          //   return <ErrorMessage />;
-          // }
+          if (!isLoading && data.length === 0) {
+            return <ErrorMessage />;
+          }
 
           if (!isLoading) {
             setShoppingList(data);
           }
 
           return isLoading ? (
+            // TODO: Make a display list function is listContext.js
             <Loading />
           ) : (
             <ul className="shopping-list">