feat: Implement SM2

backend/db.md

@@ -18,7 +18,9 @@
     lastLevel: number,
     levels: number[], 
     
-    queue: number[],
+    vocabMetadata: {
+        [id: number]: ISM2Metadata,
+    },
 }
 `
 

backend/src/api/level.ts

@@ -32,12 +32,19 @@ levelRouter.get("/:id/vocab", async (req: LRequest, res: Response) => {
     }
 
     // Find the level
-    // TODO: if (level)
     const { db } = req;
     const level = await db.collection("levels").findOne({
-        // TODO: This aint safe, boi
         level: levelId,
     });
+    if (!level) {
+        res.send({
+            error: "404",
+            data: {
+                msg: `Cannot find level with id "${levelId}"`,
+            },
+        });
+        return;
+    }
 
     // Fetch all the vocabulary
     const vocab = await db.collection("vocabulary").find({ id: { $in: level.vocab } }).toArray();

backend/src/api/user.ts

@@ -1,13 +1,15 @@
 import * as express from "express";
 import * as bodyparser from "body-parser";
 
+import { Db } from "mongodb";
+
 import { authRoute } from "../security/token";
 
 import { userFromSession } from "../utils/user";
 
 import { IUser, IUserDBModel } from "../models/user";
+import { ISM2Metadata } from "../models/review";
 import { LRequest } from "../types/express";
-import { Db } from "mongodb";
 
 const userRouter = express.Router();
 userRouter.use(authRoute);
@@ -65,13 +67,30 @@ export enum VocabType {
 userRouter.get("/queue", async (req: LRequest, res) => {
     // TODO: if (user)
     const { token, db } = req;
-    const user = await userFromSession(token, db);
+    let user = Object.assign({}, await userFromSession(token, db));
+
+    const sm2 = user.vocabMetadata;
+    const data = Object.keys(sm2).map(id => Object.assign({}, sm2[parseInt(id)], { id, }));
+    const sorted = data.sort((a: any, b: any) => {
+        if (a.nextDueDate > b.nextDueDate)
+            return 1;
+        if (a.nextDueDate < b.nextDueDate)
+            return -1;
+
+        return 0;
+    }).slice(0, 20)
+        .map((el: any) => {
+            return parseInt(el.id);
+        });
 
     // Fetch all vocab ids from the vocabulary collection
     const vocabRaw = await db.collection("vocabulary").find({
-        id: { $in: user.queue },
+        id: { $in: sorted },
     }, {
             // TODO: Make this configurable?
+            sort: {
+
+            },
             limit: 20,
         }).toArray();
 
@@ -102,18 +121,69 @@ userRouter.get("/lastReview", async (req: LRequest, res) => {
         data: user.lastReview,
     });
 });
+
+function dateInNDays(n: number): number {
+    let today = new Date();
+    today.setDate(today.getDate() + n);
+    return Date.parse(today.toString());
+}
+
 userRouter.post("/lastReview", async (req: LRequest, res) => {
-    // TODO: Check if we get the correct data
+    // Check if we get the needed data
-    // TODO: if(user)
+    if (!req.body || !("meta" in req.body) || !("sm2" in req.body)) {
+        res.send({
+            error: "400",
+            data: {
+                msg: "Last review state or SM2 data not specified!",
+            },
+        });
+        return;
+    }
+
     const { token, db } = req;
-    const user = await userFromSession(token, db);
+    let user = Object.assign({}, await userFromSession(token, db));
+    if (!user) {
+        res.send({
+            error: "404",
+            data: {
+                msg: "Failed to find user with the specified session!",
+            },
+        });
+        return;
+    }
+
+    Object.keys(req.body.sm2).forEach((id: string) => {
+        const vocabId = parseInt(id);
+        const correct: boolean = req.body.sm2[id];
+        let vocab_sm2: ISM2Metadata = Object.assign({},
+            user.vocabMetadata[vocabId]);
+
+        // TODO: Tuning?
+        // TODO: Move into another module
+        const perf = correct ? 3 : 1;
+        vocab_sm2.easiness += -0.8 + 0.28 * perf + 0.02 * Math.pow(perf, 2);
+        // Update the consecutive correct answers and the due date
+        if (correct) {
+            vocab_sm2.consecutiveCorrectAnswers += 1;
+            vocab_sm2.nextDueDate = dateInNDays(6 * Math.pow(vocab_sm2.easiness, vocab_sm2.consecutiveCorrectAnswers - 1));
+        } else {
+            vocab_sm2.consecutiveCorrectAnswers = 0;
+            vocab_sm2.nextDueDate = dateInNDays(1);
+        }
+
+        user.vocabMetadata[vocabId] = vocab_sm2;
+    });
+
+    // Update the last review
+    user.lastReview = req.body.meta;
 
     // TODO: Error handling
     await db.collection("users").updateOne({
         username: user.username,
     }, {
             $set: {
-                lastReview: req.body.meta,
+                lastReview: user.lastReview,
+                vocabMetadata: user.vocabMetadata,
             },
         });
 

backend/src/models/review.ts

@@ -0,0 +1,5 @@
+export interface ISM2Metadata {
+    easiness: number;
+    consecutiveCorrectAnswers: number;
+    nextDueDate: number;
+};

backend/src/models/user.ts

@@ -1,3 +1,5 @@
+import { ISM2Metadata } from "./review";
+
 export interface IUserDBModel {
     username: string;
     uid: string;
@@ -20,12 +22,8 @@ export interface IUserDBModel {
     queue: number[];
 
     // Vocabulary ID -> SM2 Metadata
-    metadata: {
+    vocabMetadata: {
-        [key: number]: {
+        [key: number]: ISM2Metadata;
-            easiness: number;
-            nextDueDate: number;
-            consecutiveCorrectAnswers: number;
-        };
     };
 };
 

frontend/shit.sh

@@ -4,3 +4,5 @@ rm -rf dist/
 ./node_modules/.bin/parcel build --out-dir dist/app src/index.html
 chmod 705 dist dist/app
 chmod 604 dist/app/*
+
+#sed "s/\/src/\/app\/src/" dist/app/index.html

frontend/src/components/app.tsx

@@ -106,7 +106,8 @@ export default class Application extends React.Component<IProps> {
         });
     }
 
-    setLastReview = (meta: IReviewMetadata) => {
+    // TODO: Type?
+    setLastReview = (meta: IReviewMetadata, sm2: any) => {
         // Update the state
         this.props.setLastReview(meta);
 
@@ -119,6 +120,7 @@ export default class Application extends React.Component<IProps> {
             method: "POST",
             body: JSON.stringify({
                 meta,
+                sm2,
             }),
         }).then(resp => resp.json(), err => {
             console.log("Application::setLastReview: POSTing last results failed");

frontend/src/pages/review.tsx

@@ -33,6 +33,7 @@ interface IProps {
     levelId?: number;
     vocabByLevel?: (level: number) => Promise<IVocab[]>;
     vocabByQueue?: () => Promise<IVocab[]>;
+    setLastReview: (meta: IReviewMetadata, sm2: any) => void;
     reviewType: ReviewType;
 
     history: any;
@@ -51,7 +52,6 @@ interface IProps {
     setSummary: (state: boolean) => void;
     setPopover: (state: boolean, text: string, color: string, textColor: string) => void;
     drawerButtonState: (state: boolean) => void;
-    setLastReview: (meta: IReviewMetadata) => void;
     setReview: (curent: IReviewCard, meta: IReviewMetadata) => void;
     setLoading: (state: boolean) => void;
 }
@@ -63,6 +63,7 @@ const ReviewPageWithRouter = withRouter(
         // Used for positioning the popover
         private buttonRef: HTMLButtonElement;
         private inputRef: HTMLInputElement;
+        // Mapping: Vocab Id -> Correctly answered
         private sm2_metadata: any = {};
 
         constructor(props: any) {
@@ -133,6 +134,46 @@ const ReviewPageWithRouter = withRouter(
             return this.vocab.find((el) => el.id === this.props.current.id);
         }
 
+        // When a vocabulary item has been answered, we need to update
+        // the group's SuperMemo2-data.
+        // We update based on the following State-Machine: (C = Correct; W = Wrong)
+        // Answer | Group | New group
+        //        |       |   state
+        // -------+-------+----------
+        //    C   |   C   |  C
+        //    C   |   W   |  W
+        //    W   |   C   |  W
+        //    W   |   W   |  W
+        // (1)C   |   -   |  C
+        // (2)W   |   -   |  W
+        // @correct: Was the answer given correct?
+        updateGroupSM2 = (correct: boolean) => {
+            const { id } = this.props.current;
+            switch (correct) {
+                case true:
+                    // Case (1)
+                    if (!(id in this.sm2_metadata)) {
+                        this.sm2_metadata[id] = true;
+                        break;
+                    }
+
+                    switch (this.sm2_metadata[id]) {
+                        case true:
+                            this.sm2_metadata[id] = true;
+                            break;
+                        case false:
+                            this.sm2_metadata[id] = false;
+                            break;
+                    }
+                    break;
+                case false:
+                    // We don't need to explicitly catch case (2), as we set
+                    // anything, that was incorrectly answered to false.
+                    this.sm2_metadata[id] = false;
+                    break;
+            }
+        }
+
         checkInput = () => {
             // Check if the given answer is somewhere in the german words
             const input = this.inputRef.value || "";
@@ -146,12 +187,14 @@ const ReviewPageWithRouter = withRouter(
 
             // Check if the user's answer was correct
             if (minDist === 0) {
+                this.updateGroupSM2(true);
+
                 // TODO: Show it's correct?
                 // Show the next vocab word
                 if (this.reviewQueue.size() === 0) {
                     // Update the metadata
                     this.props.setReview(this.props.current, this.increaseMeta(1, 0));
-                    this.props.setLastReview(this.props.metadata);
+                    this.props.setLastReview(this.props.metadata, this.sm2_metadata);
                     this.props.setLoading(true);
 
                     // Show the drawer button again
@@ -163,6 +206,8 @@ const ReviewPageWithRouter = withRouter(
                     // Increase the vocab
                     this.props.setReview(this.reviewQueue.dequeue(), this.increaseMeta(1, 0));
                     this.inputRef.value = "";
+
+                    // TODO(?): Show a snackbar for showing the updated score
                 }
             } else if (minDist <= LEVENSHTEIN_MAX_DISTANCE) {
                 this.props.setPopover(true, "Das war fast richtig", "yellow", "black");
@@ -178,11 +223,10 @@ const ReviewPageWithRouter = withRouter(
                  * }
                  */
                 // Update the metadata
+                this.updateGroupSM2(false);
                 this.props.setReview(this.props.current, this.increaseMeta(0, 1));
                 this.props.setPopover(true, "Das war nicht richtig", "red", "white");
             }
-
-            // TODO(?): Show a snackbar for showing the updated score
         }
 
         render() {