feat: learn

src/lib/learn/chords.ts

@@ -0,0 +1,101 @@
+import { osLayout } from "$lib/os-layout";
+import { KEYMAP_CODES } from "$lib/serial/keymap-codes";
+import { persistentWritable } from "$lib/storage";
+import { type ChordInfo, chords } from "$lib/undo-redo";
+import { derived } from "svelte/store";
+
+export const words = derived(
+  [chords, osLayout],
+  ([chords, layout]) =>
+    new Map<string, ChordInfo>(
+      chords
+        .map((chord) => ({
+          chord,
+          output: chord.phrase.map((action) =>
+            layout.get(KEYMAP_CODES.get(action)?.keyCode ?? ""),
+          ),
+        }))
+        .filter(({ output }) => output.every((it) => !!it))
+        .map(({ chord, output }) => [output.join("").trim(), chord] as const),
+    ),
+);
+
+interface Score {
+  lastTyped: number;
+  score: number;
+  total: number;
+}
+
+export const scores = persistentWritable<Record<string, Score>>("scores", {});
+
+export const learnConfigDefault = {
+  maxScore: 3,
+  minScore: -3,
+  scoreBlend: 0.5,
+  weakRate: 0.8,
+  weakBoost: 0.5,
+  maxWeak: 3,
+  newRate: 0.3,
+  initialNewRate: 0.9,
+  initialCount: 10,
+};
+export const learnConfigStored = persistentWritable<
+  Partial<typeof learnConfigDefault>
+>("learn-config", {});
+export const learnConfig = derived(learnConfigStored, (config) => ({
+  ...learnConfigDefault,
+  ...config,
+}));
+
+let lastWord: string | undefined;
+
+function shuffle<T>(array: T[]): T[] {
+  for (let i = array.length - 1; i > 0; i--) {
+    const j = Math.floor(Math.random() * (i + 1));
+    [array[i], array[j]] = [array[j]!, array[i]!];
+  }
+  return array;
+}
+
+function randomLog2<T>(array: T[], max = array.length): T | undefined {
+  return array[
+    Math.floor(Math.pow(2, Math.log2(Math.random() * Math.log2(max))))
+  ];
+}
+
+export const nextWord = derived(
+  [words, scores, learnConfig],
+  ([words, scores, config]) => {
+    const values = Object.entries(scores).filter(([it]) => it !== lastWord);
+
+    values.sort(([, a], [, b]) => a.score - b.score);
+    const weakCount =
+      (values.findIndex(([, { score }]) => score > 0) + 1 ||
+        values.length + 1) - 1;
+    const weak = randomLog2(values, weakCount);
+    if (weak && Math.random() / weakCount < config.weakRate) {
+      lastWord = weak[0];
+      return weak[0];
+    }
+
+    values.sort(([, { lastTyped: a }], [, { lastTyped: b }]) => a - b);
+    const recent = randomLog2(values);
+    const newRate =
+      values.length < config.initialCount
+        ? config.initialNewRate
+        : config.newRate;
+    if (
+      recent &&
+      (Math.random() < Math.min(1, Math.max(0, weakCount / config.maxWeak)) ||
+        Math.random() > newRate)
+    ) {
+      lastWord = recent[0];
+      return recent[0];
+    }
+
+    const newWord = shuffle(Array.from(words.keys())).find((it) => !scores[it]);
+    const word = newWord || recent?.[0] || weak?.[0];
+    lastWord = word;
+    return word;
+  },
+);