X-Git-Url: http://git.shiar.nl/sheet.git/blobdiff_plain/557e9a9b737294f5e170f8f5474ff750ab72cb4a..1d174caf0e66efe73a17b6fefb11abe8df2b0750:/word/quiz.js

diff --git a/word/quiz.js b/word/quiz.js
index 70f8500..187aea7 100644
--- a/word/quiz.js
+++ b/word/quiz.js
@@ -1,14 +1,57 @@
 Array.prototype.shuffle = function () {
-	return this.sort(() => {return .5 - Math.random()});
+	for (let i = this.length - 1; i > 0; i--) {
+		const j = Math.floor(Math.random() * (i + 1)); // random index 0..i
+		[this[i], this[j]] = [this[j], this[i]]; // swap elements
+	}
+	return this;
 };
 
 class WordQuiz {
 	dataselect(json) {
+		// find viable rows from json data
 		let rows = Object.values(json);
+		if (this.preset.cat !== undefined) {
+			let cats = {}; // category lookup
+			for (let i in json) {
+				let cat = json[i][3];
+				if (!cats[cat]) cats[cat] = [];
+				cats[cat].push(i)
+			}
+
+			rows = [];
+			let children = cats[this.preset.cat];
+			for (let loop = 0; children.length && loop < 20; loop++) {
+				rows.push(...children);
+				children = children.map(cat => cats[cat]).filter(is => is).flat();
+			}
+			rows = rows.map(row => json[row]).filter(row => row[2]);
+		}
+		if (this.preset.level !== undefined) {
+			rows = rows.filter(row => row[1] <= this.preset.level);
+		}
+
+		{
+			let cats = new Set();
+			let subcats = rows.map(row => row[3]); // direct parents
+			for (let loop = 0; subcats.length && loop < 20; loop++) {
+				subcats.forEach(cat => cats.add(cat));
+				subcats = subcats.map(row => json[row] && json[row][3]).filter(val => val); // recurse grandparents
+			}
+			rows = rows.filter(row => !cats.has(row[2])); // remove referenced categories
+		}
 		return rows.shuffle();
 	}
 
 	load(dataurl) {
+		this.preset = {};
+		let input;
+		if (input = window.location.hash.match(/\d+/)) {
+			this.preset.cat = input[0];
+		}
+		if (window.location.hash.match(/a/)) {
+			this.preset.level = 2;
+		}
+
 		fetch(dataurl).then(res => res.json()).then(json => {
 			this.words = this.dataselect(json)
 			this.setup();