Create utils.js

lib/snapsave/utils.js

@@ -0,0 +1,62 @@
+export function getEncodedSnapSave(data) {
+    return data.split('decodeURIComponent(escape(r))}(')[1]
+        ?.split('))')[0]
+        ?.split(',')
+        ?.map(v => v.replace(/"/g, '').trim()) || [];
+}
+
+export function getDecodedSnapSave(data) {
+    return data.split('getElementById("download-section").innerHTML = "')[1]
+        ?.split('"; document.getElementById("inputData").remove(); ')[0]
+        ?.replace(/\\(\\)?/g, '') || '';
+}
+
+export function decryptSnapSave(data) {
+    const args = getEncodedSnapSave(data);
+    if (args.length === 0) {
+        throw new Error("Failed to extract encoded SnapSave data.");
+    }
+    const decoded = decodeSnapSave(...args);
+    return getDecodedSnapSave(decoded);
+}
+
+export function decodeSnapSave(...args) {
+    if (args.length < 6) {
+        throw new Error("Invalid SnapSave decryption arguments.");
+    }
+
+    let [h, u, n, t, e, r] = args;
+    
+    function decode(d, e, f) {
+        const g = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/'.split('');
+        let h = g.slice(0, e);
+        let i = g.slice(0, f);
+        
+        let j = d.split('').reverse().reduce((a, b, c) => {
+            let index = h.indexOf(b);
+            return index !== -1 ? a + index * Math.pow(e, c) : a;
+        }, 0);
+
+        let k = '';
+        while (j > 0) {
+            k = i[j % f] + k;
+            j = Math.floor(j / f);
+        }
+        return k || '0';
+    }
+
+    let r = '';
+    for (let i = 0, len = h.length; i < len; i++) {
+        let s = "";
+        while (h[i] !== n[e]) {
+            s += h[i];
+            i++;
+        }
+        for (let j = 0; j < n.length; j++) {
+            s = s.replace(new RegExp(n[j], "g"), j.toString());
+        }
+        r += String.fromCharCode(decode(s, e, 10) - t);
+    }
+
+    return decodeURIComponent(encodeURIComponent(r));
+}