From 2de4174ecaea9bacb3ababcae085c2d131190ab7 Mon Sep 17 00:00:00 2001
From: Fred Boniface <fred@fjla.uk>
Date: Sun, 12 Oct 2025 20:51:56 +0100
Subject: [PATCH] Add new preferences store and migrations

---
 .../migrations/preferencesMigrations.ts       | 91 +++++++++++++++++++
 src/lib/stores/preferences.ts                 | 51 +++++++++++
 2 files changed, 142 insertions(+)
 create mode 100644 src/lib/scripts/migrations/preferencesMigrations.ts
 create mode 100644 src/lib/stores/preferences.ts

diff --git a/src/lib/scripts/migrations/preferencesMigrations.ts b/src/lib/scripts/migrations/preferencesMigrations.ts
new file mode 100644
index 0000000..0b6b7a8
--- /dev/null
+++ b/src/lib/scripts/migrations/preferencesMigrations.ts
@@ -0,0 +1,91 @@
+import { preferences, PREFERENCE_FORMAT_VERSION } from "$lib/stores/preferences";
+import type { Preferences } from "$lib/stores/preferences";
+import { get } from "svelte/store";
+
+export function CheckMigrationStatus() {
+    let currentStore = get(preferences);
+    if ( currentStore.format == 1 ) {
+        const hasOldKeys = 
+            localStorage.getItem('ql') !== null ||
+            localStorage.getItem('location') !== null ||
+            localStorage.getItem('telemetry') !== null;
+        
+        if (hasOldKeys) {
+            migrateToV1()
+        }
+    }
+
+    // Handle higher current version than supported or unparsable number
+    if (
+        !currentStore ||
+        typeof currentStore.format !== 'number' ||
+        currentStore.format > PREFERENCE_FORMAT_VERSION
+    ) {
+        preferences.reset();
+        console.warn('[Migration] Preferences reset due to invalid format version')
+        // Re-read store after reset
+        currentStore = get(preferences);
+    }
+
+    // Loop through required migrations
+    while (currentStore.format < PREFERENCE_FORMAT_VERSION) {
+        // Future Migration Logic
+        /*
+        switch (currentStore.format) {
+            case 0:
+                migrateToV1();
+                break;
+            
+            default:
+                console.warn(`[Migration] Unknown format ${currentStore.format}, resetting to default`);
+                preferences.reset();
+                break;
+        }
+
+        // Re-read store after migration
+        currentStore = get(preferences);
+        */
+        break; // Don't forget to remove this!
+    }
+
+    
+}
+
+// Migrations
+
+function migrateToV1() {
+    const oldQlRaw = localStorage.getItem('ql');
+    const oldLocationRaw = localStorage.getItem('location');
+    const oldTelemetryRaw = localStorage.getItem('telemetry');
+
+    const ql: string[] = safeParseJSON(oldQlRaw, []);
+    const location: boolean = parseBool(oldLocationRaw, false);
+    const telemetry: boolean = parseBool(oldTelemetryRaw, false);
+
+    const migrated: Preferences = { ql, location, telemetry, format: 1 };
+
+    preferences.set(migrated);
+
+    localStorage.removeItem('ql');
+    localStorage.removeItem('location');
+    localStorage.removeItem('telemetry');
+
+    console.info('[Migration] Preferences migrated to version 1');
+}
+
+// Helpers
+
+function safeParseJSON<T>(raw: string | null, fallback: T): T {
+    if (!raw) return fallback;
+    try {
+        return JSON.parse(raw) as T;
+    } catch {
+        return fallback;
+    }
+}
+
+function parseBool(raw: string | null, fallback: boolean): boolean {
+    if (raw == 'true') return true;
+    if (raw == 'false') return false;
+    return fallback;
+}
diff --git a/src/lib/stores/preferences.ts b/src/lib/stores/preferences.ts
new file mode 100644
index 0000000..cf16b31
--- /dev/null
+++ b/src/lib/stores/preferences.ts
@@ -0,0 +1,51 @@
+import { CheckMigrationStatus } from "$lib/scripts/migrations/preferencesMigrations";
+import { writable } from "svelte/store";
+
+export const PREFERENCE_FORMAT_VERSION = 1;
+
+export interface Preferences {
+    ql: string[];
+    location: boolean;
+    telemetry: boolean;
+    format: number;
+}
+
+const STORAGE_KEY = 'preferences';
+
+const DEFAULT_PREFERENCES: Preferences = {
+    ql: [],
+    location: false,
+    telemetry: false,
+    format: PREFERENCE_FORMAT_VERSION,
+};
+
+function createPreferencesStore() {
+    let stored: Preferences;
+    try {
+        const json = localStorage.getItem(STORAGE_KEY);
+        stored = json ? JSON.parse(json) : DEFAULT_PREFERENCES;
+    } catch {
+        stored = DEFAULT_PREFERENCES;
+    }
+
+    const { subscribe, set, update } = writable<Preferences>(stored);
+
+    subscribe((value) => {
+        localStorage.setItem(STORAGE_KEY, JSON.stringify(value));
+    });
+
+    return {
+        subscribe,
+        set,
+        update,
+        reset: () => set(DEFAULT_PREFERENCES)
+    }
+}
+
+export const preferences = createPreferencesStore();
+try {
+    CheckMigrationStatus();
+} catch (e) {
+    console.error("Preferences migration failed, resetting store", e);
+    preferences.reset();
+}