Prevent running multiple mod list background updates simultaneously

Online mod list is currently updated on the background every 5 minutes.
Ideally downloading and processing the mod list wouldn't take that long
that the interval would fire before an earlier round has finished, but
the most popular games have so many mods that on people with slower
connections this seems to happen. Multiple connections then compete for
the same download bandwidth, making the process even slower.

src/components/mixins/UtilityMixin.vue

@@ -39,7 +39,12 @@ export default class UtilityMixin extends Vue {
             return;
         }
 
+        if (this.$store.state.tsMods.isBackgroundUpdateInProgress) {
+            return;
+        }
+
         try {
+            this.$store.commit("tsMods/startBackgroundUpdate");
             await this.refreshThunderstoreModList();
         } catch (e) {
             if (this.tsRefreshFailed) {
@@ -49,6 +54,8 @@ export default class UtilityMixin extends Vue {
 
             this.tsRefreshFailed = true;
             return;
+        } finally {
+            this.$store.commit("tsMods/finishBackgroundUpdate");
         }
 
         this.tsRefreshFailed = false;

src/store/modules/TsModsModule.ts

@@ -18,6 +18,7 @@ interface State {
     connectionError: string;
     deprecated: Map<string, boolean>;
     exclusions?: string[];
+    isBackgroundUpdateInProgress: boolean;
     mods: ThunderstoreMod[];
     modsLastUpdated?: Date;
 }
@@ -38,6 +39,8 @@ export const TsModsModule = {
         deprecated: new Map<string, boolean>(),
         /*** Packages available through API that should be ignored by the manager */
         exclusions: [],
+        /*** Mod list is automatically and periodically updated in the background */
+        isBackgroundUpdateInProgress: false,
         /*** All mods available through API for the current active game */
         mods: [],
         /*** When was the mod list last refreshed from the API? */
@@ -116,6 +119,9 @@ export const TsModsModule = {
         clearModCache(state) {
             state.cache.clear();
         },
+        finishBackgroundUpdate(state) {
+            state.isBackgroundUpdateInProgress = false;
+        },
         setConnectionError(state, error: string|unknown) {
             if (typeof error === 'string') {
                 state.connectionError = error;
@@ -133,6 +139,9 @@ export const TsModsModule = {
         setExclusions(state, payload: string[]) {
             state.exclusions = payload;
         },
+        startBackgroundUpdate(state) {
+            state.isBackgroundUpdateInProgress = true;
+        },
         updateDeprecated(state, allMods: ThunderstoreMod[]) {
             state.deprecated = Deprecations.getDeprecatedPackageMap(allMods);
         }