Add subscription manager page (WIP)

public/js/subscription-manager.js

@@ -0,0 +1,57 @@
+const component = () => {
+	return {
+		subscriptions: [],
+		plugins: [],
+		pid: undefined,
+
+		init() {
+			fetch(`${base_url}api/admin/plugin`)
+				.then((res) => res.json())
+				.then((data) => {
+					if (!data.success) throw new Error(data.error);
+					this.plugins = data.plugins;
+
+					const pid = localStorage.getItem("plugin");
+					if (pid && this.plugins.map((p) => p.id).includes(pid))
+						this.pid = pid;
+					else if (this.plugins.length > 0)
+						this.pid = this.plugins[0].id;
+
+					if (this.pid) this.list(pid);
+				})
+				.catch((e) => {
+					alert(
+						"danger",
+						`Failed to list the available plugins. Error: ${e}`
+					);
+				});
+		},
+		pluginChanged() {
+			localStorage.setItem("plugin", this.pid);
+			this.list(this.pid);
+		},
+		list(pid) {
+			fetch(
+				`${base_url}api/admin/plugin/subscriptions?${new URLSearchParams(
+					{
+						plugin: pid,
+					}
+				)}`,
+				{
+					method: "GET",
+				}
+			)
+				.then((response) => response.json())
+				.then((data) => {
+					if (!data.success) throw new Error(data.error);
+					this.subscriptions = data.subscriptions;
+				})
+				.catch((e) => {
+					alert(
+						"danger",
+						`Failed to list subscriptions. Error: ${e}`
+					);
+				});
+		},
+	};
+};