feat: Create functions to initialise client (#19)

Needed for #7

src/lib/PoWebClient.spec.ts

@@ -0,0 +1,59 @@
+import { PoWebClient } from './PoWebClient';
+
+describe('PoWebClient', () => {
+  describe('initLocal', () => {
+    test('Host name should be the localhost IP address', () => {
+      const client = PoWebClient.initLocal();
+
+      expect(client.hostName).toEqual('127.0.0.1');
+    });
+
+    test('TLS should not be used', () => {
+      const client = PoWebClient.initLocal();
+
+      expect(client.useTLS).toBeFalsy();
+    });
+
+    test('Port should default to 276', () => {
+      const client = PoWebClient.initLocal();
+
+      expect(client.port).toEqual(276);
+    });
+
+    test('Port should be overridable', () => {
+      const port = 13276;
+      const client = PoWebClient.initLocal(port);
+
+      expect(client.port).toEqual(port);
+    });
+  });
+
+  describe('initRemote', () => {
+    const hostName = 'gw.relaycorp.tech';
+
+    test('Specified host name should be honored', () => {
+      const client = PoWebClient.initRemote(hostName);
+
+      expect(client.hostName).toEqual(hostName);
+    });
+
+    test('TLS should be used', () => {
+      const client = PoWebClient.initRemote(hostName);
+
+      expect(client.useTLS).toBeTruthy();
+    });
+
+    test('Port should default to 443', () => {
+      const client = PoWebClient.initRemote(hostName);
+
+      expect(client.port).toEqual(443);
+    });
+
+    test('Port should be overridable', () => {
+      const port = 13276;
+      const client = PoWebClient.initRemote(hostName, port);
+
+      expect(client.port).toEqual(port);
+    });
+  });
+});

src/lib/PoWebClient.ts

@@ -0,0 +1,37 @@
+/**
+ * PoWeb client.
+ */
+export class PoWebClient {
+  /**
+   * Connect to a private gateway from a private endpoint.
+   *
+   * @param port The port for the PoWeb server
+   *
+   * TLS won't be used.
+   */
+  public static initLocal(port: number = PoWebClient.DEFAULT_LOCAL_PORT): PoWebClient {
+    return new PoWebClient('127.0.0.1', port, false);
+  }
+
+  /**
+   * Connect to a public gateway from a private gateway via TLS.
+   *
+   * @param hostName The IP address or domain for the PoWeb server
+   * @param port The port for the PoWeb server
+   */
+  public static initRemote(
+    hostName: string,
+    port: number = PoWebClient.DEFAULT_REMOVE_PORT,
+  ): PoWebClient {
+    return new PoWebClient(hostName, port, true);
+  }
+
+  private static readonly DEFAULT_LOCAL_PORT = 276;
+  private static readonly DEFAULT_REMOVE_PORT = 443;
+
+  protected constructor(
+    public readonly hostName: string,
+    public readonly port: number,
+    public readonly useTLS: boolean,
+  ) {}
+}