api-client: move base api and session to internal subfolder

packages/api-client/src/internal/base-api.ts

@@ -0,0 +1,51 @@
+import { CobaltResponseType, type CobaltAPIResponse } from "../types/response";
+import type { CobaltRequest } from "../types/request";
+import { CobaltReachabilityError } from "../types/errors";
+
+export default class BaseCobaltAPI {
+    #baseURL: string;
+    #userAgent: string | undefined;
+
+    constructor(baseURL: string, userAgent?: string) {
+        const url = new URL(baseURL);
+
+        if (baseURL !== url.origin && baseURL !== `${url.origin}/`) {
+            throw new Error('Invalid cobalt instance URL');
+        }
+
+        this.#baseURL = url.origin;
+        this.#userAgent = userAgent;
+    }
+
+    protected async _request(data: CobaltRequest, headers: Record<string, string>) {
+        if (this.#userAgent) {
+            headers['user-agent'] = this.#userAgent;
+        }
+
+        const response: CobaltAPIResponse = await fetch(this.#baseURL, {
+            method: 'POST',
+            redirect: 'manual',
+            signal: AbortSignal.timeout(10000),
+            body: JSON.stringify(data),
+            headers: {
+                'Accept': 'application/json',
+                'Content-Type': 'application/json',
+                ...headers
+            }
+        })
+        .then(r => r.json())
+        .catch((e) => {
+            const timedOut = e?.message?.includes("timed out");
+            return {
+                status: CobaltResponseType.Error,
+                error: {
+                    code: timedOut
+                            ? CobaltReachabilityError.TimedOut
+                            : CobaltReachabilityError.Unreachable
+                }
+            };
+        });
+
+        return response;
+    }
+};