import type { FrakClient } from "../types";
import { withCache } from "../utils/cache";

/**
 * Fetch a merge token for the current anonymous identity.
 *
 * Used by in-app browser redirect flows to preserve identity
 * when switching from a WebView to the system browser.
 * The token is appended as `?fmt=` to the redirect URL.
 *
 * Results are cached in memory for 30 seconds by default. Concurrent calls
 * while a request is in-flight are deduplicated automatically.
 *
 * @param client - The current Frak Client
 * @param options - Optional cache configuration
 * @param options.cacheTime - Time in ms to cache the result. Default: 30_000 (30s). Set to 0 to disable.
 * @returns The merge token string, or null if unavailable
 */
export async function getMergeToken(
    client: FrakClient,
    options?: { cacheTime?: number }
): Promise<string | null> {
    return withCache(
        () =>
            client.request({
                method: "frak_getMergeToken",
            }),
        {
            cacheKey: "frak_getMergeToken",
            cacheTime: options?.cacheTime,
        }
    );
}