// How the CLI reads its saved session file back into a `Client`.
//
// A missing file means "not logged in" and returns null. A file that exists but
// cannot be read back into a client (bad JSON, a missing field, a key of the
// wrong length) throws an error saying the session file is corrupt, so the CLI
// can tell the user which of the two it is. Needs `init()` first.

import { existsSync, readFileSync } from "node:fs";
import type { ApiClientOptions } from "./api/client.js";
import { Client } from "./client.js";

export const loadSession = (
    path: string,
    apiOptions?: ApiClientOptions,
): Client | null => {
    if (!existsSync(path)) return null;
    try {
        return Client.fromJSON(
            JSON.parse(readFileSync(path, "utf-8")),
            apiOptions,
        );
    } catch (err) {
        const reason = err instanceof Error ? err.message : String(err);
        throw new Error(`Session file ${path} is corrupt: ${reason}`);
    }
};