export interface SessionRecord {
	value: Record<string, unknown>;
	expires: number;
}

export interface SessionStore {
	get(key: string): Promise<SessionRecord | undefined>;
	set(key: string, record: SessionRecord): Promise<void>;
	delete(key: string): Promise<void>;
	/** Atomically removes and returns a transaction, preventing callback replay. */
	consume(key: string): Promise<SessionRecord | undefined>;
}

export class MemorySessionStore implements SessionStore {
	private readonly records = new Map<string, SessionRecord>();
	async get(key: string): Promise<SessionRecord | undefined> {
		const record = this.records.get(key);
		if (!record || record.expires <= Date.now()) { this.records.delete(key); return undefined; }
		return structuredClone(record);
	}
	async set(key: string, record: SessionRecord): Promise<void> { this.records.set(key, structuredClone(record)); }
	async delete(key: string): Promise<void> { this.records.delete(key); }
	async consume(key: string): Promise<SessionRecord | undefined> {
		const record = this.records.get(key);
		this.records.delete(key);
		return record && record.expires > Date.now() ? structuredClone(record) : undefined;
	}
}