// Copyright (c) Cratis. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

import { AsyncLocalStorage } from 'async_hooks';
import { CorrelationId } from './CorrelationId.js';
import { ICorrelationIdAccessor } from './ICorrelationIdAccessor.js';
import { ICorrelationIdSetter } from './ICorrelationIdSetter.js';

/**
 * Implements both {@link ICorrelationIdAccessor} and {@link ICorrelationIdSetter},
 * using {@link AsyncLocalStorage} to scope the correlation identifier to the active async call context.
 */
export class CorrelationIdManager implements ICorrelationIdAccessor, ICorrelationIdSetter {
    private readonly _storage = new AsyncLocalStorage<CorrelationId>();

    /** @inheritdoc */
    get current(): CorrelationId {
        return this._storage.getStore() ?? CorrelationId.create();
    }

    /** The explicitly scoped identifier, without generating an identifier when no scope exists. */
    get scoped(): CorrelationId | undefined {
        return this._storage.getStore();
    }

    /** Runs an async or synchronous operation with a correlation id, restoring the caller afterward. */
    run<T>(correlationId: CorrelationId, callback: () => T): T {
        return this._storage.run(correlationId, callback);
    }

    /** Runs work without inheriting a business correlation, restoring the caller afterward. */
    runWithout<T>(callback: () => T): T {
        return this._storage.exit(callback);
    }

    /** @inheritdoc */
    setCurrent(correlationId: CorrelationId): void {
        this._storage.enterWith(correlationId);
    }

    /** @inheritdoc */
    clear(): void {
        this._storage.enterWith(CorrelationId.create());
    }
}