/**
 * Lightweight pair of `setInterval` timers managing the heartbeat / cleanup
 * cadence of a `TypedBroadcastChannel`. Extracted from `channel.ts` so the
 * channel core stays under the 300-line hard budget while keeping each timer
 * lifecycle visible and individually testable.
 */
export interface HeartbeatRunnerOptions {
    readonly heartbeatInterval: number;
    readonly onHeartbeat: () => void;
    readonly onCleanup: () => void;
}

/** Mutable pair of timers; `start` schedules, `stop` clears. */
export class HeartbeatRunner {
    private readonly opts: HeartbeatRunnerOptions;
    private heartbeatTimer: ReturnType<typeof setInterval> | null = null;
    private cleanupTimer: ReturnType<typeof setInterval> | null = null;

    public constructor(opts: HeartbeatRunnerOptions) {
        this.opts = opts;
    }

    public start(): void {
        this.heartbeatTimer = setInterval(
            () => this.opts.onHeartbeat(),
            this.opts.heartbeatInterval
        );
        this.cleanupTimer = setInterval(
            () => this.opts.onCleanup(),
            this.opts.heartbeatInterval * 2
        );
    }

    public stop(): void {
        if (this.heartbeatTimer !== null) {
            clearInterval(this.heartbeatTimer);
            this.heartbeatTimer = null;
        }
        if (this.cleanupTimer !== null) {
            clearInterval(this.cleanupTimer);
            this.cleanupTimer = null;
        }
    }
}