import {
	CONNECTION_CONNECT_REASON_DISPOSED,
	CONNECTION_STATE_OPEN
} from './consts.ts';
import type { ConnectionConnectResult, ConnectionState } from './types.ts';

export interface ConnectionConnectController {
	connect(reconnect: boolean): Promise<ConnectionConnectResult>;
}

export interface ConnectionConnectControllerOptions {
	getState(): ConnectionState;
	isDisposed(): boolean;
	isConnected(): boolean;
	beforeAttempt(): void;
	runConnect(reconnect: boolean): Promise<ConnectionConnectResult>;
}

export function createConnectionConnectController(
	options: ConnectionConnectControllerOptions
): ConnectionConnectController {
	let connectPromise: Promise<ConnectionConnectResult> | null = null;

	function connect(reconnect: boolean): Promise<ConnectionConnectResult> {
		const state = options.getState();
		if (options.isDisposed()) {
			return Promise.resolve({
				ok: false,
				state,
				reason: CONNECTION_CONNECT_REASON_DISPOSED
			});
		}
		if (state === CONNECTION_STATE_OPEN && options.isConnected()) {
			return Promise.resolve({ ok: true, state, reused: true });
		}
		if (connectPromise !== null) return connectPromise;

		connectPromise = (async () => {
			options.beforeAttempt();
			try {
				return await options.runConnect(reconnect);
			} finally {
				connectPromise = null;
			}
		})();

		return connectPromise;
	}

	return { connect };
}