import { ConnectError } from '../connect-error.js';
import { Code } from '../code.js';

// Copyright 2021-2024 The Connect Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
 * Create an AbortController that is automatically aborted if one of the given
 * signals is aborted.
 *
 * For convenience, the linked AbortSignals can be undefined.
 *
 * If the controller or any of the signals is aborted, all event listeners are
 * removed.
 *
 * @private Internal code, does not follow semantic versioning.
 */
function createLinkedAbortController(...signals) {
    const controller = new AbortController();
    const sa = signals.filter((s) => s !== undefined).concat(controller.signal);
    for (const signal of sa) {
        if (signal.aborted) {
            onAbort.apply(signal);
            break;
        }
        signal.addEventListener("abort", onAbort);
    }
    function onAbort() {
        if (!controller.signal.aborted) {
            controller.abort(getAbortSignalReason(this));
        }
        for (const signal of sa) {
            signal.removeEventListener("abort", onAbort);
        }
    }
    return controller;
}
/**
 * Create a deadline signal. The returned object contains an AbortSignal, but
 * also a cleanup function to stop the timer, which must be called once the
 * calling code is no longer interested in the signal.
 *
 * Ideally, we would simply use AbortSignal.timeout(), but it is not widely
 * available yet.
 *
 * @private Internal code, does not follow semantic versioning.
 */
function createDeadlineSignal(timeoutMs) {
    const controller = new AbortController();
    const listener = () => {
        controller.abort(new ConnectError("the operation timed out", Code.DeadlineExceeded));
    };
    let timeoutId;
    if (timeoutMs !== undefined) {
        if (timeoutMs <= 0)
            listener();
        else
            timeoutId = setTimeout(listener, timeoutMs);
    }
    return {
        signal: controller.signal,
        cleanup: () => clearTimeout(timeoutId),
    };
}
/**
 * Returns the reason why an AbortSignal was aborted. Returns undefined if the
 * signal has not been aborted.
 *
 * The property AbortSignal.reason is not widely available. This function
 * returns an AbortError if the signal is aborted, but reason is undefined.
 *
 * @private Internal code, does not follow semantic versioning.
 */
function getAbortSignalReason(signal) {
    if (!signal.aborted) {
        return undefined;
    }
    if (signal.reason !== undefined) {
        return signal.reason;
    }
    // AbortSignal.reason is available in Node.js v16, v18, and later,
    // and in all browsers since early 2022.
    const e = new Error("This operation was aborted");
    e.name = "AbortError";
    return e;
}

export { createDeadlineSignal, createLinkedAbortController, getAbortSignalReason };
