const pending_requests = [];

function add_pending_request(jqXHR) {
    pending_requests.push(jqXHR);
    if (pending_requests.length > 50) {
        blueslip.warn(
            "The length of pending_requests is over 50. Most likely " +
                "they are not being correctly removed.",
        );
    }
}

function remove_pending_request(jqXHR) {
    const pending_request_index = pending_requests.indexOf(jqXHR);
    if (pending_request_index !== -1) {
        pending_requests.splice(pending_request_index, 1);
    }
}

function call(args, idempotent) {
    if (reload_state.is_in_progress() && !args.ignore_reload) {
        // If we're in the process of reloading, most HTTP requests
        // are useless, with exceptions like cleaning up our event
        // queue and blueslip (Which doesn't use channel.js).
        return undefined;
    }

    // Wrap the error handlers to reload the page if we get a CSRF error
    // (What probably happened is that the user logged out in another tab).
    let orig_error = args.error;
    if (orig_error === undefined) {
        orig_error = function () {};
    }
    args.error = function wrapped_error(xhr, error_type, xhn) {
        remove_pending_request(xhr);

        if (reload_state.is_in_progress()) {
            // If we're in the process of reloading the browser,
            // there's no point in running the success handler,
            // because all of our state is about to be discarded
            // anyway.
            blueslip.log(`Ignoring ${args.type} ${args.url} error response while reloading`);
            return;
        }

        if (xhr.status === 403) {
            try {
                if (JSON.parse(xhr.responseText).code === "CSRF_FAILED") {
                    reload.initiate({
                        immediate: true,
                        save_pointer: true,
                        save_narrow: true,
                        save_compose: true,
                    });
                }
            } catch (error) {
                blueslip.error(
                    "Unexpected 403 response from server",
                    {xhr: xhr.responseText, args},
                    error.stack,
                );
            }
        }
        orig_error(xhr, error_type, xhn);
    };
    let orig_success = args.success;
    if (orig_success === undefined) {
        orig_success = function () {};
    }
    args.success = function wrapped_success(data, textStatus, jqXHR) {
        remove_pending_request(jqXHR);

        if (reload_state.is_in_progress()) {
            // If we're in the process of reloading the browser,
            // there's no point in running the success handler,
            // because all of our state is about to be discarded
            // anyway.
            blueslip.log(`Ignoring ${args.type} ${args.url} response while reloading`);
            return;
        }

        if (!data && idempotent) {
            // If idempotent, retry
            blueslip.log("Retrying idempotent" + args);
            setTimeout(() => {
                const jqXHR = $.ajax(args);
                add_pending_request(jqXHR);
            }, 0);
            return;
        }
        orig_success(data, textStatus, jqXHR);
    };

    const jqXHR = $.ajax(args);
    add_pending_request(jqXHR);
    return jqXHR;
}

export function get(options) {
    const args = {type: "GET", dataType: "json", ...options};
    return call(args, options.idempotent);
}

export function post(options) {
    const args = {type: "POST", dataType: "json", ...options};
    return call(args, options.idempotent);
}

export function put(options) {
    const args = {type: "PUT", dataType: "json", ...options};
    return call(args, options.idempotent);
}

// Not called exports.delete because delete is a reserved word in JS
export function del(options) {
    const args = {type: "DELETE", dataType: "json", ...options};
    return call(args, options.idempotent);
}

export function patch(options) {
    // Send a PATCH as a POST in order to work around QtWebkit
    // (Linux/Windows desktop app) not supporting PATCH body.
    if (options.processData === false) {
        // If we're submitting a FormData object, we need to add the
        // method this way
        options.data.append("method", "PATCH");
    } else {
        options.data = {...options.data, method: "PATCH"};
    }
    return post(options, options.idempotent);
}

export function xhr_error_message(message, xhr) {
    if (xhr.status.toString().charAt(0) === "4") {
        // Only display the error response for 4XX, where we've crafted
        // a nice response.
        message += ": " + JSON.parse(xhr.responseText).msg;
    }
    return message;
}