Libation/Source/LibationCli/Options/LoginExternalOptions.cs

using AudibleApi;
using AudibleUtilities;
using CommandLine;
using System;
using System.Net;
using System.Threading.Tasks;

namespace LibationCli;

[Verb("login-external", HelpText = "Sign in with Audible using an external browser: open the printed URL, then paste the final URL from the address bar.")]
internal class LoginExternalOptions : OptionsBase
{
	[Option('a', "account", Required = true, HelpText = "Audible login id (email) for this account.")]
	public string? AccountId { get; set; }

	[Option('l', "locale", Required = true, HelpText = "Audible marketplace / locale (e.g. us, uk, de).")]
	public string? Locale { get; set; }

	[Option("response-url", Required = false, HelpText = "Final browser URL after login. Use when stdin is not a TTY (e.g. scripts, Docker).")]
	public string? ResponseUrl { get; set; }

	protected override async Task ProcessAsync()
	{
		var accountId = AccountId?.Trim();
		var localeName = Locale?.Trim();
		if (string.IsNullOrEmpty(accountId) || string.IsNullOrEmpty(localeName))
		{
			PrintVerbUsage("ERROR", "=====", "Both --account and --locale are required.");
			Environment.ExitCode = (int)ExitCode.RunTimeError;
			return;
		}

		Locale locale;
		try
		{
			locale = Localization.Get(localeName);
		}
		catch (Exception ex)
		{
			PrintVerbUsage("ERROR", "=====", $"Unknown locale '{localeName}': {ex.Message}");
			Environment.ExitCode = (int)ExitCode.RunTimeError;
			return;
		}

		using var persister = AudibleApiStorage.GetAccountsSettingsPersister();
		var account = persister.AccountsSettings.Upsert(accountId, localeName);

		if (account.IdentityTokens?.IsValid == true)
		{
			Console.WriteLine(
				$"Account '{accountId}' ({localeName}) is already authenticated. No browser login needed.");
			return;
		}

		var presetResponse = ResponseUrl?.Trim();
		if (string.IsNullOrEmpty(presetResponse) && Console.IsInputRedirected)
		{
			Console.Error.WriteLine(
				"Standard input is redirected. Provide the post-login URL with --response-url \"...\".");
			Environment.ExitCode = (int)ExitCode.RunTimeError;
			return;
		}

		var loginExternal = new CliLoginExternal(presetResponse);
		try
		{
			_ = await EzApiCreator.GetApiAsync(
				loginExternal,
				locale,
				AudibleApiStorage.AccountsSettingsFile,
				account.GetIdentityTokensJsonPath());
		}
		catch (Exception ex)
		{
			PrintVerbUsage("ERROR", "=====", ex.Message, "", ex.StackTrace);
			Environment.ExitCode = (int)ExitCode.RunTimeError;
			return;
		}

		Console.WriteLine($"Successfully authenticated account '{accountId}' ({localeName}).");
	}

	private sealed class CliLoginExternal : ILoginExternal
	{
		private readonly string? _presetResponseUrl;

		public CliLoginExternal(string? presetResponseUrl) => _presetResponseUrl = presetResponseUrl;

		public string DeviceName => "Libation";

		public string GetResponseUrl(string loginUrl, CookieCollection signInCookies)
		{
			if (!string.IsNullOrEmpty(_presetResponseUrl))
				return ValidateResponseUrl(_presetResponseUrl);

			Console.WriteLine();
			Console.WriteLine("Open this URL in your web browser and sign in:");
			Console.WriteLine(loginUrl);
			Console.WriteLine();
			Console.WriteLine(
				"After you finish signing in, copy the full URL from your browser's address bar and paste it below.");
			Console.WriteLine("(It is normal if the page says it does not exist.)");
			Console.WriteLine();
			Console.Write("Paste URL: ");

			var line = Console.ReadLine()?.Trim();
			if (string.IsNullOrEmpty(line))
				throw new OperationCanceledException("No response URL was entered.");

			return ValidateResponseUrl(line);
		}

		private static string ValidateResponseUrl(string url)
		{
			if (!Uri.TryCreate(url, UriKind.Absolute, out _))
				throw new ArgumentException("The response URL must be a valid absolute URL.");

			return url;
		}
	}
}