using System.Collections.Concurrent;
using System.Runtime.CompilerServices;

namespace ZymonicServices;

internal static class ZymonicHttpClients
{
	private static readonly ConcurrentDictionary<string, Lazy<HttpClient>> Clients = new();

	public static HttpClient Anonymous(IZymonicLogger logger, string baseUri)
	{
		return GetOrCreate(
			$"anonymous:{NormalizeBaseUri(baseUri)}",
				() => new HttpClient(new HttpLoggingHandler(logger, new HttpClientHandler() { UseCookies = false }))
				{
					BaseAddress = new Uri(NormalizeBaseUri(baseUri)),
					// Shared clients cannot safely vary HttpClient.Timeout per request; callers use TimeoutToken instead.
					Timeout = Timeout.InfiniteTimeSpan
				});
	}

	public static HttpClient Authenticated(IZymonicLogger logger, IZymonicAA authService, string baseUri)
	{
		return GetOrCreate(
			$"authenticated:{RuntimeHelpers.GetHashCode(authService)}:{NormalizeBaseUri(baseUri)}",
				() => new HttpClient(new ZymonicAPIHandler(logger, authService, new HttpLoggingHandler(logger)))
				{
					BaseAddress = new Uri(NormalizeBaseUri(baseUri)),
					// Shared clients cannot safely vary HttpClient.Timeout per request; callers use TimeoutToken instead.
					Timeout = Timeout.InfiniteTimeSpan
				});
	}

	public static CancellationTokenSource TimeoutToken(CancellationToken ct, int timeoutSeconds)
	{
		var timeoutCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
		timeoutCts.CancelAfter(TimeSpan.FromSeconds(timeoutSeconds));
		return timeoutCts;
	}

	private static HttpClient GetOrCreate(string key, Func<HttpClient> createClient)
	{
		return Clients.GetOrAdd(key, _ => new Lazy<HttpClient>(createClient, LazyThreadSafetyMode.ExecutionAndPublication)).Value;
	}

	private static string NormalizeBaseUri(string baseUri)
	{
		return baseUri.EndsWith("/", StringComparison.Ordinal) ? baseUri : $"{baseUri}/";
	}
}