// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using Aspire.Hosting.ApplicationModel;
 
namespace Aspire.Hosting;
 
/// <summary>
/// Wraps a gateway <see cref="EndpointReference"/> so publishers can emit a deployer-configurable
/// placeholder (e.g., <c>${GATEWAY_BINDINGS_HTTPS_URL}</c>) while dev mode resolves the actual URL.
/// </summary>
/// <remarks>
/// The origin is served to browsers, so it must never resolve to an address that is only reachable
/// inside the local Aspire container network. Deployment networks are still honored so publishers can
/// resolve their own browser-facing hosts.
/// </remarks>
internal sealed class GatewayOriginReference(EndpointReference endpoint) : IValueProvider, IManifestExpressionProvider
{
    public string ValueExpression => $"{{{endpoint.Resource.Name}.bindings.{endpoint.EndpointName}.url}}";
 
    public async ValueTask<string?> GetValueAsync(CancellationToken cancellationToken = default)
    {
        var url = await endpoint.GetValueAsync(cancellationToken).ConfigureAwait(false);
        return url?.TrimEnd('/');
    }
 
    public async ValueTask<string?> GetValueAsync(ValueProviderContext context, CancellationToken cancellationToken = default)
    {
        var url = await endpoint.GetValueAsync(GetBrowserContext(context), cancellationToken).ConfigureAwait(false);
        return url?.TrimEnd('/');
    }
 
    private static ValueProviderContext GetBrowserContext(ValueProviderContext context)
    {
        if (context.GetNetworkIdentifier() != KnownNetworkIdentifiers.DefaultAspireContainerNetwork)
        {
            return context;
        }
 
        return new ValueProviderContext
        {
            ExecutionContext = context.ExecutionContext,
            Caller = context.Caller,
            Network = KnownNetworkIdentifiers.LocalhostNetwork
        };
    }
}