// 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.Publishing;
using System.Text.Json.Nodes;
using System.Text.Json;
using Microsoft.Extensions.DependencyInjection;
 
namespace Aspire.Hosting.Utils;
 
public sealed class ManifestUtils
{
    public static async Task<JsonNode> GetManifest(IResource resource, string? manifestDirectory = null)
    {
        var node = await GetManifestOrNull(resource, manifestDirectory);
        Assert.NotNull(node);
        return node;
    }
 
    public static async Task<JsonNode?> GetManifestOrNull(IResource resource, string? manifestDirectory = null)
    {
        manifestDirectory ??= Environment.CurrentDirectory;
 
        using var ms = new MemoryStream();
        var writer = new Utf8JsonWriter(ms);
 
        var serviceCollection = new ServiceCollection();
        var options = new DistributedApplicationExecutionContextOptions(DistributedApplicationOperation.Publish);
        var executionContext = new DistributedApplicationExecutionContext(options);
        serviceCollection.AddSingleton(executionContext);
        options.ServiceProvider = serviceCollection.BuildServiceProvider();
        
        writer.WriteStartObject();
        var context = new ManifestPublishingContext(executionContext, Path.Combine(manifestDirectory, "manifest.json"), writer);
        await context.WriteResourceAsync(resource);
        writer.WriteEndObject();
        writer.Flush();
        ms.Position = 0;
        var obj = JsonNode.Parse(ms);
        Assert.NotNull(obj);
        var resourceNode = obj[resource.Name];
        return resourceNode;
    }
 
    public static async Task<JsonNode> GetManifestForModel(DistributedApplicationModel model, string? manifestDirectory = null)
    {
        manifestDirectory ??= Environment.CurrentDirectory;
 
        using var ms = new MemoryStream();
        var writer = new Utf8JsonWriter(ms, new() { Indented = true });
        var options = new DistributedApplicationExecutionContextOptions(DistributedApplicationOperation.Publish)
        {
            ServiceProvider = new ServiceCollection().BuildServiceProvider()
        };
        var executionContext = new DistributedApplicationExecutionContext(options);
        var context = new ManifestPublishingContext(executionContext, Path.Combine(manifestDirectory, "manifest.json"), writer);
 
        await context.WriteModel(model, CancellationToken.None);
 
        ms.Position = 0;
        var obj = JsonNode.Parse(ms);
        Assert.NotNull(obj);
        return obj;
    }
 
    public static async Task<JsonNode[]> GetManifests(IResource[] resources)
    {
        using var ms = new MemoryStream();
        var writer = new Utf8JsonWriter(ms);
        var options = new DistributedApplicationExecutionContextOptions(DistributedApplicationOperation.Publish)
        {
            ServiceProvider = new ServiceCollection().BuildServiceProvider()
        };
        var executionContext = new DistributedApplicationExecutionContext(options);
        var context = new ManifestPublishingContext(executionContext, Path.Combine(Environment.CurrentDirectory, "manifest.json"), writer);
 
        var results = new List<JsonNode>();
 
        foreach (var r in resources)
        {
            writer.WriteStartObject();
            await context.WriteResourceAsync(r);
            writer.WriteEndObject();
            writer.Flush();
            ms.Position = 0;
            var obj = JsonNode.Parse(ms);
            Assert.NotNull(obj);
            var resourceNode = obj[r.Name];
            Assert.NotNull(resourceNode);
            results.Add(resourceNode);
 
            ms.Position = 0;
            writer.Reset(ms);
        }
 
        return [.. results];
    }
}