// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
#pragma warning disable AZPROVISION001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
 
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using Aspire.Hosting.ApplicationModel;
using Azure.Provisioning;
using Azure.Provisioning.Expressions;
using Azure.Provisioning.Primitives;
using Azure.Provisioning.RedisEnterprise;
 
namespace Aspire.Hosting.Azure;
 
/// <summary>
/// Represents an Azure Cache for Redis Enterprise resource.
/// </summary>
/// <param name="name">The name of the resource.</param>
/// <param name="configureInfrastructure">Callback to configure the Azure resources.</param>
[Experimental("ASPIREAZUREREDIS001", UrlFormat = "https://aka.ms/aspire/diagnostics/{0}")]
public class AzureRedisEnterpriseResource(string name, Action<AzureResourceInfrastructure> configureInfrastructure)
    : AzureProvisioningResource(name, configureInfrastructure), IResourceWithConnectionString
{
    /// <summary>
    /// Gets the "connectionString" output reference from the bicep template for the Azure Redis Enterprise resource.
    ///
    /// This is used when Entra ID authentication is used. The connection string is an output of the bicep template.
    /// </summary>
    private BicepOutputReference ConnectionStringOutput => new("connectionString", this);
 
    /// <summary>
    /// Gets the "connectionString" secret reference from the key vault associated with this resource.
    ///
    /// This is set when access key authentication is used. The connection string is stored in a secret in the Azure Key Vault.
    /// </summary>
    internal IAzureKeyVaultSecretReference? ConnectionStringSecretOutput { get; set; }
 
    /// <summary>
    /// Gets the "name" output reference for the resource.
    /// </summary>
    public BicepOutputReference NameOutputReference => new("name", this);
 
    /// <summary>
    /// Gets the "hostName" output reference from the bicep template for the Azure Redis resource.
    /// </summary>
    private BicepOutputReference HostNameOutput => new("hostName", this);
 
    /// <summary>
    /// Gets a value indicating whether the resource uses access key authentication.
    /// </summary>
    [MemberNotNullWhen(true, nameof(ConnectionStringSecretOutput))]
    public bool UseAccessKeyAuthentication => ConnectionStringSecretOutput is not null;
 
    /// <summary>
    /// Gets the inner Redis resource.
    /// 
    /// This is set when RunAsContainer is called on the AzureRedisEnterpriseResource resource to create a local Redis container.
    /// </summary>
    internal RedisResource? InnerResource { get; private set; }
 
    /// <inheritdoc />
    public override ResourceAnnotationCollection Annotations => InnerResource?.Annotations ?? base.Annotations;
 
    /// <summary>
    /// Gets the connection string template for the manifest for the Azure Cache for Redis Enterprise resource.
    /// </summary>
    public ReferenceExpression ConnectionStringExpression =>
        InnerResource?.ConnectionStringExpression ??
            (UseAccessKeyAuthentication ?
                ReferenceExpression.Create($"{ConnectionStringSecretOutput}") :
                ReferenceExpression.Create($"{ConnectionStringOutput}"));
 
    /// <summary>
    /// Gets the host name for the Redis server.
    /// </summary>
    /// <remarks>
    /// In container mode, resolves to the container's primary endpoint host and port.
    /// In Azure mode, resolves to the Azure Redis server's hostname.
    /// </remarks>
    public ReferenceExpression HostName =>
        InnerResource is not null ?
            ReferenceExpression.Create($"{InnerResource.PrimaryEndpoint.Property(EndpointProperty.HostAndPort)}") :
            ReferenceExpression.Create($"{HostNameOutput}");
 
    /// <summary>
    /// Gets the password for the Redis server when running as a container.
    /// </summary>
    /// <remarks>
    /// This property returns null when running in Azure mode, as Redis access is handled via connection strings.
    /// When running as a container, it resolves to the password parameter value if one exists.
    /// </remarks>
    public ReferenceExpression? Password =>
        InnerResource is not null && InnerResource.PasswordParameter is not null ?
            ReferenceExpression.Create($"{InnerResource.PasswordParameter}") :
            null;
 
    internal void SetInnerResource(RedisResource innerResource)
    {
        // Copy the annotations to the inner resource before making it the inner resource
        foreach (var annotation in Annotations)
        {
            innerResource.Annotations.Add(annotation);
        }
 
        InnerResource = innerResource;
    }
 
    /// <inheritdoc/>
    public override ProvisionableResource AddAsExistingResource(AzureResourceInfrastructure infra)
    {
        var bicepIdentifier = this.GetBicepIdentifier();
        var resources = infra.GetProvisionableResources();
 
        // Check if a RedisEnterpriseCluster with the same identifier already exists
        var existingCluster = resources.OfType<RedisEnterpriseCluster>().SingleOrDefault(cluster => cluster.BicepIdentifier == bicepIdentifier);
 
        if (existingCluster is not null)
        {
            return existingCluster;
        }
 
        // Create and add new resource if it doesn't exist
        var cluster = RedisEnterpriseCluster.FromExisting(bicepIdentifier);
 
        if (!TryApplyExistingResourceNameAndScope(
            this,
            infra,
            cluster))
        {
            cluster.Name = NameOutputReference.AsProvisioningParameter(infra);
        }
 
        infra.Add(cluster);
        return cluster;
    }
 
    /// <inheritdoc/>
    public override void AddRoleAssignments(IAddRoleAssignmentsContext roleAssignmentContext)
    {
        Debug.Assert(!UseAccessKeyAuthentication, "AddRoleAssignments should not be called when using AccessKeyAuthentication");
 
        var infra = roleAssignmentContext.Infrastructure;
        var redisEnterprise = (RedisEnterpriseCluster)AddAsExistingResource(infra);
 
        var redisEnterpriseDatabase = infra.GetProvisionableResources()
            .OfType<RedisEnterpriseDatabase>()
            .SingleOrDefault(db => db.BicepIdentifier == redisEnterprise.BicepIdentifier + "_default");
        if (redisEnterpriseDatabase is null)
        {
            redisEnterpriseDatabase = RedisEnterpriseDatabase.FromExisting(redisEnterprise.BicepIdentifier + "_default");
            redisEnterpriseDatabase.Name = "default";
            redisEnterpriseDatabase.Parent = redisEnterprise;
            infra.Add(redisEnterpriseDatabase);
        }
 
        var principalId = roleAssignmentContext.PrincipalId;
 
        AddEnterpriseContributorPolicyAssignment(infra, redisEnterpriseDatabase, principalId);
    }
 
    private static void AddEnterpriseContributorPolicyAssignment(AzureResourceInfrastructure infra, RedisEnterpriseDatabase database, BicepValue<Guid> principalId)
    {
        // For Redis Enterprise, we need to use the appropriate access policy assignment
        // This may need to be adjusted based on the actual Azure.Provisioning.Redis types available
        infra.Add(new AccessPolicyAssignment($"{database.BicepIdentifier}_contributor")
        {
            Name = BicepFunction.CreateGuid(database.Id, principalId, "default"),
            Parent = database,
            AccessPolicyName = "default",
            UserObjectId = principalId
        });
    }
}