// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using Aspire.Hosting.ApplicationModel;
using Aspire.Hosting.Azure;
using Aspire.Hosting.Azure.CosmosDB;
using Azure.Provisioning.CosmosDB;
using Azure.Provisioning.Primitives;
 
namespace Aspire.Hosting;
 
/// <summary>
/// A resource that represents an Azure Cosmos DB.
/// </summary>
public class AzureCosmosDBResource(string name, Action<AzureResourceInfrastructure> configureInfrastructure)
    : AzureProvisioningResource(name, configureInfrastructure),
    IResourceWithConnectionString,
    IResourceWithEndpoints,
    IResourceWithAzureFunctionsConfig
{
    internal List<AzureCosmosDBDatabaseResource> Databases { get; } = [];
 
    internal EndpointReference EmulatorEndpoint => new(this, "emulator");
 
    /// <summary>
    /// Gets the "connectionString" reference from the secret outputs of the Azure Cosmos DB resource.
    /// </summary>
    public BicepSecretOutputReference ConnectionString => new("connectionString", this);
 
    /// <summary>
    /// Gets the "connectionString" output reference from the bicep template for the Azure Cosmos DB resource.
    ///
    /// This is used when Entra ID authentication is used. The connection string is an output of the bicep template.
    /// </summary>
    public 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; }
 
    private BicepOutputReference NameOutputReference => new("name", 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 a value indicating whether the Azure Cosmos DB resource is running in the local emulator.
    /// </summary>
    public bool IsEmulator => this.IsContainer();
 
    internal bool IsPreviewEmulator =>
        this.TryGetContainerImageName(out var imageName) &&
        imageName == $"{CosmosDBEmulatorContainerImageTags.Registry}/{CosmosDBEmulatorContainerImageTags.Image}:{CosmosDBEmulatorContainerImageTags.TagVNextPreview}";
 
    /// <summary>
    /// Gets the connection string template for the manifest for the Azure Cosmos DB resource.
    /// </summary>
    public ReferenceExpression ConnectionStringExpression =>
        IsEmulator
        ? AzureCosmosDBEmulatorConnectionString.Create(EmulatorEndpoint, IsPreviewEmulator)
        : UseAccessKeyAuthentication ?
            ReferenceExpression.Create($"{ConnectionStringSecretOutput}") :
            ReferenceExpression.Create($"{ConnectionStringOutput}");
 
    void IResourceWithAzureFunctionsConfig.ApplyAzureFunctionsConfiguration(IDictionary<string, object> target, string connectionName)
    {
        if (IsEmulator || UseAccessKeyAuthentication)
        {
            SetConnectionString(target, connectionName, ConnectionStringExpression);
        }
        else
        {
            SetAccountEndpoint(target, connectionName);
        }
    }
 
    internal void SetConnectionString(IDictionary<string, object> target, string connectionName, ReferenceExpression connectionStringExpression)
    {
        // Always inject the connection string associated with the top-level resource
        // for the Azure Functions host.
        target[connectionName] = ConnectionStringExpression;
        // Injected to support Aspire client integration for CosmosDB in Azure Functions projects.
        // Use the child resource connection string here to support child resource integrations.
        target[$"Aspire__Microsoft__EntityFrameworkCore__Cosmos__{connectionName}__ConnectionString"] = connectionStringExpression;
        target[$"Aspire__Microsoft__Azure__Cosmos__{connectionName}__ConnectionString"] = connectionStringExpression;
    }
 
    internal void SetAccountEndpoint(IDictionary<string, object> target, string connectionName)
    {
        // Always inject the connection string associated with the top-level resource
        // for the Azure Functions host.
        target[$"{connectionName}__accountEndpoint"] = ConnectionStringExpression;
        // Injected to support Aspire client integration for CosmosDB in Azure Functions projects.
        target[$"Aspire__Microsoft__EntityFrameworkCore__Cosmos__{connectionName}__AccountEndpoint"] = ConnectionStringExpression;
        target[$"Aspire__Microsoft__Azure__Cosmos__{connectionName}__AccountEndpoint"] = ConnectionStringExpression;
    }
 
    /// <inheritdoc/>
    public override ProvisionableResource AddAsExistingResource(AzureResourceInfrastructure infra)
    {
        var store = CosmosDBAccount.FromExisting(this.GetBicepIdentifier());
        store.Name = NameOutputReference.AsProvisioningParameter(infra);
        infra.Add(store);
        return store;
    }
 
    /// <inheritdoc/>
    public override void AddRoleAssignments(IAddRoleAssignmentsContext roleAssignmentContext)
    {
        Debug.Assert(!UseAccessKeyAuthentication, "AddRoleAssignments should not be called when using AccessKeyAuthentication");
 
        var infra = roleAssignmentContext.Infrastructure;
        var cosmosAccount = (CosmosDBAccount)AddAsExistingResource(infra);
 
        var principalId = roleAssignmentContext.PrincipalId;
 
        AzureCosmosExtensions.AddContributorRoleAssignment(infra, cosmosAccount, principalId);
    }
 
    internal ReferenceExpression GetChildConnectionString(string childResourceName, string? databaseName = null, string? containerName = null)
    {
        if (string.IsNullOrEmpty(databaseName) && string.IsNullOrEmpty(containerName))
        {
            return ConnectionStringExpression;
        }
 
        var builder = new ReferenceExpressionBuilder();
 
        if (UseAccessKeyAuthentication && !IsEmulator)
        {
            builder.AppendFormatted(ConnectionStringSecretOutput.Resource.GetSecret(GetKeyValueSecretName(childResourceName)));
        }
        else
        {
            if (IsEmulator)
            {
                builder.AppendFormatted(ConnectionStringExpression);
            }
            else
            {
                builder.Append($"AccountEndpoint={ConnectionStringExpression}");
            }
 
            if (!string.IsNullOrEmpty(databaseName))
            {
                builder.Append($";Database={databaseName}");
 
                if (!string.IsNullOrEmpty(containerName))
                {
                    builder.Append($";Container={containerName}");
                }
            }
        }
 
        return builder.Build();
    }
 
    internal static string GetKeyValueSecretName(string resourceName)
        => $"connectionstrings--{resourceName}";
}