// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Data.Common;
using System.Diagnostics;
 
namespace Aspire.Hosting.Azure.CosmosDB;
 
internal static class CosmosUtils
{
    internal static bool IsEmulatorConnectionString(string? connectionString)
    {
        if (connectionString == null)
        {
            return false;
        }
 
        var builder = new DbConnectionStringBuilder();
        builder.ConnectionString = connectionString;
        if (!builder.TryGetValue("AccountKey", out var v))
        {
            return false;
        }
        var accountKeyFromConnectionString = v.ToString();
        return accountKeyFromConnectionString == CosmosConstants.EmulatorAccountKey;
    }
 
    /// <summary>
    /// Parses the connection string to extract the account endpoint and connection string.
    /// </summary>
    /// <remarks>
    /// The connection string can be in the following formats:
    /// A valid Uri
    /// AccountEndpoint={valid Uri} - optionally with [;Database={databaseName}[;Container={containerName}]]
    /// {valid CosmosDB ConnectionString} - optionally with [;Database={databaseName}[;Container={containerName}]]
    /// </remarks>
    internal static CosmosConnectionInfo ParseConnectionString(string connectionString)
    {
        Uri? accountEndpoint;
        if (Uri.TryCreate(connectionString, UriKind.Absolute, out accountEndpoint))
        {
            return new CosmosConnectionInfo(accountEndpoint, null);
        }
 
        var connectionBuilder = new DbConnectionStringBuilder()
        {
            ConnectionString = connectionString
        };
 
        // Strip out the database and container from the connection string in order
        // to tell if we are left with just AccountEndpoint.
        if (connectionBuilder.TryGetValue("Database", out var _))
        {
            connectionBuilder["Database"] = null;
        }
 
        if (connectionBuilder.TryGetValue("Container", out var _))
        {
            connectionBuilder["Container"] = null;
        }
 
        // if we are only left with the AccountEndpoint, then we set the AccountEndpoint and
        // not the connection string.
        if (connectionBuilder.Count == 1 &&
            connectionBuilder.TryGetValue("AccountEndpoint", out var accountEndpointValue) &&
            Uri.TryCreate(accountEndpointValue.ToString(), UriKind.Absolute, out accountEndpoint))
        {
            return new CosmosConnectionInfo(accountEndpoint, null);
        }
 
        return new CosmosConnectionInfo(null, connectionBuilder.ConnectionString);
    }
}
 
internal readonly struct CosmosConnectionInfo
{
    public CosmosConnectionInfo(Uri? accountEndpoint, string? connectionString)
    {
        Debug.Assert(accountEndpoint is not null ^ connectionString is not null, "only one should be set.");
 
        AccountEndpoint = accountEndpoint;
        ConnectionString = connectionString;
    }
 
    public Uri? AccountEndpoint { get; }
    public string? ConnectionString { get; }
}