SnowflakeCommand.Having.cs

//-----------------------------------------------------------------------
// <copyright file="SnowflakeCommand.Having.cs" company="Jonas Schubert">
//     Copyright (c) Jonas Schubert. All rights reserved.
// </copyright>
// <author>Jonas Schubert</author>
//-----------------------------------------------------------------------

namespace Snowflake.Data.Xt;

/// <summary>
/// The snowflake command.
/// </summary>
/// <typeparam name="T">The generic type. This is used to parse properties for the query.</typeparam>
public partial class SnowflakeCommand<T>
  where T : class
{
  /// <summary>
  /// Adds a having value. Requires a group by clause.
  /// https://docs.snowflake.com/en/sql-reference/constructs/having .
  /// </summary>
  /// <param name="having">The having value.</param>
  /// <returns>The snowflake command.</returns>
  /// <exception cref="InvalidOperationException">Command already has a having clause.</exception>
  /// <exception cref="InvalidOperationException">Group By is missing and has to be called before Having.</exception>
  /// <exception cref="ArgumentNullException">Value for having predicate may not be empty.</exception>
  public SnowflakeCommand<T> Having(string having)
  {
    if (this.Sql.Contains("HAVING", StringComparison.Ordinal))
    {
      throw new InvalidOperationException("Command already has a having clause!");
    }

    if (!this.Sql.Contains("GROUP BY", StringComparison.Ordinal))
    {
      throw new InvalidOperationException("Group By is missing and has to be called before Having!");
    }

    if (string.IsNullOrWhiteSpace(having))
    {
      throw new ArgumentNullException(nameof(having), "Value for having predicate may not be empty!");
    }

    this.SqlBuilder.Append($" {(having.Trim().StartsWith("HAVING", ignoreCase: true, CultureInfo.InvariantCulture) ? having.Trim() : $"HAVING {having.Trim()}")}");

    return this;
  }
}