using System.Text;

namespace Connected.Data.Schema.Sql
{
	internal class DefaultAdd : ColumnTransaction
	{
		public DefaultAdd(ISchemaColumn column, string tableName) : base(column)
		{
			TableName = tableName;
		}

		private string TableName { get; }

		protected override async Task OnExecute()
		{
			await Context.Execute(CommandText);
		}

		private string CommandText
		{
			get
			{
				var text = new StringBuilder();

				var defValue = SchemaExtensions.ParseDefaultValue(Column.DefaultValue);

				text.AppendLine($"ALTER TABLE {Escape(Context.Schema.SchemaName(), TableName)}");
				text.AppendLine($"ADD CONSTRAINT {Context.GenerateConstraintName(Context.Schema.SchemaName(), TableName, ConstraintNameType.Default)} DEFAULT {defValue} FOR {Column.Name}");

				return text.ToString();
			}
		}
	}
}