using System;

using System.Text;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        TableBuilder builder = new TableBuilder();

        builder.Create("table1", (table) => new

                          {

                              Id = table.Column("int", false).Annotation("SqlServer:Identity", "1,1").GetColumnDetails(),

                              Name = table.Column("nvarchar", false).GetColumnDetails(),

                              Age = table.Column("int", true).GetColumnDetails()

                          }, (table) =>  "");

        Console.WriteLine();

        builder.Create("table2", (table) => new 

                       {

                           Id = table.Column("UNIQUEIDENTIFIER", false, defaultValue: "NEWID()").GetColumnDetails(),

                           Data = table.Column("nvarchar", true).GetColumnDetails()

                       }, (table) => 

                           table.PrimaryKey("PK_table2", "Id")

                       );

    }

}

​

public class TableBuilder

    {

        private string TableGenQuery;

        private string TableAlterQuery;

        private string TableDropQuery;

​

        public ColumnBuilder ColumnBuilder { get;  }

        public TableBuilder()

        {

        }

        /// <summary>

        /// Creates a table with columns and constraints.

        /// </summary>

        /// <param name="name">The table name</param>

        /// <param name="columns">The table columns builder</param>

        public void CreateTable(string name, Func<ColumnBuilder, ColumnBuilder> columns)

        {

            var columnBuilder = new ColumnBuilder();

            columns.Invoke(columnBuilder);

            Console.WriteLine("Columns: {0}", columnBuilder.GetType());

        }

       public void Create(string name, Func<ColumnBuilder, object> columns, Func<ConstraintBuilder, string> constraint) 

       {

            ColumnBuilder columnBuilder = new();

            ConstraintBuilder constraintBuilder = new();

            var eleColumns = columns.Invoke(columnBuilder);

            var eleConstraint = constraint.Invoke(constraintBuilder);

            StringBuilder sb = new StringBuilder();

            sb.AppendLine($"IF NOT EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[{name}]') AND type in (N'U')");

            sb.AppendLine("BEGIN");

            sb.AppendLine($"CREATE TABLE [dbo].[{name}](");

            foreach (var ele in (eleColumns.GetType().GetProperties()))

            {

                sb.AppendLine($"[{ele.Name}] {ele.GetValue(eleColumns)},");

            }

            if (!string.IsNullOrEmpty(eleConstraint))

            {

                sb.AppendLine(eleConstraint);

            }

            else

            {

                sb.Remove(sb.Length - 3, 2);

            }

            sb.AppendLine(") ON [PRIMARY]");

            sb.AppendLine("END");

            string tableGenQuery = sb.ToString();

           Console.WriteLine(tableGenQuery);

       }

    }

​

    public class ColumnBuilder

    {

        private string ColumnDetail { get; set; }

​

        public ColumnBuilder() { }

​

        public ColumnBuilder Column(string type, bool isNullable, object defaultValue = null, int? maxLength = null)

        {

            string nullable = isNullable ? "NULL" : "NOT NULL";

            string maxLen = maxLength != null ? $"({maxLength})" : "";

            string defaultVal = defaultValue != null ? $"DEFAULT {defaultValue}" : "";

            ColumnDetail = $"{type}{maxLen} {nullable} {defaultVal}";

            return this;

        }

        public ColumnBuilder Annotation(string name, string value) 

        {

            if (name.Contains("Identity")) 

            {

                ColumnDetail = $"{ColumnDetail} IDENTITY({value})";

            }

            return this;

        }

        public string GetColumnDetails() 

        {

            return ColumnDetail;

        }

    }

​

    public class ConstraintBuilder

    {

        private string ConstraintDetail { get; set; }

​

        public ConstraintBuilder() { }

​

        public string PrimaryKey(string name, string column)

        {

            ConstraintDetail = $@"CONSTRAINT [{name}] PRIMARY KEY CLUSTERED

                                 (

                                     [{column}] ASC

                                 )WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]";

            return ConstraintDetail;

        }

​

    }