ServerDatabase/Database/Table.cs

using System.Data;
using System.Diagnostics.CodeAnalysis;
using System.Reflection;
using Npgsql;
using ServerDatabase.Utils;
using ServerDatabase.Utils.Enums;

namespace ServerDatabase;

public class Table<TRow> : IBetterTable where TRow : class, new()
{
    public Table(string Name, Database DB)
    {
        if (Name == "table_versions") throw new ArgumentException("The table name 'table_versions' is not allowed", nameof(Name));
        this.Name = Name;
        DatabaseHandler = DB;
    }
    
    internal Table(Database DB)
    {
        this.Name = "table_versions";
        DatabaseHandler = DB;
    }

    public CommandHandler CreateCommand()
    {
        return new CommandHandler(this);
    }

    public Table<TRow> WithColumn(ITableColumn Column, string name)
    {
        Colums_.Add(Column);
        colnamesraw.Add(Column.Name, name);
        return this;
    }
    
    public void AddColumn(ITableColumn Column, string name)
    {
        colnamesraw.Add(Column.Name, name);
        Colums_.Add(Column);
    }
    
    public IReadOnlyList<ITableColumn> GetMissingColumns(out IReadOnlyList<ITableColumn> UpdatedColumns, out string[] ExtraColumns)
    {
        List<ITableColumn> coll = new(Colums_);
        List<ITableColumn> col = new(Colums_);
        List<string> co = new();
        foreach (DataRow row in DatabaseHandler.CreateConnection().GetSchema("Columns", new[] { DatabaseHandler.DB, null, Name }).Rows)
        {
            string name = row.Field<string>("COLUMN_NAME")!,
                ty = row.Field<string>("DATA_TYPE")!;
            IEnumerable<ITableColumn> t = Colums_.Where(s => s.Name == name);
            if (t.Any())
            {
                col.Remove(t.First());
                if (t.First()!.GetDatabaseTypeStr() == ty)  coll.Remove(t.First());
            }
            else
            {
                co.Add(name);
            }
        }

        UpdatedColumns = coll;
        ExtraColumns = co.ToArray();
        return col.AsReadOnly();
    }

    public void UpdateTable()
    {
        Console.WriteLine("Verifying Table: {0}", Name);
        bool i = true;
        IReadOnlyList<ITableColumn> m = GetMissingColumns(out IReadOnlyList<ITableColumn> n, out string[] o);
        if (m.Any())
        {
            if (i)
            {
                i = false;
                Console.WriteLine("Fixing Table: {0}", Name);
            }
            if (DatabaseHandler.Read<long>(
                    $"SELECT COUNT(table_name) FROM information_schema.tables WHERE table_schema LIKE 'public' AND table_type LIKE 'BASE TABLE' AND table_name = '{Name}';") ==
                0)
            {
                Create();
            }
            else
            {
                foreach (ITableColumn col in m)
                {
                    try
                    {
                        if (col.IsPrimaryKey) throw new Exception($"DELETE THE TABLE '{Name}' TO FIX TABLE GENERATION");
                        string sql = $"ALTER TABLE IF EXISTS public.{Name} ADD COLUMN {col.Name} {col.GetDatabaseTypeStr()}";
                        sql += " NOT NULL";
                        if (col.GetDefaultStr() is not null) sql += $" DEFAULT {col.GetDefaultStr()}";
                        sql += ";";
                        DatabaseHandler.ExecuteNonQuery(sql);
                    }
                    catch (Exception e)
                    {
                        Console.WriteLine("Posible fail to set default for public.{0}.{1}", Name, col.Name);
                    }
                }
            }
        }

        if (n.Any())
        {
            if (i)
            {
                i = false;
                Console.WriteLine("Fixing Table: {0}", Name);
            }
            foreach (ITableColumn col in n)
            {
                string sql = $"ALTER TABLE public.{Name} ALTER COLUMN {col.Name} TYPE {col.GetDatabaseTypeStr()};";
                
                DatabaseHandler.ExecuteNonQuery(sql);
                if (col.GetDefaultStr() is not null)
                {
                    try
                    {
                        sql = $"ALTER TABLE IF EXISTS public.{Name} ALTER COLUMN {col.Name} SET DEFAULT {col.GetDefaultStr()};";
                        DatabaseHandler.ExecuteNonQuery(sql);
                    }
                    catch (Exception e)
                    {
                        Console.WriteLine("Failed to set default for public.{0}.{1}\nSQL: {2}", Name, col.Name, sql);
                    }
                }
            }
        }

        if (o.Any())
        {
            if (i)
            {
                i = false;
                Console.WriteLine("Fixing Table: {0}", Name);
            }
            foreach (string c in o)
            {
                DatabaseHandler.ExecuteNonQuery($"ALTER TABLE IF EXISTS {Name} DROP COLUMN IF EXISTS {c};");
            }
        }
    }

    public Table<TRow> DropColumn<TType>(TableColumn<TType> Column) where TType : notnull
    {
        Colums_.Remove(Column);
        return this;
    }

    private Dictionary<string, string> colnamesraw = new();

    private List<ITableColumn> Colums_ { get; set; } = new();
    
    public IReadOnlyList<ITableColumn> Colums => Colums_.AsReadOnly();

    public string Name { get; set; } = default!;

    public Database DatabaseHandler { get; set; } = default!;
    
    public void Insert(params Parameter[] Parameters)
    {
        if (string.IsNullOrEmpty(DatabaseHandler.DB) || string.IsNullOrEmpty(DatabaseHandler.IP) || string.IsNullOrEmpty(DatabaseHandler.Uname) || string.IsNullOrEmpty(DatabaseHandler.PW)) throw new Exception("Database conection not fully defined");
        using NpgsqlConnection con = new(DatabaseHandler.ConectionString);
        con.Open();
        using NpgsqlCommand cmd = new();
        cmd.Connection = con;
        string vals = "";
        List<ITableColumn> l = new List<ITableColumn>(Colums_);
        foreach (Parameter param in Parameters)
        {
            l.Remove(l.Where(s => s.Name == param.PGParameter.ParameterName).First());
            vals += "@" + param.PGParameter.ParameterName + ", ";
            cmd.Parameters.Add(param.PGParameter);
        }

        foreach (ITableColumn cop in l)
        {
            var param = cop.CreateDefaultParameter();
            vals += "@" + param.PGParameter.ParameterName + ", ";
            cmd.Parameters.Add(param.PGParameter);
        }
        vals = vals.Remove(vals.Length - 2, 2);
        cmd.CommandText = $"INSERT INTO {Name} ({vals.Replace("@", "")}) VALUES({vals})";
        cmd.Prepare();
        cmd.ExecuteNonQuery();
        con.Close();
    }
    
    public void DeleteRow(Parameter Parameter)
    {
        if (string.IsNullOrEmpty(DatabaseHandler.DB) || string.IsNullOrEmpty(DatabaseHandler.IP) || string.IsNullOrEmpty(DatabaseHandler.Uname) || string.IsNullOrEmpty(DatabaseHandler.PW)) throw new Exception("Database conection not fully defined");
        using NpgsqlConnection con = new(DatabaseHandler.ConectionString);
        con.Open();
        using NpgsqlCommand cmd = new();
        cmd.Connection = con;
        cmd.Parameters.Add(Parameter.PGParameter);
        cmd.CommandText = $"DELETE FROM {Name} WHERE {Parameter.PGParameter.ParameterName} IN (@{Parameter.PGParameter.ParameterName});";
        cmd.Prepare();
        cmd.ExecuteNonQuery();
        con.Close();
    }
    
    public void DeleteRows()
    {
        if (string.IsNullOrEmpty(DatabaseHandler.DB) || string.IsNullOrEmpty(DatabaseHandler.IP) || string.IsNullOrEmpty(DatabaseHandler.Uname) || string.IsNullOrEmpty(DatabaseHandler.PW)) throw new Exception("Database conection not fully defined");
        using NpgsqlConnection con = new(DatabaseHandler.ConectionString);
        con.Open();
        using NpgsqlCommand cmd = new();
        cmd.Connection = con;
        cmd.CommandText = $"DELETE FROM {Name};";
        cmd.Prepare();
        cmd.ExecuteNonQuery();
        con.Close();
    }

    public void Create()
    {
        Console.WriteLine("Making Table: {0}", Name);
        if (string.IsNullOrEmpty(DatabaseHandler.DB) || string.IsNullOrEmpty(DatabaseHandler.IP) || string.IsNullOrEmpty(DatabaseHandler.Uname) || string.IsNullOrEmpty(DatabaseHandler.PW)) throw new Exception("Database conection not fully defined");
        using NpgsqlConnection con = new(DatabaseHandler.ConectionString);
        con.Open();
        using NpgsqlCommand cmd = new();
        cmd.Connection = con;
        string command = $"CREATE TABLE IF NOT EXISTS public.{Name}(";
        List<string> Keys = new();
        
        List<Tuple<ITableColumn, IForeignKey>> FKeys = new();
        foreach (ITableColumn column in Colums_)
        {
            command += $"{column.Name} {column.GetDatabaseTypeStr()}";
            if (column.IsPrimaryKey) Keys.Add(column.Name);
            command += " NOT NULL, ";
            if (column.ForeignKeys.Length > 0)
            {
                foreach (IForeignKey Fkey in column.ForeignKeys)
                {
                    FKeys.Add(new(column, Fkey));
                }
            }
        }
        
        if (Keys.Count > 0)
        {
            string key = $"CONSTRAINT {Name}_pkey PRIMARY KEY (";
            foreach (var Key in Keys)
            {
                key += Key + ", ";
            }

            key = key.Remove(key.Length - 2, 2);
            key += "), ";
            command += key;
        }
        
        if (FKeys.Count > 0)
        {
            foreach (Tuple<ITableColumn, IForeignKey> K in FKeys)
            {
                string key = $"CONSTRAINT {Name}_{K.Item1.Name}_{K.Item2.Table.Name}_{K.Item2.Column.Name}_fkey FOREIGN KEY ({K.Item1.Name}) REFERENCES public.{K.Item2.Table.Name} ({K.Item2.Column.Name}) MATCH ";
                if (K.Item2.MatchType == KeyMatchType.Full) key += "FULL ON UPDATE ";
                else key += "SIMPLE ON UPDATE ";
                switch (K.Item2.OnUpdate)
                {
                    case ConstraintAction.None:
                        key += "NO ACTION ON DELETE ";
                        break;
                    case ConstraintAction.Cascade:
                        key += "CASCADE ON DELETE ";
                        break;
                    case ConstraintAction.Restrict:
                        key += "RESTRICT ON DELETE ";
                        break;
                    case ConstraintAction.SetDefault:
                        key += "SET DEFAULT ON DELETE ";
                        break;
                }
                switch (K.Item2.OnDelete)
                {
                    case ConstraintAction.None:
                        key += "NO ACTION ";
                        break;
                    case ConstraintAction.Cascade:
                        key += "CASCADE ";
                        break;
                    case ConstraintAction.Restrict:
                        key += "RESTRICT ";
                        break;
                    case ConstraintAction.SetDefault:
                        key += "SET DEFAULT ";
                        break;
                }

                if (K.Item2.Deferrable) key += "DEFERRABLE ";
                if (K.Item2.Deferred) key += "INITIALLY DEFERRED ";
                if (!K.Item2.Validated) key += "NOT VALID ";
                key = key.Remove(key.Length - 1, 1) + ", ";
                command += key;
            }
        }

        command = command.Remove(command.Length - 2, 2);
        
        command += ");";
        cmd.CommandText = command;
        cmd.Prepare();
        cmd.ExecuteNonQuery();
        con.Close();
        DatabaseHandler.ExecuteNonQuery($"ALTER TABLE IF EXISTS public.{Name} OWNER to \"{DatabaseHandler.Uname}\";");
    }
    
    public bool TryRead<T>(TableColumn<T> column, Order order, [NotNullWhen(true)]out T? result, params Parameter[] Parameters) where T : notnull
    {
        if (string.IsNullOrEmpty(DatabaseHandler.DB) || string.IsNullOrEmpty(DatabaseHandler.IP) || string.IsNullOrEmpty(DatabaseHandler.Uname) || string.IsNullOrEmpty(DatabaseHandler.PW)) throw new Exception("Database conection not fully defined");
        using NpgsqlConnection con = new(DatabaseHandler.ConectionString);
        con.Open();
        using NpgsqlCommand cmd = new();
        cmd.Connection = con;
        string vals = "";
        string command = $"SELECT {column.Name} FROM {Name} WHERE";
        foreach (Parameter param in Parameters)
        {
            vals += $"{param.PGParameter.ParameterName} {param.Sign} @{param.PGParameter.ParameterName} AND ";
            cmd.Parameters.Add(param.PGParameter);
        }
        if (command.EndsWith(";")) command = command.Remove(command.Length - 1, 1);
        if (!string.IsNullOrWhiteSpace(vals)) vals = vals.Remove(vals.Length - 5, 5);
        if (!string.IsNullOrWhiteSpace(vals) && command.EndsWith("WHERE")) command += $" {vals}";
        if (order is not null) command += $" ORDER BY {order.Type} ";
        if (order is not null && order.Assending) command += "ASC";
        else { if (order is not null) command += "DESC"; }
        command += ";";
        cmd.CommandText = command;
        //object? temp = cmd.ExecuteScalar();
        object? temp = null;
        try
        {
            temp = cmd.ExecuteScalar();
        }
        catch
        {
            result = default(T);
            return false;
        }
        con.Close();
        if (temp is DBNull || temp is null)
        {
            result = default(T);
            return false;
        }

        if (typeof(T).IsEnum)
        {
            result = (T)Enum.Parse(typeof(T), temp.ToString()!)!;
            return true;
        }
/*
        if (typeof(T).IsNullableEnum())
        {
            result = (T?)Enum.Parse(Nullable.GetUnderlyingType(typeof(T))!, temp.ToString()!)!;
            return true;
        }
*/
        result = (T)temp!;
        return true;
    }

    public bool TryReadRow(out TRow row, params Parameter[] Parameters) => TryReadRow(null, out row, Parameters);
    
    public bool TryReadRow(Order order, out TRow row, params Parameter[] Parameters)
    {
        if (string.IsNullOrEmpty(DatabaseHandler.DB) || string.IsNullOrEmpty(DatabaseHandler.IP) || string.IsNullOrEmpty(DatabaseHandler.Uname) || string.IsNullOrEmpty(DatabaseHandler.PW)) throw new Exception("Database conection not fully defined");
        using NpgsqlConnection con = new(DatabaseHandler.ConectionString);
        string command = $"SELECT * FROM {Name} WHERE";
        con.Open();
        using NpgsqlCommand cmd = new();
        cmd.Connection = con;
        string vals = "";
        foreach (Parameter param in Parameters)
        {
            vals += $"{param.PGParameter.ParameterName} {param.Sign} @{param.PGParameter.ParameterName} AND ";
            cmd.Parameters.Add(param.PGParameter);
        }
        if (command.EndsWith(";")) command = command.Remove(command.Length - 1, 1);
        if (!string.IsNullOrWhiteSpace(vals)) vals = vals.Remove(vals.Length - 5, 5);
        if (!string.IsNullOrWhiteSpace(vals) && command.EndsWith("WHERE")) command += $" {vals}";
        if (order is not null) command += $" ORDER BY {order.Type} ";
        if (order is not null && order.Assending) command += "ASC";
        else { if (order is not null) command += "DESC"; }
        command += ";";
        cmd.CommandText = command;
        NpgsqlDataReader reader = cmd.ExecuteReader();
        TRow Row = new();
        reader.Read();
        bool r = false;
        for (int i = 0; i < reader.FieldCount; i++)
        {
            r = true;
            string colname = reader.GetName(i);
            object? val = null;
            try
            {
                val = reader.GetValue(i);
            }
            catch
            {
                row = default(TRow);
                return false;
            }
            
            if (colnamesraw.ContainsKey(colname))
            {
                if (val is DBNull || val is null)
                {
                    row = default(TRow);
                    return false;
                }
                PropertyInfo? pi = Row.GetType()
                    .GetProperty(colnamesraw[colname]);
                if (pi is null)
                {
                    Console.WriteLine("Could not find row {0}", colnamesraw[colname]);
                    continue;
                }
                pi.SetValue(Row, val, null);
            }
        }

        row = Row;
        return r;
    }

    public bool TryReadRows([NotNullWhen(true)]out TRow[]? rows, params Parameter[] Parameters) => TryReadRows(null!, out rows, Parameters);
    
    public bool TryReadRows(Order order, [NotNullWhen(true)]out TRow[]? rows, params Parameter[] Parameters)
    {
        if (string.IsNullOrEmpty(DatabaseHandler.DB) || string.IsNullOrEmpty(DatabaseHandler.IP) || string.IsNullOrEmpty(DatabaseHandler.Uname) || string.IsNullOrEmpty(DatabaseHandler.PW)) throw new Exception("Database conection not fully defined");
        using NpgsqlConnection con = new(DatabaseHandler.ConectionString);
        string command = $"SELECT * FROM {Name} WHERE";
        con.Open();
        using NpgsqlCommand cmd = new();
        cmd.Connection = con;
        string vals = "";
        foreach (Parameter param in Parameters)
        {
            vals += $"{param.PGParameter.ParameterName} {param.Sign} @{param.PGParameter.ParameterName} AND ";
            cmd.Parameters.Add(param.PGParameter);
        }
        if (command.EndsWith(";")) command = command.Remove(command.Length - 1, 1);
        if (!string.IsNullOrWhiteSpace(vals)) vals = vals.Remove(vals.Length - 5, 5);
        if (!string.IsNullOrWhiteSpace(vals) && command.EndsWith("WHERE")) command += $" {vals}";
        if (order is not null) command += $" ORDER BY {order.Type} ";
        if (order is not null && order.Assending) command += "ASC";
        else { if (order is not null) command += "DESC"; }
        command += ";";
        cmd.CommandText = command;
        NpgsqlDataReader reader = cmd.ExecuteReader();
        List<TRow> Rows = new();
        while (reader.Read())
        {
            TRow Row = new();
            for (int i = 0; i < reader.FieldCount; i++)
            {
                string colname = reader.GetName(i);
                object? val = reader.GetValue(i);
                if (colnamesraw.ContainsKey(colname))
                {
                    PropertyInfo? pi = Row.GetType()
                        .GetProperty(colnamesraw[colname]);
                    if (pi is null)
                    {
                        Console.WriteLine("Could not find row {0}", colnamesraw[colname]);
                        continue;
                    }
                    pi.SetValue(Row, val, null);
                }
            }
            Rows.Add(Row);
        }

        rows = Rows.ToArray();
        return Rows.Any();
    }

	public bool TryRead<T>(TableColumn<T> column, [NotNullWhen(true)]out T? result, params Parameter[] Parameters) where T : notnull
	{
        return TryRead(column, null!, out result, Parameters);
	}

	public void Update<Ttype>(TableColumn<Ttype> condiction_column, Ttype condiction_value, params Parameter[] Parameters) where Ttype : notnull
    {
        Update(condiction_column, condiction_value, "=", Parameters);
    }

    public void Update<Ttype>(TableColumn<Ttype> condiction_column, Ttype condiction_value, string Sign, params Parameter[] Parameters) where Ttype : notnull
    {
        CommandHandler command = CreateCommand().WithFilter(condiction_column, condiction_value, Sign);
        foreach (var Parameter in Parameters)
        {
            command.WithValue(Parameter);
        }
        command.Update();
    }

    public TRow ReadRow(params Parameter[] Parameters) => ReadRow(null, Parameters);

    public TRow ReadRow(Order order, params Parameter[] Parameters)
    {
        if (string.IsNullOrEmpty(DatabaseHandler.DB) || string.IsNullOrEmpty(DatabaseHandler.IP) || string.IsNullOrEmpty(DatabaseHandler.Uname) || string.IsNullOrEmpty(DatabaseHandler.PW)) throw new Exception("Database conection not fully defined");
        using NpgsqlConnection con = new(DatabaseHandler.ConectionString);
        string command = $"SELECT * FROM {Name} WHERE";
        con.Open();
        using NpgsqlCommand cmd = new();
        cmd.Connection = con;
        string vals = "";
        foreach (Parameter param in Parameters)
        {
            vals += $"{param.PGParameter.ParameterName} {param.Sign} @{param.PGParameter.ParameterName} AND ";
            cmd.Parameters.Add(param.PGParameter);
        }
        if (command.EndsWith(";")) command = command.Remove(command.Length - 1, 1);
        if (!string.IsNullOrWhiteSpace(vals)) vals = vals.Remove(vals.Length - 5, 5);
        if (!string.IsNullOrWhiteSpace(vals) && command.EndsWith("WHERE")) command += $" {vals}";
        if (order is not null) command += $" ORDER BY {order.Type} ";
        if (order is not null && order.Assending) command += "ASC";
        else { if (order is not null) command += "DESC"; }
        command += ";";
        cmd.CommandText = command;
        NpgsqlDataReader reader = cmd.ExecuteReader();
        TRow Row = new();
        reader.Read();
        for (int i = 0; i < reader.FieldCount; i++)
        {
            string colname = reader.GetName(i);
            object? val = reader.GetValue(i);
            if (colnamesraw.ContainsKey(colname))
            {
                PropertyInfo? pi = Row.GetType()
                    .GetProperty(colnamesraw[colname]);
                if (pi is null)
                {
                    Console.WriteLine("Could not find row {0}", colnamesraw[colname]);
                    continue;
                }
                pi.SetValue(Row, val, null);
            }
        }

        return Row;
    }
    
    public TColumn[] ReadColumn<TColumn>(TableColumn<TColumn> column, params Parameter[] Parameters) where TColumn : notnull => ReadColumn(column, uint.MaxValue, null, Parameters);

    public TColumn[] ReadColumn<TColumn>(TableColumn<TColumn> column, uint NumRows, params Parameter[] Parameters) where TColumn : notnull => ReadColumn(column, NumRows, null, Parameters);
    
    public TColumn[] ReadColumn<TColumn>(TableColumn<TColumn> column, Order? Order, params Parameter[] Parameters) where TColumn : notnull => ReadColumn(column, uint.MaxValue, Order, Parameters);

    public TColumn[] ReadColumn<TColumn>(TableColumn<TColumn> column, uint NumRows, Order? order, params Parameter[] Parameters) where TColumn : notnull
    {
        if (string.IsNullOrEmpty(DatabaseHandler.DB) || string.IsNullOrEmpty(DatabaseHandler.IP) || string.IsNullOrEmpty(DatabaseHandler.Uname) || string.IsNullOrEmpty(DatabaseHandler.PW)) throw new Exception("Database conection not fully defined");
        using NpgsqlConnection con = new(DatabaseHandler.ConectionString);
        string command = $"SELECT {column.Name} FROM {Name} WHERE";
        con.Open();
        using NpgsqlCommand cmd = new();
        cmd.Connection = con;
        string vals = "";
        foreach (Parameter param in Parameters)
        {
            vals += $"{param.PGParameter.ParameterName} {param.Sign} @{param.PGParameter.ParameterName} AND ";
            cmd.Parameters.Add(param.PGParameter);
        }
        if (command.EndsWith(";")) command = command.Remove(command.Length - 1, 1);
        if (!string.IsNullOrWhiteSpace(vals)) vals = vals.Remove(vals.Length - 5, 5);
        if (!string.IsNullOrWhiteSpace(vals) && command.EndsWith("WHERE")) command += $" {vals}";
        if (command.EndsWith("WHERE")) command = command.Remove(command.Length - 6, 6);
        if (order is not null) command += $" ORDER BY {order.Type} ";
        if (order is not null && order.Assending) command += "ASC";
        else { if (order is not null) command += "DESC"; }
        command += $" LIMIT {NumRows};";
        cmd.CommandText = command;
        NpgsqlDataReader reader = cmd.ExecuteReader();
        List<TColumn> Rows = new();
        for (int j = 0; j < NumRows; j++)
        {
            if (!reader.Read()) break;
            Rows.Add((TColumn)reader.GetValue(0));
        }
        
        return Rows.ToArray();
    }
    
    public TRow[] ReadRows(params Parameter[] Parameters) => ReadRows(uint.MaxValue, null, Parameters);

    public TRow[] ReadRows(uint NumRows, params Parameter[] Parameters) => ReadRows(NumRows, null, Parameters);
    
    public TRow[] ReadRows(Order? Order, params Parameter[] Parameters) => ReadRows(uint.MaxValue, Order, Parameters);
    
    public TRow[] ReadRows(uint NumRows, Order? order, params Parameter[] Parameters)
    {
        if (string.IsNullOrEmpty(DatabaseHandler.DB) || string.IsNullOrEmpty(DatabaseHandler.IP) || string.IsNullOrEmpty(DatabaseHandler.Uname) || string.IsNullOrEmpty(DatabaseHandler.PW)) throw new Exception("Database conection not fully defined");
        using NpgsqlConnection con = new(DatabaseHandler.ConectionString);
        string command = $"SELECT * FROM {Name} WHERE";
        con.Open();
        using NpgsqlCommand cmd = new();
        cmd.Connection = con;
        string vals = "";
        foreach (Parameter param in Parameters)
        {
            vals += $"{param.PGParameter.ParameterName} {param.Sign} @{param.PGParameter.ParameterName} AND ";
            cmd.Parameters.Add(param.PGParameter);
        }
        if (command.EndsWith(";")) command = command.Remove(command.Length - 1, 1);
        if (!string.IsNullOrWhiteSpace(vals)) vals = vals.Remove(vals.Length - 5, 5);
        if (!string.IsNullOrWhiteSpace(vals) && command.EndsWith("WHERE")) command += $" {vals}";
        if (command.EndsWith("WHERE")) command = command.Remove(command.Length - 6, 6);
        if (order is not null) command += $" ORDER BY {order.Type} ";
        if (order is not null && order.Assending) command += "ASC";
        else { if (order is not null) command += "DESC"; }
        command += $" LIMIT {NumRows};";
        cmd.CommandText = command;
        NpgsqlDataReader reader = cmd.ExecuteReader();
        List<TRow> Rows = new();
        for (int j = 0; j < NumRows; j++)
        {
            if (!reader.Read()) break;
            TRow Row = new();
            for (int i = 0; i < reader.FieldCount; i++)
            {
                string colname = reader.GetName(i);
                object? val = reader.GetValue(i);
                if (colnamesraw.ContainsKey(colname))
                {
                    PropertyInfo? pi = Row.GetType()
                        .GetProperty(colnamesraw[colname]);
                    if (pi is null)
                    {
                        Console.WriteLine("Could not find row {0}", colnamesraw[colname]);
                        continue;
                    }
                    pi.SetValue(Row, val, null);
                }
            }
            Rows.Add(Row);
        }
        
        return Rows.ToArray();
    }

    public T Read<T>(TableColumn<T> column, params Parameter[] Parameters) where T : notnull
    {
        if (Parameters is null) throw new ArgumentNullException(nameof(Parameters));
        return DatabaseHandler.Read<T>($"SELECT {column.Name} FROM {Name} WHERE", (Order?)null, Parameters);
    }

    public T Read<T>(TableColumn<T> column, Order order, params Parameter[] Parameters) where T : notnull
    {
        if (Parameters is null) throw new ArgumentNullException(nameof(Parameters));
        return DatabaseHandler.Read<T>($"SELECT {column.Name} FROM {Name} WHERE", order, Parameters);
    }
}