Signum Framework Principles

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using System.Diagnostics;

namespace Signum.Utilities
{
    [DebuggerStepThrough]
    public static class Extensions
    {
        #region Parse Number
        public static int? ToInt(this string str)
        {
            int result;
            if (int.TryParse(str, out result))
                return result;
            else
                return null;
        }

        public static long? ToLong(this string str)
        {
            long result;
            if (long.TryParse(str, out result))
                return result;
            else
                return null;
        }

        public static short? ToShort(this string str)
        {
            short result;
            if (short.TryParse(str, out result))
                return result;
            else
                return null;
        }

        public static float? ToFloat(this string str)
        {
            float result;
            if (float.TryParse(str, out result))
                return result;
            else
                return null;
        }

        public static double? ToDouble(this string str)
        {
            double result;
            if (double.TryParse(str, out result))
                return result;
            else
                return null;
        }

        public static decimal? ToDecimal(this string str)
        {
            decimal result;
            if (decimal.TryParse(str, out result))
                return result;
            else
                return null;
        }

        public static int ToInt(this string str, string error)
        {
            int result;
            if (int.TryParse(str, out result))
                return result;

            throw new FormatException(error);
        }

        public static long ToLong(this string str, string error)
        {
            long result;
            if (long.TryParse(str, out result))
                return result;

            throw new FormatException(error);
        }

        public static short ToShort(this string str, string error)
        {
            short result;
            if (short.TryParse(str, out result))
                return result;

            throw new FormatException(error);
        }


        public static float? ToFloat(this string str, string error)
        {
            float result;
            if (float.TryParse(str, out result))
                return result;

            throw new FormatException(error);
        }

        public static double ToDouble(this string str, string error)
        {
            double result;
            if (double.TryParse(str, out result))
                return result;

            throw new FormatException(error);
        }

        public static decimal ToDecimal(this string str, string error)
        {
            decimal result;
            if (decimal.TryParse(str, out result))
                return result;

            throw new FormatException(error);
        }
        
        #endregion

        public static T? DefaultToNull<T>(this T value)
            where T : struct
        {
            return EqualityComparer<T>.Default.Equals(default(T), value) ? (T?)null : value;
        }

        public static T ThrowIfNullS<T>(this T? t, string mensaje)
         where T : struct
        {
            if (t == null)
                throw new NullReferenceException(mensaje);
            return t.Value;
        }

        public static T ThrowIfNullC<T>(this T t, string mensaje)
            where T : class
        {
            if (t == null)
                throw new NullReferenceException(mensaje);
            return t;
        }

        #region Map Try Do TryDo
        public static R Map<T, R>(this T t, Func<T, R> func)
        {
            return func(t);
        }

        public static R TryCC<T, R>(this T t, Func<T, R> func)
            where T : class
            where R : class
        {
            if (t == null) return null;
            return func(t);
        }

        public static R? TryCS<T, R>(this T t, Func<T, R> func)
            where T : class
            where R : struct
        {
            if (t == null) return null;
            return func(t);
        }

        public static R? TryCS<T, R>(this T t, Func<T, R?> func)
            where T : class
            where R : struct
        {
            if (t == null) return null;
            return func(t);
        }

        public static R TrySC<T, R>(this T? t, Func<T, R> func)
            where T : struct
            where R : class
        {
            if (t == null) return null;
            return func(t.Value);
        }

        public static R? TrySS<T, R>(this T? t, Func<T, R> func)
            where T : struct
            where R : struct
        {
            if (t == null) return null;
            return func(t.Value);
        }

        public static R? TrySS<T, R>(this T? t, Func<T, R?> func)
            where T : struct
            where R : struct
        {
            if (t == null) return null;
            return func(t.Value);
        }



        public static T Do<T>(this T t, Action<T> action)
        {
            action(t);
            return t;
        }

        public static T TryDoC<T>(this T t, Action<T> action) where T : class
        {
            if (t != null)
                action(t);
            return t;
        }

        public static T? TryDoS<T>(this T? t, Action<T> action) where T : struct
        {
            if (t != null)
                action(t.Value);
            return t;
        } 
        #endregion

        public static IEnumerable<int> To(this int start, int endNotIncluded)
        {
            for (int i = start; i < endNotIncluded; i++)
                yield return i;
        }

        public static IEnumerable<int> To(this int start, int endNotIncluded, int step)
        {
            for (int i = start; i < endNotIncluded; i += step)
                yield return i;
        }

        public static IEnumerable<int> DownTo(this int startNotIncluded, int end)
        {
            for (int i = startNotIncluded - 1; i >= end; i--)
                yield return i;
        }

        public static IEnumerable<int> DownTo(this int startNotIncluded, int end, int step)
        {
            for (int i = startNotIncluded - 1; i >= end; i-= step)
                yield return i;
        }

        public static IEnumerable<T> For<T>(this T start, Func<T, bool> condition, Func<T, T> incremento)
        {
            for (T i = start; condition(i); i = incremento(i))
                yield return i;
        }

        public static IEnumerable<T> FollowC<T>(this T start, Func<T, T> next) where T : class
        {
            for (T i = start; i != null; i = next(i))
                yield return i;
        }

        public static IEnumerable<T> FollowS<T>(this T start, Func<T, T?> next) where T : struct
        {
            for (T? i = start; i.HasValue; i = next(i.Value))
                yield return i.Value;
        }

        public static IEnumerable<T> FollowS<T>(this T? start, Func<T, T?> next) where T : struct
        {
            for (T? i = start; i.HasValue; i = next(i.Value))
                yield return i.Value;
        }
    }

}