Signum Framework Tutorials Part 2 – Southwind Logic

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Signum.Utilities
{
    public enum ProgressAction
    {
        Interval= 1,
        Position = 2,
        Task = 4, 
    }

    public class ProgressArgs:EventArgs
    {
        public readonly ProgressAction Action;
        public ProgressArgs(ProgressAction a)
        {
            Action = a; 
        }
    }

    public class ProgressProxy
    {
        const int numUpdates = 10000; 

        private int min;
        private int max;
        private int position;
        private int step;
        public event EventHandler<ProgressArgs> Changed;
        private string currentTask;      
        
        public ProgressProxy()
        { }

        public void Start(int numTasks)
        {
            Start(0, numTasks, "");
        }

        public void Start(string currentTask)
        {
            this.currentTask = currentTask;
            this.position = -1;
            OnChanged(ProgressAction.Interval | ProgressAction.Task);
        }

        public void Start(int max, string currentTask)
        {
            Start(0, max, currentTask);
        }

        public void Start(int min, int max, string currentTask)
        {
            if (min < 0 || max < 0 || max < min)
                throw new ArgumentException();

            this.currentTask = currentTask; 
            this.min = this.position = min;
            this.max = max;

            if (max - min > numUpdates*2)
                step = RoundToPowerOfTwoMinusOne((max - min) / numUpdates)-1;
            else
                step = 1;

            OnChanged(ProgressAction.Interval| ProgressAction.Task);
        }

        public void NextTask(int position, string currentTask)
        {
            this.position = position;
            this.currentTask = currentTask;
            OnChanged(ProgressAction.Position | ProgressAction.Task);
        }

        public void NextTask( string currentTask)
        {
            this.position++;
            this.currentTask = currentTask;
            OnChanged(ProgressAction.Position | ProgressAction.Task);
        }

        public int Min
        {
            get { return min; }
        }

        public int Max
        {
            get { return max; }
        }


        public int Position
        {
            get { return position; }
            set
            {
                if (min <= value && value <= max)
                {
                    position = value;
                    if ((step & position)== 0 )
                        OnChanged(ProgressAction.Position);
                }
            }
        }

        public string CurrentTask
        {
            get { return currentTask; }
            set
            {
                currentTask = value;
                OnChanged(ProgressAction.Task);
            }
        }

        private void OnChanged(ProgressAction pa)
        {
            if (Changed != null)
                Changed(this, new ProgressArgs(pa));
        }


        static int RoundToPowerOfTwoMinusOne(int n)
        {
            n |= n >> 1;
            n |= n >> 2;
            n |= n >> 4;
            n |= n >> 8;
            n |= n >> 16; 
            return n;
        }

        public void Reset()
        {
            currentTask = null; 
            position = min;
            OnChanged(ProgressAction.Task | ProgressAction.Position);
        }
    }
}