using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using FastReport.Design;
using System.Drawing;
using System.Collections;
using FastReport.Utils;

namespace FastReport
{
    /// <summary>
    /// Holds the list of <see cref="ComponentBase"/> objects currently selected in the designer.
    /// </summary>
    /// <remarks>
    /// This class is used by the "Alignment" toolbar. Use methods of this class to perform some 
    /// operations on the selected objects. 
    /// <para/>Note: after calling any method in this class, call the 
    /// <see cref="Designer.SetModified()">Designer.SetModified</see> method to reflect changes.
    /// <para/>Note: this list contains only objects of <see cref="ComponentBase"/> type. If you want to access all
    /// selected objects, use the <see cref="Designer.SelectedObjects"/> property.
    /// </remarks>
    public class SelectedComponents
    {
        private List<ComponentBase> list;
        private Designer designer;

        /// <summary>
        /// Gets the first selected object.
        /// </summary>
        public ComponentBase First
        {
            get { return list.Count > 0 ? list[0] : null; }
        }

        /// <summary>
        /// Gets the number of selected objects.
        /// </summary>
        public int Count
        {
            get { return list.Count; }
        }

        private List<ComponentBase> MoveList
        {
            get { return list.FindAll(CanMove); }
        }

        private List<ComponentBase> ResizeList
        {
            get { return list.FindAll(CanResize); }
        }

        private bool CanMove(ComponentBase c)
        {
            return c.HasFlag(Flags.CanMove) && !c.HasRestriction(Restrictions.DontMove);
        }

        private bool CanResize(ComponentBase c)
        {
            return c.HasFlag(Flags.CanResize) && !c.HasRestriction(Restrictions.DontResize);
        }

        internal void Update()
        {
            list.Clear();
            if (designer.SelectedObjects != null)
            {
                foreach (Base c in designer.SelectedObjects)
                {
                    if (c is ComponentBase)
                        list.Add(c as ComponentBase);
                }
            }
        }

        /// <summary>
        /// Aligns left edges of the selected objects.
        /// </summary>
        public void AlignLeft(object sender = null, EventArgs e = null)
        {
            foreach (ComponentBase c in MoveList)
            {
                c.Left = First.Left;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Aligns right edges of the selected objects.
        /// </summary>
        public void AlignRight(object sender = null, EventArgs e = null)
        {
            foreach (ComponentBase c in MoveList)
            {
                c.Left = First.Right - c.Width;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Aligns centers of the selected objects.
        /// </summary>
        public void AlignCenter(object sender = null, EventArgs e = null)
        {
            foreach (ComponentBase c in MoveList)
            {
                c.Left = First.Left + (First.Width - c.Width) / 2;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Aligns top edges of the selected objects.
        /// </summary>
        public void AlignTop(object sender = null, EventArgs e = null)
        {
            foreach (ComponentBase c in MoveList)
            {
                c.Top = First.Top;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Aligns bottom edges of the selected objects.
        /// </summary>
        public void AlignBottom(object sender = null, EventArgs e = null)
        {
            foreach (ComponentBase c in MoveList)
            {
                c.Top = First.Bottom - c.Height;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Aligns middles of the selected objects.
        /// </summary>
        public void AlignMiddle(object sender = null, EventArgs e = null)
        {
            foreach (ComponentBase c in MoveList)
            {
                c.Top = First.Top + (First.Height - c.Height) / 2;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Makes the selected objects the same width as the first object.
        /// </summary>
        public void SameWidth(object sender = null, EventArgs e = null)
        {
            foreach (ComponentBase c in ResizeList)
            {
                c.Width = First.Width;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Makes the selected objects the same height as the first object.
        /// </summary>
        public void SameHeight(object sender = null, EventArgs e = null)
        {
            foreach (ComponentBase c in ResizeList)
            {
                c.Height = First.Height;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Makes the selected objects the same size as the first object.
        /// </summary>
        public void SameSize(object sender = null, EventArgs e = null)
        {
            foreach (ComponentBase c in ResizeList)
            {
                c.Width = First.Width;
                c.Height = First.Height;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Centers the selected objects horizontally.
        /// </summary>
        public void CenterHorizontally(object sender = null, EventArgs e = null)
        {
            if (!(First.Parent is ComponentBase))
                return;
            float min = 100000;
            float max = -100000;

            foreach (ComponentBase c in MoveList)
            {
                if (c.Left < min)
                    min = c.Left;
                if (c.Right > max)
                    max = c.Right;
            }

            float parentWidth = (First.Parent as ComponentBase).ClientSize.Width;
            float dx = (parentWidth - (max - min)) / 2;
            foreach (ComponentBase c in MoveList)
            {
                c.Left += dx - min;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Centers the selected objects vertically.
        /// </summary>
        public void CenterVertically(object sender = null, EventArgs e = null)
        {
            if (!(First.Parent is ComponentBase))
                return;
            float min = 100000;
            float max = -100000;

            foreach (ComponentBase c in MoveList)
            {
                if (c.Top < min)
                    min = c.Top;
                if (c.Bottom > max)
                    max = c.Bottom;
            }

            float parentHeight = (First.Parent as ComponentBase).ClientSize.Height;
            float dy = (parentHeight - (max - min)) / 2;
            foreach (ComponentBase c in MoveList)
            {
                c.Top += dy - min;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Aligns the selected objects to the grid.
        /// </summary>
        public void AlignToGrid(object sender = null, EventArgs e = null)
        {
            SizeF snapSize = First.Page.SnapSize;
            foreach (ComponentBase c in MoveList)
            {
                c.Left = (int)Math.Round(c.Left / snapSize.Width) * snapSize.Width;
                c.Top = (int)Math.Round(c.Top / snapSize.Height) * snapSize.Height;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Adjusts the size of selected objects to the grid.
        /// </summary>
        public void SizeToGrid(object sender = null, EventArgs e = null)
        {
            SizeF snapSize = First.Page.SnapSize;
            foreach (ComponentBase c in list)
            {
                if (c.HasFlag(Flags.CanMove) && !c.HasRestriction(Restrictions.DontMove))
                {
                    c.Left = (int)Math.Round(c.Left / snapSize.Width) * snapSize.Width;
                    c.Top = (int)Math.Round(c.Top / snapSize.Height) * snapSize.Height;
                }
                if (c.HasFlag(Flags.CanResize) && !c.HasRestriction(Restrictions.DontResize))
                {
                    c.Width = (int)Math.Round(c.Width / snapSize.Width) * snapSize.Width;
                    c.Height = (int)Math.Round(c.Height / snapSize.Height) * snapSize.Height;
                }
            }
            designer.SetModified();
        }

        /// <summary>
        /// Spaces the selected objects horizontally.
        /// </summary>
        public void SpaceHorizontally(object sender = null, EventArgs e = null)
        {
            List<ObjItem> list = new List<ObjItem>();
            foreach (ComponentBase c in MoveList)
            {
                list.Add(new ObjItem(c.Left, c));
            }
            list.Sort();
            if (list.Count < 3)
                return;

            float dx = list[list.Count - 1].obj.Left - list[0].obj.Right;
            float actualSize = 0;
            for (int i = 1; i < list.Count - 1; i++)
            {
                actualSize += list[i].obj.Width;
            }
            float sizeBetweenObj = actualSize < dx ? (dx - actualSize) / (list.Count - 1) : 0;
            float count = sizeBetweenObj > 0 ? list.Count - 1 : list.Count;
            for (int i = 1; i < count; i++)
            {
                list[i].obj.Left = list[i - 1].obj.Right + sizeBetweenObj;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Increases horizontal spacing between the selected objects.
        /// </summary>
        public void IncreaseHorizontalSpacing(object sender = null, EventArgs e = null)
        {
            List<ObjItem> list = new List<ObjItem>();
            foreach (ComponentBase c in MoveList)
            {
                list.Add(new ObjItem(c.Left, c));
            }
            list.Sort();

            SizeF snapSize = First.Page.SnapSize;
            for (int i = 1; i < list.Count; i++)
            {
                list[i].obj.Left += snapSize.Width * i;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Decreases horizontal spacing between the selected objects.
        /// </summary>
        public void DecreaseHorizontalSpacing(object sender = null, EventArgs e = null)
        {
            List<ObjItem> list = new List<ObjItem>();
            foreach (ComponentBase c in MoveList)
            {
                list.Add(new ObjItem(c.Left, c));
            }
            list.Sort();

            SizeF snapSize = First.Page.SnapSize;
            for (int i = 1; i < list.Count; i++)
            {
                list[i].obj.Left -= snapSize.Width * i;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Removes horizontal spacing between the selected objects.
        /// </summary>
        public void RemoveHorizontalSpacing(object sender = null, EventArgs e = null)
        {
            List<ObjItem> list = new List<ObjItem>();
            foreach (ComponentBase c in MoveList)
            {
                list.Add(new ObjItem(c.Left, c));
            }
            list.Sort();

            for (int i = 1; i < list.Count; i++)
            {
                list[i].obj.Left = list[i - 1].obj.Right;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Spaces the selected objects vertically.
        /// </summary>
        public void SpaceVertically(object sender = null, EventArgs e = null)
        {
            List<ObjItem> list = new List<ObjItem>();
            foreach (ComponentBase c in MoveList)
            {
                list.Add(new ObjItem(c.Top, c));
            }
            list.Sort();
            if (list.Count < 3)
                return;

            float dy = list[list.Count - 1].obj.Top - list[0].obj.Bottom;
            float actualSize = 0;
            for (int i = 1; i < list.Count - 1; i++)
            {
                actualSize += list[i].obj.Height;
            }
            float sizeBetweenObj = actualSize < dy ? (dy - actualSize) / (list.Count - 1) : 0;
            float count = sizeBetweenObj > 0 ? list.Count - 1 : list.Count;
            for (int i = 1; i < count; i++)
            {
                list[i].obj.Top = list[i - 1].obj.Bottom + sizeBetweenObj;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Increases vertical spacing between the selected objects.
        /// </summary>
        public void IncreaseVerticalSpacing(object sender = null, EventArgs e = null)
        {
            List<ObjItem> list = new List<ObjItem>();
            foreach (ComponentBase c in MoveList)
            {
                list.Add(new ObjItem(c.Top, c));
            }
            list.Sort();

            SizeF snapSize = First.Page.SnapSize;
            for (int i = 1; i < list.Count; i++)
            {
                list[i].obj.Top += snapSize.Height * i;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Decreases vertical spacing between the selected objects.
        /// </summary>
        public void DecreaseVerticalSpacing(object sender = null, EventArgs e = null)
        {
            List<ObjItem> list = new List<ObjItem>();
            foreach (ComponentBase c in MoveList)
            {
                list.Add(new ObjItem(c.Top, c));
            }
            list.Sort();

            SizeF snapSize = First.Page.SnapSize;
            for (int i = 1; i < list.Count; i++)
            {
                list[i].obj.Top -= snapSize.Height * i;
            }
            designer.SetModified();
        }

        /// <summary>
        /// Removes vertical spacing between the selected objects.
        /// </summary>
        public void RemoveVerticalSpacing(object sender = null, EventArgs e = null)
        {
            List<ObjItem> list = new List<ObjItem>();
            foreach (ComponentBase c in MoveList)
            {
                list.Add(new ObjItem(c.Left, c));
            }
            list.Sort();

            for (int i = 1; i < list.Count; i++)
            {
                list[i].obj.Top = list[i - 1].obj.Bottom;
            }
            designer.SetModified();
        }

        internal SelectedComponents(Designer designer)
        {
            this.designer = designer;
            list = new List<ComponentBase>();
        }


        private class ObjItem : IComparable
        {
            public float coord;
            public ComponentBase obj;

            public int CompareTo(object obj)
            {
                if (coord < (obj as ObjItem).coord)
                    return -1;
                if (coord > (obj as ObjItem).coord)
                    return 1;
                return 0;
            }

            public ObjItem(float coord, ComponentBase obj)
            {
                this.coord = coord;
                this.obj = obj;
            }
        }
    }
}