/*
 * NPlot - A charting library for .NET
 * 
 * ArrowItem.cs
 * Copyright (C) 2003-2006 Matt Howlett and others.
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. Neither the name of NPlot nor the names of its contributors may
 *    be used to endorse or promote products derived from this software without
 *    specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Drawing;

namespace NPlot
{

    /// <summary>
    /// An Arrow IDrawable, with a text label that is automatically
    /// nicely positioned at the non-pointy end of the arrow. Future
    /// feature idea: have constructor that takes a dataset, and have
    /// the arrow know how to automatically set it's angle to avoid 
    /// the data.
    /// </summary>
    public class ArrowItem : IDrawable
    {

        private void Init()
        {
            FontFamily fontFamily = new FontFamily("Arial");
            font_ = new Font(fontFamily, 10, FontStyle.Regular, GraphicsUnit.Pixel);
        }


        /// <summary>
        /// Default constructor : 
        /// text = ""
        /// angle = 45 degrees anticlockwise from horizontal.
        /// </summary>
        /// <param name="position">The position the arrow points to.</param>
        public ArrowItem( PointD position )
        {
            to_ = position;
            Init();
        }


        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="position">The position the arrow points to.</param>
        /// <param name="angle">angle of arrow with respect to x axis.</param>
        public ArrowItem( PointD position, double angle )
        {
            to_ = position;
            angle_ = -angle;
            Init();
        }


        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="position">The position the arrow points to.</param>
        /// <param name="angle">angle of arrow with respect to x axis.</param>
        /// <param name="text">The text associated with the arrow.</param>
        public ArrowItem( PointD position, double angle, string text )
        {
            to_ = position;
            angle_ = -angle;
            text_ = text;
            Init();
        }


        /// <summary>
        /// Text associated with the arrow.
        /// </summary>
        public string Text 
        {
            get
            {
                return text_;
            }
            set
            {
                text_ = value;
            }
        }
        private string text_ = "";


        /// <summary>
        /// Angle of arrow anti-clockwise to right horizontal in degrees.
        /// </summary>
        /// <remarks>The code relating to this property in the Draw method is
        /// a bit weird. Internally, all rotations are clockwise [this is by 
        /// accient, I wasn't concentrating when I was doing it and was half
        /// done before I realised]. The simplest way to make angle represent
        /// anti-clockwise rotation (as it is normal to do) is to make the 
        /// get and set methods negate the provided value.</remarks>
        public double Angle
        {
            get
            {
                return -angle_;
            }
            set
            {
                angle_ = -value;
            }
        }
        private double angle_ = -45.0;


        /// <summary>
        /// Physical length of the arrow. 
        /// </summary>
        public float PhysicalLength
        {
            get
            {
                return physicalLength_;
            }
            set
            {
                physicalLength_ = value;
            }
        }
        private float physicalLength_ = 40.0f;


        /// <summary>
        /// The point the arrow points to.
        /// </summary>
        public PointD To
        {
            get
            {
                return to_;
            }
            set
            {
                to_ = value;
            }
        }
        private PointD to_;


        /// <summary>
        /// Size of the arrow head sides in pixels.
        /// </summary>
        public float HeadSize
        {
            get
            {
                return headSize_;
            }
            set
            {
                headSize_ = value;
            }
        }
        private float headSize_ = 10.0f;


        /// <summary>
        /// angle between sides of arrow head in degrees
        /// </summary>
        public float HeadAngle
        {
            get
            {
                return headAngle_;
            }
            set
            {
                headAngle_ = value;
            }
        }
        private float headAngle_ = 40.0f;


        /// <summary>
        /// Draws the arrow on a plot surface.
        /// </summary>
        /// <param name="g">graphics surface on which to draw</param>
        /// <param name="xAxis">The X-Axis to draw against.</param>
        /// <param name="yAxis">The Y-Axis to draw against.</param>
        public void Draw( System.Drawing.Graphics g, PhysicalAxis xAxis, PhysicalAxis yAxis )
        {
            if (this.To.X > xAxis.Axis.WorldMax || this.To.X < xAxis.Axis.WorldMin)
                return;

            if (this.To.Y > yAxis.Axis.WorldMax || this.To.Y < yAxis.Axis.WorldMin)
                return;

            double angle = this.angle_;

            if (this.angle_ < 0.0)
            {
                int mul = -(int)(this.angle_ / 360.0) + 2;
                angle = angle_ + 360.0 * (double)mul;
            }

            double normAngle = (double)angle % 360.0;   // angle in range 0 -> 360.

            Point toPoint = new Point( 
                (int)xAxis.WorldToPhysical( to_.X, true ).X,
                (int)yAxis.WorldToPhysical( to_.Y, true ).Y );


            float xDir = (float)Math.Cos( normAngle * 2.0 * Math.PI / 360.0 );
            float yDir = (float)Math.Sin( normAngle * 2.0 * Math.PI / 360.0 );

            toPoint.X += (int)(xDir*headOffset_);
            toPoint.Y += (int)(yDir*headOffset_);

            float xOff = physicalLength_ * xDir;
            float yOff = physicalLength_ * yDir;

            Point fromPoint = new Point(
                (int)(toPoint.X + xOff),
                (int)(toPoint.Y + yOff) );

            g.DrawLine( pen_, toPoint, fromPoint );

            Point[] head = new Point[3];

            head[0] = toPoint;

            xOff = headSize_ * (float)Math.Cos( (normAngle-headAngle_/2.0f) * 2.0 * Math.PI / 360.0 );
            yOff = headSize_ * (float)Math.Sin( (normAngle-headAngle_/2.0f) * 2.0 * Math.PI / 360.0 );

            head[1] = new Point(
                (int)(toPoint.X + xOff),
                (int)(toPoint.Y + yOff) );

            float xOff2 = headSize_ * (float)Math.Cos( (normAngle+headAngle_/2.0f) * 2.0 * Math.PI / 360.0 );
            float yOff2 = headSize_ * (float)Math.Sin( (normAngle+headAngle_/2.0f) * 2.0 * Math.PI / 360.0 );

            head[2] = new Point(
                (int)(toPoint.X + xOff2),
                (int)(toPoint.Y + yOff2) );

            g.FillPolygon( arrowBrush_, head );

            SizeF textSize = g.MeasureString( text_, font_ );
            SizeF halfSize = new SizeF( textSize.Width / 2.0f, textSize.Height / 2.0f );

            float quadrantSlideLength = halfSize.Width + halfSize.Height;

            float quadrantF = (float)normAngle / 90.0f;       // integer part gives quadrant.
            int quadrant = (int)quadrantF;              // quadrant in. 
            float prop = quadrantF - (float)quadrant; // proportion of way through this qadrant. 
            float dist = prop * quadrantSlideLength;      // distance along quarter of bounds rectangle.
            
            // now find the offset from the middle of the text box that the
            // rear end of the arrow should end at (reverse this to get position
            // of text box with respect to rear end of arrow).
            //
            // There is almost certainly an elgant way of doing this involving
            // trig functions to get all the signs right, but I'm about ready to 
            // drop off to sleep at the moment, so this blatent method will have 
            // to do.
            PointF offsetFromMiddle = new PointF( 0.0f, 0.0f );
            switch (quadrant)
            {
                case 0:
                    if (dist > halfSize.Height)
                    {
                        dist -= halfSize.Height;
                        offsetFromMiddle = new PointF( -halfSize.Width + dist, halfSize.Height );
                    }
                    else
                    {
                        offsetFromMiddle = new PointF( -halfSize.Width, - dist );
                    }
                    break;

                case 1:
                    if (dist > halfSize.Width)
                    {
                        dist -= halfSize.Width;
                        offsetFromMiddle = new PointF( halfSize.Width, halfSize.Height - dist );
                    }
                    else
                    {
                        offsetFromMiddle = new PointF( dist, halfSize.Height );
                    }
                    break;

                case 2:
                    if (dist > halfSize.Height)
                    {
                        dist -= halfSize.Height;
                        offsetFromMiddle = new PointF( halfSize.Width - dist, -halfSize.Height );
                    }
                    else
                    {
                        offsetFromMiddle = new PointF( halfSize.Width, -dist );
                    }

                    break;

                case 3:
                    if (dist > halfSize.Width)
                    {
                        dist -= halfSize.Width;
                        offsetFromMiddle = new PointF( -halfSize.Width, -halfSize.Height + dist );
                    }
                    else
                    {
                        offsetFromMiddle = new PointF( -dist, -halfSize.Height );
                    }

                    break;

                default:
                    throw new NPlotException( "Programmer error." );

            }

            g.DrawString( 
                text_, font_, textBrush_,
                (int)(fromPoint.X - halfSize.Width - offsetFromMiddle.X),
                (int)(fromPoint.Y - halfSize.Height + offsetFromMiddle.Y) );

        }


        /// <summary>
        /// The brush used to draw the text associated with the arrow.
        /// </summary>
        public Brush TextBrush
        {
            get
            {
                return textBrush_;
            }
            set
            {
                textBrush_ = value;
            }
        }

    
        /// <summary>
        /// Set the text to be drawn with a solid brush of this color.
        /// </summary>
        public Color TextColor
        {
            set
            {
                textBrush_ = new SolidBrush( value );
            }
        }


        /// <summary>
        /// The color of the pen used to draw the arrow.
        /// </summary>
        public Color ArrowColor
        {
            get
            {
                return pen_.Color;
            }
            set
            {
                pen_.Color = value;
                arrowBrush_ = new SolidBrush( value );
            }
        }
            
        
        /// <summary>
        /// The font used to draw the text associated with the arrow.
        /// </summary>
        public Font TextFont
        {
            get
            {
                return this.font_;
            }
            set
            {
                this.font_ = value;
            }
        }


        /// <summary>
        /// Offset the whole arrow back in the arrow direction this many pixels from the point it's pointing to.
        /// </summary>
        public int HeadOffset
        {
            get
            {
                return headOffset_;
            }
            set
            {
                headOffset_ = value;
            }
        }
        private int headOffset_ = 2;


        private Brush arrowBrush_ = new SolidBrush( Color.Black );
        private Brush textBrush_ = new SolidBrush( Color.Black );
        private Pen pen_ = new Pen( Color.Black );
        private Font font_;
    }
}
