/// Version 1.0.0
/// Last modified 24.5.2014
///
/// Copyright (C) 2014 Niko Mononen, Atte Söderlund
///
/// Halyri-system is a prototype emergency call system. Its purpose is to
/// demonstrate the use of the advanced capabilities available in the current
/// generation smartphones in facilitating the emergency service dispatcher's
/// capability to determine the nature of the emergency and to dispatch help.
///
/// For more information, see the README file of this package.
///
/// The MIT License (MIT)
///
/// Permission is hereby granted, free of charge, to any person obtaining a copy
/// of this software and associated documentation files (the "Software"), to
/// deal in the Software without restriction, including without limitation the
/// rights to use, copy, modify, merge, publish, distribute, sublicense,
/// and/or sell copies of the Software, and to permit persons to whom the
/// Software is furnished to do so, subject to the following conditions:
///
/// The above copyright notice and this permission notice shall be included in
/// all copies or substantial portions of the Software.
///
/// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
/// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
/// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
/// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
/// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
/// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
/// IN THE SOFTWARE.
///

using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Shapes;
using System;


namespace GraphClass
{
    /// <author>Niko Mononen</author>
    /// <summary>
    /// The class adds a graph to the given grid. A user can add points, set bytes per second and scroll to the end of the graph.
    /// </summary>
    class Graph
    {
        private static Canvas GraphCanvas;
        private static ScrollViewer GraphContainer;
        private static ScaleTransform GraphScaleTransform;
        private static Polyline GraphLine;
        private static Color GraphColor = Color.FromArgb(200, 255, 187, 187);
        private static Color GraphSecondColor = Color.FromArgb(150, 255, 229, 229);
        private static SolidColorBrush color1 = new SolidColorBrush(GraphColor);
        private static SolidColorBrush color2 = new SolidColorBrush(GraphSecondColor);
        private EventHandler renderHandler = null;
        private static double GraphLineX = 0;
        private const double ScaleRate = 1.1;
        private static int BytesPerSecond = 50;

        /// <summary>
        /// The function makes canvas to the given grid with a black background and initializes a green line that connetcts
        /// the points that are added by addpoint method.
        /// </summary>
        /// <param name="grid">The Grid where this graph is added.</param>
        public Graph(Grid grid)
        {
            GraphCanvas = new Canvas();
            GraphCanvas.MouseWheel += new MouseWheelEventHandler(
                (sender, e) =>
                {
                    if (e.Delta > 0)
                    {
                        GraphScaleTransform.ScaleX *= ScaleRate;
                    }
                    else
                    {
                        GraphScaleTransform.ScaleX /= ScaleRate;
                    }
                }
            );
            GraphScaleTransform = new ScaleTransform();
            GraphCanvas.RenderTransform = GraphScaleTransform;
            GraphContainer = new ScrollViewer();
            GraphContainer.Content = GraphCanvas;
            GraphContainer.VerticalScrollBarVisibility = ScrollBarVisibility.Hidden;
            GraphContainer.HorizontalScrollBarVisibility = ScrollBarVisibility.Visible;
            GraphContainer.Background = Brushes.Black;
            GraphLine = new Polyline();
            GraphLine.Stroke = Brushes.LightGreen;
            GraphLine.StrokeThickness = 2;
            grid.Children.Add(GraphContainer);
            GraphCanvas.Background = Brushes.Black;
            GraphCanvas.Height = 258;
            GraphCanvas.Children.Add(GraphLine);
        }

        /// <summary>
        /// The function sets the Bytes per second for the data.
        /// </summary>
        /// <param name="bps">The value in bytes per second.</param>
        public void SetBytesPerSecond(int bps)
        {
            BytesPerSecond = bps;
        }

        /// <summary>
        /// The function adds a point to the graph and scales the points so that scrvollviewers width is 1 second of measurement data.
        /// </summary>
        /// <param name="y">The y point of the graph.</param>
        public void AddPoint(int y)
        {
            double x = GraphContainer.ActualWidth / BytesPerSecond;
            GraphLineX += x;
            GraphLine.Points.Add(new Point(GraphLineX, GraphCanvas.ActualHeight-y));
            GraphCanvas.Width = GraphLineX;
        }

        /// <summary>
        /// The function scrolls to the end of the graph.
        /// </summary>
        public void ScrollToEnd()
        {
            CompositionTarget.Rendering -= renderHandler;
            double distance = GraphLineX - GraphContainer.HorizontalOffset;
            double startOffset = GraphContainer.HorizontalOffset;
            double destinationOffset = GraphContainer.HorizontalOffset + distance;

            if (destinationOffset < 0)
            {
                destinationOffset = 0;
                distance = GraphContainer.HorizontalOffset;
            }

            if (destinationOffset > GraphCanvas.ActualWidth)
            {
                destinationOffset = GraphCanvas.ActualWidth;
                distance = GraphCanvas.ActualWidth - GraphContainer.HorizontalOffset;
            }

            double animationTime = distance / BytesPerSecond;
            DateTime startTime = DateTime.Now;
            renderHandler = (sender, args) =>
            {
                double elapsed = (DateTime.Now - startTime).TotalSeconds;

                if (elapsed >= animationTime)
                {
                    GraphContainer.ScrollToHorizontalOffset(destinationOffset);
                    CompositionTarget.Rendering -= renderHandler;
                }

                GraphContainer.ScrollToHorizontalOffset(startOffset + (elapsed * BytesPerSecond));
            };

            CompositionTarget.Rendering += renderHandler;
        }
        
    }
}