#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2016 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace HeuristicLab.Visualization {
  public class Chart : IChart {
    private PointD originalLowerLeft;
    private PointD originalUpperRight;
    protected List<Offset> zoomHistory;
    protected List<RenderStage> renderStages;

    private bool enabled;
    public bool Enabled {
      get { return enabled; }
      set {
        if (enabled == value) return;
        enabled = value;
        OnRedrawRequired();
      }
    }

    private Color backgroundColor;
    public Color BackgroundColor {
      get { return backgroundColor; }
      set {
        if (backgroundColor == value) return;
        backgroundColor = value;
        OnRedrawRequired();
      }
    }

    protected bool SuppressRedraw { get; set; }

    public bool SuppressEvents { get; set; }

    private PointD myLowerLeft;
    public virtual PointD LowerLeft {
      get { return myLowerLeft; }
    }
    private PointD myUpperRight;
    public virtual PointD UpperRight {
      get { return myUpperRight; }
    }
    public virtual SizeD Size {
      get { return new SizeD(UpperRight.X - LowerLeft.X, UpperRight.Y - LowerLeft.Y); }
    }
    private Size mySizeInPixels;

    public Size SizeInPixels {
      get { return mySizeInPixels; }
    }
    public SizeD PixelToWorldRatio {
      get { return new SizeD(Size.Width / SizeInPixels.Width, Size.Height / SizeInPixels.Height); }
    }
    public SizeD WorldToPixelRatio {
      get { return new SizeD(SizeInPixels.Width / Size.Width, SizeInPixels.Height / Size.Height); }
    }
    public double Scale { get; set; }
    public double MinimumZoomDistance { get; set; }
    public IGroup Group { get; protected set; }
    public IGrid Grid { get; protected set; }

    public Chart(PointD lowerLeft, PointD upperRight) {
      zoomHistory = new List<Offset>();
      SetPosition(lowerLeft, upperRight);
      mySizeInPixels = new Size((int)Size.Width, (int)Size.Height);
      backgroundColor = Color.White;
      Scale = 1.0;
      Group = new Group(this);
      Grid = new Grid(this);
      renderStages = new List<RenderStage> {
        new BackgroundColorRenderStage(this),
        new GridRenderStage(this),
        new GroupRenderStage(this),
        new EnabledRenderStage(this)
      };
      Group.RedrawRequired += GroupOnRedrawRequired;
      MinimumZoomDistance = 0.01;
    }

    public Chart(double x1, double y1, double x2, double y2)
      : this(new PointD(x1, y1), new PointD(x2, y2)) { }

    public PointD TransformPixelToWorld(Point point) {
      var x = LowerLeft.X + point.X * PixelToWorldRatio.Width;
      var y = LowerLeft.Y + (SizeInPixels.Height - point.Y) * PixelToWorldRatio.Height;
      return new PointD(x, y);
    }

    public SizeD TransformPixelToWorld(Size size) {
      var width = size.Width * PixelToWorldRatio.Width;
      var height = size.Height * PixelToWorldRatio.Height;
      return new SizeD(width, height);
    }

    public Point TransformWorldToPixel(PointD point) {
      var x = (int)((point.X - LowerLeft.X) * WorldToPixelRatio.Width);
      var y = (int)((UpperRight.Y - point.Y) * WorldToPixelRatio.Height);
      return new Point(x, y);
    }

    public Size TransformWorldToPixel(SizeD size) {
      var width = (int)(size.Width * WorldToPixelRatio.Width);
      var height = (int)(size.Height * WorldToPixelRatio.Height);
      return new Size(width, height);
    }

    public virtual void SetPosition(PointD lowerLeft, PointD upperRight) {
      if ((lowerLeft.X >= upperRight.X) || (lowerLeft.Y >= upperRight.Y))
        throw new ArgumentException("Lower left point is greater or equal than upper right point");

      originalLowerLeft = lowerLeft;
      originalUpperRight = upperRight;
      if (zoomHistory != null) zoomHistory.Clear();
      myLowerLeft = lowerLeft;
      myUpperRight = upperRight;
      OnRedrawRequired();
    }

    public virtual void Move(Offset delta) {
      myLowerLeft += delta;
      myUpperRight += delta;
      OnRedrawRequired();
    }

    public virtual void Zoom(Point mousePosition, double delta) {
      var cursor = TransformPixelToWorld(mousePosition);

      double zoomLevel = (100 + delta) / 100;
      double width = this.UpperRight.X - this.LowerLeft.X;
      double height = this.UpperRight.Y - this.LowerLeft.Y;
      double newWidth = width * zoomLevel;
      double newHeight = height * zoomLevel;
      double xAdaption = (UpperRight.X - cursor.X) / width;
      double yAdaption = (UpperRight.Y - cursor.Y) / height;

      ZoomIn(new PointD(cursor.X - newWidth * (1 - xAdaption), cursor.Y - newHeight * (1 - yAdaption)), new PointD(cursor.X + newWidth * xAdaption, cursor.Y + newHeight * yAdaption));
      OnRedrawRequired();
    }

    public virtual void ZoomIn(Point mousePosition) {
      Zoom(mousePosition, -10);
    }

    public virtual void ZoomIn(PointD lowerLeft, PointD upperRight) {
      // maintain a 1:1 ratio between x and y axis
      var pixels = SizeInPixels;
      var diagonal = upperRight - lowerLeft;
      var windowRatio = pixels.Height / (double)pixels.Width;
      var viewRatio = diagonal.DY / diagonal.DX;
      if (viewRatio < windowRatio) {
        var neededHeight = windowRatio * diagonal.DX;
        var diff = (neededHeight - diagonal.DY) / 2.0;
        lowerLeft.Y -= diff;
        upperRight.Y += diff;
      } else {
        var neededWidth = diagonal.DY / windowRatio;
        var diff = (neededWidth - diagonal.DX) / 2.0;
        lowerLeft.X -= diff;
        upperRight.X += diff;
      }
      if ((lowerLeft - upperRight).Length < MinimumZoomDistance) return;
      zoomHistory.Insert(0, LowerLeft - lowerLeft);
      zoomHistory.Insert(0, UpperRight - upperRight);
      myLowerLeft = lowerLeft;
      myUpperRight = upperRight;
      OnRedrawRequired();
    }

    public virtual void ZoomIn(Point lowerLeft, Point upperRight) {
      ZoomIn(TransformPixelToWorld(lowerLeft), TransformPixelToWorld(upperRight));
    }

    public virtual void ZoomOut() {
      if (zoomHistory.Count > 0) {
        Offset upperRight = zoomHistory[0];
        zoomHistory.RemoveAt(0);
        Offset lowerLeft = zoomHistory[0];
        zoomHistory.RemoveAt(0);
        myLowerLeft = LowerLeft + lowerLeft;
        myUpperRight = UpperRight + upperRight;
        OnRedrawRequired();
      } else {
        var lowerLeft = new PointD(myLowerLeft.X - Size.Width / 4, myLowerLeft.Y - Size.Height / 4);
        var upperRight = new PointD(myUpperRight.X + Size.Width / 4, myUpperRight.Y + Size.Height / 4);
        ZoomIn(lowerLeft, upperRight);
        if (zoomHistory.Count >= 2) {
          zoomHistory.RemoveRange(0, 2);
        }
      }
    }

    public virtual void Unzoom() {
      SetPosition(originalLowerLeft, originalUpperRight);
    }

    public virtual void IntoForeground(IPrimitive primitive) {
      Group.IntoForeground(primitive);
    }
    public virtual void IntoBackground(IPrimitive primitive) {
      Group.IntoBackground(primitive);
    }
    public virtual void OneLayerUp(IPrimitive primitive) {
      Group.OneLayerUp(primitive);
    }
    public virtual void OneLayerDown(IPrimitive primitive) {
      Group.OneLayerDown(primitive);
    }

    public virtual Cursor GetCursor(Point point) {
      return Group.GetCursor(TransformPixelToWorld(point)) ?? Cursors.Default;
    }

    public virtual string GetToolTipText(Point point) {
      return Group.GetToolTipText(TransformPixelToWorld(point));
    }

    public virtual IPrimitive GetPrimitive(Point point) {
      return Group.GetPrimitive(TransformPixelToWorld(point));
    }

    public virtual IEnumerable<IPrimitive> GetAllPrimitives(Point point) {
      return Group.GetAllPrimitives(TransformPixelToWorld(point));
    }

    public virtual void Render(Graphics graphics, int width, int height) {
      mySizeInPixels = new Size(width, height);
      foreach (var renderStage in renderStages)
        renderStage.Render(graphics);
    }

    public event EventHandler RedrawRequired;
    protected virtual void OnRedrawRequired() {
      if (SuppressRedraw) return;
      var handler = RedrawRequired;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    public void RaiseRedrawRequired() {
      var handler = RedrawRequired;
      if (handler != null) handler(this, EventArgs.Empty);
    }

    private void GroupOnRedrawRequired(object sender, EventArgs e) {
      OnRedrawRequired();
    }
  }
}