using System;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
using TSP;

namespace Plotter
{
    public class TourPlot
    {
        public Tour Tour { get; set; }
        public PictureBox Canvas { get; set; }
        public Label WeightLabel { get; set; }
        public Label RuntimeLabel { get; set; }
        public TimeSpan RunTime { get; set; }

        public TourPlot(PictureBox canvas, Label weightLabel, Label runtimeLabel)
        {
            Canvas = canvas;
            WeightLabel = weightLabel;
            RuntimeLabel = runtimeLabel;
        }

        public void Render()
        {
            const int Scaler = 25;
            const int PlotSize = 100;

            using Bitmap bmp = new(Canvas.Width, Canvas.Height);
            using Graphics gfx = Graphics.FromImage(bmp);
            using Pen pen = new(Color.Black);
            using Pen gridPen = new(Color.LightGray);
            using Font font = new("Arial", 16);
            using Font gridFont = new("Arial", 10);
            using SolidBrush brush = new(Color.Black);
            using StringFormat stringFormat = new StringFormat();

            gfx.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            gfx.Clear(Color.White);

            for (int i = 0; i <= 100; i += 10)
            {
                Point left = ScaleLocation(new Coordinate(0, i));
                Point right = ScaleLocation(new Coordinate(100, i));
                gfx.DrawLine(gridPen, left, right);
                stringFormat.Alignment = StringAlignment.Far;
                stringFormat.LineAlignment = StringAlignment.Center;
                gfx.DrawString(i.ToString(), gridFont, brush, left, stringFormat);

                Point bottom = ScaleLocation(new Coordinate(i, 0));
                Point top = ScaleLocation(new Coordinate(i, 100));
                gfx.DrawLine(gridPen, bottom, top);
                stringFormat.Alignment = StringAlignment.Center;
                stringFormat.LineAlignment = StringAlignment.Near;
                gfx.DrawString(i.ToString(), gridFont, brush, bottom, stringFormat);
            }

            // iterate through each city and draw line from Location to parent.Location 
            foreach (City city in Tour.Cities.Where(city => city.Parent != -1))
            {
                City parent = Tour[city.Parent];

                Point cityPoint = ScaleLocation(city.Location);
                Point parentPoint = ScaleLocation(parent.Location);

                gfx.DrawString(city.Id.ToString(), font, brush, cityPoint);
                gfx.DrawLine(pen, cityPoint, parentPoint);
            }

            // copy the bitmap to the picturebox (double buffered)
            Canvas.Image?.Dispose();
            Canvas.Image = (Bitmap)bmp.Clone();

            // set runtime and weight labels
            RuntimeLabel.Text = String.Format("{0:00}:{1:00}:{2:00}.{3:00}",
                RunTime.Hours, RunTime.Minutes, RunTime.Seconds, RunTime.Milliseconds / 10);

            WeightLabel.Text = Tour.Weight.ToString("F3");

            // helper function to unify the scaling of images
            Point ScaleLocation(Coordinate coordinate)
            {
                int x = Canvas.Width * (coordinate.X + Scaler / 2) / (Scaler + PlotSize);
                int y = Canvas.Height * ((coordinate.Y - PlotSize) * -1 + Scaler / 2) / (Scaler + PlotSize);

                return new Point(x, y);
            }
        }

        public void Save(string filename) =>
            Canvas.Image.Save(filename);
    }
}