using System.Collections.Generic;
using System.Diagnostics;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;

public class Line
{
    private List<Vector2> points;
    private float thickness = 1.0f;

    public enum JoinType
    {
        None,
        Miter,
        Bevel,
        Round
    }

    public enum LineCaps
    {
        None,
        Round
    }

    private Color LineColor { get; set; }

    //Graphical representation
    private VertexBuffer vbo;
    private IndexBuffer ibo;
    private GraphicsDevice gDevice;

    public Line(List<Vector2> points)
    {
        this.points = points;
        this.LineColor = Color.Black;
    }

    public Line(List<Vector2> points, float thickness)
    {
        this.points = points;
        this.thickness = thickness;
        this.LineColor = Color.Black;
    }

    public Line(List<Vector2> points, float thickness, Color color)
    {
        this.points = points;
        this.thickness = thickness;
        this.LineColor = color;
    }

    public void InitOnGraphicalDevice(GraphicsDevice device)
    {
        this.gDevice = device;
        Debug.Assert(this.points.Count >= 2);
        List<VertexPositionColorTexture> vertices = new List<VertexPositionColorTexture>();
        List<ushort> indices = new List<ushort>();
        
        for(int i = 0; i < this.points.Count - 1 ; i++)
        {
            var p = this.points[i];
            var pNext = this.points[i+1];

            Vector2 dir = pNext - p;
            Vector2 perpendincularVector = new Vector2(dir.Y, -dir.X);
            perpendincularVector.Normalize();
            
            var offsetPoint1 = new Vector3(p.X, p.Y ,0.0f);
            var offsetPoint2 = new Vector3(p.X, p.Y ,0.0f);
            vertices.Add(new VertexPositionColorTexture(offsetPoint1,this.LineColor, perpendincularVector));
            vertices.Add(new VertexPositionColorTexture(offsetPoint2,this.LineColor, perpendincularVector * -1));
            var offsetPoint1Next = new Vector3(pNext.X, pNext.Y ,0.0f);
            var offsetPoint2Next = new Vector3(pNext.X, pNext.Y ,0.0f);
            vertices.Add(new VertexPositionColorTexture(offsetPoint1Next,this.LineColor, perpendincularVector));
            vertices.Add(new VertexPositionColorTexture(offsetPoint2Next,this.LineColor, perpendincularVector * -1));
        }

        for (int i = 0; i < vertices.Count; i+=4)
        {
            indices.Add((ushort)(i));
            indices.Add((ushort)(i + 1));
            indices.Add((ushort)(i + 2));

            indices.Add((ushort)(i + 2));
            indices.Add((ushort)(i + 1));
            indices.Add((ushort)(i + 3));
        }


        this.vbo = new VertexBuffer(device, typeof(VertexPositionColorTexture), (this.points.Count - 1) * 4, BufferUsage.WriteOnly);
        this.vbo.SetData<VertexPositionColorTexture>(vertices.ToArray());
        this.ibo = new IndexBuffer(device, typeof(ushort), indices.Count,BufferUsage.WriteOnly);
        this.ibo.SetData<ushort>(indices.ToArray());
    }

    public void Draw(Effect lineEffect)
    {
        this.gDevice.SetVertexBuffer(this.vbo);
        this.gDevice.Indices = this.ibo;
        RasterizerState rasterizerState = new RasterizerState();
        rasterizerState.CullMode = CullMode.None;
        this.gDevice.RasterizerState = rasterizerState;
        lineEffect.Parameters["thickness"].SetValue(this.thickness);
        foreach (EffectPass pass in lineEffect.CurrentTechnique.Passes)
        {
            pass.Apply();
            this.gDevice.DrawIndexedPrimitives(PrimitiveType.TriangleList,0,0,this.ibo.IndexCount / 3);
            //this.gDevice.DrawPrimitives(PrimitiveType.LineList, 0, this.vbo.VertexCount);
        }        
    }
}