using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework;

namespace OperationDrawDown
{
    public class SelectionRectangle
    {
        Rectangle rectangle;
        Texture2D selectionTexture;
        Color color = Color.White;

        public Rectangle Rectangle { get { return rectangle ; } }
        public int StartX { get { return rectangle.X; } }
        public int StartY { get { return rectangle.Y; } }
        public int EndX { get { return rectangle.X + rectangle.Width; } }
        public int EndY { get { return rectangle.Y + rectangle.Height; } }
        public int Width { get { return rectangle.Width; } }
        public int Height { get { return rectangle.Height; } }


        public SelectionRectangle()
        {
            rectangle = new Rectangle(0,0,0,0);
            selectionTexture = Engine.content.Load<Texture2D>("_textures/SelectionRectangle");
        }
        public SelectionRectangle(int x, int y, int width, int height)
        {
            rectangle = new Rectangle(x, y, width, height);
            selectionTexture = Engine.content.Load<Texture2D>("_textures/SelectionRectangle");
        }
        public SelectionRectangle(int x, int y, int width, int height, Color backColor)
        {
            rectangle = new Rectangle(x, y, width, height);
            selectionTexture = Engine.content.Load<Texture2D>("_textures/SelectionRectangle");
            color = backColor;
        }
        public SelectionRectangle(int x, int y, int width, int height, Color backColor, Texture2D drawTexture)
        {
            rectangle = new Rectangle(x, y, width, height);
            selectionTexture = drawTexture;
            color = backColor;
        }

        public SelectionRectangle Clone()
        {
            return new SelectionRectangle(
                this.rectangle.X, this.rectangle.Y, 
                this.rectangle.Width, this.rectangle.Height, this.color,
                this.selectionTexture
                );
        }
        /// <summary>
        /// Draw the selection Rectangle.
        /// </summary>
        public void Draw()
        {
            Engine.spriteBatch.Draw(selectionTexture, rectangle, color);
        }

        /// <summary>
        /// Returns true if rectangle contains x/y point.
        /// Enforces that startpoint is at top/left, and endpoint is at bottom/right.
        /// </summary>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <returns>Returns true if rectangle contains x/y point.</returns>
        public bool Contains(int x, int y)
        {
            if (rectangle.Width < 0)
            {
                rectangle.X += rectangle.Width;
                rectangle.Width = -rectangle.Width;
            }
            if (rectangle.Height < 0)
            {
                rectangle.Y += rectangle.Height;
                rectangle.Height = -rectangle.Height;
            }
            

            // See if point is within startpoint and endpoint
            if (
                (rectangle.X < x) && (x < rectangle.X + rectangle.Width) &&
                (rectangle.Y < y) && (y < rectangle.Y + rectangle.Height)
                )
                return true;
            return false;
        }

        /// <summary>
        /// Auto-snap selection to a discrete selection of block based on block width.
        /// Includes all partially selected blocks.
        /// </summary>
        /// <param name="selectionRectangle">Approximate selection of blocks (usually from mouse selection).</param>
        /// <param name="blockWidth">Number of Pixels in each cell or tile.</param>
        public void DescretizeSelection(int blockWidth)
        {
            rectangle.X = (rectangle.X / blockWidth) * blockWidth;
            rectangle.Y = (rectangle.Y / blockWidth) * blockWidth;
            rectangle.Width = ((rectangle.Width + blockWidth) / blockWidth) * blockWidth;
            rectangle.Height = ((rectangle.Height + blockWidth) / blockWidth) * blockWidth;
        }

        /// <summary>
        /// Move Start Point by amount X/Y, keeping the same width and height
        /// </summary>
        /// <param name="dx">Distance to move X</param>
        /// <param name="dy">Distance to move Y</param>
        public void Move(int dx, int dy)
        {
            rectangle.X += dx;
            rectangle.Y += dy;
        }
        /// <summary>
        /// Move Start Point to posiition X/Y, keeping the same width and height. 
        /// </summary>
        /// <param name="x">New X Position</param>
        /// <param name="y">New Y Position</param>
        public void MoveTo(int x, int y)
        {
            rectangle.X = x;
            rectangle.Y = y;
        }
        /// <summary>
        /// Sets Start Point position w/o effecting End Point position
        /// </summary>
        /// <param name="x">New X position</param>
        /// <param name="y">New Y position</param>
        public void SetStartPoint(int x, int y)
        {
            rectangle.Width += rectangle.X - x;
            rectangle.Height += rectangle.Y - y;
            rectangle.X = x;
            rectangle.Y = y;
        }
        /// <summary>
        /// Set End Point position w/o effecting Start Point position
        /// </summary>
        /// <param name="x">New End Point X</param>
        /// <param name="y">New End Point Y</param>
        public void SetEndPoint(int x, int y)
        {
            rectangle.Width = x - rectangle.X;
            rectangle.Height= y - rectangle.Y;
        }

        /// <summary>
        /// Set Color of the Selection Rectangle.
        /// </summary>
        /// <param name="r">Red (0-1)</param>
        /// <param name="g">Green (0-1)</param>
        /// <param name="b">Blue (0-1)</param>
        /// <param name="a">Alpha (0-1)</param>
        public void Color_Set(float r, float g, float b, float a)
        {
            color = new Color(new Vector4(r, g, b, a));
        }

        /// <summary>
        /// Modify the Color of the Selection Rectangle.
        /// </summary>
        /// <param name="r">Red (0-1)</param>
        /// <param name="g">Green (0-1)</param>
        /// <param name="b">Blue (0-1)</param>
        /// <param name="a">Alpha (0-1)</param>
        public void Color_Modify(float r, float g, float b, float a)
        {
            color = new Color(new Vector4(
                r + color.R,
                g + color.G,
                b + color.B,
                a + color.A
                ));
        }
    }
}