using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Drawing.Imaging;
using System.IO;
using System.Drawing.Printing;
using System.Diagnostics;

using GraEditor.DrawTools;
using GraEditor.Elements;
namespace GraEditor
{
    public class Canvas
    {
        //Construct graList to save the drawing actions
        protected Canvas()
        {
            this.graList = new ArrayList(); // define an arraylist with name gralist for saving all the drawing actions

        }

        //Initialize the canvas. Set name,size and background color of canvas
        public void Init(string name, Size size, Color backColor)
        {
            this.name = name;//Set name of canvas
            this.Size = size;//Set size of canvas
            this.backColor = backColor;//Set background color of canvas

            this.graList.Clear();//Clear all the elements in graList

            //this.mainView.AutoScrollMinSize = this.Size;//this.Size;//Set the size of mainView as canvas size



            this.isSavedOnce = false;
            this.IsModified = false;

        }

        private static Canvas _single;
        public static Canvas Instance
        {
            //Get canvas instance
            get
            {
                if (_single == null)
                    _single = new Canvas();

                return _single;
            }
        }

        public event EventHandler Modified;
        protected void OnModified()
        {
            if (Modified != null)
                Modified(this, EventArgs.Empty);
        }

        //Dirty flag
        private bool isModified;
        public bool IsModified
        {
            get { return this.isModified; }
            set
            {
                this.isModified = value;
                OnModified();
            }
        }

        private bool isSavedOnce;
        public bool IsSavedOnce
        {
            get { return this.isSavedOnce; }
            set { this.isSavedOnce = value; }
        }

        private MainView mainView;//private Mainview variable of canvas
        public MainView MainView
        {
            get { return mainView; }
            set { mainView = value; }
        }



        public void Update()//Refresh canvas
        {
            this.mainView.UpdateView();
        }

        private string name;//canvas name
        public string Name
        {
            get { return name; }
            set { name = value; }
        }

        private Size size;//canvas size
        public Size Size
        {
            get { return size; }
            set
            {
                size = value;
                this.mainView.AutoScrollMinSize = this.size;//this.Size;//Set the size of mainView as canvas size

            }
        }

        private Color backColor;//canvas color i.e. background color of the image
        public Color BackColor
        {
            get { return backColor; }
            set
            {
                backColor = value;
                this.Update();
            }
        }

        private ArrayList graList;//Save drawing action on canvas
        public ArrayList GraList
        {
            get { return graList; }
        }

        public void AddGra(GraElement gra)
        {
            this.graList.Add(gra);
            this.IsModified = true;
            this.Update();
        }

        public void DelGra(GraElement gra)
        {
            this.graList.Remove(gra);
            this.IsModified = true;
            this.Update();
        }

        //Draw function of canvas
        public void Draw(Graphics g)
        {
            foreach (GraElement gra in graList)//Draw all the element in the graList
                gra.Draw(g);
        }

        public bool Open()
        {
            OpenFileDialog dlg = new OpenFileDialog(); // new open dialog box is instantiated
            dlg.Filter = "位图文件(*.bmp;*.jpg;*.gif;*.png)|*.bmp;*.jpg;*.gif;*.png";
            dlg.FilterIndex = 1;
            dlg.RestoreDirectory = true;

            bool bRtn = false;
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                try
                {
                    bRtn = this.OpenFile(dlg.FileName);
                }
                catch (Exception ex)
                {
                    MessageBox.Show("文件打开错误 - " + ex.Message);
                }
            }

            return bRtn;
        }

        private FileStream canvasStream;

        public bool OpenFile(string fileName)
        {
            FileInfo fi = new FileInfo(fileName);
            if (!fi.Exists)
            {
                MessageBox.Show("选择的文不存在!", "Open File");
                return false;
            }
            
            try
            {
                canvasStream = File.Open(fileName, FileMode.Open, FileAccess.ReadWrite, FileShare.None);
            }
            catch (Exception ex)
            {
                MessageBox.Show("文件打开错误 - " + ex.Message);

            }
            
            Bitmap bmp = new Bitmap(canvasStream);
            //fs.Close();
            if (bmp != null)
            {
                Canvas.Instance.Init(fileName, bmp.Size, Color.White);

                ImageGra imageGra = new ImageGra(bmp, new Rectangle(new Point(0, 0), bmp.Size));
                Canvas.Instance.GraList.Clear();
                Canvas.Instance.GraList.Add(imageGra);//Add to GraList
                Canvas.Instance.Update();//Update canvas
                CurrentBgImage = new Bitmap(bmp);
            }

            return true;
        }
        Bitmap currentBgImage = null;

        public Bitmap CurrentBgImage
        {
            get { return currentBgImage; }
            set {
                if (currentBgImage != null) {
                    currentBgImage.Dispose();
                }
                currentBgImage = value; }
        }
        /// <summary>
        /// 重置 恢复打开时的原始状态
        /// </summary>
        public void ReloadCanvas()
        {
            if (currentBgImage != null)
            {
                Bitmap bmp = new Bitmap(currentBgImage);
                ImageGra imageGra = new ImageGra(bmp, new Rectangle(new Point(0, 0), bmp.Size));
                Canvas.Instance.GraList.Clear();
                Canvas.Instance.GraList.Add(imageGra);//Add to GraList
                Canvas.Instance.Update();//Update canvas
            }
            else {
                Canvas.Instance.GraList.Clear();
                Canvas.Instance.Update();//Update canvas
            }
        }

        private ImageFormat GetImageFormatByFileName(string fileName)
        {
            string ext = Path.GetExtension(fileName);
            ImageFormat format = ImageFormat.Bmp;
            switch (ext)
            {
                case ".jpg":
                    format = ImageFormat.Jpeg;
                    break;
                case ".gif":
                    format = ImageFormat.Gif;
                    break;
                default:
                    format = ImageFormat.Bmp;
                    break;
            }

            return format;
        }
        /// <summary>
        /// 获取新绘制的图片
        /// </summary>
        /// <returns></returns>
        public Bitmap GetNewBitmap()
        {
            Size s = Canvas.Instance.Size;
            Bitmap bmp = new Bitmap(s.Width, s.Height);
            Graphics gBmp = Graphics.FromImage(bmp);
            gBmp.Clear(Canvas.Instance.BackColor);
            this.Draw(gBmp);
            return bmp;
        }
        public void Save()
        {
            //if(this.canvasStream == null)
            //	return;

            if (this.name == null ||
                this.name.Length == 0)
            {
                MessageBox.Show("文件名无效!", "警告");
                return;
            }

            Bitmap bmp = GetNewBitmap();
            try
            {
                if (this.canvasStream != null)
                    this.canvasStream.Close();
                ImageFormat format = GetImageFormatByFileName(Canvas.Instance.Name);
                bmp.Save(Canvas.Instance.Name, format);
                bmp.Dispose();
                this.IsModified = false;
                this.IsSavedOnce = true;

              //  this.canvasStream = File.Open(this.name, FileMode.Open, FileAccess.ReadWrite, FileShare.None);
            }
            catch (Exception ex)
            {
                MessageBox.Show("文件保存错误 - " + ex.Message);
            }


        }


        public bool Close()
        {
            if (canvasStream != null)
            {
                canvasStream.Close();
                canvasStream = null;
            }

            return true;
        }
    }


    //Redo & Undo operation
    public class GraEditStackMgr
    {

        private GraEditStackMgr()//construct a redo list
        {
            this.graRedoList = new ArrayList();
        }

        private static GraEditStackMgr instance;
        public static GraEditStackMgr Instance
        {
            get
            {
                if (instance == null)
                    instance = new GraEditStackMgr();
                return instance;
            }
        }

        private ArrayList graRedoList;//Redo list
        public ArrayList GraRedoList
        {
            get { return graRedoList; }
        }

        public void Clear()
        {
            this.graRedoList.Clear();
        }

        //Redo operation
        public void Redo()
        {
            if (this.graRedoList.Count == 0)//no undo happen
                return;

            int lastIndex = this.graRedoList.Count - 1;//Get the last undo action

            //Save last undo action to graLast
            GraElement graLast = this.graRedoList[lastIndex] as GraElement;
            this.graRedoList.RemoveAt(lastIndex);//Remove the last undo action from redo list

            //Canvas.Instance.GraList.Add(graLast);//Save the last undo action to GraList
            //Canvas.Instance.Update();//Update canvas
            Canvas.Instance.AddGra(graLast);

        }

        //Undo operation
        public void Undo()
        {
            ArrayList graList = Canvas.Instance.GraList;//Get the GraList of Canvas
            if (graList.Count == 0)//No drawing action happen
                return;

            int lastIndex = graList.Count - 1;//Last drawing action position in graList

            //Save the last drawing action to graLast
            GraElement graLast = graList[lastIndex] as GraElement;
            graList.RemoveAt(lastIndex);//Remove the last drawing action 
            this.graRedoList.Add(graLast);//Add the last drawing action to redo list

            Canvas.Instance.Update();//Update canvas
            Canvas.Instance.IsModified = true;
        }


    }
}