/*=============================================================================

  Project:   SharpImage
  Module:    siSceneSpatialObject.cs
  Language:  C#
  Author:    Dan Mueller
  Date:      $Date: 2007-07-06 10:57:00 +1000 (Fri, 06 Jul 2007) $
  Revision:  $Revision: 2 $

  Copyright (c) Queensland University of Technology (QUT) 2007.
  All rights reserved.

  This software is distributed WITHOUT ANY WARRANTY; without even
  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  PURPOSE.  See the above copyright notices for more information.
  
=============================================================================*/

using System;
using System.IO;
using System.Collections.Generic;
using System.Text;

using SharpImage.Rendering;

namespace SharpImage.SpatialObject
{
    public class siSceneSpatialObject : siSpatialObject
    {
        #region Constants
        //=====================================================================
        private const string MET_SCENE_OBJECT_TYPE = MET_OBJECT_TYPE + "Scene";
        private const string MET_NUM_OBJECTS = "NObjects = ";        
        //=====================================================================
        #endregion

        #region Instance Variables
        //=====================================================================
        private int m_ExpectedNumberOfObjects = 0;
        private int m_CurrentObject = 0;
        //=====================================================================
        #endregion

        #region Construction and Disposal
        //=====================================================================
        /// <summary>
        /// Protected constructor.
        /// </summary>
        protected siSceneSpatialObject()
        {

        }

        /// <summary>
        /// Static factory constructor.
        /// </summary>
        /// <returns></returns>
        public static siSceneSpatialObject New()
        {
            return new siSceneSpatialObject();
        }
        //=====================================================================
        #endregion

        #region Properties
        //=====================================================================
        
        #region CurrentLine
        //=====================================================================
        private int m_CurrentLine = 0;
        private int CurrentLine
        {
            get { return this.m_CurrentLine; }
        }
        //=====================================================================
        #endregion

        #region MetaLines
        //=====================================================================
        private string[] m_MetaLines;
        private string[] MetaLines
        {
            get { return this.m_MetaLines; }
        }
        //=====================================================================
        #endregion
        
        //=====================================================================
        #endregion

        #region Public Methods
        //=====================================================================
        /// <summary>
        /// Read the scene spatial object from a meta file (*.mhd).
        /// </summary>
        /// <param name="filename"></param>
        public override void Read(string filename)
        {
            // Check filename is valid
            if (filename != null && filename.Length > 0 && File.Exists(filename))
            {
                // Set the name
                this.Name = filename;

                // Read the file as lines
                this.m_MetaLines = File.ReadAllLines(filename);

                // Read header info
                this.ReadSceneObjectType();
                this.ReadNumDims();
                this.ReadNumObjects();

                while (this.m_CurrentObject < this.m_ExpectedNumberOfObjects)
                {
                    string objectType = this.ParseObjectType(this.PeekCurrentLine());

                    if (objectType == "Group")
                        this.ReadGroup();
                    else if (objectType == "Tube")
                        this.ReadTube();
                    else if (objectType == null)
                        // Reached the end of the file, stop reading
                        this.m_CurrentObject = this.m_ExpectedNumberOfObjects;
                    else
                        throw new FileLoadException("Unknown object type: " + objectType);

                    this.m_CurrentObject++;
                }               
            }
            else
            {
                throw new FileNotFoundException("The given meta filename is not valid.", filename);
            }
        }

        /// <summary>
        /// Write the scene spatial object to a meta file (*.mhd).
        /// </summary>
        /// <param name="filename"></param>
        public override void Write(string filename)
        {
            // Check filename is valid
            if (filename != null && filename.Length > 0 && File.Exists(filename))
            {
                // Set the name
                this.Name = filename;

                // Write to the file
                // TODO:
                throw new NotImplementedException("siSpatialObject.Write() is not yet implemented!");
            }
            else
            {
                throw new FileNotFoundException("The given meta filename is not valid.", filename);
            }
        }

        /// <summary>
        /// Renders the spatial object using OpenGL.
        /// </summary>
        /// <param name="renderer">The renderer this spatial object is being renderered to.</param>
        public override void Render(siRenderer renderer)
        {
            foreach (siSpatialObject child in this.Children)
                child.Render(renderer);
        }

        /// <summary>
        /// Initialises the spatial object for rendering.
        /// </summary>
        public override void Initialise(siRenderer renderer)
        {
            foreach (siSpatialObject child in this.Children)
                child.Initialise(renderer);
        }

        /// <summary>
        /// Return a string reprentation of the scene spatial object.
        /// </summary>
        /// <returns></returns>
        public override string ToString()
        {
            string result = "GroupSpatialObject: NObjects = " + this.Children.Count.ToString() + Environment.NewLine;
            foreach (siSpatialObject child in this.Children)
                result += child.ToString() + Environment.NewLine;
            return result;
        }
        //=====================================================================
        #endregion

        #region Private Methods
        //=====================================================================
        private string ReadCurrentLine()
        {
            if (this.CurrentLine < this.MetaLines.Length)
            {
                string result = this.MetaLines[this.CurrentLine];
                this.m_CurrentLine++;
                return result;
            }
            else
                return null;
        }

        private string PeekCurrentLine()
        {
            if (this.CurrentLine < this.MetaLines.Length)
                return this.MetaLines[this.CurrentLine];
            else 
                return null;
        }
        
        private void ReadSceneObjectType()
        {
            string line = this.ReadCurrentLine();
            if (line != MET_SCENE_OBJECT_TYPE)
                throw new FileLoadException("Could not find scene object type: expecting '" + MET_SCENE_OBJECT_TYPE + "', found '" + line + "'.");
        }

        private void ReadNumDims()
        {
            string line = this.ReadCurrentLine();
            if (line != MET_NUM_DIMS + "3")
                throw new FileLoadException("Could not read number of dimensions: expecting '" + MET_NUM_DIMS + "3" + "', found '" + line + "'.");
        }

        private void ReadNumObjects()
        {
            string line = this.ReadCurrentLine();
            if (!line.StartsWith(MET_NUM_OBJECTS))
                throw new FileLoadException("Could not read number of objects: expecting '" + MET_NUM_OBJECTS + "X" + "', but found '" + line + "'.");

            try
            {
                this.m_ExpectedNumberOfObjects = Int32.Parse(line.Replace(MET_NUM_OBJECTS, ""));
                this.m_CurrentObject = 0;
            }
            catch (Exception ex)
            {
                throw new FileLoadException("Could not read number of objects: expecting '" + MET_NUM_OBJECTS + "X" + "', but found '" + line + "'.", ex);
            }
        }

        private string ParseObjectType(string line)
        {
            if (line != null && line.Length > 0)
                return line.Replace(MET_OBJECT_TYPE, "");
            else
                return null;
        }

        private void ReadGroup()
        {
            // Consume all group objects - we don't want them
            string line = this.ReadCurrentLine();
            while (!line.StartsWith("EndGroup =") && line != null)
                line = this.ReadCurrentLine();
        }

        private void ReadTube()
        {
            List<string> tubeLines = new List<string>();
            
            string line = this.ReadCurrentLine(); // Read the object type
            line = this.ReadCurrentLine(); // Read the next line
            tubeLines.Add(line);
            while (line != null && !line.StartsWith(MET_OBJECT_TYPE))
            {
                line = this.ReadCurrentLine();
                tubeLines.Add(line);
            }

            // Back track to have the current line point to the object type
            if (line != null)
                this.m_CurrentLine--;

            // Parse the tube
            siTubeSpatialObject tube = siTubeSpatialObject.Parse(tubeLines.ToArray());
            if (tube != null)
                this.Children.Add(tube);

            // Copy the scene metadata to the tube
            foreach (string key in this.Metadata.Keys)
                tube.Metadata[key] = this.Metadata[key];
        }
        //=====================================================================
        #endregion        
    }
}