/*
  OpenMW - The completely unofficial reimplementation of Morrowind
  Copyright (C) 2008-2010  Nicolay Korslund
  Email: < korslund@gmail.com >
  WWW: http://openmw.sourceforge.net/

  This file (nif_file.h) is part of the OpenMW package.

  OpenMW is distributed as free software: you can redistribute it
  and/or modify it under the terms of the GNU General Public License
  version 3, as published by the Free Software Foundation.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  version 3 along with this program. If not, see
  http://www.gnu.org/licenses/ .

 */

#ifndef _NIF_FILE_H_
#define _NIF_FILE_H_

#include <string>
#include "../mangle/stream/stream.h"
#include "../mangle/stream/filters/buffer_stream.h"
#include "../mangle/tools/str_exception.h"
#include "../tools/stringops.h"

#include <vector>

// Only used during development. Remove later.
#include <iostream>
using namespace std;

using namespace Mangle::Stream;

// A simple array implementation containing a pointer and a
// length. Used for holding slices into a data buffer.
#include <string.h>
template <class T>
struct SliceArray
{
  const T* ptr;
  size_t length;

  SliceArray(const T* _ptr, size_t _length)
    : ptr(_ptr), length(_length) {}

  bool operator==(SliceArray &t)
  {
    return
      length == t.length &&
      (memcmp(ptr,t.ptr, length*sizeof(T)) == 0);
  }

  /// Only use this for stings
  bool operator==(const char* str)
  {
    return
      str[length] == 0 &&
      (strncmp(ptr, str, length) == 0);
  }

  /** This allocates a copy of the data. Only use this for debugging
      and error messages.
  */
  std::string toString()
  { return std::string(ptr,length); }
};

typedef SliceArray<char> SString;
typedef SliceArray<int> IntArray;
typedef SliceArray<float> FloatArray;

class NIFFile
{
  enum NIFVersion
    {
      VER_MW    = 0x04000002    // Morrowind NIFs
    };

  /// Nif file version
  int ver;

  /// Input stream
  StreamPtr inp;

  /// File name, used for error messages
  std::string filename;

  /// Record list
  typedef void NifRecord;
  std::vector<NifRecord*> records;

  /// Used for error handling
  void fail(const std::string &msg)
    {
      std::string err = "NIFFile Error: " + msg;
      err += "\nFile: " + filename;
      throw str_exception(err);
    }

  /// Parse the file
  void parse()
    {
      // Check the header string
      const char* head = getString(40);
      if(!begins(head, "NetImmerse File Format"))
        fail("Invalid NIF header");

      // Get BCD version
      ver = getInt();
      if(ver != VER_MW)
        fail("Unsupported NIF version");

      // Number of records
      int recNum = getInt();
      records.resize(recNum);

      for(int i=0;i<recNum;i++)
        {
          SString rec = getString();

          cout << i << ": " << rec.toString() << endl;

          if(rec == "NiNode") cout << " got a node!\n";

          break;
        }
    }

 public:
  /// Open a NIF stream. The name is used for error messages.
  NIFFile(StreamPtr nif, const std::string &name)
    : filename(name)
    {
      /* Load the entire file into memory. This allows us to use
         direct pointers to the data arrays in the NIF, instead of
         individually allocating and copying each one.

         The NIF data is only stored temporarily in memory, since once
         the mesh data is loaded it is siphoned into OGRE and
         deleted. For that reason, we might improve this further and
         use a shared region/pool based allocation scheme in the
         future, especially since only one NIFFile will ever be loaded
         at any given time.
      */
      inp = StreamPtr(new BufferStream(nif));

      parse();
    }


  /* ************************************************

               Parser functions

  ****************************************************/

  template<class X> X getType() { return *((X*)inp->getPtr(sizeof(X))); }
  int getInt() { return getType<int>(); }

  template<class X>
  SliceArray<X> getArray()
    {
      int len = getInt();
      return SliceArray<X>((const X*)inp->getPtr(len), len);
    }

  SString getString() { return getArray<char>(); }

  const char *getString(int size)
    { return (const char*)inp->getPtr(size); }
};

#endif