/*
Copyright (c) 2011 Juan Mellado

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

/*
References:
- "OpenCTM: The Open Compressed Triangle Mesh file format" by Marcus Geelnard
  http://openctm.sourceforge.net/
*/

var CTM = CTM || {};

CTM.CompressionMethod = {
  RAW: 0x00574152,
  MG1: 0x0031474d,
  MG2: 0x0032474d
};

CTM.Flags = {
  NORMALS: 0x00000001
};

CTM.File = function(stream){
  this.load(stream);
};

CTM.File.prototype.load = function(stream){
  this.header = new CTM.FileHeader(stream);

  this.body = new CTM.FileBody(this.header);
  
  this.getReader().read(stream, this.body);
};

CTM.File.prototype.getReader = function(){
  var reader;

  switch(this.header.compressionMethod){
    case CTM.CompressionMethod.RAW:
      reader = new CTM.ReaderRAW();
      break;
    case CTM.CompressionMethod.MG1:
      reader = new CTM.ReaderMG1();
      break;
    case CTM.CompressionMethod.MG2:
      reader = new CTM.ReaderMG2();
      break;
  }

  return reader;
};

CTM.FileHeader = function(stream){
  stream.readInt32(); //magic "OCTM"
  this.fileFormat = stream.readInt32();
  this.compressionMethod = stream.readInt32();
  this.vertexCount = stream.readInt32();
  this.triangleCount = stream.readInt32();
  this.uvMapCount = stream.readInt32();
  this.attrMapCount = stream.readInt32();
  this.flags = stream.readInt32();
  this.comment = stream.readString();
};

CTM.FileHeader.prototype.hasNormals = function(){
  return this.flags & CTM.Flags.NORMALS;
};

CTM.FileBody = function(header){
  var i = header.triangleCount * 3,
      v = header.vertexCount * 3,
      n = header.hasNormals()? header.vertexCount * 3: 0,
      u = header.vertexCount * 2,
      a = header.vertexCount * 4,
      j = 0;

  var data = new ArrayBuffer(
    (i + v + n + (u * header.uvMapCount) + (a * header.attrMapCount) ) * 4);

  this.indices = new Uint32Array(data, 0, i);

  this.vertices = new Float32Array(data, i * 4, v);

  if ( header.hasNormals() ){
    this.normals = new Float32Array(data, (i + v) * 4, n);
  }
  
  if (header.uvMapCount){
    this.uvMaps = [];
    for (j = 0; j < header.uvMapCount; ++ j){
      this.uvMaps[j] = {uv: new Float32Array(data,
        (i + v + n + (j * u) ) * 4, u) };
    }
  }
  
  if (header.attrMapCount){
    this.attrMaps = [];
    for (j = 0; j < header.attrMapCount; ++ j){
      this.attrMaps[j] = {attr: new Float32Array(data,
        (i + v + n + (u * header.uvMapCount) + (j * a) ) * 4, a) };
    }
  }
};

CTM.FileMG2Header = function(stream){
  stream.readInt32(); //magic "MG2H"
  this.vertexPrecision = stream.readFloat32();
  this.normalPrecision = stream.readFloat32();
  this.lowerBoundx = stream.readFloat32();
  this.lowerBoundy = stream.readFloat32();
  this.lowerBoundz = stream.readFloat32();
  this.higherBoundx = stream.readFloat32();
  this.higherBoundy = stream.readFloat32();
  this.higherBoundz = stream.readFloat32();
  this.divx = stream.readInt32();
  this.divy = stream.readInt32();
  this.divz = stream.readInt32();
  
  this.sizex = (this.higherBoundx - this.lowerBoundx) / this.divx;
  this.sizey = (this.higherBoundy - this.lowerBoundy) / this.divy;
  this.sizez = (this.higherBoundz - this.lowerBoundz) / this.divz;
};

CTM.ReaderRAW = function(){
};

CTM.ReaderRAW.prototype.read = function(stream, body){
  this.readIndices(stream, body.indices);
  this.readVertices(stream, body.vertices);
  
  if (body.normals){
    this.readNormals(stream, body.normals);
  }
  if (body.uvMaps){
    this.readUVMaps(stream, body.uvMaps);
  }
  if (body.attrMaps){
    this.readAttrMaps(stream, body.attrMaps);
  }
};

CTM.ReaderRAW.prototype.readIndices = function(stream, indices){
  stream.readInt32(); //magic "INDX"
  stream.readArrayInt32(indices);
};

CTM.ReaderRAW.prototype.readVertices = function(stream, vertices){
  stream.readInt32(); //magic "VERT"
  stream.readArrayFloat32(vertices);
};

CTM.ReaderRAW.prototype.readNormals = function(stream, normals){
  stream.readInt32(); //magic "NORM"
  stream.readArrayFloat32(normals);
};

CTM.ReaderRAW.prototype.readUVMaps = function(stream, uvMaps){
  var i = 0;
  for (; i < uvMaps.length; ++ i){
    stream.readInt32(); //magic "TEXC"

    uvMaps[i].name = stream.readString();
    uvMaps[i].filename = stream.readString();
    stream.readArrayFloat32(uvMaps[i].uv);
  }
};

CTM.ReaderRAW.prototype.readAttrMaps = function(stream, attrMaps){
  var i = 0;
  for (; i < attrMaps.length; ++ i){
    stream.readInt32(); //magic "ATTR"

    attrMaps[i].name = stream.readString();
    stream.readArrayFloat32(attrMaps[i].attr);
  }
};

CTM.ReaderMG1 = function(){
};

CTM.ReaderMG1.prototype.read = function(stream, body){
  this.readIndices(stream, body.indices);
  this.readVertices(stream, body.vertices);
  
  if (body.normals){
    this.readNormals(stream, body.normals);
  }
  if (body.uvMaps){
    this.readUVMaps(stream, body.uvMaps);
  }
  if (body.attrMaps){
    this.readAttrMaps(stream, body.attrMaps);
  }
};

CTM.ReaderMG1.prototype.readIndices = function(stream, indices){
  stream.readInt32(); //magic "INDX"
  stream.readInt32(); //packed size
  
  var interleaved = new CTM.InterleavedStream(indices, 3);
  LZMA.decompress(stream, stream, interleaved, interleaved.data.length);

  CTM.restoreIndices(indices, indices.length);
};

CTM.ReaderMG1.prototype.readVertices = function(stream, vertices){
  stream.readInt32(); //magic "VERT"
  stream.readInt32(); //packed size
  
  var interleaved = new CTM.InterleavedStream(vertices, 1);
  LZMA.decompress(stream, stream, interleaved, interleaved.data.length);
};

CTM.ReaderMG1.prototype.readNormals = function(stream, normals){
  stream.readInt32(); //magic "NORM"
  stream.readInt32(); //packed size

  var interleaved = new CTM.InterleavedStream(normals, 3);
  LZMA.decompress(stream, stream, interleaved, interleaved.data.length);
};

CTM.ReaderMG1.prototype.readUVMaps = function(stream, uvMaps){
  var i = 0;
  for (; i < uvMaps.length; ++ i){
    stream.readInt32(); //magic "TEXC"

    uvMaps[i].name = stream.readString();
    uvMaps[i].filename = stream.readString();
    
    stream.readInt32(); //packed size

    var interleaved = new CTM.InterleavedStream(uvMaps[i].uv, 2);
    LZMA.decompress(stream, stream, interleaved, interleaved.data.length);
  }
};

CTM.ReaderMG1.prototype.readAttrMaps = function(stream, attrMaps){
  var i = 0;
  for (; i < attrMaps.length; ++ i){
    stream.readInt32(); //magic "ATTR"

    attrMaps[i].name = stream.readString();
    
    stream.readInt32(); //packed size

    var interleaved = new CTM.InterleavedStream(attrMaps[i].attr, 4);
    LZMA.decompress(stream, stream, interleaved, interleaved.data.length);
  }
};

CTM.ReaderMG2 = function(){
};

CTM.ReaderMG2.prototype.read = function(stream, body){
  this.MG2Header = new CTM.FileMG2Header(stream);
  
  this.readVertices(stream, body.vertices);
  this.readIndices(stream, body.indices);
  
  if (body.normals){
    this.readNormals(stream, body);
  }
  if (body.uvMaps){
    this.readUVMaps(stream, body.uvMaps);
  }
  if (body.attrMaps){
    this.readAttrMaps(stream, body.attrMaps);
  }
};

CTM.ReaderMG2.prototype.readVertices = function(stream, vertices){
  stream.readInt32(); //magic "VERT"
  stream.readInt32(); //packed size

  var interleaved = new CTM.InterleavedStream(vertices, 3);
  LZMA.decompress(stream, stream, interleaved, interleaved.data.length);
  
  var gridIndices = this.readGridIndices(stream, vertices);
  
  CTM.restoreVertices(vertices, this.MG2Header, gridIndices, this.MG2Header.vertexPrecision);
};

CTM.ReaderMG2.prototype.readGridIndices = function(stream, vertices){
  stream.readInt32(); //magic "GIDX"
  stream.readInt32(); //packed size
  
  var gridIndices = new Uint32Array(vertices.length / 3);
  
  var interleaved = new CTM.InterleavedStream(gridIndices, 1);
  LZMA.decompress(stream, stream, interleaved, interleaved.data.length);
  
  CTM.restoreGridIndices(gridIndices, gridIndices.length);
  
  return gridIndices;
};

CTM.ReaderMG2.prototype.readIndices = function(stream, indices){
  stream.readInt32(); //magic "INDX"
  stream.readInt32(); //packed size

  var interleaved = new CTM.InterleavedStream(indices, 3);
  LZMA.decompress(stream, stream, interleaved, interleaved.data.length);

  CTM.restoreIndices(indices, indices.length);
};

CTM.ReaderMG2.prototype.readNormals = function(stream, body){
  stream.readInt32(); //magic "NORM"
  stream.readInt32(); //packed size

  var interleaved = new CTM.InterleavedStream(body.normals, 3);
  LZMA.decompress(stream, stream, interleaved, interleaved.data.length);

  var smooth = CTM.calcSmoothNormals(body.indices, body.vertices);

  CTM.restoreNormals(body.normals, smooth, this.MG2Header.normalPrecision);
};

CTM.ReaderMG2.prototype.readUVMaps = function(stream, uvMaps){
  var i = 0;
  for (; i < uvMaps.length; ++ i){
    stream.readInt32(); //magic "TEXC"

    uvMaps[i].name = stream.readString();
    uvMaps[i].filename = stream.readString();
    
    var precision = stream.readFloat32();
    
    stream.readInt32(); //packed size

    var interleaved = new CTM.InterleavedStream(uvMaps[i].uv, 2);
    LZMA.decompress(stream, stream, interleaved, interleaved.data.length);
    
    CTM.restoreMap(uvMaps[i].uv, 2, precision);
  }
};

CTM.ReaderMG2.prototype.readAttrMaps = function(stream, attrMaps){
  var i = 0;
  for (; i < attrMaps.length; ++ i){
    stream.readInt32(); //magic "ATTR"

    attrMaps[i].name = stream.readString();
    
    var precision = stream.readFloat32();
    
    stream.readInt32(); //packed size

    var interleaved = new CTM.InterleavedStream(attrMaps[i].attr, 4);
    LZMA.decompress(stream, stream, interleaved, interleaved.data.length);
    
    CTM.restoreMap(attrMaps[i].attr, 4, precision);
  }
};

CTM.restoreIndices = function(indices, len){
  var i = 3;
  if (len > 0){
    indices[2] += indices[0];
    indices[1] += indices[0];
  }
  for (; i < len; i += 3){
    indices[i] += indices[i - 3];
    
    if (indices[i] === indices[i - 3]){
      indices[i + 1] += indices[i - 2];
    }else{
      indices[i + 1] += indices[i];
    }

    indices[i + 2] += indices[i];
  }
};

CTM.restoreGridIndices = function(gridIndices, len){
  var i = 1;
  for (; i < len; ++ i){
    gridIndices[i] += gridIndices[i - 1];
  }
};

CTM.restoreVertices = function(vertices, grid, gridIndices, precision){
  var gridIdx, delta, x, y, z,
      intVertices = new Uint32Array(vertices.buffer, vertices.byteOffset, vertices.length),
      ydiv = grid.divx, zdiv = ydiv * grid.divy,
      prevGridIdx = 0x7fffffff, prevDelta = 0,
      i = 0, j = 0, len = gridIndices.length;

  for (; i < len; j += 3){
    x = gridIdx = gridIndices[i ++];
    
    z = ~~(x / zdiv);
    x -= ~~(z * zdiv);
    y = ~~(x / ydiv);
    x -= ~~(y * ydiv);

    delta = intVertices[j];
    if (gridIdx === prevGridIdx){
      delta += prevDelta;
    }

    vertices[j]     = grid.lowerBoundx +
      x * grid.sizex + precision * delta;
    vertices[j + 1] = grid.lowerBoundy +
      y * grid.sizey + precision * intVertices[j + 1];
    vertices[j + 2] = grid.lowerBoundz +
      z * grid.sizez + precision * intVertices[j + 2];

    prevGridIdx = gridIdx;
    prevDelta = delta;
  }
};

CTM.restoreNormals = function(normals, smooth, precision){
  var ro, phi, theta, sinPhi,
      nx, ny, nz, by, bz, len,
      intNormals = new Uint32Array(normals.buffer, normals.byteOffset, normals.length),
      i = 0, k = normals.length,
      PI_DIV_2 = 3.141592653589793238462643 * 0.5;

  for (; i < k; i += 3){
    ro = intNormals[i] * precision;
    phi = intNormals[i + 1];

    if (phi === 0){
      normals[i]     = smooth[i]     * ro;
      normals[i + 1] = smooth[i + 1] * ro;
      normals[i + 2] = smooth[i + 2] * ro;
    }else{
      
      if (phi <= 4){
        theta = (intNormals[i + 2] - 2) * PI_DIV_2;
      }else{
        theta = ( (intNormals[i + 2] * 4 / phi) - 2) * PI_DIV_2;
      }
      
      phi *= precision * PI_DIV_2;
      sinPhi = ro * Math.sin(phi);

      nx = sinPhi * Math.cos(theta);
      ny = sinPhi * Math.sin(theta);
      nz = ro * Math.cos(phi);

      bz = smooth[i + 1];
      by = smooth[i] - smooth[i + 2];

      len = Math.sqrt(2 * bz * bz + by * by);
      if (len > 1e-20){
        by /= len;
        bz /= len;
      }

      normals[i]     = smooth[i]     * nz +
        (smooth[i + 1] * bz - smooth[i + 2] * by) * ny - bz * nx;
      normals[i + 1] = smooth[i + 1] * nz -
        (smooth[i + 2]      + smooth[i]   ) * bz  * ny + by * nx;
      normals[i + 2] = smooth[i + 2] * nz +
        (smooth[i]     * by + smooth[i + 1] * bz) * ny + bz * nx;
    }
  }
};

CTM.restoreMap = function(map, count, precision){
  var delta, value,
      intMap = new Uint32Array(map.buffer, map.byteOffset, map.length),
      i = 0, j, len = map.length;

  for (; i < count; ++ i){
    delta = 0;

    for (j = i; j < len; j += count){
      value = intMap[j];
      
      delta += value & 1? -( (value + 1) >> 1): value >> 1;
      
      map[j] = delta * precision;
    }
  }
};

CTM.calcSmoothNormals = function(indices, vertices){
  var smooth = new Float32Array(vertices.length),
      indx, indy, indz, nx, ny, nz,
      v1x, v1y, v1z, v2x, v2y, v2z, len,
      i, k;

  for (i = 0, k = indices.length; i < k;){
    indx = indices[i ++] * 3;
    indy = indices[i ++] * 3;
    indz = indices[i ++] * 3;

    v1x = vertices[indy]     - vertices[indx];
    v2x = vertices[indz]     - vertices[indx];
    v1y = vertices[indy + 1] - vertices[indx + 1];
    v2y = vertices[indz + 1] - vertices[indx + 1];
    v1z = vertices[indy + 2] - vertices[indx + 2];
    v2z = vertices[indz + 2] - vertices[indx + 2];
    
    nx = v1y * v2z - v1z * v2y;
    ny = v1z * v2x - v1x * v2z;
    nz = v1x * v2y - v1y * v2x;
    
    len = Math.sqrt(nx * nx + ny * ny + nz * nz);
    if (len > 1e-10){
      nx /= len;
      ny /= len;
      nz /= len;
    }
    
    smooth[indx]     += nx;
    smooth[indx + 1] += ny;
    smooth[indx + 2] += nz;
    smooth[indy]     += nx;
    smooth[indy + 1] += ny;
    smooth[indy + 2] += nz;
    smooth[indz]     += nx;
    smooth[indz + 1] += ny;
    smooth[indz + 2] += nz;
  }

  for (i = 0, k = smooth.length; i < k; i += 3){
    len = Math.sqrt(smooth[i] * smooth[i] + 
      smooth[i + 1] * smooth[i + 1] +
      smooth[i + 2] * smooth[i + 2]);

    if(len > 1e-10){
      smooth[i]     /= len;
      smooth[i + 1] /= len;
      smooth[i + 2] /= len;
    }
  }

  return smooth;
};

CTM.isLittleEndian = (function(){
  var buffer = new ArrayBuffer(2),
      bytes = new Uint8Array(buffer),
      ints = new Uint16Array(buffer);

  bytes[0] = 1;

  return ints[0] === 1;
}());

CTM.InterleavedStream = function(data, count){
  this.data = new Uint8Array(data.buffer, data.byteOffset, data.byteLength);
  this.offset = CTM.isLittleEndian? 3: 0;
  this.count = count * 4;
  this.len = this.data.length;
};

CTM.InterleavedStream.prototype.writeByte = function(value){
  this.data[this.offset] = value;
  
  this.offset += this.count;
  if (this.offset >= this.len){
  
    this.offset -= this.len - 4;
    if (this.offset >= this.count){
    
      this.offset -= this.count + (CTM.isLittleEndian? 1: -1);
    }
  }
};

CTM.Stream = function(data){
  this.data = data;
  this.offset = 0;
};

CTM.Stream.prototype.TWO_POW_MINUS23 = Math.pow(2, -23);

CTM.Stream.prototype.TWO_POW_MINUS126 = Math.pow(2, -126);

CTM.Stream.prototype.readByte = function(){
  return this.data[this.offset ++] & 0xff;
};

CTM.Stream.prototype.readInt32 = function(){
  var i = this.readByte();
  i |= this.readByte() << 8;
  i |= this.readByte() << 16;
  return i | (this.readByte() << 24);
};

CTM.Stream.prototype.readFloat32 = function(){
  var m = this.readByte();
  m += this.readByte() << 8;

  var b1 = this.readByte();
  var b2 = this.readByte();

  m += (b1 & 0x7f) << 16; 
  var e = ( (b2 & 0x7f) << 1) | ( (b1 & 0x80) >>> 7);
  var s = b2 & 0x80? -1: 1;

  if (e === 255){
    return m !== 0? NaN: s * Infinity;
  }
  if (e > 0){
    return s * (1 + (m * this.TWO_POW_MINUS23) ) * Math.pow(2, e - 127);
  }
  if (m !== 0){
    return s * m * this.TWO_POW_MINUS126;
  }
  return s * 0;
};

CTM.Stream.prototype.readString = function(){
  var len = this.readInt32();

  this.offset += len;

  return String.fromCharCode.apply(null,this.data.subarray(this.offset - len, this.offset));
};

CTM.Stream.prototype.readArrayInt32 = function(array){
  var i = 0, len = array.length;
  
  while(i < len){
    array[i ++] = this.readInt32();
  }

  return array;
};

CTM.Stream.prototype.readArrayFloat32 = function(array){
  var i = 0, len = array.length;

  while(i < len){
    array[i ++] = this.readFloat32();
  }

  return array;
};
