// Copyright (c) 2012 Kuba Niegowski
//
// 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.

'use strict';


var util = require('util');
var Stream = require('stream');
var zlib = require('zlib');
var Filter = require('./filter');
var CrcStream = require('./crc');
var constants = require('./constants');


var Packer = module.exports = function(options) {
  Stream.call(this);

  this._options = options;

  options.deflateChunkSize = options.deflateChunkSize || 32 * 1024;
  options.deflateLevel = options.deflateLevel != null ? options.deflateLevel : 9;
  options.deflateStrategy = options.deflateStrategy != null ? options.deflateStrategy : 3;

  this.readable = true;
};
util.inherits(Packer, Stream);


Packer.prototype.pack = function(data, width, height, gamma) {

  // Signature
  this.emit('data', new Buffer(constants.PNG_SIGNATURE));
  this.emit('data', this._packIHDR(width, height));

  if (gamma) {
    this.emit('data', this._packGAMA(gamma));
  }

  // filter pixel data
  //TODO {}
  var filter = new Filter(width, height, 4, 8, false, this._options, {});
  var filteredData = filter.filter(data);

  // compress it
  var deflate = zlib.createDeflate({
    chunkSize: this._options.deflateChunkSize,
    level: this._options.deflateLevel,
    strategy: this._options.deflateStrategy
  });
  deflate.on('error', this.emit.bind(this, 'error'));

  deflate.on('data', function(compressedData) {
    this.emit('data', this._packIDAT(compressedData));
  }.bind(this));

  deflate.on('end', function() {
    this.emit('data', this._packIEND());
    this.emit('end');
  }.bind(this));

  deflate.end(filteredData);
};

Packer.prototype._packChunk = function(type, data) {

  var len = (data ? data.length : 0),
    buf = new Buffer(len + 12);

  buf.writeUInt32BE(len, 0);
  buf.writeUInt32BE(type, 4);

  if (data) data.copy(buf, 8);

  buf.writeInt32BE(CrcStream.crc32(buf.slice(4, buf.length - 4)), buf.length - 4);
  return buf;
};

Packer.prototype._packGAMA = function(gamma) {
  var buf = new Buffer(4);
  buf.writeUInt32BE(Math.floor(gamma * 100000), 0); // TODO constant
  return this._packChunk(constants.TYPE_gAMA, buf);
};

Packer.prototype._packIHDR = function(width, height) {

  var buf = new Buffer(13);
  buf.writeUInt32BE(width, 0);
  buf.writeUInt32BE(height, 4);
  buf[8] = 8;
  buf[9] = 6; // colorType
  buf[10] = 0; // compression
  buf[11] = 0; // filter
  buf[12] = 0; // interlace

  return this._packChunk(constants.TYPE_IHDR, buf);
};

Packer.prototype._packIDAT = function(data) {
  return this._packChunk(constants.TYPE_IDAT, data);
};

Packer.prototype._packIEND = function() {
  return this._packChunk(constants.TYPE_IEND, null);
};