// 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'),
    Stream = require('stream'),
    zlib = require('zlib'),
    Filter = require('./filter'),
    CrcStream = require('./crc'),
    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) {

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

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

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

    deflate.end(data);
};

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._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);
};
