'use strict';

var nano = require('cssnano'),

assign = require('object-assign'),

PluginError = require('gulp-util').PluginError,

Transform = require('stream').Transform,

applySourceMap = require('vinyl-sourcemaps-apply'),

PLUGIN_NAME = 'gulp-cssnano';

module.exports = function(options) {

options = options || {};

var stream = new Transform({objectMode: true});

stream._transform = function(file, encoding, cb) {

if (file.isNull()) {

return cb(null, file);

}

if (file.isStream()) {

var error = 'Streaming not supported';

return cb(new PluginError(PLUGIN_NAME, error));

} else if (file.isBuffer()) {

try {

var result = nano(String(file.contents), assign(options, {

map: (file.sourceMap) ? {annotation: false} : false,

from: file.relative,

to: file.relative

}));

if (result.map && file.sourceMap) {

applySourceMap(file, String(result.map));

file.contents = new Buffer(result.css);

} else {

file.contents = new Buffer(result);

}

this.push(file);

} catch (e) {

var p = new PluginError(PLUGIN_NAME, e, {fileName: file.path});

this.emit('error', p);

}

cb();

}

};

return stream;

};