var request = require('request');
var through = require('through');
var UError = require('./error').UserError;
var URL = require('url');

//
// Implements Storage interface
// (same for storage.js, local-storage.js, up-storage.js)
//
function Storage(config, mainconfig) {
	if (!(this instanceof Storage)) return new Storage(config);
	this.config = config;
	this.ua = mainconfig.user_agent;
	this.ca;

	this.url = URL.parse(this.config.url);
	if (this.url.hostname === 'registry.npmjs.org') {
		this.ca = require('./npmsslkeys');

		// npm registry is too slow working with ssl :(
		/*if (this.config._autogenerated) {
			// encrypt all the things!
			this.url.protocol = 'https';
			this.config.url = URL.format(this.url);
		}*/
	}

	this.config.url = this.config.url.replace(/\/$/, '');
	return this;
}

Storage.prototype.can_fetch_url = function(url) {
	url = URL.parse(url);

	return url.protocol === this.url.protocol
	    && url.host === this.url.host
	    && url.path.indexOf(this.url.path) === 0
}

Storage.prototype.add_package = function(name, metadata, callback) {
	throw new Error('unimplemented');
}

Storage.prototype.add_version = function(name, version, metadata, tag, callback) {
	throw new Error('unimplemented');
}

Storage.prototype.add_tarball = function(name, filename) {
	throw new Error('unimplemented');
}

Storage.prototype.get_package = function(name, callback) {
	request({
		url: this.config.url + '/' + name,
		json: true,
		headers: {
			'User-Agent': this.ua,
		},
		ca: this.ca,
	}, function(err, res, body) {
		if (err) return callback(err);
		if (res.statusCode === 404) {
			return callback(new UError({
				msg: 'package doesn\'t exist on uplink',
				status: 404,
			}));
		}
		if (!(res.statusCode >= 200 && res.statusCode < 300)) {
			return callback(new Error('bad status code: ' + res.statusCode));
		}
		callback(null, body);
	});
}

Storage.prototype.get_tarball = function(name, filename) {
	return this.get_url(this.config.url + '/' + name + '/-/' + filename);
}

Storage.prototype.get_url = function(url) {
	var stream = through(function(data) {
		this.queue(data);
	}, function() {
		this.queue(null);
	});

	var rstream = request({
		url: url,
		headers: {
			'User-Agent': this.ua,
		},
		ca: this.ca,
		encoding: null,
	});

	rstream.on('response', function(res) {
		if (res.statusCode === 404) {
			return stream.emit('error', new UError({
				msg: 'file doesn\'t exist on uplink',
				status: 404,
			}));
		}
		if (!(res.statusCode >= 200 && res.statusCode < 300)) {
			return stream.emit('error', new UError({
				msg: 'bad uplink status code: ' + res.statusCode,
				status: 500,
			}));
		}

		rstream.pipe(stream);
	});

	rstream.on('error', function(err) {
		stream.emit('error', err);
	});
	return stream;
}

module.exports = Storage;