/*
 * 				Firetweet - Twitter client for Android
 * 
 *  Copyright (C) 2012-2014 Mariotaku Lee <mariotaku.lee@gmail.com>
 * 
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 * 
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 * 
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.getlantern.firetweet.util;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

public class HostsFileParser {

	private final Map<String, String> mHosts = new HashMap<String, String>();
	private final String mPath;

	public HostsFileParser() {
		this("/etc/hosts");
	}

	public HostsFileParser(final String path) {
		mPath = path;
	}

	public boolean contains(final String host) {
		return mHosts.containsKey(host);
	}

	public String getAddress(final String host) {
		return mHosts.get(host);
	}

	public Map<String, String> getAll() {
		return new HashMap<String, String>(mHosts);
	}

	public boolean reload() {
		BufferedReader reader = null;
		try {
			reader = new BufferedReader(new FileReader(mPath));
			mHosts.clear();
			String line = null;
			while ((line = reader.readLine()) != null) {
				final String trimmed = line.trim();
				// Skip if this line is empty or commented out
				if (trimmed.length() == 0 || trimmed.startsWith("#")) {
					continue;
				}
				final String[] segments = trimmed.replaceAll("(\\s|\t)+", " ").split("\\s");
				if (segments.length < 2) {
					continue;
				}
				final String host = segments[1];
				if (!contains(host)) {
					mHosts.put(host, segments[0]);
				}
			}
			return true;
		} catch (final IOException e) {
			return false;
		} finally {
			if (reader != null) {
				Utils.closeSilently(reader);
			}
		}
	}

	public void reloadIfNeeded() {
		if (!mHosts.isEmpty()) return;
		reload();
	}
}