/*******************************************************************************
 * Copyright (c) 2008, 2017 Oakland Software Incorporated and others
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *		Oakland Software Incorporated - initial API and implementation
 *		IBM Corporation - implementation
 *******************************************************************************/
package org.eclipse.core.internal.net.proxy.unix;

import java.io.IOException;
import java.lang.reflect.Method;
import java.net.URI;
import java.util.ArrayList;
import java.util.Locale;
import java.util.Objects;
import java.util.Properties;

import org.eclipse.core.internal.net.AbstractProxyProvider;
import org.eclipse.core.internal.net.Activator;
import org.eclipse.core.internal.net.Policy;
import org.eclipse.core.internal.net.ProxyData;
import org.eclipse.core.internal.net.StringUtil;
import org.eclipse.core.net.proxy.IProxyData;

public class UnixProxyProvider extends AbstractProxyProvider {

	private static final String LIBRARY_GCONF2 = "gconf-2"; //$NON-NLS-1$

	private static final String LIBRARY_NAME = "gnomeproxy-1.0.0"; //$NON-NLS-1$

	private static final String ENABLE_GNOME = Activator.ID + ".enableGnome"; //$NON-NLS-1$

	private static boolean isGnomeLibLoaded = false;

	static {
		// We have to load this here otherwise gconf seems to have problems
		// causing hangs and various other bad behavior,
		// please don't move this to be initialized on another thread.
		String value = System.getProperty(ENABLE_GNOME);
		if ("".equals(value) || "true".equals(value)) { //$NON-NLS-1$ //$NON-NLS-2$
			loadGnomeLib();
		}
	}

	public UnixProxyProvider() {
		// Nothing to initialize
	}

	@Override
	public IProxyData[] select(URI uri) {
		String[] nonProxyHosts = getNonProxiedHosts();
		if (nonProxyHosts != null) {
			String host = uri.getHost();
			for (int npIndex = 0; npIndex < nonProxyHosts.length; npIndex++) {
				if (StringUtil.hostMatchesFilter(host, nonProxyHosts[npIndex])) {
					return new IProxyData[0];
				}
			}
		}
		IProxyData[] proxies = new IProxyData[0];
		if (uri.getScheme() != null) {
			ProxyData pd = getSystemProxyInfo(uri.getScheme());
			proxies = pd != null ? new IProxyData[] { pd } : new IProxyData[0];
		} else {
			proxies = getProxyData();
		}
		if (Policy.DEBUG) {
			Policy.debug("UnixProxyProvider#select result for [" + uri + "]"); //$NON-NLS-1$ //$NON-NLS-2$
			for (int i = 0; i < proxies.length; i++)
				System.out.println("	" + proxies[i]); //$NON-NLS-1$
		}
		return proxies;
	}

	@Override
	public IProxyData[] getProxyData() {
		String[] commonTypes = new String[] { IProxyData.HTTP_PROXY_TYPE,
				IProxyData.SOCKS_PROXY_TYPE, IProxyData.HTTPS_PROXY_TYPE };
		return getProxyForTypes(commonTypes);
	}

	private IProxyData[] getProxyForTypes(String[] types) {
		ArrayList<IProxyData> allData = new ArrayList<>();
		for (int i = 0; i < types.length; i++) {
			String type = types[i];
			ProxyData pd = getSystemProxyInfo(type);
			if (pd != null && pd.getHost() != null) {
				allData.add(pd);
			}
		}
		return allData.toArray(new IProxyData[0]);
	}

	@Override
	public String[] getNonProxiedHosts() {
		String[] npHosts;

		if (Policy.DEBUG_SYSTEM_PROVIDERS)
			Policy.debug("Getting no_proxy"); //$NON-NLS-1$

		// First try the environment variable which is a URL
		String npEnv = getEnv("no_proxy"); //$NON-NLS-1$
		if (npEnv != null) {
			npHosts = StringUtil.split(npEnv, new String[] { "," }); //$NON-NLS-1$
			for (int i = 0; i < npHosts.length; i++)
				npHosts[i] = npHosts[i].trim();
			if (Policy.DEBUG_SYSTEM_PROVIDERS) {
				Policy.debug("Got Env no_proxy: " + npEnv); //$NON-NLS-1$
				debugPrint(npHosts);
			}
			return npHosts;
		}

		if (isGnomeLibLoaded) {
			try {
				npHosts = getGConfNonProxyHosts();
				if (npHosts != null && npHosts.length > 0) {
					if (Policy.DEBUG_SYSTEM_PROVIDERS) {
						Policy.debug("Got Gnome no_proxy"); //$NON-NLS-1$
						debugPrint(npHosts);
					}
					return npHosts;
				}
			} catch (UnsatisfiedLinkError e) {
				// The library should be loaded, so this is a real exception
				Activator.logError(
						"Problem during accessing Gnome library", e); //$NON-NLS-1$
			}
		}

		return new String[0];
	}

	// Returns null if something wrong or there is no proxy for the protocol
	protected ProxyData getSystemProxyInfo(String protocol) {
		ProxyData pd = null;
		String envName = null;

		if (Policy.DEBUG_SYSTEM_PROVIDERS)
			Policy.debug("Getting proxies for: " + protocol); //$NON-NLS-1$

		try {
			// protocol schemes are ISO 8859 (ASCII)
			protocol = protocol.toLowerCase(Locale.ENGLISH);

			// First try the environment variable which is a URL
			envName = protocol + "_proxy"; //$NON-NLS-1$
			String proxyEnv = getEnv(envName);
			if (Policy.DEBUG_SYSTEM_PROVIDERS)
				Policy.debug("Got proxyEnv: " + proxyEnv); //$NON-NLS-1$

			if (proxyEnv != null) {
				int colonInd = proxyEnv.indexOf(":"); //$NON-NLS-1$
				if (colonInd !=-1 && proxyEnv.length() > colonInd + 2 && !"//".equals(proxyEnv.substring(colonInd + 1, colonInd + 3))) { //$NON-NLS-1$
					proxyEnv = "http://" + proxyEnv; //$NON-NLS-1$
				}
				URI uri = new URI(proxyEnv);
				pd = new ProxyData(protocol);
				pd.setHost(Objects.requireNonNull(uri.getHost(), "no host in " + proxyEnv)); //$NON-NLS-1$
				int port = uri.getPort();
				if (port == -1) {
					throw new IllegalStateException("no port in " + proxyEnv); //$NON-NLS-1$
				}
				pd.setPort(port);
				String userInfo = uri.getUserInfo();
				if (userInfo != null) {
					String user = null;
					String password = null;
					int pwInd = userInfo.indexOf(':');
					if (pwInd >= 0) {
						user = userInfo.substring(0, pwInd);
						password = userInfo.substring(pwInd + 1);
					} else {
						user = userInfo;
					}
					pd.setUserid(user);
					pd.setPassword(password);
				}
				pd.setSource("LINUX_ENV"); //$NON-NLS-1$
				if (Policy.DEBUG_SYSTEM_PROVIDERS)
					Policy.debug("Got Env proxy: " + pd); //$NON-NLS-1$
				return pd;
			}
		} catch (Exception e) {
			Activator.logError(
					"Problem during accessing system variable: " + envName, e); //$NON-NLS-1$
		}

		if (isGnomeLibLoaded) {
			try {
				// Then ask Gnome
				pd = getGConfProxyInfo(protocol);
				if (pd != null) {
					if (Policy.DEBUG_SYSTEM_PROVIDERS)
						Policy.debug("Got Gnome proxy: " + pd); //$NON-NLS-1$
					pd.setSource("LINUX_GNOME"); //$NON-NLS-1$
					return pd;
				}
			} catch (UnsatisfiedLinkError e) {
				// The library should be loaded, so this is a real exception
				Activator.logError(
						"Problem during accessing Gnome library", e); //$NON-NLS-1$
			}
		}

		return null;
	}

	private static String getEnv(String env) {
		try {
			Method m = System.class.getMethod(
					"getenv", new Class[] { String.class }); //$NON-NLS-1$
			return (String) m.invoke(null, new Object[] { env });
		} catch (Throwable t) {
			// Fall-back to running 'env' directly. Warning this is very slow...
			// up to 200ms
			String cmd[] = { "/bin/sh", //$NON-NLS-1$
					"-c", //$NON-NLS-1$
					"env | grep -i proxy" }; //$NON-NLS-1$
			Properties props = new Properties();
			Process proc = null;
			try {
				proc = Runtime.getRuntime().exec(cmd);
				props.load(proc.getInputStream());
			} catch (IOException e) {
				Activator.logError(
						"Problem during accessing system variable: " + env, e); //$NON-NLS-1$
			} catch (IllegalArgumentException e) {
				Activator.logError(
						"Problem during accessing system variable: " + env, e); //$NON-NLS-1$
			} finally {
				if (proc != null) {
					proc.destroy();
				}
			}
			return props.getProperty(env);
		}
	}

	private static void loadGnomeLib() {
		try {
			System.loadLibrary(LIBRARY_GCONF2);
		} catch (final UnsatisfiedLinkError e) {
			// Expected on systems that are missing Gnome
			if (Policy.DEBUG_SYSTEM_PROVIDERS)
				Policy.debug("Could not load library: " //$NON-NLS-1$
						+ System.mapLibraryName(LIBRARY_GCONF2));
			return;
		}

		try {
			System.loadLibrary(LIBRARY_NAME);
			isGnomeLibLoaded = true;
			if (Policy.DEBUG_SYSTEM_PROVIDERS)
				Policy.debug("Loaded " + //$NON-NLS-1$
						System.mapLibraryName(LIBRARY_NAME) + " library"); //$NON-NLS-1$
		} catch (final UnsatisfiedLinkError e) {
			// Expected on systems that are missing Gnome library
			if (Policy.DEBUG_SYSTEM_PROVIDERS)
				Policy.debug("Could not load library: " //$NON-NLS-1$
						+ System.mapLibraryName(LIBRARY_NAME));
		}
	}


	private void debugPrint(String[] strs) {
		for (int i = 0; i < strs.length; i++)
			System.out.println(i + ": " + strs[i]); //$NON-NLS-1$
	}

	protected static native void gconfInit();

	protected static native ProxyData getGConfProxyInfo(String protocol);

	protected static native String[] getGConfNonProxyHosts();
}