// Copyright 2000-2005 the Contributors, as shown in the revision logs.
// Licensed under the Apache Public Source License 2.0 ("the License").
// You may not use this file except in compliance with the License.

package org.ibex.js;

import java.net.*;
import java.io.*;
import java.util.*;
import java.net.*;
import org.ibex.util.*;
import org.ibex.net.*;
import org.ibex.crypto.*;

public class ProxyAutoConfig {

    public static class PacProxy extends HTTP.Proxy {
        private final JS pacFunc;
        public PacProxy(JS pacFunc) { this.pacFunc = pacFunc; }
        public Socket attempt(String url, String host, HTTP http) {
            if (Log.verbose) Log.info(this, "evaluating PAC script");
            String pac = null;
            try {
                pac = JSU.toString(pacFunc.call(null, new JS[] { JSU.S(url), JSU.S(host) }));
                if (Log.verbose) Log.info(this, "  PAC script returned \"" + pac + "\"");
            } catch (Throwable e) {
                if (Log.on) Log.info(this, "PAC script threw exception " + e);
                return null;
            }
            StringTokenizer st = new StringTokenizer(pac, ";", false);
            while (st.hasMoreTokens()) {
                String token = st.nextToken().trim();
                if (Log.verbose) Log.info(this, "  trying \"" + token + "\"...");
                try {
                    Socket ret = null;
                    if (token.startsWith("DIRECT"))
                        ret = attemptDirect(http);
                    else if (token.startsWith("PROXY"))
                        ret = attemptHttpProxy(http,
                                               token.substring(token.indexOf(' ') + 1, token.indexOf(':')),
                                               Integer.parseInt(token.substring(token.indexOf(':') + 1)));
                    else if (token.startsWith("SOCKS"))
                        ret = attemptSocksProxy(http,
                                                token.substring(token.indexOf(' ') + 1, token.indexOf(':')),
                                                Integer.parseInt(token.substring(token.indexOf(':') + 1)));
                    if (ret != null) return ret;
                } catch (Throwable e) {
                    if (Log.on) Log.info(this, "attempt at \"" + token + "\" failed due to " + e + "; trying next token");
                }
            }
            if (Log.on) Log.info(this, "all PAC results exhausted");
            return null;
        }
    }
    
    public static class ProxyAutoConfigRootScope extends JSScope.Global {

        public ProxyAutoConfigRootScope() { super(); }
        
        private final static JS.Method METHOD = new JS.Method();
        public JS get(JS name) throws JSExn {
            //#jsswitch(name)
            case "isPlainHostName": return METHOD;
            case "dnsDomainIs": return METHOD;
            case "localHostOrDomainIs": return METHOD;
            case "isResolvable": return METHOD;
            case "isInNet": return METHOD;
            case "dnsResolve": return METHOD;
            case "myIpAddress": return METHOD;
            case "dnsDomainLevels": return METHOD;
            case "shExpMatch": return METHOD;
            case "weekdayRange": return METHOD;
            case "dateRange": return METHOD;
            case "timeRange": return METHOD;
            case "ProxyConfig": return ProxyConfig;
                //#end
                return super.get(name);
        }
        
        private static final JS proxyConfigBindings = new JS.Obj();
        private static final JS ProxyConfig = new JS.Obj() {
                public JS get(JS name) throws JSExn {
                    //#jsswitch(name)
                    case "bindings": return proxyConfigBindings;
                        //#end
                        return null;
                }
            };

        public JS call(JS method, JS[] args) throws JSExn {
            //#jsswitch(method)
            case "isPlainHostName": return JSU.B(JSU.toString(args[0]).indexOf('.') == -1);
            case "dnsDomainIs":     return JSU.B(JSU.toString(args[0]).endsWith(JSU.toString(args[1])));
            case "localHostOrDomainIs":
                return JSU.B(args[0].equals(args[1]) ||
                             (JSU.toString(args[0]).indexOf('.') == -1 && JSU.toString(args[1]).startsWith(JSU.toString(args[0]))));
            case "isResolvable": try {
                return JSU.B(InetAddress.getByName(JSU.toString(args[0])) != null);
            } catch (UnknownHostException e) { return JSU.F; }
            case "isInNet":
                if (args.length != 3) return JSU.F;
                try {
                    byte[] host = InetAddress.getByName(JSU.toString(args[0])).getAddress();
                    byte[] net = InetAddress.getByName(JSU.toString(args[1])).getAddress();
                    byte[] mask = InetAddress.getByName(args[2].toString()).getAddress();
                    return JSU.B((host[0] & mask[0]) == net[0] &&
                                 (host[1] & mask[1]) == net[1] &&
                                 (host[2] & mask[2]) == net[2] &&
                                 (host[3] & mask[3]) == net[3]);
                } catch (Exception e) {
                    throw new JSExn("exception in isInNet(): " + e);
                }
            case "dnsResolve":
                try {
                    return JSU.S(InetAddress.getByName(JSU.toString(args[0])).getHostAddress());
                } catch (UnknownHostException e) {
                    return null;
                }
            case "myIpAddress":
                try {
                    return JSU.S(InetAddress.getLocalHost().getHostAddress());
                } catch (UnknownHostException e) {
                    if (Log.on) Log.info(this, "strange... host does not know its own address");
                    return null;
                }
            case "dnsDomainLevels":
                String s = JSU.toString(args[0]);
                int i = 0;
                while((i = s.indexOf('.', i)) != -1) i++;
                return JSU.N(i);
            case "shExpMatch":
                StringTokenizer st = new StringTokenizer(JSU.toString(args[1]), "*", false);
                String[] arr = new String[st.countTokens()];
                String s = JSU.toString(args[0]);
                for (int i=0; st.hasMoreTokens(); i++) arr[i] = st.nextToken();
                return JSU.B(match(arr, s, 0));
            case "weekdayRange":
                TimeZone tz = (args.length < 3 || args[2] == null || !args[2].equals("GMT")) ?
                    TimeZone.getTimeZone("UTC") : TimeZone.getDefault();
                Calendar c = new GregorianCalendar();
                c.setTimeZone(tz);
                c.setTime(new java.util.Date());
                java.util.Date d = c.getTime();
                int day = d.getDay();
                String d1s = JSU.toString(args[0]).toUpperCase();
                int d1 = 0, d2 = 0;
                for(int i=0; i<days.length; i++) if (days[i].equals(d1s)) d1 = i;
                    
                if (args.length == 1) return JSU.B(d1 == day);
                    
                String d2s = JSU.toString(args[1]).toUpperCase();
                for(int i=0; i<days.length; i++) if (days[i].equals(d2s)) d2 = i;
                    
                return JSU.B((d1 <= d2 && day >= d1 && day <= d2) || (d1 > d2 && (day >= d1 || day <= d2)));
                    
            case "dateRange": throw new JSExn("Ibex does not support dateRange() in PAC scripts");
            case "timeRange": throw new JSExn("Ibex does not support timeRange() in PAC scripts");
                //#end
                return super.call(method, args);
        }       
        private static boolean match(String[] arr, String s, int index) {
            if (index >= arr.length) return true;
            for(int i=0; i<s.length(); i++) {
                String s2 = s.substring(i);
                if (s2.startsWith(arr[index]) && match(arr, s2.substring(arr[index].length()), index + 1)) return true;
            }
            return false;
        }
        public static String[] days = { "SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT" };
    }

    public static JS proxyAutoConfigRootScope = new ProxyAutoConfigRootScope();
    public static JS getProxyAutoConfigFunction(String url) {
        try { 
            BufferedReader br = new BufferedReader(new InputStreamReader(new HTTP(url, true).GET(null, null)));
            String s = null;
            String script = "";
            while((s = br.readLine()) != null) script += s + "\n";
            if (Log.on) Log.info(Proxy.class, "successfully retrieved WPAD PAC:");
            if (Log.on) Log.info(Proxy.class, script);
            
            // MS CARP hack
            Vector carpHosts = new Vector();
            for(int i=0; i<script.length(); i++)
                if (script.regionMatches(i, "new Node(", 0, 9)) {
                    String host = script.substring(i + 10, script.indexOf('\"', i + 11));
                    if (Log.on) Log.info(Proxy.class, "Detected MS Proxy Server CARP Script, Host=" + host);
                    carpHosts.addElement(host);
                }
            if (carpHosts.size() > 0) {
                script = "function FindProxyForURL(url, host) {\nreturn \"";
                for(int i=0; i<carpHosts.size(); i++)
                    script += "PROXY " + carpHosts.elementAt(i) + "; ";
                script += "\";\n}";
                if (Log.on) Log.info(Proxy.class, "DeCARPed PAC script:");
                if (Log.on) Log.info(Proxy.class, script);
            }

            JS scr = JSU.fromReader("PAC script at " + url, 0, new StringReader(script));
            JSU.cloneWithNewGlobalScope(scr, proxyAutoConfigRootScope).call(null, null);
            return (JS)proxyAutoConfigRootScope.get(JSU.S("FindProxyForURL"));
        } catch (Exception e) {
            if (Log.on) {
                Log.info(ProxyAutoConfig.class, "WPAD detection failed due to:");
                if (e instanceof JSExn) {
                    try {
                        org.ibex.js.JSArray arr = new org.ibex.js.JSArray();
                        arr.add(((JSExn)e).getObject());
                    } catch (Exception e2) {
                        Log.info(ProxyAutoConfig.class, e);
                    }
                }
                else Log.info(ProxyAutoConfig.class, e);
            }
            return null;
        }
    }
}