/**
 * Copyright (c) 2013 LEAP Encryption Access Project and contributers
 * 
 * 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 se.leap.bitmaskclient.eip;

import android.content.SharedPreferences;
import android.util.Log;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.Iterator;

import se.leap.bitmaskclient.Provider;

public class VpnConfigGenerator {

    private JSONObject general_configuration;
    private JSONObject gateway;
    private JSONObject secrets;

    public final static String TAG = VpnConfigGenerator.class.getSimpleName();
    private final String new_line = System.getProperty("line.separator"); // Platform new line

    public VpnConfigGenerator(JSONObject general_configuration, JSONObject secrets, JSONObject gateway) {
	this.general_configuration = general_configuration;
	this.gateway = gateway;
        this.secrets = secrets;
    }
    
    public String generate() {
	return
	    generalConfiguration()
	    + new_line
	    + gatewayConfiguration()
	    + new_line
	    + secretsConfiguration()
	    + new_line
	    + androidCustomizations();
    }

    private String generalConfiguration() {
	String common_options = "";
	try {
	    Iterator keys = general_configuration.keys();
	    while ( keys.hasNext() ){
		String key = keys.next().toString();
					
		common_options += key + " ";
		for ( String word : general_configuration.getString(key).split(" ") )
		    common_options += word + " ";
		common_options += new_line;
			
	    }
	} catch (JSONException e) {
	    // TODO Auto-generated catch block
	    e.printStackTrace();
	}

	common_options += "client";

	return common_options;
    }
    
    private String gatewayConfiguration() {
	String remotes = "";
		
	String ip_address_keyword = "ip_address";
	String remote_keyword = "remote";
	String ports_keyword = "ports";
	String protocol_keyword = "protocols";
	String capabilities_keyword = "capabilities";
	String udp = "udp";
		
	try {
	    String ip_address = gateway.getString(ip_address_keyword);
	    JSONObject capabilities = gateway.getJSONObject(capabilities_keyword);
	    JSONArray ports = capabilities.getJSONArray(ports_keyword);
	    for (int i=0; i<ports.length(); i++) {
		String port_specific_remotes = "";
		int port = ports.getInt(i);
		JSONArray protocols = capabilities.getJSONArray(protocol_keyword);
		for ( int j=0; j<protocols.length(); j++ ) {
		    String protocol = protocols.optString(j);
		    String new_remote = remote_keyword + " " + ip_address + " " + port + " " + protocol + new_line;

		    port_specific_remotes = protocol.equalsIgnoreCase(udp) ?
			port_specific_remotes.replaceFirst(remote_keyword, new_remote + new_line + remote_keyword) :
			new_remote;
		}
		remotes += port_specific_remotes;
	    }
	} catch (JSONException e) {
	    // TODO Auto-generated catch block
	    e.printStackTrace();
	}
		
	return remotes;
    }

    private String secretsConfiguration() {
        try {
            String ca =
                    "<ca>"
                            + new_line
                            + secrets.getString(Provider.CA_CERT)
                            + new_line
                            + "</ca>";

            String key =
                    "<key>"
                            + new_line
                            + secrets.getString(Constants.PRIVATE_KEY)
                            + new_line
                            + "</key>";

            String openvpn_cert =
                    "<cert>"
                            + new_line
                            + secrets.getString(Constants.CERTIFICATE)
                            + new_line
                            + "</cert>";

            return ca + new_line + key + new_line + openvpn_cert;
        } catch(JSONException e) {
            e.printStackTrace();
            return "";
        }
    }

    private String androidCustomizations() {
	return
	    "remote-cert-tls server"
	    + new_line
	    + "persist-tun"
	    + new_line
	    + "auth-retry nointeract";
    }
}