#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <WinSock2.h>

#include "udp_server.h"
#include "../pandora.h"
#include "../windows/pandora_wmi.h"

using namespace Pandora;

/** 
 * Get the address of the server.
 * 
 * @return Server address.
 */
unsigned long UDP_Server::getAddress () {
    return this->address;
}

/** 
 * Get the address authorized to send commands to
 * the server.
 * 
 * @return Authorized address.
 */
unsigned long UDP_Server::getAuthAddress () {
    return this->auth_address;
}

/** 
 * Get the port of the server.
 * 
 * @return Server port.
 */
unsigned long UDP_Server::getPort () {
    return this->port;
}

/** 
 * Get the windows service associated to the server.
 * 
 * @return Windows service associated to the server.
 */
Pandora_Windows_Service *UDP_Server::getService () {
    return this->service;
}

/** 
 * Returns the state of the server.
 * 
 * @return 1 if the server is running, 0 if not.
 */
unsigned char UDP_Server::isRunning () {
    return this->running;
}

/** 
 * UDP_Server constructor.
 * 
 * @param service Service associated to the server.
 * @param address Server address.
 * @param auth_address Authorized address.
 * @param port Server port.
 */
UDP_Server::UDP_Server (Pandora_Windows_Service *service, string address, string auth_address, unsigned int port) {
	if (address.empty ()) {
	   this->address = INADDR_ANY;
	} else {
        this->address = inet_addr (address.c_str ());
    }
    if (auth_address.empty ()) {
        this->auth_address = INADDR_ANY;
    } else {
	   this->auth_address = inet_addr (auth_address.c_str ());
	}
	this->port = port;
	this->running = 0;
	this->service = service;
}

/** 
 * Starts the server.
 * 
 * @return 1 on error, 0 otherwise.
 */
int UDP_Server::start () {
	if (this->running != 0) {
		return 1;
	}
	
	/* Run in a new thread */
	this->running = 1;
	if (CreateThread (NULL, 0, (LPTHREAD_START_ROUTINE) listen, this, 0, NULL) == NULL) {
        this->running = 0;
		pandoraLog ("UDP Server: Error starting UDP Server thread");
		return 1;
	}

	pandoraLog ("UDP Server: UDP Server started on port %d", this->port);
	return 0;
}

/** 
 * Stops the server.
 * 
 * @return 1 on error, 0 otherwise.
 */
int UDP_Server::stop () {
	if (this->running != 0) {
		return 1;
	}
	
	this->running = 0;
	pandoraLog ("UDP Server: UDP Server going down");
	return 0;
}

/** 
 * Listens for incoming packets.
 * 
 * @param server UDP Server.
 */
void Pandora::listen (UDP_Server *server) {
    int sockfd,n;
    struct sockaddr_in servaddr, cliaddr;
    int len, err;
    char mesg[MAX_PACKET_SIZE];  
    unsigned long auth_addr;
    WSADATA wsa;

    err = WSAStartup (MAKEWORD (2,0), &wsa);
    if (err != 0) {
        /* Could not find a usable Winsock DLL */
        printf("UDP Server: WSAStartup failed with error: %d\n", err);
        return;
    }

    sockfd = socket (AF_INET, SOCK_DGRAM, 0);

    memset (&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl (server->getAddress ());
    servaddr.sin_port = htons (server->getPort ());
    bind(sockfd, (struct sockaddr *)&servaddr, sizeof (servaddr));

    /* Get authorised address */
    auth_addr = server->getAuthAddress ();

	while (server->isRunning () == 1) {
		len = sizeof(cliaddr);
		n = recvfrom(sockfd, mesg, MAX_PACKET_SIZE, 0, (struct sockaddr *)&cliaddr, &len);
		if (n == SOCKET_ERROR) {
            pandoraLog ("UDP Server: Error %d", WSAGetLastError ());
            break;
        }

		/* Authenticate client */
		if (auth_addr != INADDR_ANY && auth_addr != cliaddr.sin_addr.s_addr) {
            pandoraLog ("UDP Server: Unauthorised access from %s", inet_ntoa (cliaddr.sin_addr));
            continue;
		}

    	mesg[n] = 0;
    	process_command (server->getService (), mesg);
	}

    WSACleanup ();
}

/** 
 * Processes and executes server commands.
 * 
 * @param service Windows service associated to the server.
 * @param command Server command.
 * 
 * @return 1 on error, 0 otherwise.
 */
int Pandora::process_command (Pandora_Windows_Service *service, char *command) {
	int rc;
	char operation[MAX_PACKET_SIZE], action[MAX_PACKET_SIZE], target[MAX_PACKET_SIZE];
	string var, value;
    Pandora_Agent_Conf  *conf = NULL;

	rc = sscanf (command, "%s %s %s", operation, action, target);
	if (rc < 3) {
		pandoraLog ("UDP Server: Received invalid data: %s", command);
		return 1;
	}

    /* Re-run */	
	if (strcmp (operation, "REFRESH") == 0) {
        service->pandora_run ();
        return 0;
    }
    
    conf = service->getConf();
    
    /* Service management */
    if (strcmp (action, "SERVICE") == 0) {
        var = "service_";
        var.append (target);
        std::transform(var.begin(), var.end(), var.begin(), ::tolower);
        value = conf->getValue (var);
        if (atoi (value.c_str ()) != 1) {
            pandoraLog ("UDP Server: Unauthorised access to service %s", target);
            return 1;
        }

        if (strcmp (operation, "START") == 0) {
            Pandora_Wmi::startService (target);
        } else if (strcmp (operation, "STOP") == 0) {
            Pandora_Wmi::stopService (target);
        }
    }

    /* Process management */
    if (strcmp (action, "PROCESS") == 0) {
        var = "process_";
        var.append (target);
        std::transform(var.begin(), var.end(), var.begin(), ::tolower);

        if (strcmp (operation, "START") == 0) {
            var.append ("_start");
        } else if (strcmp (operation, "STOP") == 0) {
            var.append ("_stop");
        } else {
            return 1;
        }

        value = conf->getValue (var);
        if (value.empty ()) {
            pandoraLog ("UDP Server: Unauthorised access to process %s", target);
            return 1;
        }
        
        system (value.c_str());
    }

	return 0;
}