#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <openssl/md5.h>
#include <unistd.h>
#include <iconv.h>
#include <libxml/xmlmemory.h>
#include <libxml/parser.h>

#include "fbsh.h"

std::string generateMD5 (char* input, int size) {
    int i;
    MD5_CTX md5;
    unsigned char out[MD5_DIGEST_LENGTH];
    char txt[32];
    std::string md5sum = "";

    MD5_Init(&md5);
    MD5_Update(&md5, input, size);
    MD5_Final(out, &md5);

    for ( i = 0; i < MD5_DIGEST_LENGTH; i++) {
    	snprintf (txt, 32, "%02x", out[i]);
    	md5sum += txt;
    }

	return md5sum;
}


FBSmartHome::FBSmartHome() {
	hostname = "";
	SID = "00 not yet set 00";
	fsidfile = NULL;
}


FBSmartHome::~FBSmartHome() {
	if (fsidfile != NULL) CloseSIDFile();
}


/*
 * try to connect with the last known SID.
 */
int FBSmartHome::Connect(std::string host) {
	int len;
	xmlDocPtr xmldoc;
	xmlNodePtr xmlnode;

	hostname = host;

	// is sid working?
	len = tcp.WebGetFile(hostname+"/login_sid.lua?sid="+SID, inbuffer, FB_BUFFER, NULL);
	if (len > FB_BUFFER) len = FB_BUFFER;
	else if (len < 0) {
		fprintf (stderr, "%s:%d Error getting challenge from Fritzbox\n", __FILE__, __LINE__);
		errno = EAI_FAIL;
		return -1;
	}
	inbuffer[len] = '\0';
	XMLPrepare(inbuffer, len, &xmldoc, &xmlnode);

	//
	// parse for SID and Challange
	while (xmlnode) {
		if ((!xmlStrcmp(xmlnode->name, (const xmlChar *)"SessionInfo"))){
			xmlNodePtr xmlchild = xmlnode->xmlChildrenNode;
			while (xmlchild) {
				if ((!xmlStrcmp(xmlchild->name, (const xmlChar *)"SID")))
					SID = (char *)xmlNodeListGetString(xmldoc, xmlchild->children, 1);
				xmlchild = xmlchild->next;
			}
		}
		xmlnode = xmlnode->next;
	}
	xmlFreeDoc(xmldoc);

	if (SID.compare("0000000000000000") == 0) {
		hostname = "";
		errno = ENOTCONN;
		return -1;
	}

	errno = 0;
	return 0;
}



int FBSmartHome::XMLPrepare(char *buffer, int len, xmlDocPtr *xmldoc, xmlNodePtr *xmlnode) {
	//
	// read the xml data from memory and select root node.
	if (xmldoc == NULL || xmlnode == NULL) return -1;

	*xmldoc = xmlReadMemory(inbuffer, len, "hostname", NULL, 0);
	if (xmldoc == NULL) {
		fprintf (stderr, "%s: Could not read XML Document\n", __FUNCTION__);
		errno = EAI_FAIL;
		return -1;
	}

	*xmlnode = xmlDocGetRootElement(*xmldoc);
	if (*xmlnode == NULL) {
		fprintf (stderr, "%s: Empty XML Document\n", __FUNCTION__);
		xmlFreeDoc(*xmldoc);
		errno = EOF;
		return -1;
	}

	return 0;
}

/*
 * connect with username and password, if connect is successfull the
 * SID will be returned.
 */
#define PWSSIZE 512
int FBSmartHome::Connect (std::string host, std::string username, std::string password) {
	int len;
	xmlDocPtr xmldoc;
	xmlNodePtr xmlnode;
	std::string challenge;
	std::string formdata;

	hostname = host;
	SID = "";
	tcp.Close();

	//
	// get challenge from FritzBox
	len = tcp.WebGetFile(hostname+"/login_sid.lua", inbuffer, FB_BUFFER, NULL);
	if (len > FB_BUFFER) len = FB_BUFFER;
	else if (len < 0) {
		fprintf (stderr, "%s:%d Error getting challenge from Fritzbox\n", __FILE__, __LINE__);
		errno = EAI_FAIL;
		return -1;
	}
	inbuffer[len] = '\0';
	XMLPrepare(inbuffer, len, &xmldoc, &xmlnode);

	//
	// parse for SID and Challange
	while (xmlnode) {
		if ((!xmlStrcmp(xmlnode->name, (const xmlChar *)"SessionInfo"))){
			xmlNodePtr xmlchild = xmlnode->xmlChildrenNode;
			while (xmlchild) {
				if ((!xmlStrcmp(xmlchild->name, (const xmlChar *)"SID")))
					SID = (char *)xmlNodeListGetString(xmldoc, xmlchild->children, 1);
				else if ((!xmlStrcmp(xmlchild->name, (const xmlChar *)"Challenge")))
					challenge = (char*) xmlNodeListGetString(xmldoc, xmlchild->children, 1);
				xmlchild = xmlchild->next;
			}
		}
		xmlnode = xmlnode->next;
	}
	xmlFreeDoc(xmldoc);

	//
	// create Challenge-PSW -> MD5 sum
	//

	//
	// convert to UTF16_LE
	std::string convertfrom = challenge+"-"+password;
	char *conv_input = (char *)convertfrom.c_str();
	size_t conv_inbytes = strlen (conv_input);
	size_t conv_size;
	char convertedpsw[PWSSIZE];
	char *conv_output = (char*)convertedpsw;
	size_t conv_outbytes = PWSSIZE;

	iconv_t ic = iconv_open("UTF-16LE", "UTF-8");
	if ((long int)ic == -1) {
		fprintf (stderr, "iconv_open error: %s\n", strerror(errno));
		return -1;
	}
	conv_size = iconv(ic, &conv_input, &conv_inbytes, (char**)&conv_output, &conv_outbytes);
	if ((long int)conv_size == -1) {
		fprintf (stderr, "iconv error: %s\n", strerror(errno));
		return -1;
	}
	iconv_close(ic);

	//
	// create password
	formdata = "response="+challenge+"-"+generateMD5(convertedpsw, conv_output-convertedpsw)+"&username="+username;
	len = tcp.WebGetFile(hostname+"/login_sid.lua", inbuffer, FB_BUFFER, (char*)formdata.c_str());
	if (len > FB_BUFFER) len = FB_BUFFER;
	else if (len < 0) {
		errno = EAI_FAIL;
		return -1;
	}
	inbuffer[len] = '\0';

	//
	// parse for SID and Challange
	XMLPrepare(inbuffer, len, &xmldoc, &xmlnode);
	while (xmlnode) {
		if ((!xmlStrcmp(xmlnode->name, (const xmlChar *)"SessionInfo"))){
			xmlNodePtr xmlchild = xmlnode->xmlChildrenNode;
			while (xmlchild) {
				if ((!xmlStrcmp(xmlchild->name, (const xmlChar *)"SID")))
					SID = (char *)xmlNodeListGetString(xmldoc, xmlchild->children, 1);
				else if ((!xmlStrcmp(xmlchild->name, (const xmlChar *)"Challenge")))
					challenge = (char*) xmlNodeListGetString(xmldoc, xmlchild->children, 1);
				xmlchild = xmlchild->next;
			}
		}
		xmlnode = xmlnode->next;
	}
	xmlFreeDoc(xmldoc);

	errno = 0;
	return 0;
};



/*
 * read sidfile, if it does not exist create file.
 */
#define BUFSIZE 1024
int FBSmartHome::UseSIDFile(std::string fn) {
	char buffer[BUFSIZE];
	int i;

	if ((fsidfile = fopen (fn.c_str(), "r+")) == NULL) {
		// file not found create file
		if ((fsidfile = fopen (fn.c_str(), "w")) == NULL) {
			fprintf (stderr, "error on writing sidfile '%s' : %s\n", fn.c_str(),
					strerror(errno));
			return -1;
		}
	}
	else {
		// sidfile found and open
		fseek (fsidfile, 0, SEEK_SET);
		if (fgets(buffer, BUFSIZE, fsidfile) != NULL) {
			buffer[BUFSIZE] = '\0';
			i = strlen (buffer);
			if (i > 0 && buffer[i-1] == '\n') buffer[i-1] = '\0';
			SID = buffer;
		}
	}
	return 0;
}


/*
 * if the sid file is open save current sid.
 */
int FBSmartHome::CloseSIDFile() {
	if (fsidfile != NULL) {
		fseek (fsidfile, 0, SEEK_SET);
		fprintf (fsidfile, "%s", SID.c_str());
		fclose(fsidfile);
		fsidfile = NULL;
	}
	return 0;
}



/*
 * retrieve the device list from the fritzbox
 */
std::list<FBSmartHomeDevice> *FBSmartHome::GetDevices() {
	std::list<FBSmartHomeDevice> *devlist = NULL;
	FBSmartHomeDevice smd;
	xmlDocPtr xmldoc;
	xmlNodePtr xmlnode;
	xmlAttr *xmlattr;

	int len;

	// retrieve data
	len = tcp.WebGetFile(hostname+"/webservices/homeautoswitch.lua?sid="+SID+"&switchcmd=getdevicelistinfos", inbuffer, FB_BUFFER, NULL);
	if (len > FB_BUFFER) len = FB_BUFFER;
	else if (len < 0) {
		fprintf (stderr, "%s:%d Error getting challenge from Fritzbox\n", __FILE__, __LINE__);
		errno = EAI_FAIL;
		return NULL;
	}
	inbuffer[len] = '\0';
	XMLPrepare(inbuffer, len, &xmldoc, &xmlnode);
	printf ("*********************************************\n%s\n*********************************\n", inbuffer);

	//
	// parse for SID and Challange
	while (xmlnode) {
		if ((!xmlStrcmp(xmlnode->name, (const xmlChar *)"devicelist"))){
			xmlNodePtr xmlchild = xmlnode->xmlChildrenNode;

			//
			// read each device details
			//
			while (xmlchild) {
				printf ("Name:%s\n", xmlchild->name);
				//
				// read attributes
				xmlattr = xmlchild->properties;
				while (xmlattr) {
					printf (" %s:%s ", xmlattr->name, xmlNodeListGetString(xmldoc, xmlattr->children, 1));
					xmlattr = xmlattr->next;
				}
				printf ("\n");

				// go thought all the subchildreen
				xmlNodePtr xmlsubchild = xmlchild->children;
				while (xmlsubchild) {
					printf ("  %s,%s ", xmlsubchild->name,
							(char *)xmlNodeListGetString(xmldoc, xmlsubchild->children, 1));
					xmlattr = xmlsubchild->properties;
					while (xmlattr) {
						printf (" %s:%s ", xmlattr->name, xmlNodeListGetString(xmldoc, xmlattr->children, 1));
						xmlattr = xmlattr->next;
					}
					printf ("\n");

					xmlNodePtr xmlsubchild2 = xmlsubchild->children;
					while (xmlsubchild2) {
						printf ("      %s,%s ", xmlsubchild2->name,
								(char *)xmlNodeListGetString(xmldoc, xmlsubchild2->children, 1));
						xmlattr = xmlsubchild2->properties;
						while (xmlattr) {
							printf (" %s:%s ", xmlattr->name, xmlNodeListGetString(xmldoc, xmlattr->children, 1));
							xmlattr = xmlattr->next;
						}
						printf ("\n");
						xmlsubchild2 = xmlsubchild2->next;
					}

					xmlsubchild = xmlsubchild->next;
				}
				printf ("\n");
				xmlchild = xmlchild->next;
			}
		}
		xmlnode = xmlnode->next;
	}
	xmlFreeDoc(xmldoc);

	if (SID.compare("0000000000000000") == 0) {
		hostname = "";
		errno = ENOTCONN;
		return NULL;
	}

	return devlist;
}