#pragma implementation
/*
	Generic IMAP server. It handles the protocol, the session, but
	does not care about networking and the message store.


TODO:
	Messages flags
	auto-logout 30 minutes
*/
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <misc.h>
#include <dialog.h>
#include "imap.h"
#include <syslog.h>

enum IMAP_STATE{
	IMAP_IDLE,		// Original connection, not logged in
	IMAP_AUTHSTEP,	// We are running the authentication steps
	IMAP_AUTH,		// We know the user ID
	IMAP_SELECT,	// We are logged and a folder is selected
};

class IMAP_CLIENT{
public:
	IMAP_INFO info;
	IMAP_STUFF stuff;
	IMAP_STATE state;
	int authstep;
	SSTRING authuser;
	SSTRING lasttag;
	SSTRINGS subs;		// Folder subscribed
	IMAP_CLIENT(){
		state = IMAP_IDLE;
		stuff.userid = -1;
		stuff.domainid = -1;
		stuff.data = NULL;
		info.sessiontime = time(NULL);
	}
};

class _F_IMAP_private{
public:
	_F_IMAP *c;
	IMAP_CLIENT **tb;
	int maxclient;
	char hostname[1000];
	int client;
	_F_IMAP_private(){
		tb = NULL;
		maxclient = 0;
		if (gethostname(hostname,sizeof(hostname)-1)==-1){
			hostname[0] = '\0';
		}
	}
};


int _F_IMAP::send (int client, const char *line, int len)
{
	return write (client,line,len);
}
	
void _F_IMAP::sendf (const char *ctl, ...)
{
	va_list list;
	va_start (list,ctl);
	char buf[10000];
	int len = vsnprintf (buf,sizeof(buf)-1,ctl,list);
	va_end (list);
	send (priv->client,buf,len);
}


PUBLIC IMAP::IMAP(_F_IMAP &c)
{
	priv = new _F_IMAP_private;
	c.priv = priv;
	priv->c = &c;
}

PUBLIC IMAP::~IMAP()
{
	delete priv;
}

PRIVATE void IMAP::notsupported(int client, const char *tag)
{
	sendf (client,"%s BAD Not implemented yet\r\n",tag);
}

PRIVATE bool IMAP::folder_exist(IMAP_CLIENT *cli, const char *folder)
{
	SSTRINGS tb;
	priv->c->listfolders (cli->info,cli->stuff,tb);
	return tb.ilookup(folder)!=-1;
}

PRIVATE void IMAP::select (
	int client,
	const char *tag,
	IMAP_CLIENT *cli,
	const char *line,
	bool examine)
{
	SSTRING folder;
	folder.copyword(line);
	if (folder_exist(cli,folder.get())){
		cli->info.folder.setfrom(folder);
		cli->info.readonly = examine;
		IMAP_STATUS rep;
		priv->c->status (cli->info,cli->stuff,rep);
		sendf (client,"* FLAGS %d\r\n",rep.flags);
		sendf (client,"* %d EXISTS\r\n",rep.exists);
		sendf (client,"* %d RECENT\r\n",rep.recent);
		sendf (client,"* OK [UIDVALIDITY %d]\r\n",rep.uid);
		sendf (client,"%s OK [READ-WRITE] SELECT completed\r\n",tag);
		cli->state = IMAP_SELECT;
	}else{
		sendf (client,"%s NO SELECT failed\r\n",tag);
		cli->state = IMAP_AUTH;
	}
}

/*
	Parse a set (val val val) or simply val
*/
static const char *imap_parse_set (const char *line, SSTRINGS &tb)
{
	line = str_skip(line);
	if (line[0] == '('){
		line++;
		while (1){
			line = str_skip(line);
			if (line[0] == '\0'){
				break;
			}else if (line[0] == ')'){
				line++;
				break;
			}else{
				const char *start = line;
				while (*line > ' ' && *line != ')') line++;
				int len = (int)(line-start);
				if (len > 0){
					SSTRING *s = new SSTRING;
					s->setfrom (start,len);
					tb.add (s);
				}
			}
		}
	}else{
		SSTRING *s = new SSTRING;
		line = s->copyword (line);
		tb.add (s);
	}
	return line;
}

/*
	Return -1 if a critical error. The client must be disconnected.
	Or -1 is returned to mean, end of session.
*/
PUBLIC int IMAP::oneline (int client, const char *line)
{
	int ret = 0;
	priv->client = client;
	IMAP_CLIENT *cli = priv->tb[client];
	if (cli->state == IMAP_AUTHSTEP){
		if (line[0] == '*'){
			cli->state = IMAP_IDLE;
			sendf (client,"%s BAD AUTHENTICATE aborted\r\n",cli->lasttag.get());
		}else{
			char buf[100+1];
			base64_decode (buf,100,line);
			if (cli->authstep == 0){
				cli->authuser.setfrom (buf);
				sendf (client,"+ allo\r\n");
				cli->authstep = 1;
			}else if (cli->authstep == 1){
				if (priv->c->auth (cli->info,cli->stuff,cli->authuser.get()
					,buf)){
					sendf (client,"%s OK AUTHENTICATE completed\r\n",cli->lasttag.get());
					cli->state = IMAP_AUTH;
				}else{
					sendf (client,"%s NO AUTHTICATE failure\r\n",cli->lasttag.get());
					cli->state = IMAP_IDLE;
				}
			}
		}
	}else{
		SSTRING cmd;	
		line = cli->lasttag.copyword (line);
		line = cmd.copyword (line);
		const char *pttag = cli->lasttag.get();
		if (pttag[0] == '\0'){
			sendf (client,"* BAD null command\r\n");
		}else if (cmd.is_empty()){
			sendf (client,"%s BAD missing command\r\n",pttag);
		}else if (cmd.icmp("logout")==0){
			sendf (client,"* BYE IMAP4rev1 Server logging out\r\n");
			sendf (client,"%s OK logout completed\r\n",pttag);
			ret = -1;
		}else if (cmd.icmp("capability")==0){
			sendf (client,"* CAPABILITY IMAP4 IMAP4REV1 LOGIN-REFERRALS AUTH=LOGIN\r\n");
			sendf (client,"%s OK CAPABILITY completed\r\n",pttag);
		}else if (cmd.icmp("noop")==0){
			sendf (client,"%s OK NOOP completed\r\n",pttag);
		}else if (cli->state == IMAP_IDLE){
			if (cmd.icmp("login")==0){
				SSTRING user,pass;
				line = user.copyword(line);
				line = pass.copyword(line);
				if (priv->c->auth(cli->info,cli->stuff,user.get(),pass.get())){
					sendf (client,"%s OK LOGIN completed\r\n",pttag);
					cli->state = IMAP_AUTH;
				}else{
					sendf (client,"%s NO login failure\r\n",pttag);
				}
			}else if (cmd.icmp("authenticate")==0){
				SSTRING method;
				method.copyword (line);
				if (method.icmp("login")==0){
					cli->state = IMAP_AUTHSTEP;
					cli->authstep = 0;
					char buf[100];
					strcpy (buf,"allo");
					sendf (client,"+ %s\r\n",buf);
					//sendf (client,"%s OK AUTHENTICATE LOGIN\r\n",pttag);
				}else{
					sendf (client,"%s NO AUTHENTICATE mechanism not supported\r\n",pttag);
				}
			}else{
				sendf (client,"%s BAD unknown command\r\n",pttag);
			}
		}else if (cli->state == IMAP_AUTH || cli->state == IMAP_SELECT){
			if (cmd.icmp("SELECT")==0){
				select (client,pttag,cli,line,false);
			}else if (cmd.icmp("EXAMINE")==0){
				select (client,pttag,cli,line,true);
			}else if (cmd.icmp("CREATE")==0){
				SSTRING folder;
				folder.copyword (line);
				const char *ptfolder = folder.get();
				if (ptfolder[0] == '\0' || folder_exist(cli,ptfolder)){
					sendf (client,"%s NO CREATE failed, folder exist\r\n"
						,pttag);
				}else if (priv->c->create (cli->info,cli->stuff,ptfolder)==-1){
					sendf (client,"%s NO CREATE failed, server error\r\n"
						,pttag);
				}else{
					sendf (client,"%s OK CREATE completed\r\n"
						,pttag);
				}
			}else if (cmd.icmp("DELETE")==0){
				SSTRING folder;
				folder.copyword (line);
				const char *ptfolder = folder.get();
				if (stricmp(ptfolder,"INBOX")==0){
					sendf (client,"%s NO DELETE failed, Can't delete INBOX\r\n"
						,pttag);
				}else if (ptfolder[0] == '\0' || !folder_exist(cli,ptfolder)){
					sendf (client,"%s NO DELETE failed, folder does not exist\r\n"
						,pttag);
				}else if (priv->c->delbox (cli->info,cli->stuff,ptfolder)==-1){
					sendf (client,"%s NO DELETE failed, server error\r\n"
						,pttag);
				}else{
					sendf (client,"%s OK DELETE completed\r\n"
						,pttag);
				}
			}else if (cmd.icmp("RENAME")==0){
				SSTRING oldfolder,newfolder;
				line = oldfolder.copyword(line);
				newfolder.copyword (line);
				if (!folder_exist(cli,oldfolder.get())){
					sendf (client,"%s NO RENAME failed, folder %s does exist\r\n",pttag,oldfolder.get());
				}else if (folder_exist(cli,newfolder.get())){
					sendf (client,"%s NO RENAME failed, folder %s exist\r\n",pttag,newfolder.get());
				}else if (priv->c->rename(cli->info,cli->stuff,oldfolder.get()
					,newfolder.get())==-1){
					sendf (client,"%s NO RENAME failed, server error\r\n",pttag);
				}else{
					sendf (client,"%s OK RENAME completed\r\n",pttag);
				}
				notsupported (client,pttag);
			}else if (cmd.icmp("SUBSCRIBE")==0){
				SSTRING folder;
				folder.copyword(line);
				const char *ptfold = folder.get();
				if (ptfold[0] == '\0'){
					sendf (client,"%s BAD SUBSCRIBE failed, no folder specified\r\n",pttag);
				}else if (!folder_exist(cli,ptfold)){
					sendf (client,"%s NO SUBSCRIBE failed, folder does not exist\r\n",pttag);
				}else{
					if(cli->subs.ilookup(ptfold)==-1){
						cli->subs.add (new SSTRING(ptfold));
					}
					sendf (client,"%s OK SUBSCRIBE completed\r\n",pttag);
				}
			}else if (cmd.icmp("UNSUBSCRIBE")==0){
				SSTRING folder;
				folder.copyword(line);
				const char *ptfold = folder.get();
				if (ptfold[0] == '\0'){
					sendf (client,"%s BAD UNSUBSCRIBE failed, no folder specified\r\n",pttag);
				}else if (!folder_exist(cli,ptfold)){
					sendf (client,"%s NO UNSUBSCRIBE failed, folder does not exist\r\n",pttag);
				}else{
					int no = cli->subs.ilookup(ptfold);
					if (no==-1){
						sendf (client,"%s NO UNSUBSCRIBE failed, folder was not subscribed\r\n",pttag);
					}else{
						cli->subs.remove_del(no);
						sendf (client,"%s OK SUBSCRIBE completed\r\n",pttag);
					}
				}	
			}else if (cmd.icmp("LIST")==0){
				SSTRING ref,folder;
				line = ref.copyword (line);
				folder.copyword (line);
				SSTRINGS tb;
				priv->c->listfolders (cli->info,cli->stuff,tb);
				for (int i=0; i<tb.getnb(); i++){
					sendf (client,"* LIST {} / %s\n",tb.getitem(i)->get());
				}
				sendf (client,"%s OK LIST completed\r\n",pttag);
			}else if (cmd.icmp("LSUB")==0){
				notsupported (client,pttag);
			}else if (cmd.icmp("STATUS")==0){
				notsupported (client,pttag);
			}else if (cmd.icmp("APPEND")==0){
				notsupported (client,pttag);
			}else if (cli->state == IMAP_SELECT){
				if (cmd.icmp("CHECK")==0){
					sendf (client,"%s OK CHECK completed\r\n",pttag);
				}else if (cmd.icmp("CLOSE")==0){
					if (!cli->info.readonly){
						if (priv->c->expunge (cli->info,cli->stuff
							,cli->info.folder.get(),false)==-1){
							sendf (client,"%s NO CLOSE failed, server error\r\n",pttag);
						}else{
							sendf (client,"%s OK CLOSE completed\r\n",pttag);
						}
					}else{
						sendf (client,"%s OK CLOSE completed\r\n",pttag);
					}
					cli->state = IMAP_AUTH;
				}else if (cmd.icmp("EXPUNGE")==0){
					if (priv->c->expunge (cli->info,cli->stuff
						,cli->info.folder.get(),true)==-1){
						sendf (client,"%s NO EXPUNGE failed, server error\r\n",pttag);
					}else{
						sendf (client,"%s OK EXPUNGE completed\r\n",pttag);
					}
				}else if (cmd.icmp("SEARCH")==0){
					while (*line != '\0'){
						SSTRING f;
						line = f.copyword(line);
						//
					}
					IMAP_STATUS rep;
					priv->c->status (cli->info,cli->stuff,rep);
					for (int i=0; i<rep.exists; i++){
						sendf (client,"* SEARCH %d\r\n",i+1);
					}
					sendf (client,"%s OK SEARCH completed\r\n",pttag);
				}else if (cmd.icmp("FETCH")==0){
					SSTRING range,items;
					line = range.copyword (line);
					items.copyword(line);
					int start = atoi(range.get());
					int end = start;
					const char *pt = range.strchr(':');
					if (pt != NULL) end = atoi(pt+1);
					for (int i=start; i<=end; i++){
						priv->c->getmsg (cli->info,cli->stuff,i);
					}
					sendf (client,"%s OK FETCH completed\r\n",pttag);
				}else if (cmd.icmp("STORE")==0){
					notsupported (client,pttag);
				}else if (cmd.icmp("COPY")==0){
					notsupported (client,pttag);
				}else if (cmd.icmp("UID")==0){
					notsupported (client,pttag);
				}else{
					sendf (client,"%s BAD unknown command\r\n",pttag);
				}
			}else{
				sendf (client,"%s BAD unknown command\r\n",pttag);
			}
		}
	}
	return ret;
}

PUBLIC void IMAP::sendf (int client, const char *ctl, ...)
{
	char buf[10000];
	va_list list;
	va_start (list,ctl);
	int len = vsnprintf (buf,sizeof(buf)-1,ctl,list);
	va_end (list);
	priv->c->send (client,buf,len);
}

PUBLIC int IMAP::newclient (int client)
{
	if (client >= priv->maxclient){
		int oldmax = priv->maxclient;
		priv->maxclient += 1000;
		priv->tb = (IMAP_CLIENT**)realloc(priv->tb
			,priv->maxclient*sizeof(IMAP_CLIENT*));
		if (priv->tb == NULL){
			syslog (LOG_CRIT,"Out of memory\n");
			exit (-1);
		}
		for (int i=oldmax; i<priv->maxclient; i++) priv->tb[i] = NULL;
	}
	priv->tb[client] = new IMAP_CLIENT;
	sendf (client,"* OK [CAPABILITY IMAP4 IMAP4rev1 LOGIN-REFERRALS AUTH=LOGIN] %s vimap_sql\r\n"
		,priv->hostname);
	return 0;
}
PUBLIC int IMAP::endclient (int client)
{
	if (client >= 0 && client < priv->maxclient){
		delete priv->tb[client];
		priv->tb[client] = NULL;
	}
	return 0;
}