/*
 * Asterisk -- A telephony toolkit for Linux.
 *
 * Routines implementing call parking
 * 
 * Copyright (C) 1999, Mark Spencer
 *
 * Mark Spencer <markster@linux-support.net>
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License
 */

#include <asterisk/file.h>
#include <asterisk/logger.h>
#include <asterisk/channel.h>
#include <asterisk/pbx.h>
#include <asterisk/options.h>
#include <asterisk/module.h>
#include <asterisk/translate.h>
#include <asterisk/say.h>
#include <asterisk/channel_pvt.h>
#include <asterisk/parking.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
#include <sys/signal.h>
#include <netinet/in.h>

#include <pthread.h>

static char *parkedcall = "ParkedCall";

/* No more than 45 seconds parked before you do something with them */
static int parkingtime = 45000;

/* Context for which parking is made accessible */
static char parking_con[AST_MAX_EXTENSION] = "parkedcalls";

/* Extension you type to park the call */
static char parking_ext[AST_MAX_EXTENSION] = "700";

/* First available extension for parking */
static int parking_start = 701;

/* Last available extension for parking */
static int parking_stop = 750;

/* Registrar for operations */
static char *registrar = "res_parking";

static char *synopsis = "Answer a parked call";

static char *descrip = "ParkedCall(exten):"
"Used to connect to a parked call.  This Application is always\n"
"registered internally and does not need to be explicitly added\n"
"into the dialplan, although you should include the 'parkedcalls'\n"
"context.\n";

struct parkeduser {
	struct ast_channel *chan;
	struct timeval start;
	int parkingnum;
	/* Where to go if our parking time expires */
	char context[AST_MAX_EXTENSION];
	char exten[AST_MAX_EXTENSION];
	int priority;
	struct parkeduser *next;
};

static struct parkeduser *parkinglot;

static pthread_mutex_t parking_lock = PTHREAD_MUTEX_INITIALIZER;

static pthread_t parking_thread;

STANDARD_LOCAL_USER;

LOCAL_USER_DECL;

char *ast_parking_ext(void)
{
	return parking_ext;
}

int ast_park_call(struct ast_channel *chan, struct ast_channel *peer)
{
	/* We put the user in the parking list, then wake up the parking thread to be sure it looks
	   after these channels too */
	struct parkeduser *pu, *cur;
	int x;
	pu = malloc(sizeof(struct parkeduser));
	if (pu) {
		ast_pthread_mutex_lock(&parking_lock);
		for (x=parking_start;x<=parking_stop;x++) {
			cur = parkinglot;
			while(cur) {
				if (cur->parkingnum == x) 
					break;
				cur = cur->next;
			}
			if (!cur)
				break;
		}
		if (x <= parking_stop) {
			pu->chan = chan;
			gettimeofday(&pu->start, NULL);
			pu->parkingnum = x;
			/* Remember what had been dialed, so that if the parking
			   expires, we try to come back to the same place */
			strncpy(pu->context, chan->context, sizeof(pu->context)-1);
			strncpy(pu->exten, chan->exten, sizeof(pu->exten)-1);
			pu->priority = chan->priority;
			pu->next = parkinglot;
			parkinglot = pu;
			ast_pthread_mutex_unlock(&parking_lock);
			/* Wake up the (presumably select()ing) thread */
			pthread_kill(parking_thread, SIGURG);
			if (option_verbose > 1) 
				ast_verbose(VERBOSE_PREFIX_2 "Parked %s on %d\n", pu->chan->name, pu->parkingnum);
			ast_say_digits(peer, pu->parkingnum, "", peer->language);
			return 0;
		} else {
			ast_log(LOG_WARNING, "No more parking spaces\n");
			free(pu);
			ast_pthread_mutex_unlock(&parking_lock);
			return -1;
		}
	} else {
		ast_log(LOG_WARNING, "Out of memory\n");
		return -1;
	}
	return 0;
}

int ast_masq_park_call(struct ast_channel *rchan, struct ast_channel *peer)
{
	struct ast_channel *chan;
	struct ast_frame *f;
	/* Make a new, fake channel that we'll use to masquerade in the real one */
	chan = ast_channel_alloc();
	if (chan) {
		/* Let us keep track of the channel name */
		snprintf(chan->name, sizeof (chan->name), "Parked/%s",rchan->name);
		/* Make formats okay */
		chan->readformat = rchan->readformat;
		chan->writeformat = rchan->writeformat;
		ast_channel_masquerade(chan, rchan);
		/* Setup the extensions and such */
		strncpy(chan->context, rchan->context, sizeof(chan->context) - 1);
		strncpy(chan->exten, rchan->exten, sizeof(chan->exten) - 1);
		chan->priority = rchan->priority;
		/* Make the masq execute */
		f = ast_read(chan);
		if (f)
			ast_frfree(f);
		ast_park_call(chan, peer);
	} else {
		ast_log(LOG_WARNING, "Unable to create parked channel\n");
		return -1;
	}
	return 0;
}

int ast_bridge_call(struct ast_channel *chan, struct ast_channel *peer, int allowredirect)
{
	/* Copy voice back and forth between the two channels.  Give the peer
	   the ability to transfer calls with '#<extension' syntax. */
	int len;
	struct ast_frame *f;
	struct ast_channel *who;
	char newext[256], *ptr;
	int res;
	struct ast_option_header *aoh;
	/* Answer if need be */
	if (chan->state != AST_STATE_UP) {
		if (ast_answer(chan))
			return -1;
	}
	peer->appl = "Bridged Call";
	peer->data = chan->name;
	for (;;) {
		res = ast_channel_bridge(chan, peer, allowredirect ? AST_BRIDGE_DTMF_CHANNEL_1 : 0, &f, &who);
		if (res < 0) {
			ast_log(LOG_WARNING, "Bridge failed on channels %s and %s\n", chan->name, peer->name);
			return -1;
		}
		
		if (!f || ((f->frametype == AST_FRAME_CONTROL) && ((f->subclass == AST_CONTROL_HANGUP) || (f->subclass == AST_CONTROL_BUSY) || 
			(f->subclass == AST_CONTROL_CONGESTION)))) {
				res = -1;
				break;
		}
		if ((f->frametype == AST_FRAME_CONTROL) && (f->subclass == AST_CONTROL_RINGING)) {
			if (who == chan)
				ast_indicate(peer, AST_CONTROL_RINGING);
			else
				ast_indicate(chan, AST_CONTROL_RINGING);
		}
		if ((f->frametype == AST_FRAME_CONTROL) && (f->subclass == AST_CONTROL_OPTION)) {
			aoh = f->data;
			/* Forward option Requests */
			if (aoh && (aoh->flag == AST_OPTION_FLAG_REQUEST)) {
				if (who == chan)
					ast_channel_setoption(peer, ntohs(aoh->option), aoh->data, f->datalen - sizeof(struct ast_option_header), 0);
				else
					ast_channel_setoption(chan, ntohs(aoh->option), aoh->data, f->datalen - sizeof(struct ast_option_header), 0);
			}
		}
		if ((f->frametype == AST_FRAME_DTMF) && (who == peer) && allowredirect &&
		     (f->subclass == '#')) {
				memset(newext, 0, sizeof(newext));
				ptr = newext;
					/* Transfer */
				if ((res=ast_streamfile(peer, "pbx-transfer", chan->language)))
					break;
				if ((res=ast_waitstream(peer, AST_DIGIT_ANY)) < 0)
					break;
				ast_stopstream(peer);
				if (res > 0) {
					/* If they've typed a digit already, handle it */
					newext[0] = res;
					ptr++;
					len --;
				}
				res = 0;
				while(strlen(newext) < sizeof(newext - 1)) {
					res = ast_waitfordigit(peer, 3000);
					if (res < 1)
						break;
					*(ptr++) = res;
					if (!ast_canmatch_extension(peer, peer->context, newext, 1, peer->callerid) ||
						ast_exists_extension(peer, peer->context, newext, 1, peer->callerid)) {
						res = 0;
						break;
					}
				}
				if (res)
					break;
				if (!strcmp(newext, ast_parking_ext())) {
					if (!ast_park_call(chan, peer)) {
						/* We return non-zero, but tell the PBX not to hang the channel when
						   the thread dies -- We have to be careful now though.  We are responsible for 
						   hanging up the channel, else it will never be hung up! */
						res=AST_PBX_KEEPALIVE;
						break;
					} else {
						ast_log(LOG_WARNING, "Unable to park call %s\n", chan->name);
					}
					/* XXX Maybe we should have another message here instead of invalid extension XXX */
				} else if (ast_exists_extension(chan, peer->context, newext, 1, peer->callerid)) {
					/* Set the channel's new extension, since it exists, using peer context */
					strncpy(chan->exten, newext, sizeof(chan->exten)-1);
					strncpy(chan->context, peer->context, sizeof(chan->context)-1);
					chan->priority = 0;
					ast_frfree(f);
					if (option_verbose > 2) 
						ast_verbose(VERBOSE_PREFIX_3 "Transferring %s to '%s' (context %s) priority 1\n", chan->name, chan->exten, chan->context);
					res=0;
					break;
				} else {
					if (option_verbose > 2)	
						ast_verbose(VERBOSE_PREFIX_3 "Unable to find extension '%s' in context %s\n", newext, peer->context);
				}
				res = ast_streamfile(peer, "pbx-invalid", chan->language);
				if (res)
					break;
				res = ast_waitstream(peer, AST_DIGIT_ANY);
				ast_stopstream(peer);
				res = 0;
			} else {
            if (f && (f->frametype == AST_FRAME_DTMF)) {
                  if (who == peer)
                        ast_write(chan, f);
                  else
                        ast_write(peer, f);
            }            
#if 1
				ast_log(LOG_DEBUG, "Read from %s (%d,%d)\n", who->name, f->frametype, f->subclass);
#endif
			}
         if (f)
               ast_frfree(f);
	}
	return res;
}

static void *do_parking_thread(void *ignore)
{
	int ms, tms, max;
	struct parkeduser *pu, *pl, *pt = NULL;
	struct timeval tv;
	struct ast_frame *f;
	int x;
	fd_set rfds, efds;
	fd_set nrfds, nefds;
	FD_ZERO(&rfds);
	FD_ZERO(&efds);
	for (;;) {
		ms = -1;
		max = -1;
		ast_pthread_mutex_lock(&parking_lock);
		pl = NULL;
		pu = parkinglot;
		gettimeofday(&tv, NULL);
		FD_ZERO(&nrfds);
		FD_ZERO(&nefds);
		while(pu) {
			tms = (tv.tv_sec - pu->start.tv_sec) * 1000 + (tv.tv_usec - pu->start.tv_usec) / 1000;
			if (tms > parkingtime) {
				/* They've been waiting too long, send them back to where they came.  Theoretically they
				   should have their original extensions and such, but we copy to be on the safe side */
				strncpy(pu->chan->exten, pu->exten, sizeof(pu->chan->exten)-1);
				strncpy(pu->chan->context, pu->context, sizeof(pu->chan->context)-1);
				pu->chan->priority = pu->priority;
				/* Start up the PBX, or hang them up */
				if (ast_pbx_start(pu->chan))  {
					ast_log(LOG_WARNING, "Unable to restart the PBX for user on '%s', hanging them up...\n", pu->chan->name);
					ast_hangup(pu->chan);
				}
				/* And take them out of the parking lot */
				if (pl) 
					pl->next = pu->next;
				else
					parkinglot = pu->next;
				pt = pu;
				pu = pu->next;
				free(pt);
			} else {
				for (x=0;x<AST_MAX_FDS;x++) {
					if ((pu->chan->fds[x] > -1) && (FD_ISSET(pu->chan->fds[x], &rfds) || FD_ISSET(pu->chan->fds[x], &efds))) {
							if (FD_ISSET(pu->chan->fds[x], &efds))
								pu->chan->exception = 1;
							pu->chan->fdno = x;
							/* See if they need servicing */
							f = ast_read(pu->chan);
							if (!f || ((f->frametype == AST_FRAME_CONTROL) && (f->subclass ==  AST_CONTROL_HANGUP))) {
							/* There's a problem, hang them up*/
							if (option_verbose > 1) 
								ast_verbose(VERBOSE_PREFIX_2 "%s got tired of being parked\n", pu->chan->name);
							ast_hangup(pu->chan);
							/* And take them out of the parking lot */
							if (pl) 
								pl->next = pu->next;
							else
								parkinglot = pu->next;
							pt = pu;
							pu = pu->next;
							free(pt);
							break;
						} else {
							/* XXX Maybe we could do something with packets, like dial "0" for operator or something XXX */
							ast_frfree(f);
							goto std;	/* XXX Ick: jumping into an else statement??? XXX */
						}
					}
				}
				if (x >= AST_MAX_FDS) {
std:					for (x=0;x<AST_MAX_FDS;x++) {
						/* Keep this one for next one */
						if (pu->chan->fds[x] > -1) {
							FD_SET(pu->chan->fds[x], &nrfds);
							FD_SET(pu->chan->fds[x], &nefds);
							if (pu->chan->fds[x] > max)
								max = pu->chan->fds[x];
						}
					}
					/* Keep track of our longest wait */
					if ((tms < ms) || (ms < 0))
						ms = tms;
					pl = pu;
					pu = pu->next;
				}
			}
		}
		ast_pthread_mutex_unlock(&parking_lock);
		rfds = nrfds;
		efds = nefds;
		tv.tv_sec = ms / 1000;
		tv.tv_usec = (ms % 1000) * 1000;
		/* Wait for something to happen */
		select(max + 1, &rfds, NULL, &efds, (ms > -1) ? &tv : NULL);
		pthread_testcancel();
	}
	return NULL;	/* Never reached */
}

static int park_exec(struct ast_channel *chan, void *data)
{
	int res=0;
	struct localuser *u;
	struct ast_channel *peer=NULL;
	struct parkeduser *pu, *pl=NULL;
	int park;
	if (!data) {
		ast_log(LOG_WARNING, "Park requires an argument (extension number)\n");
		return -1;
	}
	LOCAL_USER_ADD(u);
	park = atoi((char *)data);
	ast_pthread_mutex_lock(&parking_lock);
	pu = parkinglot;
	while(pu) {
		if (pu->parkingnum == park) {
			if (pl)
				pl->next = pu->next;
			else
				parkinglot = pu->next;
			break;
		}
		pu = pu->next;
	}
	ast_pthread_mutex_unlock(&parking_lock);
	if (pu) {
		peer = pu->chan;
		free(pu);
	}
	if (peer) {
		res = ast_channel_make_compatible(chan, peer);
		if (res < 0) {
			ast_log(LOG_WARNING, "Could not make channels %s and %s compatible for bridge\n", chan->name, peer->name);
			ast_hangup(peer);
			return -1;
		}
		/* This runs sorta backwards, since we give the incoming channel control, as if it
		   were the person called. */
		if (option_verbose > 2) 
			ast_verbose(VERBOSE_PREFIX_3 "Channel %s connected to parked call %d\n", chan->name, park);
		res = ast_bridge_call(peer, chan, 1);
		/* Simulate the PBX hanging up */
		if (res != AST_PBX_KEEPALIVE)
			ast_hangup(peer);
		return -1;
	} else {
		/* XXX Play a message XXX */
		if (option_verbose > 2) 
			ast_verbose(VERBOSE_PREFIX_3 "Channel %s tried to talk to non-existant parked call %d\n", chan->name, park);
		res = -1;
	}
	LOCAL_USER_REMOVE(u);
	return res;
}

int load_module(void)
{
	int res;
	int x;
	struct ast_context *con;
	char exten[AST_MAX_EXTENSION];
	con = ast_context_find(parking_con);
	if (!con) {
		con = ast_context_create(parking_con, registrar);
		if (!con) {
			ast_log(LOG_ERROR, "Parking context '%s' does not exist and unable to create\n", parking_con);
			return -1;
		}
	}
	for(x=parking_start; x<=parking_stop;x++) {
		snprintf(exten, sizeof(exten), "%d", x);
		ast_add_extension2(con, 1, exten, 1, NULL, parkedcall, strdup(exten), free, registrar);
	}
	pthread_create(&parking_thread, NULL, do_parking_thread, NULL);
	res = ast_register_application(parkedcall, park_exec, synopsis, descrip);
	return res;
}

int unload_module(void)
{
	STANDARD_HANGUP_LOCALUSERS;
	return ast_unregister_application(parkedcall);
}

char *description(void)
{
	return "Call Parking Resource";
}

int usecount(void)
{
	/* Never allow parking to be unloaded because it will
	   unresolve needed symbols in the dialer */
#if 0
	int res;
	STANDARD_USECOUNT(res);
	return res;
#else
	return 1;
#endif
}

char *key()
{
	return ASTERISK_GPL_KEY;
}