manager_channels.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2013, Digium, Inc.
 *
 * David M. Lee, II <[email protected]>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 *
 * \brief The Asterisk Management Interface - AMI (channel event handling)
 *
 * \author David M. Lee, II <[email protected]>
 *
 * AMI generated many per-channel and global-channel events by converting Stasis
 * messages to AMI events. It makes sense to simply put them into a single file.
 */

#include "asterisk.h"

#include "asterisk/callerid.h"
#include "asterisk/channel.h"
#include "asterisk/manager.h"
#include "asterisk/stasis_message_router.h"
#include "asterisk/pbx.h"
#include "asterisk/stasis_channels.h"

/*** DOCUMENTATION
   <managerEvent language="en_US" name="Newchannel">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a new channel is created.</synopsis>
         <syntax>
            <channel_snapshot/>
         </syntax>
         <see-also>
            <ref type="managerEvent">Newstate</ref>
            <ref type="managerEvent">Hangup</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="Newstate">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a channel's state changes.</synopsis>
         <syntax>
            <channel_snapshot/>
         </syntax>
         <see-also>
            <ref type="managerEvent">Newchannel</ref>
            <ref type="managerEvent">Hangup</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="Hangup">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a channel is hung up.</synopsis>
         <syntax>
            <channel_snapshot/>
            <parameter name="Cause">
               <para>A numeric cause code for why the channel was hung up.</para>
            </parameter>
            <parameter name="Cause-txt">
               <para>A description of why the channel was hung up.</para>
            </parameter>
         </syntax>
         <see-also>
            <ref type="managerEvent">Newchannel</ref>
            <ref type="managerEvent">SoftHangupRequest</ref>
            <ref type="managerEvent">HangupRequest</ref>
            <ref type="managerEvent">Newstate</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="HangupRequest">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a hangup is requested.</synopsis>
         <syntax>
            <channel_snapshot/>
            <xi:include xpointer="xpointer(/docs/managerEvent[@name='Hangup']/managerEventInstance/syntax/parameter[@name='Cause'])" />
         </syntax>
         <see-also>
            <ref type="managerEvent">SoftHangupRequest</ref>
            <ref type="managerEvent">Hangup</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="SoftHangupRequest">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a soft hangup is requested with a specific cause code.</synopsis>
         <syntax>
            <channel_snapshot/>
            <xi:include xpointer="xpointer(/docs/managerEvent[@name='Hangup']/managerEventInstance/syntax/parameter[@name='Cause'])" />
         </syntax>
         <see-also>
            <ref type="managerEvent">HangupRequest</ref>
            <ref type="managerEvent">Hangup</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="NewExten">
      <managerEventInstance class="EVENT_FLAG_DIALPLAN">
         <synopsis>Raised when a channel enters a new context, extension, priority.</synopsis>
         <syntax>
            <channel_snapshot/>
            <parameter name="Extension">
               <para>Deprecated in 12, but kept for
               backward compatability. Please use
               'Exten' instead.</para>
            </parameter>
            <parameter name="Application">
               <para>The application about to be executed.</para>
            </parameter>
            <parameter name="AppData">
               <para>The data to be passed to the application.</para>
            </parameter>
         </syntax>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="NewCallerid">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a channel receives new Caller ID information.</synopsis>
         <syntax>
            <channel_snapshot/>
            <parameter name="CID-CallingPres">
               <para>A description of the Caller ID presentation.</para>
            </parameter>
         </syntax>
         <see-also>
            <ref type="function">CALLERID</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="NewConnectedLine">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a channel's connected line information is changed.</synopsis>
         <syntax>
            <channel_snapshot/>
         </syntax>
         <see-also>
            <ref type="function">CONNECTEDLINE</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="NewAccountCode">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a Channel's AccountCode is changed.</synopsis>
         <syntax>
            <channel_snapshot/>
            <parameter name="OldAccountCode">
               <para>The channel's previous account code</para>
            </parameter>
         </syntax>
         <see-also>
            <ref type="function">CHANNEL</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="DialBegin">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a dial action has started.</synopsis>
         <syntax>
            <channel_snapshot/>
            <channel_snapshot prefix="Dest"/>
            <parameter name="DialString">
               <para>The non-technology specific device being dialed.</para>
            </parameter>
         </syntax>
         <see-also>
            <ref type="application">Dial</ref>
            <ref type="application">Originate</ref>
            <ref type="manager">Originate</ref>
            <ref type="managerEvent">DialEnd</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="DialState">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when dial status has changed.</synopsis>
         <syntax>
            <channel_snapshot/>
            <channel_snapshot prefix="Dest"/>
            <parameter name="DialStatus">
               <para> The new state of the outbound dial attempt.</para>
               <enumlist>
                  <enum name="RINGING">
                     <para>The outbound channel is ringing.</para>
                  </enum>
                  <enum name="PROCEEDING">
                     <para>The call to the outbound channel is proceeding.</para>
                  </enum>
                  <enum name="PROGRESS">
                     <para>Progress has been received on the outbound channel.</para>
                  </enum>
               </enumlist>
            </parameter>
            <parameter name="Forward" required="false">
               <para>If the call was forwarded, where the call was
               forwarded to.</para>
            </parameter>
         </syntax>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="DialEnd">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a dial action has completed.</synopsis>
         <syntax>
            <channel_snapshot/>
            <channel_snapshot prefix="Dest"/>
            <parameter name="DialStatus">
               <para>The result of the dial operation.</para>
               <enumlist>
                  <enum name="ABORT">
                     <para>The call was aborted.</para>
                  </enum>
                  <enum name="ANSWER">
                     <para>The caller answered.</para>
                  </enum>
                  <enum name="BUSY">
                     <para>The caller was busy.</para>
                  </enum>
                  <enum name="CANCEL">
                     <para>The caller cancelled the call.</para>
                  </enum>
                  <enum name="CHANUNAVAIL">
                     <para>The requested channel is unavailable.</para>
                  </enum>
                  <enum name="CONGESTION">
                     <para>The called party is congested.</para>
                  </enum>
                  <enum name="CONTINUE">
                     <para>The dial completed, but the caller elected
                     to continue in the dialplan.</para>
                  </enum>
                  <enum name="GOTO">
                     <para>The dial completed, but the caller jumped to
                     a dialplan location.</para>
                     <para>If known, the location the caller is jumping
                     to will be appended to the result following a
                     ":".</para>
                  </enum>
                  <enum name="NOANSWER">
                     <para>The called party failed to answer.</para>
                  </enum>
               </enumlist>
            </parameter>
            <parameter name="Forward" required="false">
               <para>If the call was forwarded, where the call was
               forwarded to.</para>
            </parameter>
         </syntax>
         <see-also>
            <ref type="application">Dial</ref>
            <ref type="application">Originate</ref>
            <ref type="manager">Originate</ref>
            <ref type="managerEvent">DialBegin</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="Hold">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a channel goes on hold.</synopsis>
         <syntax>
            <channel_snapshot/>
            <parameter name="MusicClass">
               <para>The suggested MusicClass, if provided.</para>
            </parameter>
         </syntax>
         <see-also>
            <ref type="managerEvent">Unhold</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="Unhold">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a channel goes off hold.</synopsis>
         <syntax>
            <channel_snapshot/>
         </syntax>
         <see-also>
            <ref type="managerEvent">Hold</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="ChanSpyStart">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when one channel begins spying on another channel.</synopsis>
         <syntax>
            <channel_snapshot prefix="Spyer"/>
            <channel_snapshot prefix="Spyee"/>
         </syntax>
         <see-also>
            <ref type="managerEvent">ChanSpyStop</ref>
            <ref type="application">ChanSpy</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="ChanSpyStop">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when a channel has stopped spying.</synopsis>
         <syntax>
            <channel_snapshot prefix="Spyer"/>
            <channel_snapshot prefix="Spyee"/>
         </syntax>
         <see-also>
            <ref type="managerEvent">ChanSpyStart</ref>
            <ref type="application">ChanSpy</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="HangupHandlerRun">
      <managerEventInstance class="EVENT_FLAG_DIALPLAN">
         <synopsis>Raised when a hangup handler is about to be called.</synopsis>
         <syntax>
            <channel_snapshot/>
            <parameter name="Handler">
               <para>Hangup handler parameter string passed to the Gosub application.</para>
            </parameter>
         </syntax>
         <see-also>
            <ref type="function">CHANNEL</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="HangupHandlerPop">
      <managerEventInstance class="EVENT_FLAG_DIALPLAN">
         <synopsis>
            Raised when a hangup handler is removed from the handler stack
            by the CHANNEL() function.
         </synopsis>
         <syntax>
            <channel_snapshot/>
            <xi:include xpointer="xpointer(/docs/managerEvent[@name='HangupHandlerRun']/managerEventInstance/syntax/parameter)" />
         </syntax>
         <see-also>
            <ref type="managerEvent">HangupHandlerPush</ref>
            <ref type="function">CHANNEL</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="HangupHandlerPush">
      <managerEventInstance class="EVENT_FLAG_DIALPLAN">
         <synopsis>
            Raised when a hangup handler is added to the handler stack by
            the CHANNEL() function.
         </synopsis>
         <syntax>
            <channel_snapshot/>
            <xi:include xpointer="xpointer(/docs/managerEvent[@name='HangupHandlerRun']/managerEventInstance/syntax/parameter)" />
         </syntax>
         <see-also>
            <ref type="managerEvent">HangupHandlerPop</ref>
            <ref type="function">CHANNEL</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="FAXStatus">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>
            Raised periodically during a fax transmission.
         </synopsis>
         <syntax>
            <channel_snapshot/>
            <parameter name="Operation">
               <enumlist>
                  <enum name="gateway"/>
                  <enum name="receive"/>
                  <enum name="send"/>
               </enumlist>
            </parameter>
            <parameter name="Status">
               <para>A text message describing the current status of the fax</para>
            </parameter>
            <xi:include xpointer="xpointer(/docs/managerEvent[@name='ReceiveFAX']/managerEventInstance/syntax/parameter[@name='LocalStationID'])" />
            <xi:include xpointer="xpointer(/docs/managerEvent[@name='ReceiveFAX']/managerEventInstance/syntax/parameter[@name='FileName'])" />
         </syntax>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="ReceiveFAX">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>
            Raised when a receive fax operation has completed.
         </synopsis>
         <syntax>
            <channel_snapshot/>
            <parameter name="LocalStationID">
               <para>The value of the <variable>LOCALSTATIONID</variable> channel variable</para>
            </parameter>
            <parameter name="RemoteStationID">
               <para>The value of the <variable>REMOTESTATIONID</variable> channel variable</para>
            </parameter>
            <parameter name="PagesTransferred">
               <para>The number of pages that have been transferred</para>
            </parameter>
            <parameter name="Resolution">
               <para>The negotiated resolution</para>
            </parameter>
            <parameter name="TransferRate">
               <para>The negotiated transfer rate</para>
            </parameter>
            <parameter name="FileName" multiple="yes">
               <para>The files being affected by the fax operation</para>
            </parameter>
         </syntax>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="SendFAX">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>
            Raised when a send fax operation has completed.
         </synopsis>
         <syntax>
            <channel_snapshot/>
            <xi:include xpointer="xpointer(/docs/managerEvent[@name='ReceiveFAX']/managerEventInstance/syntax/parameter)" />
         </syntax>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="MusicOnHoldStart">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when music on hold has started on a channel.</synopsis>
         <syntax>
            <channel_snapshot/>
            <parameter name="Class">
               <para>The class of music being played on the channel</para>
            </parameter>
         </syntax>
         <see-also>
            <ref type="managerEvent">MusicOnHoldStop</ref>
            <ref type="application">StartMusicOnHold</ref>
            <ref type="application">MusicOnHold</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="MusicOnHoldStop">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when music on hold has stopped on a channel.</synopsis>
         <syntax>
            <channel_snapshot/>
         </syntax>
         <see-also>
            <ref type="managerEvent">MusicOnHoldStart</ref>
            <ref type="application">StopMusicOnHold</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="MonitorStart">
      <managerEventInstance class="EVENT_FLAG_CALL">
         <synopsis>Raised when monitoring has started on a channel.</synopsis>
         <syntax>
            <channel_snapshot/>
         </syntax>
         <see-also>
            <ref type="managerEvent">MonitorStop</ref>
            <ref type="application">Monitor</ref>
            <ref type="manager">Monitor</ref>
         </see-also>
      </managerEventInstance>
   </managerEvent>
   <managerEvent language="en_US" name="MonitorStop">
      <managerEventInstance class="EVENT_FLAG_CALL">
      <synopsis>Raised when monitoring has stopped on a channel.</synopsis>
      <syntax>
         <channel_snapshot/>
      </syntax>
      <see-also>
         <ref type="managerEvent">MonitorStart</ref>
         <ref type="application">StopMonitor</ref>
         <ref type="manager">StopMonitor</ref>
      </see-also>
      </managerEventInstance>
   </managerEvent>
***/

/*! \brief The \ref stasis subscription returned by the forwarding of the channel topic
 * to the manager topic
 */
static struct stasis_forward *topic_forwarder;

struct ast_str *ast_manager_build_channel_state_string_prefix(
      const struct ast_channel_snapshot *snapshot,
      const char *prefix)
{
   struct ast_str *out;
   char *caller_name;
   char *connected_name;
   int res;

   if (snapshot->base->tech_properties & AST_CHAN_TP_INTERNAL) {
      return NULL;
   }

   out = ast_str_create(1024);
   if (!out) {
      return NULL;
   }

   caller_name = ast_escape_c_alloc(snapshot->caller->name);
   connected_name = ast_escape_c_alloc(snapshot->connected->name);

   res = ast_str_set(&out, 0,
      "%sChannel: %s\r\n"
      "%sChannelState: %u\r\n"
      "%sChannelStateDesc: %s\r\n"
      "%sCallerIDNum: %s\r\n"
      "%sCallerIDName: %s\r\n"
      "%sConnectedLineNum: %s\r\n"
      "%sConnectedLineName: %s\r\n"
      "%sLanguage: %s\r\n"
      "%sAccountCode: %s\r\n"
      "%sContext: %s\r\n"
      "%sExten: %s\r\n"
      "%sPriority: %d\r\n"
      "%sUniqueid: %s\r\n"
      "%sLinkedid: %s\r\n",
      prefix, snapshot->base->name,
      prefix, snapshot->state,
      prefix, ast_state2str(snapshot->state),
      prefix, S_OR(snapshot->caller->number, "<unknown>"),
      prefix, S_OR(caller_name, "<unknown>"),
      prefix, S_OR(snapshot->connected->number, "<unknown>"),
      prefix, S_OR(connected_name, "<unknown>"),
      prefix, snapshot->base->language,
      prefix, snapshot->base->accountcode,
      prefix, snapshot->dialplan->context,
      prefix, snapshot->dialplan->exten,
      prefix, snapshot->dialplan->priority,
      prefix, snapshot->base->uniqueid,
      prefix, snapshot->peer->linkedid);

   ast_free(caller_name);
   ast_free(connected_name);

   if (!res) {
      ast_free(out);
      return NULL;
   }

   if (snapshot->manager_vars) {
      struct ast_var_t *var;
      char *val;
      AST_LIST_TRAVERSE(snapshot->manager_vars, var, entries) {
         val = ast_escape_c_alloc(var->value);
         ast_str_append(&out, 0, "%sChanVariable: %s=%s\r\n",
                   prefix,
                   var->name, S_OR(val, ""));
         ast_free(val);
      }
   }

   return out;
}

struct ast_str *ast_manager_build_channel_state_string(
      const struct ast_channel_snapshot *snapshot)
{
   return ast_manager_build_channel_state_string_prefix(snapshot, "");
}

/*! \brief Typedef for callbacks that get called on channel snapshot updates */
typedef struct ast_manager_event_blob *(*channel_snapshot_monitor)(
   struct ast_channel_snapshot *old_snapshot,
   struct ast_channel_snapshot *new_snapshot);

/*! \brief Handle channel state changes */
static struct ast_manager_event_blob *channel_state_change(
   struct ast_channel_snapshot *old_snapshot,
   struct ast_channel_snapshot *new_snapshot)
{
   int is_hungup, was_hungup;

   /* The Newchannel, Newstate and Hangup events are closely related, in
    * in that they are mutually exclusive, basically different flavors
    * of a new channel state event.
    */

   if (!old_snapshot) {
      return ast_manager_event_blob_create(
         EVENT_FLAG_CALL, "Newchannel", NO_EXTRA_FIELDS);
   }

   was_hungup = ast_test_flag(&old_snapshot->flags, AST_FLAG_DEAD) ? 1 : 0;
   is_hungup = ast_test_flag(&new_snapshot->flags, AST_FLAG_DEAD) ? 1 : 0;

   if (!was_hungup && is_hungup) {
      return ast_manager_event_blob_create(
         EVENT_FLAG_CALL, "Hangup",
         "Cause: %d\r\n"
         "Cause-txt: %s\r\n",
         new_snapshot->hangup->cause,
         ast_cause2str(new_snapshot->hangup->cause));
   }

   if (old_snapshot->state != new_snapshot->state) {
      return ast_manager_event_blob_create(
         EVENT_FLAG_CALL, "Newstate", NO_EXTRA_FIELDS);
   }

   /* No event */
   return NULL;
}

static struct ast_manager_event_blob *channel_newexten(
   struct ast_channel_snapshot *old_snapshot,
   struct ast_channel_snapshot *new_snapshot)
{
   /* Empty application is not valid for a Newexten event */
   if (ast_strlen_zero(new_snapshot->dialplan->appl)) {
      return NULL;
   }

   /* Ignore any updates if we're hungup */
   if (ast_test_flag(&new_snapshot->flags, AST_FLAG_DEAD)) {
      return NULL;
   }

   /* Ignore updates if the CEP is unchanged */
   if (old_snapshot && ast_channel_snapshot_cep_equal(old_snapshot, new_snapshot)) {
      return NULL;
   }

   /* DEPRECATED: Extension field deprecated in 12; remove in 14 */
   return ast_manager_event_blob_create(
      EVENT_FLAG_DIALPLAN, "Newexten",
      "Extension: %s\r\n"
      "Application: %s\r\n"
      "AppData: %s\r\n",
      new_snapshot->dialplan->exten,
      new_snapshot->dialplan->appl,
      new_snapshot->dialplan->data);
}

static struct ast_manager_event_blob *channel_new_callerid(
   struct ast_channel_snapshot *old_snapshot,
   struct ast_channel_snapshot *new_snapshot)
{
   struct ast_manager_event_blob *res;
   char *callerid;

   /* No NewCallerid event on first channel snapshot */
   if (!old_snapshot) {
      return NULL;
   }

   if (ast_channel_snapshot_caller_id_equal(old_snapshot, new_snapshot)) {
      return NULL;
   }

   if (!(callerid = ast_escape_c_alloc(
            ast_describe_caller_presentation(new_snapshot->caller->pres)))) {
      return NULL;
   }

   res = ast_manager_event_blob_create(
      EVENT_FLAG_CALL, "NewCallerid",
      "CID-CallingPres: %d (%s)\r\n",
      new_snapshot->caller->pres,
      callerid);

   ast_free(callerid);
   return res;
}

static struct ast_manager_event_blob *channel_new_connected_line(
   struct ast_channel_snapshot *old_snapshot,
   struct ast_channel_snapshot *new_snapshot)
{
   /* No NewConnectedLine event on first channel snapshot */
   if (!old_snapshot) {
      return NULL;
   }

   if (ast_channel_snapshot_connected_line_equal(old_snapshot, new_snapshot)) {
      return NULL;
   }

   return ast_manager_event_blob_create(
      EVENT_FLAG_CALL, "NewConnectedLine", "%s", "");
}

static struct ast_manager_event_blob *channel_new_accountcode(
   struct ast_channel_snapshot *old_snapshot,
   struct ast_channel_snapshot *new_snapshot)
{
   if (!old_snapshot) {
      return NULL;
   }

   if (!strcmp(old_snapshot->base->accountcode, new_snapshot->base->accountcode)) {
      return NULL;
   }

   return ast_manager_event_blob_create(
      EVENT_FLAG_CALL, "NewAccountCode",
      "OldAccountCode: %s\r\n", old_snapshot->base->accountcode);
}

channel_snapshot_monitor channel_monitors[] = {
   channel_state_change,
   channel_newexten,
   channel_new_callerid,
   channel_new_accountcode,
   channel_new_connected_line,
};

static void channel_snapshot_update(void *data, struct stasis_subscription *sub,
                struct stasis_message *message)
{
   RAII_VAR(struct ast_str *, channel_event_string, NULL, ast_free);
   struct ast_channel_snapshot_update *update;
   size_t i;

   update = stasis_message_data(message);

   for (i = 0; i < ARRAY_LEN(channel_monitors); ++i) {
      RAII_VAR(struct ast_manager_event_blob *, ev, NULL, ao2_cleanup);
      ev = channel_monitors[i](update->old_snapshot, update->new_snapshot);

      if (!ev) {
         continue;
      }

      /* If we haven't already, build the channel event string */
      if (!channel_event_string) {
         channel_event_string =
            ast_manager_build_channel_state_string(update->new_snapshot);
         if (!channel_event_string) {
            return;
         }
      }

      manager_event(ev->event_flags, ev->manager_event, "%s%s",
         ast_str_buffer(channel_event_string),
         ev->extra_fields);
   }
}

static void publish_basic_channel_event(const char *event, int class, struct ast_channel_snapshot *snapshot)
{
   RAII_VAR(struct ast_str *, channel_event_string, NULL, ast_free);

   channel_event_string = ast_manager_build_channel_state_string(snapshot);
   if (!channel_event_string) {
      return;
   }

   manager_event(class, event,
      "%s",
      ast_str_buffer(channel_event_string));
}

static void channel_hangup_request_cb(void *data,
   struct stasis_subscription *sub,
   struct stasis_message *message)
{
   struct ast_channel_blob *obj = stasis_message_data(message);
   struct ast_str *extra;
   struct ast_str *channel_event_string;
   struct ast_json *cause;
   int is_soft;
   char *manager_event = "HangupRequest";

   if (!obj->snapshot) {
      /* No snapshot?  Likely an earlier allocation failure creating it. */
      return;
   }

   extra = ast_str_create(20);
   if (!extra) {
      return;
   }

   channel_event_string = ast_manager_build_channel_state_string(obj->snapshot);
   if (!channel_event_string) {
      ast_free(extra);
      return;
   }

   cause = ast_json_object_get(obj->blob, "cause");
   if (cause) {
      ast_str_append(&extra, 0,
         "Cause: %jd\r\n",
         ast_json_integer_get(cause));
   }

   is_soft = ast_json_is_true(ast_json_object_get(obj->blob, "soft"));
   if (is_soft) {
      manager_event = "SoftHangupRequest";
   }

   manager_event(EVENT_FLAG_CALL, manager_event,
      "%s%s",
      ast_str_buffer(channel_event_string),
      ast_str_buffer(extra));

   ast_free(channel_event_string);
   ast_free(extra);
}

static void channel_chanspy_stop_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   RAII_VAR(struct ast_str *, spyer_channel_string, NULL, ast_free);
   RAII_VAR(struct ast_str *, spyee_channel_string, NULL, ast_free);
   struct ast_channel_snapshot *spyer;
   struct ast_channel_snapshot *spyee;
   const char *spyee_info = "";
   struct ast_multi_channel_blob *payload = stasis_message_data(message);

   spyer = ast_multi_channel_blob_get_channel(payload, "spyer_channel");
   if (!spyer) {
      ast_log(AST_LOG_WARNING, "Received ChanSpy Stop event with no spyer channel!\n");
      return;
   }

   spyer_channel_string = ast_manager_build_channel_state_string_prefix(spyer, "Spyer");
   if (!spyer_channel_string) {
      return;
   }

   spyee = ast_multi_channel_blob_get_channel(payload, "spyee_channel");
   if (spyee) {
      spyee_channel_string = ast_manager_build_channel_state_string_prefix(spyee, "Spyee");
      if (spyee_channel_string) {
         spyee_info = ast_str_buffer(spyee_channel_string);
      }
   }

   manager_event(EVENT_FLAG_CALL, "ChanSpyStop",
            "%s%s",
            ast_str_buffer(spyer_channel_string),
            spyee_info);
}

static void channel_chanspy_start_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   RAII_VAR(struct ast_str *, spyer_channel_string, NULL, ast_free);
   RAII_VAR(struct ast_str *, spyee_channel_string, NULL, ast_free);
   struct ast_channel_snapshot *spyer;
   struct ast_channel_snapshot *spyee;
   struct ast_multi_channel_blob *payload = stasis_message_data(message);

   spyer = ast_multi_channel_blob_get_channel(payload, "spyer_channel");
   if (!spyer) {
      ast_log(AST_LOG_WARNING, "Received ChanSpy Start event with no spyer channel!\n");
      return;
   }
   spyee = ast_multi_channel_blob_get_channel(payload, "spyee_channel");
   if (!spyee) {
      ast_log(AST_LOG_WARNING, "Received ChanSpy Start event with no spyee channel!\n");
      return;
   }

   spyer_channel_string = ast_manager_build_channel_state_string_prefix(spyer, "Spyer");
   if (!spyer_channel_string) {
      return;
   }
   spyee_channel_string = ast_manager_build_channel_state_string_prefix(spyee, "Spyee");
   if (!spyee_channel_string) {
      return;
   }

   manager_event(EVENT_FLAG_CALL, "ChanSpyStart",
            "%s%s",
            ast_str_buffer(spyer_channel_string),
            ast_str_buffer(spyee_channel_string));
}

static void channel_dtmf_begin_cb(void *data, struct stasis_subscription *sub,
   struct stasis_message *message)
{
   struct ast_channel_blob *obj = stasis_message_data(message);
   RAII_VAR(struct ast_str *, channel_event_string, NULL, ast_free);
   const char *digit =
      ast_json_string_get(ast_json_object_get(obj->blob, "digit"));
   const char *direction =
      ast_json_string_get(ast_json_object_get(obj->blob, "direction"));

   channel_event_string = ast_manager_build_channel_state_string(obj->snapshot);

   if (!channel_event_string) {
      return;
   }

   /*** DOCUMENTATION
      <managerEventInstance>
         <synopsis>Raised when a DTMF digit has started on a channel.</synopsis>
            <syntax>
               <channel_snapshot/>
               <parameter name="Digit">
                  <para>DTMF digit received or transmitted (0-9, A-E, # or *</para>
               </parameter>
               <parameter name="Direction">
                  <enumlist>
                     <enum name="Received"/>
                     <enum name="Sent"/>
                  </enumlist>
               </parameter>
            </syntax>
            <see-also>
               <ref type="managerEvent">DTMFEnd</ref>
            </see-also>
      </managerEventInstance>
   ***/
   manager_event(EVENT_FLAG_DTMF, "DTMFBegin",
      "%s"
      "Digit: %s\r\n"
      "Direction: %s\r\n",
      ast_str_buffer(channel_event_string),
      digit, direction);
}

static void channel_dtmf_end_cb(void *data, struct stasis_subscription *sub,
   struct stasis_message *message)
{
   struct ast_channel_blob *obj = stasis_message_data(message);
   RAII_VAR(struct ast_str *, channel_event_string, NULL, ast_free);
   const char *digit =
      ast_json_string_get(ast_json_object_get(obj->blob, "digit"));
   const char *direction =
      ast_json_string_get(ast_json_object_get(obj->blob, "direction"));
   long duration_ms =
      ast_json_integer_get(ast_json_object_get(obj->blob, "duration_ms"));

   channel_event_string = ast_manager_build_channel_state_string(obj->snapshot);

   if (!channel_event_string) {
      return;
   }

   /*** DOCUMENTATION
      <managerEventInstance>
         <synopsis>Raised when a DTMF digit has ended on a channel.</synopsis>
            <syntax>
               <channel_snapshot/>
               <parameter name="Digit">
                  <para>DTMF digit received or transmitted (0-9, A-E, # or *</para>
               </parameter>
               <parameter name="DurationMs">
                  <para>Duration (in milliseconds) DTMF was sent/received</para>
               </parameter>
               <parameter name="Direction">
                  <enumlist>
                     <enum name="Received"/>
                     <enum name="Sent"/>
                  </enumlist>
               </parameter>
            </syntax>
            <see-also>
               <ref type="managerEvent">DTMFBegin</ref>
            </see-also>
      </managerEventInstance>
   ***/
   manager_event(EVENT_FLAG_DTMF, "DTMFEnd",
      "%s"
      "Digit: %s\r\n"
      "DurationMs: %ld\r\n"
      "Direction: %s\r\n",
      ast_str_buffer(channel_event_string),
      digit, duration_ms, direction);
}

static void channel_flash_cb(void *data, struct stasis_subscription *sub,
   struct stasis_message *message)
{
   struct ast_channel_blob *obj = stasis_message_data(message);
   struct ast_str *channel_event_string;

   channel_event_string = ast_manager_build_channel_state_string(obj->snapshot);
   if (!channel_event_string) {
      return;
   }

   manager_event(EVENT_FLAG_CALL, "Flash",
      "%s",
      ast_str_buffer(channel_event_string));

   ast_free(channel_event_string);
}

static void channel_hangup_handler_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   RAII_VAR(struct ast_str *, channel_event_string, NULL, ast_free);
   struct ast_channel_blob *payload = stasis_message_data(message);
   const char *action = ast_json_string_get(ast_json_object_get(payload->blob, "type"));
   const char *handler = ast_json_string_get(ast_json_object_get(payload->blob, "handler"));
   const char *event;

   channel_event_string = ast_manager_build_channel_state_string(payload->snapshot);

   if (!channel_event_string) {
      return;
   }

   if (!strcmp(action, "run")) {
      event = "HangupHandlerRun";
   } else if (!strcmp(action, "pop")) {
      event = "HangupHandlerPop";
   } else if (!strcmp(action, "push")) {
      event = "HangupHandlerPush";
   } else {
      return;
   }
   manager_event(EVENT_FLAG_DIALPLAN, event,
      "%s"
      "Handler: %s\r\n",
      ast_str_buffer(channel_event_string),
      handler);
}

static void channel_fax_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   RAII_VAR(struct ast_str *, channel_event_string, NULL, ast_free);
   RAII_VAR(struct ast_str *, event_buffer, ast_str_create(256), ast_free);
   struct ast_channel_blob *payload = stasis_message_data(message);
   const char *type = ast_json_string_get(ast_json_object_get(payload->blob, "type"));
   struct ast_json *operation = ast_json_object_get(payload->blob, "operation");
   struct ast_json *status = ast_json_object_get(payload->blob, "status");
   struct ast_json *local_station_id = ast_json_object_get(payload->blob, "local_station_id");
   struct ast_json *remote_station_id = ast_json_object_get(payload->blob, "remote_station_id");
   struct ast_json *fax_pages = ast_json_object_get(payload->blob, "fax_pages");
   struct ast_json *fax_resolution = ast_json_object_get(payload->blob, "fax_resolution");
   struct ast_json *fax_bitrate = ast_json_object_get(payload->blob, "fax_bitrate");
   struct ast_json *filenames = ast_json_object_get(payload->blob, "filenames");
   const char *event;
   size_t array_len;
   size_t i;

   if (!event_buffer) {
      return;
   }

   channel_event_string = ast_manager_build_channel_state_string(payload->snapshot);
   if (!channel_event_string) {
      return;
   }

   if (!strcmp(type, "status")) {
      event = "FAXStatus";
   } else if (!strcmp(type, "receive")) {
      event = "ReceiveFAX";
   } else if (!strcmp(type, "send")) {
      event = "SendFAX";
   } else {
      return;
   }

   if (operation) {
      ast_str_append(&event_buffer, 0, "Operation: %s\r\n", ast_json_string_get(operation));
   }
   if (status) {
      ast_str_append(&event_buffer, 0, "Status: %s\r\n", ast_json_string_get(status));
   }
   if (local_station_id) {
      ast_str_append(&event_buffer, 0, "LocalStationID: %s\r\n", ast_json_string_get(local_station_id));
   }
   if (remote_station_id) {
      ast_str_append(&event_buffer, 0, "RemoteStationID: %s\r\n", ast_json_string_get(remote_station_id));
   }
   if (fax_pages) {
      ast_str_append(&event_buffer, 0, "PagesTransferred: %s\r\n", ast_json_string_get(fax_pages));
   }
   if (fax_resolution) {
      ast_str_append(&event_buffer, 0, "Resolution: %s\r\n", ast_json_string_get(fax_resolution));
   }
   if (fax_bitrate) {
      ast_str_append(&event_buffer, 0, "TransferRate: %s\r\n", ast_json_string_get(fax_bitrate));
   }
   if (filenames) {
      array_len = ast_json_array_size(filenames);
      for (i = 0; i < array_len; i++) {
         ast_str_append(&event_buffer, 0, "FileName: %s\r\n", ast_json_string_get(ast_json_array_get(filenames, i)));
      }
   }

   manager_event(EVENT_FLAG_CALL, event,
      "%s"
      "%s",
      ast_str_buffer(channel_event_string),
      ast_str_buffer(event_buffer));
}

static void channel_moh_start_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   struct ast_channel_blob *payload = stasis_message_data(message);
   struct ast_json *blob = payload->blob;
   RAII_VAR(struct ast_str *, channel_event_string, NULL, ast_free);

   channel_event_string = ast_manager_build_channel_state_string(payload->snapshot);
   if (!channel_event_string) {
      return;
   }

   manager_event(EVENT_FLAG_CALL, "MusicOnHoldStart",
      "%s"
      "Class: %s\r\n",
      ast_str_buffer(channel_event_string),
      ast_json_string_get(ast_json_object_get(blob, "class")));

}

static void channel_moh_stop_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   struct ast_channel_blob *payload = stasis_message_data(message);

   publish_basic_channel_event("MusicOnHoldStop", EVENT_FLAG_CALL, payload->snapshot);
}

static void channel_monitor_start_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   struct ast_channel_blob *payload = stasis_message_data(message);

   publish_basic_channel_event("MonitorStart", EVENT_FLAG_CALL, payload->snapshot);
}

static void channel_monitor_stop_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   struct ast_channel_blob *payload = stasis_message_data(message);

   publish_basic_channel_event("MonitorStop", EVENT_FLAG_CALL, payload->snapshot);
}

static void channel_mixmonitor_start_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   struct ast_channel_blob *payload = stasis_message_data(message);

   publish_basic_channel_event("MixMonitorStart", EVENT_FLAG_CALL, payload->snapshot);
}

static void channel_mixmonitor_stop_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   struct ast_channel_blob *payload = stasis_message_data(message);

   publish_basic_channel_event("MixMonitorStop", EVENT_FLAG_CALL, payload->snapshot);
}

static void channel_mixmonitor_mute_cb(void *data, struct stasis_subscription *sub,
      struct stasis_message *message)
{
   RAII_VAR(struct ast_str *, channel_event_string, NULL, ast_free);
   RAII_VAR(struct ast_str *, event_buffer, ast_str_create(64), ast_free);
   struct ast_channel_blob *payload = stasis_message_data(message);
   struct ast_json *direction = ast_json_object_get(payload->blob, "direction");
   const int state = ast_json_is_true(ast_json_object_get(payload->blob, "state"));

   if (!event_buffer) {
      return;
   }

   channel_event_string = ast_manager_build_channel_state_string(payload->snapshot);
   if (!channel_event_string) {
      return;
   }

   if (direction) {
      ast_str_append(&event_buffer, 0, "Direction: %s\r\n", ast_json_string_get(direction));
   }
   ast_str_append(&event_buffer, 0, "State: %s\r\n", state ? "1" : "0");

   manager_event(EVENT_FLAG_CALL, "MixMonitorMute",
      "%s"
      "%s",
      ast_str_buffer(channel_event_string),
      ast_str_buffer(event_buffer));

}

static int dial_status_end(const char *dialstatus)
{
   return (strcmp(dialstatus, "RINGING") &&
         strcmp(dialstatus, "PROCEEDING") &&
         strcmp(dialstatus, "PROGRESS"));
}

/*!
 * \brief Callback processing messages for channel dialing
 */
static void channel_dial_cb(void *data, struct stasis_subscription *sub,
   struct stasis_message *message)
{
   struct ast_multi_channel_blob *obj = stasis_message_data(message);
   const char *dialstatus;
   const char *dialstring;
   const char *forward;
   struct ast_channel_snapshot *caller;
   struct ast_channel_snapshot *peer;
   RAII_VAR(struct ast_str *, caller_event_string, NULL, ast_free);
   RAII_VAR(struct ast_str *, peer_event_string, NULL, ast_free);

   caller = ast_multi_channel_blob_get_channel(obj, "caller");
   peer = ast_multi_channel_blob_get_channel(obj, "peer");

   /* Peer is required - otherwise, who are we dialing? */
   ast_assert(peer != NULL);
   peer_event_string = ast_manager_build_channel_state_string_prefix(peer, "Dest");
   if (!peer_event_string) {
      return;
   }

   if (caller && !(caller_event_string = ast_manager_build_channel_state_string(caller))) {
      return;
   }

   dialstatus = ast_json_string_get(ast_json_object_get(ast_multi_channel_blob_get_json(obj), "dialstatus"));
   dialstring = ast_json_string_get(ast_json_object_get(ast_multi_channel_blob_get_json(obj), "dialstring"));
   forward = ast_json_string_get(ast_json_object_get(ast_multi_channel_blob_get_json(obj), "forward"));
   if (ast_strlen_zero(dialstatus)) {
      manager_event(EVENT_FLAG_CALL, "DialBegin",
            "%s"
            "%s"
            "DialString: %s\r\n",
            caller_event_string ? ast_str_buffer(caller_event_string) : "",
            ast_str_buffer(peer_event_string),
            S_OR(dialstring, "unknown"));
   } else {
      int forwarded = !ast_strlen_zero(forward);

      manager_event(EVENT_FLAG_CALL, dial_status_end(dialstatus) ? "DialEnd" : "DialState",
            "%s"
            "%s"
            "%s%s%s"
            "DialStatus: %s\r\n",
            caller_event_string ? ast_str_buffer(caller_event_string) : "",
            ast_str_buffer(peer_event_string),
            forwarded ? "Forward: " : "", S_OR(forward, ""), forwarded ? "\r\n" : "",
            S_OR(dialstatus, "unknown"));
   }

}

static void channel_hold_cb(void *data, struct stasis_subscription *sub,
   struct stasis_message *message)
{
   struct ast_channel_blob *obj = stasis_message_data(message);
   struct ast_str *musicclass_string = ast_str_create(32);
   struct ast_str *channel_event_string;

   if (!musicclass_string) {
      return;
   }

   channel_event_string = ast_manager_build_channel_state_string(obj->snapshot);
   if (!channel_event_string) {
      ast_free(musicclass_string);
      return;
   }

   if (obj->blob) {
      const char *musicclass;

      musicclass = ast_json_string_get(ast_json_object_get(obj->blob, "musicclass"));

      if (!ast_strlen_zero(musicclass)) {
         ast_str_set(&musicclass_string, 0, "MusicClass: %s\r\n", musicclass);
      }
   }

   manager_event(EVENT_FLAG_CALL, "Hold",
      "%s"
      "%s",
      ast_str_buffer(channel_event_string),
      ast_str_buffer(musicclass_string));

   ast_free(musicclass_string);
   ast_free(channel_event_string);
}

static void channel_unhold_cb(void *data, struct stasis_subscription *sub,
   struct stasis_message *message)
{
   struct ast_channel_blob *obj = stasis_message_data(message);
   struct ast_str *channel_event_string;

   channel_event_string = ast_manager_build_channel_state_string(obj->snapshot);
   if (!channel_event_string) {
      return;
   }

   manager_event(EVENT_FLAG_CALL, "Unhold",
      "%s",
      ast_str_buffer(channel_event_string));

   ast_free(channel_event_string);
}

static void manager_channels_shutdown(void)
{
   stasis_forward_cancel(topic_forwarder);
   topic_forwarder = NULL;
}

int manager_channels_init(void)
{
   int ret = 0;
   struct stasis_topic *manager_topic;
   struct stasis_topic *channel_topic;
   struct stasis_message_router *message_router;

   manager_topic = ast_manager_get_topic();
   if (!manager_topic) {
      return -1;
   }
   message_router = ast_manager_get_message_router();
   if (!message_router) {
      return -1;
   }
   channel_topic = ast_channel_topic_all();
   if (!channel_topic) {
      return -1;
   }

   topic_forwarder = stasis_forward_all(channel_topic, manager_topic);
   if (!topic_forwarder) {
      return -1;
   }

   ast_register_cleanup(manager_channels_shutdown);

   /* The snapshot type has a special handler as it can result in multiple
    * manager events being queued due to aspects of the snapshot itself
    * changing.
    */
   ret |= stasis_message_router_add(message_router,
      ast_channel_snapshot_type(), channel_snapshot_update, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_dtmf_begin_type(), channel_dtmf_begin_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_dtmf_end_type(), channel_dtmf_end_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_flash_type(), channel_flash_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_hangup_request_type(), channel_hangup_request_cb,
      NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_dial_type(), channel_dial_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_hold_type(), channel_hold_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_unhold_type(), channel_unhold_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_fax_type(), channel_fax_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_chanspy_start_type(), channel_chanspy_start_cb,
      NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_chanspy_stop_type(), channel_chanspy_stop_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_hangup_handler_type(), channel_hangup_handler_cb,
      NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_moh_start_type(), channel_moh_start_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_moh_stop_type(), channel_moh_stop_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_monitor_start_type(), channel_monitor_start_cb,
      NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_monitor_stop_type(), channel_monitor_stop_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_mixmonitor_start_type(), channel_mixmonitor_start_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_mixmonitor_stop_type(), channel_mixmonitor_stop_cb, NULL);

   ret |= stasis_message_router_add(message_router,
      ast_channel_mixmonitor_mute_type(), channel_mixmonitor_mute_cb, NULL);

   /* If somehow we failed to add any routes, just shut down the whole
    * thing and fail it.
    */
   if (ret) {
      manager_channels_shutdown();
      return -1;
   }

   return 0;
}