#!/bin/sh
#
# change_channel
# Usage: change_channel <remote_name> <channel_number>

# The name of the application that sends IR signals
IRSEND=irsend

# This may have to be adjusted up for some models
SLEEP_TIME=0.4

# To log the usage of the change_channel script, specify a valid (writable)
# file name.  To skip logging, specify /dev/null.
LOG_FILE=/dev/null
#LOG_FILE=/home/mythtv/log/change_channel.log

# The following file is used to ensure a channel change request doesn't begin
# until any already-occurring requests have completed.
# Ensure the user running the script has write access to the named file.
LOCKFILE=/var/tmp/change_channel.lock

if [ ! -w $LOG_FILE ]; then
  LOG_FILE=""
fi

log() {
  if [ $# = 0 ]; then
    echo "Usage: log <message>"
    return 1
  fi
  echo `date`: $1 | tee -a $LOG_FILE
}

if [ $# != 2 ]; then
  echo "Usage: change_channel <remote_name> <channel_number>"
  exit 1
fi

send_button() {
  if [ $# = 0 ]; then
    log "Usage: send_button <button_name>"
    return 1
  fi

  # Uncomment to "see" the buttons being sent
  log "$IRSEND SEND_ONCE $REMOTE_NAME $1"
  $IRSEND SEND_ONCE $REMOTE_NAME $1
  sleep $SLEEP_TIME
}

# display the program info screen
dish_info() {
  # wait for mythtv to begin recording
  sleep 2
  # now display the info screen for N seconds
  send_button info
  # Uncomment to make the info screen opaque
  send_button info
  sleep 6
  # and cancel back out of the info screen
  send_button cancel
}

log "Received request: $0 $1 $2"

MYPID="$$"

while [ "${HAVELOCK}" != "true" ]; do
  echo ${MYPID} >>${LOCKFILE}
  if [ "`cat ${LOCKFILE} 2>/dev/null | head -n 1`" = "$MYPID" ]; then
    HAVELOCK=true
  else
    log "Channel change in progress.  Waiting."
    sleep 1
  fi
done

REMOTE_NAME=$1

log "Processing: $0 $1 $2"

# Send cancel (can be used if first-digit is always skipped)
#send_button cancel

for digit in $(echo $2 | sed -e 's/./& /g'); do
  send_button ${digit}
done

# Send select to immediately change the channel
send_button select

# Send cancel to remove the OSD
send_button cancel

# Uncomment to display the Dish network OSD program info
#dish_info

rm ${LOCKFILE}

exit 0