#!/bin/bash

# Convert a dialplan from Asterisk language to AEL
#
# Not perfect but far better than nothing
#
# Does not aim to create a fully-functional AEL dialplan (although it may if you haven't used too many Asterisk language constructs)
# but is more intended to deal with the 98% of tedious stuff and leave the human to deal with the 2% of interesting stuff.
#
# Handles:
# - Goto
# - GotoIf
# - ExecIf
# - Set
# - Comments
#
# Things that will need human attention to tidy up afterwards:
# - Gosub
# - GosubIf
# - any conditional where the 'true' response contains a colon
# - mathematical expressions using $[ ... ]
# - While .. EndWhile
#
# There may be more...

if [ -n "$1" ]
then
  dialplan=$1
else
  echo "Please tell me which dialplan to try to convert."
  exit 1
fi

indent=0
(cat asterisk/dialplan.$dialplan.conf; echo EndOfFile) | while read stuff
do
  restofline=
# Is this a comment?
  if [ "${stuff:0:1}" = ";" ]
  then
    echo "// ${stuff:1}"
# Is this a new context name?
  elif [ "${stuff:0:1}" = "[" ]
  then
    while [ "$indent" -gt 0 ]
    do
      indent=$(($indent-2))
      printf "%${indent}s"
      echo "}"
    done
    echo
    echo "context $stuff {" | tr -d '[]'
    indent=2
# Start of a new extension definition?
  elif [ "${stuff:0:9}" = "exten => " ]
  then
    if [ "$indent" -gt 2 ]
    then
      indent=$(($indent-2))
      printf "%${indent}s"
      echo "}"
      echo
    fi
    printf "%${indent}s"
    echo -n "${stuff#exten => }" | sed 's/,.*//'
    echo " => {"
    indent=$(($indent+2))
    restofline=`echo -n "$stuff" | sed 's/exten => [^,]*,1,//'`
# Have we finished and need to close down the braces?
  elif [ "$stuff" = "EndOfFile" ]
  then
    while [ "$indent" -gt 0 ]
    do
      indent=$(($indent-2))
      printf "%${indent}s}\n"
    done
# Do we have a label?
  elif [ "${stuff:0:10}" = "same => n(" ]
  then
    echo -n "${stuff:10}" | sed 's/).*//'
    echo ":"
    restofline="${stuff#*),}"
# Standard line in the dialplan?
  elif [ "${stuff:0:10}" = "same => n," ]
  then
    restofline="${stuff:10}"
# No idea what anything else could be
  elif [ -n "$stuff" ]
  then
    echo "//// $stuff"
  fi

# Goto/Gosub?
  if [ "${restofline:0:5}" = "Goto(" ]
  then
    printf "%${indent}s"
    echo "goto ${restofline:5}" | sed 's/)$/;/'
    restofline=
  fi
  if [ "${restofline:0:6}" = "Gosub(" ]
  then
    printf "%${indent}s"
    echo "&${restofline:6};" | sed 's/,/(/'
    restofline=
  fi

# Conditional goto/gosub?
  if [ "${restofline:0:9}" = "GotoIf(\$[" -o "${restofline:0:10}" = "GosubIf(\$[" ]
  then
    printf "%${indent}s"
    [ "${restofline:2:1}" = "t" ] && condition="${restofline:9}"
    [ "${restofline:2:1}" = "s" ] && condition="${restofline:10}"
    condition="${condition%]\?*}"
    true="${restofline#*]\?}"
    true="${true%)}"
    echo "if ($condition)"
    indent=$(($indent+2))
    printf "%${indent}s"
    [ "${restofline:2:1}" = "t" ] && echo "goto ${true%,1};"
    [ "${restofline:2:1}" = "s" ] && echo "&${true});" | sed 's/,/(/'
    indent=$(($indent-2))
    true=
    restofline=
  fi

# Conditional exec?
# ExecIf($["${Scode}"="203"]?Set(Status=Cannot place two simultaneous calls));
  if [ "${restofline:0:9}" = "ExecIf(\$[" ]
  then
    printf "%${indent}s"
    condition="${restofline:9}"; condition="${condition%]\?*}"
    true="${restofline#*]\?}"; false="${true#*:}"
    if [ "$true" = "$false" ]
    then
      true="${false%)}"
      false=
    else
      false="${false%)}"
    fi
    echo "if ($condition)"
    restofline=
  fi

# Loop through conditionals, once only otherwise
  while [ -n "$true$false$restofline" ]
  do
    if [ -n "$true" ]
    then
      indent=$(($indent+2))
      restofline="$true"
    elif [ -n "$false" ]
    then
      printf "%${indent}s"
      echo "else"
      indent=$(($indent+2))
      restofline="$false"
    fi

# Assignment?
    if [ "${restofline:0:4}" = "Set(" ]
    then
      printf "%${indent}s"
      echo "${restofline:4}" | sed 's/)$/;/'
    elif [ -n "$restofline" ]
    then
      printf "%${indent}s"
      echo "$restofline;"
    fi

# Are we in a conditional?
    if [ -n "$true" ]
    then
      true=
      indent=$(($indent-2))
    elif [ -n "$false" ]
    then
      false=
      indent=$(($indent-2))
    fi
    restofline=
  done
# Finally catch any debug lines we had
done | sed 's# ; debug;$#; // debug#'