#!/usr/local/plan9/bin/rc
rfork e
PATH=/usr/local/plan9/bin:$PATH

usage='usage: edit [file]'

wd=`{pwd}
os=`{uname}

fn  owner {
   ls -l $1 | awk '{print $4}'
}

fn med {a=(){
  # usage: med file
  a=`{xattr $1}	# extended attribute
  if(~ $a ?*)
    xattr -d $a $1
  open -a $EDITOR $1 || echo $usage
  # back ground job. don't rm $1
}}

fn ided {b=() d=(){ # indirect edit in $T
  # usage: ided file
  # the file is absolute path
  b=`{basename $1}
  d=`{basename -d $1}
  if(! test -e $T$d)
    mkdir -p $T$d
  cp $1 $T$1
  $EDIT $T$1
}}

fn confirm {a=(){
  echo $1'?(y/n)' >[1=2]
  while(! ~ $a y n)
    a=`{read}
  echo $a
}}

switch($os){
case Darwin
  EDITOR=TextEdit.app
  #EDITOR=Xcode.app
  EDIT=med
case Linux FreeBSD
  EDIT=nano
case *
  echo unsuppoted OS
  exit
}

T=$home/tmp/edit # working directory for edit.
# $T is automatically created, if absent, with chmod 0700

while(~ $1 -*){
switch($1){
case -*
  echo $usage
  exit
}}

if(! test -d $T){
  mkdir -p $T
  chmod 0700 $T
}

if(~ $#* 0){
  # usage1: edit
  # usage2: command | edit
  # second case will work only for GUI based editor such as TextEdit.app
  t=$pid # identifier
  f=$T/$t
  if(u test -t 0) # input is a tty not a pipe
    touch $f
  if not
    cat > $f
  p=`{echo -n NXNAXAMXMEXE | tr X '\010'}
  if(grep -s $p $f){ # we guess man output
    cat $f | col -b  > $f^m
    mv $f^m $f
  }
  $EDIT $f
  #rm $f
  exit
}

if(! test -e $1){
  a=`{confirm create}
  if(~ $a y Y)
    touch $1
  if not
    exit
}

e=$1
if(! ~ $e /*)
  e=$wd/$e
e=`{cleanname $e}
# NB: then $e is the absolute path of $1
# $T/$e is wrong. use $T$e

# maybe better: if(! ~ `{owner $e} `{whoami})
if(~ `{owner $e} root){
  ided $e
  a=`{confirm save}
  if(~ $a y Y)
    echo sudo cp -X $T$e $e
  exit
}

$EDIT $e