overhaul e script

sh/e

@@ -1,17 +1,49 @@
 #!/bin/zsh
-# http://unix.stackexchange.com/a/37887
-#[ -n "${ZSH_VERSION:-}" ] && local -A EDITOR ${=EDITOR}
-# TODO: find actually working way of portably splitting word cmds, zsh/bash
 
-if [ $# -eq 0 ]; then
-  $=EDITOR
-  return
+local editor=(${=EDITOR})
+local running=0
+
+if [ -n "$MSYSTEM" ]; then
+    if ps -f | awk '{print $6}' | grep -qF "/usr/bin/${editor[1]}"; then
+        running=1
+    fi
+elif ps -o comm | grep -qFx "${editor[1]}"; then
+    running=1
+fi
+
+if [ "$running" -eq 1 ]; then
+    printf "%s\n" "${editor[1]} is already running" >&2
+    read -q '?Continue? [y/N] ' _ || { echo; return; }
+    echo
+fi
+
+if [ $# -eq 0 ] || [ -n "$MSYSTEM" ]; then
+    $=EDITOR
+    return
 fi
 
 local f needroot=0
-for f in $@; do
-  [ -e "$f" ] && { [ -w "$f" ] || needroot=1; }
-# TODO: check directory permissions too
+for f in "$@"; do
+    # easy: file exists, we have write permissions
+    [ -w "$f" ] && continue
+
+    # easy: file exists, but no write permissions
+    [ -e "$f" ] && { needroot=1; break }
+
+    # hard: file may be in a directory that we can't inspect
+    local d="$f"
+    while expr index "$d" / >/dev/null; do
+        d="${d%/*}"
+        # NOTE: this gets weird with the root directory, not sure how to handle
+        [ -e "$d" ] && [ ! -w "$d" ] && { needroot=1 && break; }
+    done
+    [ $needroot -eq 1 ] && break
+
+    # easy: file just doesn't exist
 done
 
-if [ $needroot -eq 0 ]; then $=EDITOR $@; else sudo -e $@; fi
+if [ $needroot -eq 0 ]; then
+    $=EDITOR "$@"
+else
+    sudo -e "$@"
+fi