rc/sh/e

#!/usr/bin/env zsh

local editor=(${=EDITOR})
local running=0

if [ -n "$MSYSTEM" ]; then
    if ps -f | awk '{print $6}' \
    | grep -o '[^/]*$' | grep -qFx "${editor[1]}"; then
        running=1
    fi
elif ps -o comm | grep -qFx "${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 "$@"; do
    # easy: file exists, we have write permissions
    [ -w "$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