gistu

#!/bin/bash
path=$1
go=$2

commands='gist grep diff cut mktemp'
for c in $commands; do
  hash $c || { echo "install $c"; exit 255; }
done

if [ ! -r $path ]; then
  echo "$path not found"
  exit 255
fi

function usage()
{
    echo "Usage: `basename $0` file [go]"
}

if [ -z "$path" ]; then
  usage
  exit 255
fi

function gist_url()
{
  local path=$1
  [ -z "$path" ] && exit 255
  local file=$(basename ${path})
  local url=$(gist -l|grep -E "^https://gist.github.com/[0-9a-z]+ ${file}( | \(secret\))$" |cut -d ' ' -f 1)
  [ -n "$url" ] || return 1
  echo $url 
}

function gist_id()
{
  local path=$1
  [ -z "$path" ] && exit 255

  local id=$(gist_url ${path} |cut -d '/' -f 4)
  [ -n "$id" ] || return 1
  echo $id
}

function gist_diff()
{
  local path=$1
  [ -z "$path" ] && exit 255

  local id=$(gist_id $path)
  [ -n "$id" ] || return 2
  
  local original_file=$(mktemp)

  gist -r $id > ${original_file} || return 2

  diff -uN $original_file $path
  local ret=$?
  rm ${original_file}
  return $ret
}

opts=""
update_opts="-p"

url=$(gist_url $path)
[ -n "$url" ] && update_opts="-u $url"

if [ "$go" = "go" ]; then
  gist_diff $path &>/dev/null
else
  gist_diff $path
fi

case $? in
  0)
    echo $url
    exit
    ;;
  1)
    update_opts="-u $url"
    ;;
  2)
    [ "$go" = "go" ] || echo "new gist"
    ;;
  *)
    exit $?
    ;;
esac

if [ "$go" != "go" ]; then
  while true; do
    read -p "Do you wish to overwrite the gist? [Y] " yn
    case $yn in
      [Yy]* ) go="go"; break;;
      * ) exit;;
    esac
  done
fi

[ "$go" = "go" ] && gist $opts $update_opts -- $path