#!/bin/bash

if [ "$1" = ":PREFIX:" ]; then
  prefix="$2"
  self="$0"
  shift 2
else
  prefix=""
  self=`dirname "$0"`
  self=`cd "$self" ; pwd`/`basename "$0"`
fi

if [ "$#" -lt 1 ]; then
  echo "Usage: $0 <other-dir> [file...]"
  exit 1
elif [ "$#" -eq 1 ]; then
  other="$1"
  set "."
else
  other="$1"
  shift 1
fi

if [ -d "$other" -a "$prefix" = "" ]; then
  other="`( cd \"$other\" ; pwd )`"
fi

if [ -d "$other" ]; then
  if [ "`pwd`" = "$other" ]; then
    echo "Cannot compare this directory with itself!"
    exit 1
  fi
else
  echo "Directory $other does not exist!"
  exit 1
fi

# Compare regular files
for x in "$@"; do
  if [ -f "$x" ]; then
    echo -n "$prefix$x... "
    if [ -f "$other/$x" ]; then
      if diff -q -- "$x" "$other/$x" > /dev/null; then
        echo "equal -- removing!"
        rm -- "$x"
      else
        echo "different"
      fi
    elif [ -e "$other/$x" ]; then
      echo "other file is not regular"
    else
      echo "other missing"
    fi
  fi
done

# Descend into subdirs
glob_dot_filenames=1
dotglob=1
shopt -s dotglob
for x in "$@"; do
  if [ -d "$x" ]; then
    if [ -L "$x" ]; then
      echo "skipping symblic link: $x"
    else
      if [ "$prefix" != "" ]; then
        if [ "$x" = "." -o "$x" = ".." ]; then
          continue
        fi
      fi
      ( cd "$x" ; "$self" :PREFIX: "$prefix$x/" "$other/$x" * )
      if [ "$x" != "." ]; then
        rmdir -- "$x" > /dev/null 2>&1
      fi
    fi
  fi
done