#!/bin/sh -u
# Answer file: Exercise #5 - gethangman.sh
#------------------------------------------------------------------
# fetch, decompress many times, and expand the mystery .hangman file
#------------------------------------------------------------------
# Syntax:  $0               (no arguments)
#------------------------------------------------------------------
# Purpose:
#  Fetch the hangman mystery file from
#     http://teaching.idallen.com/dat2330/04f/notes/.hangman
#  Decompress it several times.  Expand the tar archive.
#  Do not overwrite any existing files.
#  Quick-exit the script non-zero if anything goes wrong along the way.
#  Optional: fix the permissions in the hangman directory.
#------------------------------------------------------------------
# Student Name:                 Ian Allen
# Algonquin EMail Address:      alleni
# Student Number:               074-210-779 
# Course Number:                DAT2330  
# Lab Section Number:           010 
# Professor Name:               Ian Allen 
# Assignment Name/Number/Date:  Exercise #5 due December 7
# Comment:                      This is a sample solution.
#------------------------------------------------------------------

# Set a standard shell search path and a friendly umask.
#
PATH=/bin:/usr/bin ; export PATH
umask 022

# The name of the file we are fetching - used all through the script.
# The name of the directory inside the tar file; do not overwrite it.
#
filename='.hangman'
tardir='hangman'

# Validation Section

# current dir must have write and execute permissions
#
if [ ! -w . -o ! -x . ] ; then
    echo 1>&2 "$0: current directory . missing write or execute permissions"
    exit 1
fi

# do not overwrite any existing pathnames in current directory
#
if [ -e "$filename" ] ; then
    echo 1>&2 "$0: a pathname '$filename' already exists here; nothing done"
    exit 2
fi

if [ -e "$tardir" ] ; then
    echo 1>&2 "$0: a pathname '$tardir' already exists here; nothing done"
    exit 3
fi

# Processing Section

# fetch the mystery file and make sure the fetch got a non-empty file
#
wget http://teaching.idallen.com/dat2330/04f/notes/"$filename" || exit 4

if [ ! -s "$filename" ]; then
    echo 1>&2 "$0: the downloaded '$filename' file is missing or empty"
    echo 1>&2 "$0: nothing done"
    exit 4
fi

# Do the correct series of decompress steps to get to the tar archive.
#
mv "$filename" "$filename.bz2" || exit 5
bunzip2 "$filename.bz2" || exit 5

mv "$filename" "$filename.gz" || exit 5
gunzip "$filename.gz" || exit 5

mv "$filename" "$filename.bz2" || exit 5
bunzip2 "$filename.bz2" || exit 5

mv "$filename" "$filename.gz" || exit 5
gunzip "$filename.gz" || exit 5

mv "$filename" "$filename.bz2" || exit 5
bunzip2 "$filename.bz2" || exit 5

mv "$filename" "$filename.bz2" || exit 5
bunzip2 "$filename.bz2" || exit 5

mv "$filename" "$filename.gz" || exit 5
gunzip "$filename.gz" || exit 5

# Expand the tar archive into the current directory.
# Make sure a $tardir directory results.
# Remove the tar file.
#
tar xvf "$filename" || exit 6
if [ ! -d "$tardir" ] ; then
    echo 1>&2 "$0: cannot find '$tardir' after expanding '$filename'"
    exit 7
fi
rm "$filename"

echo "The '$tardir' directory is ready for you: cd $tardir"

# Optional: Add write permissions for owner.
# (Modifying the code is difficult if write permissions are missing.)

chmod u+rwx "$tardir"   || exit 8
chmod u+rw  "$tardir"/* || exit 8

# script exits with the return code of the last command executed