#!/bin/bash
# Author: Joshua Bailey
# Script: divApp2
# This script takes the first argument you entered
# and writes to a file with that name.
# If it exists it prompts to append, overwrite, or exit
# It then opens the other file names you pass it to redirect
# Their output for the first files input.
# syntax: divApp2 fileAddTo addFrom1 addFrom2 addFrom3 ....

# function printBeginning
printBeginning ()
{
	# append a line break
	echo "================================================================" >> $1

	# append begin
	echo "               <*** Begin \"$2\" ***>" >> $1

	# space holder
	echo " " >> $1
} # end function printBeginning

# function printEnding
printEnding ()
{
	# space holder
		echo " " >> $1

		# append the end of file line break
		echo "               <*** End \"$2\" ***>" >> $1
		echo "================================================================" >> $1

		# space holder
                echo " " >> $1
		echo " " >> $1
} # end function printEnding

# function argumentCheck
argumentCheck ()
{
	# check to see if user used enough arguments
	if [[ ! $1 > 1 ]]
	then
		# tell the user that the syntax was entered incorrectly
		echo "*** Error: too few arguments!"
		echo "*** Must have a file to append to or create."
		echo "*** Must also have atleast one file to read from."
		echo "*** Syntax: divApp2 fileAddTo addFrom1 addFrom2 addFrom3..."
		exit
	fi
} # end function argumentCheck

# function existFileAddTo
existFileAddTo ()
{
	if [[ -e $1 ]]
	then

		# if it exists say so
		echo "File \"$1\" already exists."

		# ask user what they want to do
		read -p "Do you want to append, overwrite, or exit? (a|o|e) " ans

		# make sure the variable holds the correct case
		ans=`echo $ans | tr [:upper:] [:lower:]`

		# use only the first letter to decide what to do
		ans=${ans:0:1}

		# do what the user requested
		if [[ $ans = "e" ]]
		then
			echo "*** Exiting ***"
			exit
		elif [[ $ans = "o" ]]
		then
			echo "*** Overwriting ***"
			rm -f $1
			ans="T"
		elif [[ $ans = "a" ]]
		then
			echo "*** Appending ***"
			ans="T"
		else
			if [[ $ans != "T" ]]
			then
				echo "That choice is not an option!"
				echo "*** Exiting ***"
				exit
			fi
		fi
	fi
} # end function existFileAddTo

# function viewFile
viewFile ()
{
	read -p "Do you want to display the file? (y|n) " YesNo

	# make user input lower case
	YesNo=`echo $YesNo | tr [:upper:] [:lower:]`

	# cut off all except the first letter
	YesNo=${YesNo:0:1}

	if [[ $YesNo = "y" ]]
	then

		# display the file
		cat $1 | less
	fi
} # end function viewFile

# assign the first parameter (the created file) to copyTo
copyTo=$1

# assign the number of parameters to loopCount
loopCount=$#

# declare the array
declare -a arr

# check to see if user used enough arguments
argumentCheck $loopCount

# assign the arguments to an array
for ((i=0; i != ($loopCount-1); i++))
do
	arr[$i]=$2
	shift 1

	# see if all files listed exist...exit if they don't
	if [[ ! -e ${arr[$i]} ]]
	then
		echo "File \"${arr[$i]}\" does not exist, or you typed the wrong path!"
		echo "*** Aborting ***"
		exit
	fi
done

	# see if the fileAddTo file exists or not
	existFileAddTo $copyTo

	# loop the appending the number of parameters minus one (the first one)
	for ((i=0; i < `echo ${#arr[*]}`; i++))
	do

		printBeginning $copyTo ${arr[$i]}
	
		# append the contents of the file you specified
		cat ${arr[$i]} >> $copyTo

		printEnding $copyTo ${arr[$i]}

	done

	# state that the process is complete
	echo "*** Done ***"
	
	# see if user wants to view the file created
	viewFile $copyTo