#!/bin/bash

# Todd's standard bash script library.
# Contains a bunch of useful scriptlets.
#
# YMMV


##
## bashing bash
##

# Dereferences a variable.
# Returns the contents of the variable specified as a parameter.
# E.g. if $1=foo this will return the value of the variable $foo
# $1 - the variable nam to de-reference
dereferenceVar() {
	varname="$1"

	eval result=\$${varname}

	echo "${result}"
}


##
## String handling
##

# Left pads, with zeros, a number to make
# it of a specified length
# If instead of a max lenght, you know the max number to
# be accomidated, call with ${#maxNumber}
# $1 - Number to pad
# $2 - length of final result
leftZeroPad() {
	number=$1
	resultLength=$2

	# This should provide enough potential padding
	hold="00000000000000000000000000000000000000000000000000000000000000${number}"

	echo "${hold:${#hold} - ${resultLength}:${resultLength}}"
}

# Truncates (right side) a string to a maximum length
# $1 - String to truncate
# $2 - Maximum length
truncate() {
	string="${1}"
	maxlen="${2}"
	echo "${string}" | cut -c -${maxlen}
}

# Convert the given argument into an all lowercase string.
# $1 - The String to convert to lowercase
toLower() {
	echo $1 | tr "[:upper:]" "[:lower:]"
}

# Convert the given argument into an all uppercase string.
# $1 - The String to convert to uppercase
toUpper() {
	echo $1 | tr "[:lower:]" "[:upper:]"
}

# Returns a the needle string if found in haystack
# $1 - the haystack string -- whitespace delimited string containing thru which to search
# $2 - the needle string -- the string for which to look in the haystack.
containsString() {
	haystack="${1}"
	needle="${2}"

	for str in ${haystack}; do
		if [ "${str}" == "${needle}" ]; then
			echo "${needle}"
			return
		fi
	done 
}


###
### Other stuff
###

# Gets a chmod-usable parameter from the current permissions of a file.
# E.g. if a file 'foo.sh' has the permissions:
# -rwxr-xr-x 1 usr grp     0 2000-01-01 16:20 foo.sh
# This script would return '0755'.
# Note that the sticky bit is unsupported.
# Returns the octal string or an empty string if the file doesn't exist.
# $1 - The filename.
getChmodParamFromFile() {
	file="${1}"

	# quick check
	if [ -d "${file}" ]; then
		return;
	fi

	permString="`/bin/ls -l ${file} | cut -d " " -f 1`"
	chmodString="0"

	# process the permString in three chunks
	for chunk in 0 1 2; do
		let indx=${chunk}*3+1
		subchunk="${permString:${indx}:3}"
		component=0

		if [[ "${subchunk:0:1}" != "-" ]]; then
			let component=$component+4
		fi
		if [[ "${subchunk:1:1}" != "-" ]]; then
			let component=$component+2
		fi
		if [[ "${subchunk:2:1}" != "-" ]]; then
			let component=$component+1
		fi

		# Add in this digit
		chmodString="${chmodString}${component}"
	done

	echo "${chmodString}"
}

# Sets the permissions of dirs/files within that dir.
# The supplied directory and all subdirectories will have
# their permissions set to the supplied 'directory permission',
# All files in the supplied directory and below will have
# their permssion set to the supplied 'file permssion'.
# Returns error if directory does not exist.
# $1 - The directory permission
# $2 - The file permission
# $3 - The directory on which to operate
radchmod() {
	dirPerms="${1}"
	filePerms="${2}"
	directory="${3}"

	# Quick check
	if [ ! -d "${directory}" ]; then
		# Directory does not exist
		return 1
	fi

	# Process directory
	chmod "${dirPerms}" "${directory}"
	cd "${directory}"
	find . -type d -exec chmod "${dirPerms}" {} \;
	find . -type f -exec chmod "${filePerms}" {} \;
	
	return 0
}