#!/bin/bash
#
# Developed by Fred Weinhaus 3/13/2022 .......... revised 3/13/2022
#
# ------------------------------------------------------------------------------
# 
# Licensing:
# 
# Copyright © Fred Weinhaus
# 
# My scripts are available free of charge for non-commercial use, ONLY.
# 
# For use of my scripts in commercial (for-profit) environments or 
# non-free applications, please contact me (Fred Weinhaus) for 
# licensing arrangements. My email address is fmw at alink dot net.
# 
# If you: 1) redistribute, 2) incorporate any of these scripts into other 
# free applications or 3) reprogram them in another scripting language, 
# then you must contact me for permission, especially if the result might 
# be used in a commercial or for-profit environment.
# 
# My scripts are also subject, in a subordinate manner, to the ImageMagick 
# license, which can be found at: http://www.imagemagick.org/script/license.php
# 
# ------------------------------------------------------------------------------
# 
####
#
# USAGE: lomography [-t type] infile outfile
# USAGE: lomography [-h|help]
#
# OPTIONS:
#
# -t ... type ... type of lomography; choices are turquoise (t), purple (p),
# ............... or lime (l) ; default=turquoise
#
###
#
# NAME: LOMOGRAPHY
# 
# PURPOSE: To apply a lomographic effect to an image.
# 
# DESCRIPTION: LOMOGRAPHY applies a lomographic effect to an image similar 
# to the lomography photographic film. There are three types: turquoise, 
# purple and lime. See https://thedarkroom.com/what-is-lomography/
# 
# OPTIONS: 
# 
# -t type ... TYPE of lomography. The choices are turquoise (t), purple (p),
# or lime (l). The default=turquoise
# 
# CAVEAT: No guarantee that this script will work on all platforms, 
# nor that trapping of inconsistent parameters is complete and 
# foolproof. Use At Your Own Risk. 
# 
######
#

# set directory for temporary files
dir="."    # suggestions are dir="." or dir="/tmp"

# set up functions to report Usage and Usage with Description
PROGNAME=`type $0 | awk '{print $3}'`  # search for executable on path
PROGDIR=`dirname $PROGNAME`            # extract directory of program
PROGNAME=`basename $PROGNAME`          # base name of program
usage1() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^###/g;  /^#/!q;  s/^#//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}
usage2() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^######/g;  /^#/!q;  s/^#*//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}


# function to report error messages
errMsg()
	{
	echo ""
	echo $1
	echo ""
	usage1
	exit 1
	}


# function to test for minus at start of value of second part of option 1 or 2
checkMinus()
	{
	test=`echo "$1" | grep -c '^-.*$'`   # returns 1 if match; 0 otherwise
    [ $test -eq 1 ] && errMsg "$errorMsg"
	}

# test for correct number of arguments and get values
if [ $# -eq 0 ]
	then
	# help information
   echo ""
   usage2
   exit 0
elif [ $# -gt 4 ]
	then
	errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---"
else
	while [ $# -gt 0 ]
		do
			# get parameter values
			case "$1" in
		  -h|-help)    # help information
					   echo ""
					   usage2
					   exit 0
					   ;;
				-t)    # get type
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID TYPE SPECIFICATION ---"
					   checkMinus "$1"
					   type=`echo "$1" | tr "[:upper:]" "[:lower:]"`
					   case "$type" in 
					   		turquoise|t) type="turquoise" ;;
					   		purple|p) type="purple" ;;
					   		lime|l) type="l" ;;
					   		*) errMsg "--- TYPE=$type IS AN INVALID VALUE ---" 
					   	esac
					   ;;
				 -)    # STDIN and end of arguments
					   break
					   ;;
				-*)    # any other - argument
					   errMsg "--- UNKNOWN OPTION ---"
					   ;;
		     	 *)    # end of arguments
					   break
					   ;;
			esac
			shift   # next option
	done
	#
	# get infile and outfile
	infile="$1"
	outfile="$2"
fi

# test that infile provided
[ "$infile" = "" ] && errMsg "NO INPUT FILE SPECIFIED"

# test that outfile provided
[ "$outfile" = "" ] && errMsg "NO OUTPUT FILE SPECIFIED"


tmpA1="$dir/lomography_1_$$.mpc"
tmpA2="$dir/lomography_1_$$.cache"
trap "rm -f $tmpA1 $tmpA2; exit 0" 0
trap "rm -f $tmpA1 $tmpA2; exit 1" 1 2 3 15

# read and test image
convert -quiet "$infile" +repage "$tmpA1" ||
	echo  "--- FILE $infile DOES NOT EXIST OR IS NOT AN ORDINARY FILE, NOT READABLE OR HAS ZERO SIZE  ---"

# set up for type
if [ "$type" = "turquoise" ]; then
	swapping="-swap 0,2"
elif [ "$type" = "purple" ]; then
	swapping="-swap 1,2"
else
	swapping="-swap 0,1"
fi

# process image
convert $tmpA1 -separate $swapping -combine "$outfile"

exit 0