#!/bin/bash

print_usage() {
  printf "Usage: ./comparer.sh [-d] PATTERN FIRST_DIR SECOND_DIR\n"
  printf "Compares all files (recursively) found that match the PATTERN in FIRST_DIR to files found in SECOND_DIR.\n"
  printf "If the files differ and -d is used you are offered to view the diff.\n"
}

declare -A filesFromFirstDir
declare -A filesFromSecondDir

diff=0
while getopts 'dh' flag; do
	case "${flag}" in
		d) diff=1;;
		h) print_usage; exit 0;;
	esac
done

if [ $diff -eq 1 ]; then
	shift "$((OPTIND - 1))"
fi

for filepath in $(find $2 -name "$1"); do
	filename=$(echo $filepath | rev | cut -d/ -f1 | rev)
	filesFromFirstDir[$filename]=$filepath
done

for filepath in $(find $3 -name "$1"); do
	filename=$(echo $filepath | rev | cut -d/ -f1 | rev)
	filesFromSecondDir[$filename]=$filepath
done

for filename in ${!filesFromFirstDir[@]}; do
	if [ "${filesFromSecondDir[$filename]}" == "" ]; then
		echo There is no element in second dir for ${filesFromFirstDir[$filename]}
		continue
	fi
	cmp "${filesFromFirstDir[$filename]}" "${filesFromSecondDir[$filename]}"
	if [ $? -ne 0 ] && [ $diff -eq 1 ] ; then
		read -p "Open diff? [y/n] " open_diff
		if [ "$open_diff" == "y" ] || [ -z "$open_diff" ]; then
			vimdiff "${filesFromFirstDir[$filename]}" "${filesFromSecondDir[$filename]}" 2> /dev/null
		fi
	fi
done