#!/bin/sh

usage() {
	cat << EOF

USAGE:
  $0 [options]

OPTIONS:
  -i           Input file (required)
  -o           Output file (required)
  -v           Verbose
  -h           Show this help

EOF

}

error() {
	if [ -n "$1" ]; then
		printf "%s\\n" "$1" >/dev/stderr
	fi

	exit 1
}

exitIfEmpty() {
	if [ -z "$1" ]; then
		error "$2"
	fi
}

log() {
	if [ "$VERBOSE" -eq 1 ]; then
		printf "%s\\n" "$1"
	fi
}

unzipExcel() {
	if [ "$VERBOSE" -eq 0 ]; then
		verbosity=-qq
	fi

	unzip $verbosity -d "$TEMP_DIRECTORY/excel" "$INPUT_FILE"
}

createExcel() {
	current_dir="$(pwd)"

	if [ "$VERBOSE" -eq 0 ]; then
		verbosity=-q
	fi

	cd "$TEMP_DIRECTORY/excel"
	zip $verbosity -r "../result.xslx" ./*
	cd "$current_dir"
	mv "$TEMP_DIRECTORY/result.xslx" "$OUTPUT_FILE"

	log "$OUTPUT_FILE generated"
}

createTmpDirectory() {
	TEMP_DIRECTORY="$(mktemp -d)"
	log "Temp directory created: $TEMP_DIRECTORY"
}

removePassword() {
	sed -i 's#<sheetProtection[^>]*>##' "$1"
}

removePasswords() {
	grep -Rn sheetProtection "$TEMP_DIRECTORY" | cut -d: -f1 | while read -r file; do
		removePassword "$file"
		log "Password removed in: $file"
	done
}

cleanUp() {
	rm -fr "$TEMP_DIRECTORY" && log "Temp directory removed: $TEMP_DIRECTORY"
}

ERROR=0
VERBOSE=0

while getopts "hvi:o:" option; do
	case "$option" in
		i) INPUT_FILE="$OPTARG";;
		o) OUTPUT_FILE="$OPTARG";;
		h) usage; exit 0;;
		v) VERBOSE=1;;
		:) ERROR=1;;
		?) ERROR=1;;
	esac
done

if [ "$ERROR" -eq 1 ]; then
	error "$(usage)"
fi

exitIfEmpty "$INPUT_FILE" "Input file is missing (-i)"
exitIfEmpty "$OUTPUT_FILE" "Output file is missing (-o)"

if [ ! -f "$INPUT_FILE" ]; then
	error "No such file: $INPUT_FILE"
fi

createTmpDirectory
unzipExcel
removePasswords
createExcel
cleanUp