encode

#!/usr/bin/env bash

#########################region CONSTANTS#########################
readonly NAME="encode"
readonly ERROR_BAD_METHOD=4
readonly ERROR_NO_INPUT=2
readonly ENCODE_METHOD_ESCAPE="escape"
readonly ENCODE_METHOD_URL="url"
readonly ENCODE_METHOD_URL_FULL="url_full"
readonly ENCODE_METHOD_UNDERSCORE="underscore"
readonly TRUE="[ a = a ]"
readonly FALSE="[ a = b ]"
readonly DEFAULT_ENCODE_METHOD=$ENCODE_METHOD_ESCAPE
#########################endregion CONSTANTS#########################
#########################region HELP#########################
show_help() {
    cat << __EOF__
$NAME VALUE [--escape|url|underscore] [-s|--silent] | $NAME VALUE [-e|u|_] [-s|--silent] | $NAME -h | $NAME --help

Encodes the given value(s) with the selected method. Defaults to $DEFAULT_ENCODE_METHOD. Currently only encodes spaces.

Parameters:
	-u | --url: use url decoding
	-e | --escape: use escape decoding (i.e. uses "\\\\" to encode escape sequences)
	-_ | --underscore: use underscore decoding (i.e. replaces all underscores with spaces)
		Defaults to "$DEFAULT_ENCODE_METHOD"
    -h | --help: Display this help text.
EXIT STATUS:
	Error Level of $ERROR_BAD_METHOD if selection is invalid.
__EOF__
	# -n | --preserve_newlines: encodes newlines separately from spaces
# Anything else will result in no encoding being used. If this is used, ensure there are no spaces in your values nor labels.
#    -e | --error_on_fail: Set the error level on failure.
}
show_version() {
	cat << __EOF__
$0 1.0.0

Copyright (C) 2025 Justin Morris
__EOF__
}
#########################endregion HELP#########################

#########################region ENCODE METHODS#########################
root_encode() {
	c="$1"
	shift
    echo $(echo -n "$@" | sed -z -E 's/%/'"$c"'25/g' | sed -z -E 's/\n/'"$c"'0A/g' | tr '\014' '\n'| sed -z -E 's/\n/'"$c"'0C/g' | tr '\015' '\n'| sed -z -E 's/\n/'"$c"'0D/g' | sed -E 's/\"/'"$c"'22/g' | sed -E 's/\|/'"$c"'7C/g' | sed -E 's/ /'"$c"'20/g' | sed -E 's/!/'"$c"'21/g' | sed -E 's/#/'"$c"'23/g' | sed -E 's/\$/'"$c"'24/g' | sed -E 's/&/'"$c"'26/g' | sed -E "s/'/$c""27/g" | sed -E 's/\(/'"$c"'28/g' | sed -E 's/\)/'"$c"'29/g' | sed -E 's/\*/'"$c"'2A/g' | sed -E 's/\+/'"$c"'2B/g' | sed -E 's/,/'"$c"'2C/g' | sed -E 's/:/'"$c"'3A/g' | sed -E 's/;/'"$c"'3B/g' | sed -E 's/=/'"$c"'3D/g' | sed -E 's/\?/'"$c"'3F/g' | sed -E 's/@/'"$c"'40/g' | sed -E 's/\[/'"$c"'5B/g' | sed -E 's/\]/'"$c"'5D/g')
}
# https://en.wikipedia.org/wiki/Percent-encoding#Reserved_characters
# https://www.gnu.org/software/sed/manual/html_node/Regular-Expressions.html
# https://superuser.com/questions/133780/in-bash-how-do-i-escape-an-exclamation-mark
url_encode() {
    echo $(root_encode '%' "$@")
	# escape_char='%'
    # echo -e $(echo -n "$@" | sed -z -E 's/%/'"$escape_char"'25/g' | sed -z -E 's/\n/'"$escape_char"'0A/g' | tr '\014' '\n'| sed -z -E 's/\n/'"$escape_char"'0C/g' | tr '\015' '\n'| sed -z -E 's/\n/'"$escape_char"'0D/g' | sed -E 's/\"/'"$escape_char"'22/g' | sed -E 's/\|/'"$escape_char"'7C/g' | sed -E 's/ /'"$escape_char"'20/g' | sed -E 's/!/'"$escape_char"'21/g' | sed -E 's/#/'"$escape_char"'23/g' | sed -E 's/\$/'"$escape_char"'24/g' | sed -E 's/&/'"$escape_char"'26/g' | sed -E "s/'/$escape_char""27/g" | sed -E 's/\(/'"$escape_char"'28/g' | sed -E 's/\)/'"$escape_char"'29/g' | sed -E 's/\*/'"$escape_char"'2A/g' | sed -E 's/\+/'"$escape_char"'2B/g' | sed -E 's/,/'"$escape_char"'2C/g' | sed -E 's/:/'"$escape_char"'3A/g' | sed -E 's/;/'"$escape_char"'3B/g' | sed -E 's/=/'"$escape_char"'3D/g' | sed -E 's/\?/'"$escape_char"'3F/g' | sed -E 's/@/'"$escape_char"'40/g' | sed -E 's/\[/'"$escape_char"'5B/g' | sed -E 's/\]/'"$escape_char"'5D/g')
#  | sed -E 's/\//%2F/g'
#  | sed -E 's/\n/%0A/g'
}

escape_encode() {
    echo $(root_encode '\\x' "$@")
#     echo -e $(echo "$@" | sed -E "s/ /\\\\x20/g" | sed -E "s/
# /\\\\x0A/g")
}

underscore_encode() {
    echo -e $(echo "$@" | sed -E "s/ /_/g")
}
#########################endregion ENCODE METHODS#########################

#########################region GET OPTIONS#########################
encode_method=$DEFAULT_ENCODE_METHOD
decoded=()
# preserve_newline=$FALSE
not_assigned=$TRUE
while [ "$1" != "" ]; do
    case "$1" in
        -h | --help )
            show_help
            exit
            ;;
        -v | --version )
            show_version
            exit
            ;;
        # #region Flags
		-u | --url )
		    encode_method=$ENCODE_METHOD_URL
		    ;;
		-e | --escape )
		    encode_method=$ENCODE_METHOD_ESCAPE
		    ;;
		-_ | --underscore )
		    encode_method=$ENCODE_METHOD_UNDERSCORE
		    ;;
		# #endregion Flags
        * )
			# if [[ "$encode_method" == "" && $1 =~ ^--(.*)$ ]]; then
			# 	encode_method=${BASH_REMATCH[1]}
			# elif [ "$decoded" = "" ]; then
			if $($not_assigned); then
				not_assigned="$FALSE"
            # else
            #     show_help
            #     exit 1
            fi
            decoded+=("$1")
            ;;
    esac
    shift
done
if $($not_assigned); then
    show_help
    exit 1
fi
#########################endregion GET OPTIONS#########################

if [[ "$encode_method" = $ENCODE_METHOD_URL ]]; then
    echo $(url_encode "${decoded[@]}")
elif [[ "$encode_method" = $ENCODE_METHOD_UNDERSCORE ]]; then
    echo $(underscore_encode "${decoded[@]}")
elif [[ "$encode_method" = $ENCODE_METHOD_ESCAPE ]]; then
    echo $(escape_encode "${decoded[@]}")
else
    echo $decoded
	exit $ERROR_BAD_METHOD
fi
exit # $?