snotes

#!/usr/bin/env bash
#cito M:755 O:0 G:0 T:/usr/local/bin/snotes
#------------------------------------------------------------------------------
# Project Name      - ShellProjects/source/snotes
# Started On        - Fri  9 Feb 00:07:19 GMT 2018
# Last Change       - Sat  1 Jul 23:08:55 BST 2023
# Author E-Mail     - terminalforlife@yahoo.com
# Author GitHub     - https://github.com/terminalforlife
#------------------------------------------------------------------------------
# View and filter notes. Snotes is intended for programmers, but can absolutely
# be used outside of that realm.
#
# Features:
#
#TODO: Find a way to incorporate a multi-character comment string.
#
# Bugs:
#
# N/A
#
# Dependencies:
#
#   bash (>= 4.1)
#   coreutils (>= 8.28)
#------------------------------------------------------------------------------

CurVer='2023-07-01'
Progrm='snotes'

Usage() {
	read -d '' <<-EOF
		Usage: $Progrm [OPTS] [STRING]

		  -h, --help               - Displays this help information.
		  -v, --version            - Output only the version datestamp.
		  -C, --no-color           - Disable ANSI color escape sequences.
		  -c, --comment CHAR       - Use CHAR as the single comment character.
		  -f, --file PATH          - Specify & remember the notes file to use.
		  -n, --line-number        - Print line numbers in grep(1) style.
		  -r, --random             - Display random note from results.

		  The location of the file read by ${Progrm^} is saved here:

		    ${SnotesFile/$HOME/\~}

		  Comment lines are ignored. To tell $Progrm when you wish to stop
		  searching for STRING, add a line in the file containing only:

		    ${Comment}END

		  The default comment character is '$Comment'.

		  The use of '--' to ignore proceeding flags is supported. The use of
		  '-' to read from STDIN, instead of the assigned file, is also
		  supported.
	EOF

	printf '%s' "$REPLY"
}

Err() {
	printf 'Err: %s\n' "$2" 1>&2
	(( $1 > 0 )) && exit $1
}

BRed=$'\e[91m'
Green=$'\e[32m'
Cyan=$'\e[36m'
Reset=$'\e[0m'

Random=
NoColors=
ReadSTDIN=
Comment='#'
LineNumber=
SnotesFile="$HOME/.config/$Progrm.conf"

Skip=
Args=()
while [[ -n $1 ]]; do
	case $1 in
		--)
			Args+=(--)
			Skip='True' ;;
		-[^-]*)
			if [[ $Skip == True ]]; then
				Args+=("$1")
			else
				Str=${1#-}
				Len=${#Str}
				for (( Index = 0; Index < Len; Index++ )); {
					Args+=(-"${Str:Index:1}")
				}
			fi ;;
		*)
			Args+=("$1") ;;
	esac
	shift
done

set -- "${Args[@]}"

while [[ -n $1 ]]; do
	case $1 in
		--)
			shift
			break ;;
		-)
			ReadSTDIN='True' ;;
		--help|-h)
			Usage; exit 0 ;;
		--version|-v)
			printf '%s\n' "$CurVer"; exit 0 ;;
		-C|--no-color|--no-colour)
			NoColors='True' ;;
		--comment|-c)
			ArgComment=$1
			if [[ -z $2 ]]; then
				Err 1 "Option '$ArgComment' requires an argument."
			elif (( ${#2} > 1 )); then
				Err 1 "Option '$ArgComment' only supports a single character."
			else
				Comment=$2
				shift
			fi ;;
		--file|-f)
			ArgFile=$1
			if [[ -z $2 ]]; then
				Err 1 "Option '$ArgFile' requires an argument."
			else
				NotesFile=$2
				shift
			fi ;;
		--line-number|-n)
			LineNumber='True' ;;
		--random|-r)
			Random='True' ;;
		-*)
			Err 1 'Incorrect option(s) specified.' ;;
		*)
			break ;;
	esac
	shift
done

if ! type -P mkdir &> /dev/null; then
	Err 1 "Dependency 'mkdir' not met."
fi

(( $# > 1 )) && Err 1 'Multiple matches not supported.'

#---------------------------------------------Process or Create the Snotes File

if [[ -n $NotesFile ]]; then
	ConfigDir=${SnotesFile%/*}
	[[ -d $ConfigDir ]] || mkdir -p "$ConfigDir"
	printf '%s\n' "$NotesFile" > "$SnotesFile"

	printf 'NOTE: New location saved.\n'
	exit 0
fi

if [[ $ReadSTDIN == True ]]; then
	NotesFile='/dev/stdin'
else
	[[ -r $SnotesFile ]] || Err 1 "File '$SnotesFile' unreadable."
	NotesFile=$(< "$SnotesFile")

	if ! [[ -f $NotesFile ]]; then
		Err 1 'Notes file not found.'
	elif ! [[ -r $NotesFile ]]; then
		Err 1 'Notes file unreadable.'
	fi
fi

#----------------------------------------------------------------Main Functions

# Usage: PrintLine LINE_NUMBER LINE_DATA
PrintLine() {
	if [[ $LineNumber == True ]]; then
		local NumberOut="$Green$1$Reset$Cyan:$Reset"
	fi

	printf '%s%s\n' "$NumberOut" "$2"
}

#--------------------------------------------------------Parse and Display Data

# For use when grabbing random note.
Lines=()

# Also allow removing colors when non-interactive (e.g., pipe).
if [[ $NoColors == True || ! -t 1 ]]; then
	BRed=
	Green=
	Cyan=
	Reset=
fi

Match=$1
MatchLen=${#Match}

LineNr=0
while read -r; do
	(( LineNr++ ))

	# Avoid unnecessary processing, and stop at '#END' line.
	if [[ $REPLY == "${Comment}END" ]]; then
		break
	elif [[ ${REPLY:0:1} == "$Comment" ]]; then
		continue
	elif [[ -z $REPLY || $REPLY == +([[:space:]]) ]]; then
		continue
	fi

	if [[ $Random == True ]]; then
		[[ $REPLY == *"$Match"* ]] || continue

		Lines+=("$LineNr|$REPLY")

		continue
	fi

	if (( $# == 0 )); then
		PrintLine $LineNr "$REPLY"
	else
		if [[ $REPLY == *"$Match"* ]]; then
			PrintLine $LineNr "${REPLY//"$Match"/$BRed$Match$Reset}"
		fi
	fi
done < "$NotesFile"

if [[ $Random == True ]]; then
	Chosen=${Lines[RANDOM % ${#Lines[@]}]}
	LineNr=${Chosen%%|*}
	Line=${Chosen#*|}

	PrintLine $LineNr "$Line"
fi