#!/bin/bash

function usage {
echo ' High Beam Highlighter 
- a trial to create a very generic modifyable 
syntax highlighter.

Example rules: ( ~/.highbeamrc )
--------------------
RULES=( 
    "[0-9]"      "$C" # Show numbers with Cyan color. NOTE: since the colors are represented with numbers, having this later in the rules will break coloring!
    "$USER[ ]\+$USER"  "$BGC$BLACK" # Use quotes to have rules with spaces. This colors the "ls -la" usernames. background cyan, black text
    status       "$G" # simple word matching, coloring green
    "^d[^ ]*"    "$H$G" # color words at the beginning of line, starting with d.  color bright green
    "q.\{0,3\}r" "$H$Y" # q*r with maximum 3 characters in between. color bright yellow
)
--------------------
Color variables:  $R $G $B $Y $M $C $W $BLACK
Modify to bright version by prefixing with $H  (e.g. $H$G)
Background colors: $BGR $BGG $BGB $BGY $BGC $BGM $BGW 

Usage:   highbeam [-h] [-f config]
   -h    Help
   -f    Define config file (default ~/.highbeamrc)
'

}

[[ "$1" = "-h" ]] && usage && exit

E='\x1b['
H="${E}1m"
Z="${E}0m"

# list of text colors:
BLACK="${E}30m"
R="${E}31m"
G="${E}32m"
B="${E}34m"
Y="${E}33m"
M="${E}35m"
C="${E}36m"
W="${E}37m"


# list of BG colors:
BGR="${E}41m"
BGG="${E}42m"
BGB="${E}44m"
BGY="${E}43m"
BGM="${E}45m"
BGC="${E}46m"
BGW="${E}47m"

CONF_FILE=~/.highbeamrc
[[ "$1" = "-f" ]] && CONF_FILE=$2

# user rules:
[[ -e "${CONF_FILE}" ]] && . "${CONF_FILE}" || echo You may have wrong construction in "${CONF_FILE}" >&2 || exit
[[ -e "${CONF_FILE}" ]] || {
# list of rules
RULES=( 
    "[0-9]"      "$C" # Show numbers with Cyan color. NOTE: since the colors are represented with numbers, having this later in the rules will break coloring!
    "$USER[ ]\+$USER"        "$BGC$BLACK" # Use quotes to have rules with spaces. background cyan, black text
    status       "$G" # simple word matching, coloring green
    "^d[^ ]*"    "$H$G" # color words at the beginning of line, starting with d.  color bright green
    "q.\{0,3\}r" "$H$Y" # q*r with maximum 3 characters in between. color bright yellow
)
}
# actual code starts here

for (( r=0; r<${#RULES[@]}; r++ ));
do REGEX="$REGEX -e 's/\(${RULES[$r]}\)/${RULES[$(( $r + 1 ))]}\1${Z}/ig'"
   r=$(( $r + 1 ))
done
eval sed $REGEX || echo Maybe error in .highbeamrc >&2