nyancat

#!/usr/bin/env bash

## source: https://copypastatext.com/nyan-cat-ascii/
nyancat="\
 \e[1;31m_________________________________________▄▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▄\e[0m\n\
 \e[1;31m________________________________________█░░▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒░░░█\e[0m\n\
 \e[1;33m________________________________________█░▒▒▒▒▒▒▒▒▒▒▄▀▀▄▒▒▒░░█▄▀▀▄\e[0m\n\
 \e[1;33m___________________________________▄▄___█░▒▒▒▒▒▒▒▒▒▒█▓▓▓▀▄▄▄▄▀▓▓▓█\e[0m\n\
 \e[1;32m_________________________________█▓▓█▄▄█░▒▒▒▒▒▒▒▒▒▄▀▓▓▓▓▓▓▓▓▓▓▓▓▀▄\e[0m\n\
 \e[1;32m__________________________________▀▄▄▓▓█░▒▒▒▒▒▒▒▒▒█▓▓▓▄█▓▓▓▄▓▄█▓▓█\e[0m\n\
 \e[1;36m______________________________________▀▀█░▒▒▒▒▒▒▒▒▒█▓▒▒▓▄▓▓▄▓▓▄▓▒▒█\e[0m\n\
 \e[1;36m_______________________________________▄█░░▒▒▒▒▒▒▒▒▒▀▄▓▓▀▀▀▀▀▀▀▓▄▀\e[0m\n\
 \e[1;35m_____________________________________▄▀▓▀█▄▄▄▄▄▄▄▄▄▄▄▄██████▀█▀▀\e[0m\n\
 \e[1;35m_____________________________________█▄▄▀_█▄▄▀_______█▄▄▀_▀▄▄█\e[0m\n\
"

help="\n
\e[1musage:\e[0m\tnyancat [?opts] [file] [?line]\n\n

\e[1mdescription:\e[0m\n
\tPretty print source code files in the command line.\n\n

\e[1mdependencies:\e[0m\n
\tPygments:\t\e[1;35mpip install Pygments\e[0m\n\n

\e[1mopts\e[0m:
\t-s= (--style=)\t\tThe syntax highlighting style (native)\n
\t-a (--available-styles)\tList available styles\n
\t-l (--lines)\t\tInclude line numbers in output\n
\t-x (--example)\t\tExample code with style\n
\t-v (--version)\t\tDisplay version of nyancat\n
\t-d (--debug)\t\tPrint the comand unevaluated\n
\t-h (--help)\t\tDisplay this text\n\n

\e[1mexamples:\e[0m\n
\t\e[32m#Print a whole file with syntax highlighting\e[0m\n
\tnyancat file.c
\n\n
\t\e[32m#Print a specific line of a file with syntax highlighting\e[0m\n
\tnyancat file.c 12
\n\n
\t\e[32m#Set the style of the output\e[0m\n
\tnyancat -s=nord file.c 12\n\n


\e[1;36mPowered by Pygments\e[0m"

shorthelp="usage:\tnyancat [?opts] [file] [?line]\n
\tnyancat -h for help
"

version="0.1.0"
# By default show shorthelp
cmd="echo -e $shorthelp"
# Default style is native use nyancat -a to list all available styles
style="native"
# Target file
file=""
# Target line
line=""
# Debug mode
debug=0
# Show example with style
example=0
# Show line numbers?
lines=0
# Pretty Print Command
pp_cmd="pygmentize -g -O style=[style] [file]"
# Pretty Print Command with lines
pp_line_cmd='pygmentize -g -O style=[style],linenos=1 [file]'
# Pretty Print Command with lines at line
pp_at_line_cmd='pygmentize -g -O style=[style],linenos=1 [file] | sed -n [line]p'
# Print help if 1

# Styles available in the latest Pygments
# Pygments version 2.13.0, (c) 2006-2022 by Georg Brandl, Matthäus Chajdas and contributors.
# This should be cleaned up to use the users version of pigments
available_styles='default \nemacs \nfriendly \nfriendly_grayscale \ncolorful \nautumn \nmurphy \nmanni \nmaterial \nmonokai \nperldoc \npastie \nborland \ntrac \nnative \nfruity \nbw \nvim \nvs \ntango \nrrt \nxcode \nigor \nparaiso-light \nparaiso-dark \nlovelace \nalgol \nalgol_nu \narduino \nrainbow_dash \nabap \nsolarized-dark \nsolarized-light \nsas \nstaroffice \nstata \nstata-light \nstata-dark \ninkpot \nzenburn \ngruvbox-dark \ngruvbox-light \ndracula \none-dark \nlilypond \nnord \nnord-darker \ngithub-dark'

for i in "$@"
do
case $i in
    -v|--version) # print version and exit
        echo -e "nyancat_v"$version
        exit 0
        ;;
    -h|--help) # print title nyancat help and exit
        echo -e " \e[1mnyancat:\e[0m cat + syntax highlighting\n"$nyancat$help
        exit 0
        ;;
    -d|--debug) # enable debug mode
        debug=1
        ;;
    -l|--lines) # print lines
        lines=1
        ;;
    -x|--example) # display example code rather than file
        example=1
        ;;
    -s=*|--style=*) # select style, default native
        style="${i#*=}"
        ;;
    -a|--available-styles) # list available styles in Pygments 2.13
        echo -e $available_styles
        exit 0
        ;;
    *) # Check for file and line
        if [ "$file" = "" ]
        then
            file=$i
            if [ ! -f $file ]
            then
                echo -e "\e[1;31mError! \e[4;31m$file\e[0m\e[1;31m is not a file.\e[0m"
                exit 1
            fi
        elif [ "$line" = "" ]
        then
            line=$i
        else # if there are more than two additional args exit on error
            echo -e "ERROR: unrecognized arg $i\n"
            echo -e $help
            exit 1
        fi
        ;;
esac
done

# Sample C text, used for example
# In future expand this to other languages
c_example_text="// nyancat c example for style=[style]\n\
// [cmd]\n\n\
#include <stdio.h>\n\
\n\
int main (void) {\n\
\tprintf(\"Hello World!\");\n\
\treturn 0;\n\
}"

# Generate the cmd for printing a whole file
print_file (){
    # test if it is a file
    cmd_tmp=$pp_cmd
    if [ $lines -eq 1 ]
    then
        cmd_tmp=$pp_line_cmd
    fi
    cmd=$(echo -e \
               $cmd_tmp | \
              sed "s;\\[style\\];$style;g" | \
              sed "s;\\[file\\];$file;g")
}

# Generate the cmd for printing a specific line
# Specific lines are always printed wiht line numbers
print_line (){
    cmd=$(echo -e \
               $pp_at_line_cmd | \
              sed "s;\\[style\\];$style;g" | \
              sed "s;\\[file\\];$file;g" | \
              sed "s;\\[line\\];$line;g")
}

# Print an example
print_example (){
    # we could pull this logic out as its also present in print_file
    cmd_tmp=$pp_cmd
    if [ $lines -eq 1 ]
    then
        cmd_tmp=$pp_line_cmd
    fi

    file="\\/tmp\\/nyancat.c"
    if [ $debug -eq 1 ]
    then
        echo "Printing example: $pp_cmd"
    fi
    first=$(echo $cmd_tmp | sed s/\\[style\\]/$style/g)
    if [ $debug -eq 1 ]
    then
        echo "First substitution: $first"
    fi
    second=$(echo $first | sed s/\\[file\\]/$file/g)
    if [ $debug -eq 1 ]
    then echo "Second substitution: $second"
    fi
    cmd=$second
    echo -e $c_example_text | sed s/\\[style\\]/$style/g | sed -e "s;\\[cmd\\];$cmd;g" > /tmp/nyancat.c
}

nofile=0

if [ $example -eq 1 ]; then # the -x arg is passed in always print example
    print_example
elif [ "$file" = "" ]; then # no file arg we should print help
    nofile=1
    # no file or 
elif [ "$line" = "" ]; then # file is present but not line print whole file
    print_file
else  # file and line are present print single line of file
    print_line 
fi

if [ $debug -eq 1 ]
then
    echo -e "$cmd" # in debug mode print the command
elif [ $nofile -eq 1 ]
then
    $cmd # no file or examlpe, print help
else
    eval $cmd # eval cmd in all other cases
fi