#!/bin/bash

print_help(){
    echo "Create an ASCII barchart with key-value pair from a TSV file."
    echo "Usage $0 <FILE> [KEY_COL_NUM] [VALUE_COL_NUM]"
}

# print help if requested or check if <FILE> exists
if [[ "$1" == "-h" ]]; then
    print_help
else
    [[ ! -f "$1" ]] && echo "$1 is not a valid file!" && exit
    tsv_file="$1"
fi

# get KEY_COL_NUM and VALUE_COL_NUM
num_re='([0-9]+)'
[[ "$2" =~ $num_re ]]
[[ "$2" == "${BASH_REMATCH[1]}" ]] && [[ "$2" != "" ]] && KEY_COL_NUM="$2" || KEY_COL_NUM="1"
[[ "$3" =~ $num_re ]]
[[ "$3" == "${BASH_REMATCH[1]}" ]] && [[ "$2" != "" ]] && VALUE_COL_NUM="$2" || VALUE_COL_NUM="2"

# get MAX_KEY_LENGTH and MAX_VALUE
MAX_KEY_LENGTH=1
MAX_VALUE=0
while read line; do
    key=$(echo "$line" | cut -f "$KEY_COL_NUM" )
    value=$(echo "$line" | cut -f "$VALUE_COL_NUM" )
    [ $MAX_KEY_LENGTH -lt "${#key}" ] && MAX_KEY_LENGTH="${#key}"
    [ $MAX_VALUE -lt "$value" ] && MAX_VALUE="$value"
done < $tsv_file

# print the barchart
bar="█"
MAX_BARS=60
while read line; do
    key=$(echo "$line" | cut -f "$KEY_COL_NUM" )
    value=$(echo "$line" | cut -f "$VALUE_COL_NUM" )
    barvalue=$(( value*MAX_BARS/MAX_VALUE ))
    printf "%-${MAX_KEY_LENGTH}s " "$key"
    for (( i=1;i<=$barvalue;i++ )); do
        printf "%s" "$bar"
    done
    printf " %d\n" "$value"
done < $tsv_file