wkt2bbox

#!/usr/bin/env bash
PROGRAM_NAME=$(basename "$0")
# shellcheck disable=SC2124
WKT_STRING="${@}"
WKT_STRING="${WKT_STRING:--}"

function usage {
    echo "Converts POLYGON and BOX WKT objects to a bounding box string. WKT POLYGON object is required to be rectangular"
    echo ""
    echo "usage: $PROGRAM_NAME <wkt_string|-(wkt_string on stdin)>"
    echo "  arguments:"
    echo "  - <wkt_string>: POLYGON or BOX WKT string describing bounding box (arg or stdin)"
    exit 1
}

if [ "$#" -lt 1 ]; then
    usage
fi

set -euo pipefail

function process_wktstring() {
    local input_string
    input_string="$1"

    if [[ "${input_string,,}" == *polygon* ]]; then
        echo "$input_string" | perl -pe 's/POLYGON\s?\(\((-?\d+\.?\d*)\s(-?\d+\.?\d*),\s?-?\d+\.?\d*\s-?\d+\.?\d*,\s?(-?\d+\.?\d*)\s(-?\d+\.?\d*),.*$/$1,$2,$3,$4/i'
    else
        echo "$input_string" | perl -pe 's/BOX\((-?\d+\.?\d*)\s(-?\d+\.?\d*),\s?(-?\d+\.?\d*)\s(-?\d+\.?\d*)\).*$/$1,$2,$3,$4/i'
    fi
}

if [[ $WKT_STRING == "-" ]]; then
    if [ -t 0 ]; then
        # if do not allow interactive tty
        usage
    fi
    while read -r line; do
        process_wktstring "$line"
    done <"/dev/stdin"
else
    process_wktstring "$WKT_STRING"
fi