#!/usr/bin/env bash

# 26.03.04 :: klevstul


resize() {

    test_integer() {
        if ! [[ $1 =~ ^[1-9][0-9]*$ ]]; then
            echo "error: variable (image width) must be an integer"
            exit 1
        fi
    }

    filename=$1                                     # ~/syncDir/0_downloads/frodeKlevstul.jpg
    extension="${filename##*.}"                     # jpg
    basename_without_ext="${filename%.*}"           # ~/syncDir/0_downloads/frodeKlevstul
    basename_only="${basename_without_ext##*/}"     # frodeKlevstul

    width=$2
    width=${width:=1000}                            # default: 1000
    test_integer ${width}                 # make sure the input (if given from the user) is valid

    # scale=1000:-1:    resizes the image to a width of 1000 pixels, automatically calculating the height to preserve the original aspect ratio.
    # -q:v 90:          sets the jpeg quality to 90 (lower values mean higher quality; 90 is a high quality setting for jpeg).

    ffmpeg -i ${filename} -vf "scale=${width}:-1" -q:v 90 ${basename_without_ext}_rzd.jpg

}


this_file_name=`basename "$0"`
if [ $# -lt 1 ]; then
    echo "error: path to file is missing."
    echo "usage: '$this_file_name [path_to_file] ([width (1000)])'"
    exit 1
fi

resize $1 $2