#!/bin/bash
#################################################################
# Script to resize images from the given directory
# Author: Abhir Joshi <abhir314@gmail.com>
#################################################################

if [ $# -le 0 ]; then
    echo "Usage: resize_images.sh <directory_name>"
    exit 1
fi


echo "Checking if imagemagick tools exist..."

# check if 'identify' and 'convert' executables exist
which identify > /dev/null
if [ `echo $?` == "1" ]; then
    echo "You don't seem to have imagemagick installed.  Can't proceed!"
    exit 1
fi

which convert > /dev/null
if [ `echo $?` == "1" ]; then
    echo "You don't seem to have imagemagick installed.  Can't proceed!"
    exit 1
fi


echo "Successful"


final_width=1024
final_height=768
dir_name="$1"

echo "Resizing images from $dir_name"

for file in "$dir_name"/*.[jJ][pP][gG]; do
    width=`identify -format %w "$file"`
    height=`identify -format %h "$file"`
    if [ $width -gt $height ]; then
        if [ $width -le $final_width ]; then
            echo "$file: size = $width"x"$height, size not exceeding maximum! NOT resizing"
            continue;
        fi
        new_height=`echo "$height*$final_width/$width" | bc`
        file_basename=`basename "$file"`
        file_dirname=`dirname "$file"`
        new_file_name=""$file_dirname"/scaled_$file_basename"
     
        # resize the image
        echo "$file: size = $width"x"$height, resizing to" "$final_width"x"$new_height"
        convert -resize "$finale_width"x"$new_height" "$file" "$new_file_name"
        
        # replace the original file ONLY IF the resizing was successful
        if [ `echo $?` == "0" ]; then
            # replace the original file with the scaled file
            rm -f "$file"
            if [ $? -eq "0" ]; then
                mv "$new_file_name" "$file"
            fi
        else
            echo "Failed to resize image $file"
        fi
    else
        if [ $height -le $final_height ]; then
            echo "$file: size = $width"x"$height, size not exceeding maximum! NOT resizing"
            continue;
        fi
        new_width=`echo "$width*$final_height/$height" | bc`
        file_basename=`basename "$file"`
        file_dirname=`dirname "$file"`
        new_file_name=""$file_dirname"/scaled_$file_basename"
    
        # resize the image
        echo "$file: size = $width"x"$height, resizing to $new_width"x"$final_height"    
        convert -resize "$new_width"x"$final_height" "$file" "$new_file_name"

        # replace the original file ONLY IF the resizing was successful
        if [ `echo $?` == "0" ]; then
            # replace the original file with the scaled file
            rm -f "$file"
            if [ $? -eq "0" ]; then
                mv "$new_file_name" "$file"
            fi
        else
            echo "Failed to resize image $file"
        fi
    fi
done

echo "Done"