#!/bin/bash
#
# zip_images_resize Resizing large JPGs in ZIPs
# Based on: https://shkspr.mobi/blog/2016/12/converting-rar-to-zip-in-linux/
#
# Usage: xxx.sh file [file ...]

if [ $# -eq 0 ]; then
    echo "Usage: $0 file.zip [file2.zip ...]"
    exit 1
fi

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

echo "Resizing large JPGs in ZIPs"

# Use RAM disk for temporary files.
WORKDIR="/dev/shm/"

# Cleanup function
cleanup_temp() {
    if [ -n "$TEMPDIR" ] && [ -d "$TEMPDIR" ]; then
        rm -r "$TEMPDIR"
    fi
}

# Count total files
TOTAL_FILES=$#
CURRENT_FILE=0

for INFILE in "$@"; do
    CURRENT_FILE=$((CURRENT_FILE + 1))

    # Convert to absolute path
    INFILE="$(realpath "$INFILE")"
    echo "Processing file $CURRENT_FILE of $TOTAL_FILES: $INFILE"

    OUTFILE="$(realpath "${INFILE%.zip}-compress.zip")"

    # Remove output file if it already exists
    if [ -e "${OUTFILE}" ]; then
        rm "${OUTFILE}"
    fi

    # Set name for the temp dir. This directory will be created under WORKDIR
    TEMPDIR=$(mktemp -p "$WORKDIR" -d)

    # Set up cleanup trap
    trap cleanup_temp EXIT INT TERM

    # Create a temporary folder for unzipped files
    echo "Extracting $INFILE"

    # extract files from zip
    if ! unzip "$INFILE" -d "$TEMPDIR"; then
        echo "Error: Failed to extract $INFILE"
        cleanup_temp
        continue
    fi

    # resize
    #convert '${TEMPDIR}/*.jpg' -set filename:fn '%[basename]' -resize 2800000@@\> -sampling-factor 4:2:0 -strip -quality 85% -colorspace RGB '%[filename:fn].jpg'

    if ! pushd "$TEMPDIR" > /dev/null; then
        echo "Error: Failed to change to temp directory"
        cleanup_temp
        continue
    fi
    "$SCRIPT_DIR/images_resize.sh"
    popd > /dev/null

    # Zip the files with no compression
    pushd "$TEMPDIR" > /dev/null
    if ! 7z a -tzip -mx=0 "$OUTFILE" ./*; then
        echo "Error: Failed to create ZIP"
        popd > /dev/null
        cleanup_temp
        continue
    fi
    popd > /dev/null

    # Alternative. MUCH SLOWER, but better compression
    # 7z a -mm=Deflate -mfb=258 -mpass=15 -r "$NEWNAME" *

    # Preserve file modification time
    touch -r "$INFILE" "$OUTFILE"

    # Check that OUTFILE exists and is not empty before deleting INFILE
    if [ ! -s "$OUTFILE" ]; then
        echo "Error: Output file is empty or does not exist. Keeping original file."
        cleanup_temp
        continue
    fi

    rm "$INFILE"
    mv "$OUTFILE" "$INFILE"

    # Delete the temporary directory
    cleanup_temp
    trap - EXIT INT TERM

    # OPTIONAL. Safe-remove the old file
    #gio trash "$OLDFILE"

done

echo "Conversion Done"