#!/bin/bash

die() {
    echo "$1" >&2
    exit 1
}

IMG_DEPTH=8
NUM_PAGES=$(find /dangerzone/page-*.rgb |wc -l)

echo "Document has $NUM_PAGES pages"
echo

# Convert rgb files to png files
for RGB_FILENAME in $(find /dangerzone/page-*.rgb); do
    FILENAME_BASE=${RGB_FILENAME%.rgb}
    PAGE=$(basename $FILENAME_BASE |cut -d"-" -f2)

    WIDTH_FILENAME=${FILENAME_BASE}.width
    HEIGHT_FILENAME=${FILENAME_BASE}.height
    PNG_FILENAME=/tmp/$(basename $FILENAME_BASE).png
    PDF_FILENAME=/tmp/$(basename $FILENAME_BASE).pdf

    echo "Converting page $PAGE from pixels to PNG"
    
    IMG_WIDTH=$(cat $WIDTH_FILENAME)
    IMG_HEIGHT=$(cat $HEIGHT_FILENAME)

    CONVERT_MSGS=$(convert -size "${IMG_WIDTH}x${IMG_HEIGHT}" -depth ${IMG_DEPTH} rgb:"$RGB_FILENAME" png:"$PNG_FILENAME" 2>&1)
    if [ $? -ne 0 ]; then
        die "Page $PAGE conversion failed: $CONVERT_MSGS"
    fi

    echo "Converting page $PAGE from PNG to PDF"
    CONVERT_MSGS=$(convert "$PNG_FILENAME" "$PDF_FILENAME" 2>&1)
    if [ $? -ne 0 ]; then
        die "Page $PAGE conversion failed: $CONVERT_MSGS"
    fi
done

echo "Merging $NUM_PAGES pages into a single PDF"

# Put PDF filenames into an array
declare -a args
for PAGE in $(seq 1 $NUM_PAGES); do
    args+=("/tmp/page-$PAGE.pdf")
done
args+=("/safezone/safe-output.pdf")

# Merge them
pdfunite "${args[@]}"

# Compress
echo "Compressing PDF"
ps2pdf /safezone/safe-output.pdf /safezone/safe-output-compressed.pdf