#!/bin/bash

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

# Detect the mime type
MIME_TYPE=$(file -b --mime-type /tmp/input_file)
echo "Documet MIME type is $MIME_TYPE"
echo

# .pdf
if [ $MIME_TYPE = "application/pdf" ]; then
    ORIGINAL_PDF=/tmp/input_file
# .docx
elif [ $MIME_TYPE = "application/vnd.openxmlformats-officedocument.wordprocessingml.document" ]; then
    echo "Converting DOCX to PDF"
    CONVERT_MSGS=$(libreoffice --headless --convert-to pdf:writer_pdf_Export --outdir /tmp /tmp/input_file 2>&1)
    if [ $? -ne 0 ]; then
        die "Page $PAGE conversion failed: $CONVERT_MSGS"
    fi
    ORIGINAL_PDF=/tmp/input_file.pdf
# .xlsx
elif [ $MIME_TYPE = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" ]; then
    echo "Converting XLSX to PDF"
    CONVERT_MSGS=$(libreoffice --headless --convert-to pdf:calc_pdf_Export --outdir /tmp /tmp/input_file 2>&1)
    if [ $? -ne 0 ]; then
        die "Page $PAGE conversion failed: $CONVERT_MSGS"
    fi
    ORIGINAL_PDF=/tmp/input_file.pdf
else
    die "The document format is not supported"
fi

echo "Separating document into pages"
CONVERT_MSGS=$(pdfseparate $ORIGINAL_PDF /tmp/page-%d.pdf 2>&1)
if [ $? -ne 0 ]; then
    die "Separating document into pages failed: $CONVERT_MSGS"
fi

IMG_DEPTH=8
NUM_PAGES=$(find /tmp/page-*.pdf |wc -l)
echo "Document has $NUM_PAGES pages"
echo

for PAGE in $(seq 1 $NUM_PAGES); do
    FILENAME=/tmp/page-$PAGE.pdf
    FILENAME_BASE=/tmp/page-$PAGE

    echo "Converting page $PAGE to pixels"

    # Convert to png
    pdftocairo "$FILENAME" -png -singlefile "$FILENAME_BASE"
    
    # Get the width and height
    IMG_WIDTH=$(identify -format "%w" "$FILENAME_BASE.png")
    IMG_HEIGHT=$(identify -format "%h" "$FILENAME_BASE.png")
    echo $IMG_WIDTH > $FILENAME_BASE.width
    echo $IMG_HEIGHT > $FILENAME_BASE.height
    
    # Convert to rgb
    convert "$FILENAME_BASE.png" -depth $IMG_DEPTH rgb:"$FILENAME_BASE.rgb"

    # Delete the png
    rm "$FILENAME_BASE.png"

    # Move files needed for the next step to the mounted volume
    mv "$FILENAME_BASE.rgb" /dangerzone
    mv "$FILENAME_BASE.width" /dangerzone
    mv "$FILENAME_BASE.height" /dangerzone
done