#!/bin/bash

# 1. Check if both arguments were provided
if [ -z "$1" ]; then
    echo "Error: Source folder not specified."
    echo "Usage: $0 <source_folder> <output_folder>"
    exit 1
fi

if [ -z "$2" ]; then
    echo "Error: Output folder not specified."
    echo "Usage: $0 <source_folder> <output_folder>"
    exit 1
fi

# 2. Assign arguments to variables and resolve absolute paths
TARGET_DIR=$(cd "$1" 2>/dev/null && pwd)

# 3. Check if the input directory actually exists
if [ -z "$TARGET_DIR" ]; then
    echo "Error: Source directory '$1' does not exist."
    exit 1
fi

# Set the final output path explicitly *before* creating or checking it
OUTPUT_DIR="$2/pdfa"

# 4. Create the output directory if it doesn't exist
# This is the crucial fix for Ghostscript!
if [ ! -d "$OUTPUT_DIR" ]; then
    echo "Creating output directory: $OUTPUT_DIR"
    mkdir -p "$OUTPUT_DIR"
fi

echo "Processing PDFs in: $TARGET_DIR"
echo "Saving outputs to:   $OUTPUT_DIR"
echo "----------------------------------------"

# 5. Loop through all PDF files (case-insensitive)
shopt -s nullglob nocaseglob
for pdf in "$TARGET_DIR"/*.pdf; do
    filename=$(basename "$pdf")
    echo "Processing: $filename..."

    # Run Ghostscript
    gs -sDEVICE=pdfwrite \
       -dCompatibilityLevel=1.4 \
       -dPDFSETTINGS=/ebook \
       -dNOPAUSE \
       -dQUIET \
       -dBATCH \
       -sOutputFile="$OUTPUT_DIR/$filename_converted" "$pdf"
       
done
shopt -u nullglob nocaseglob

echo "----------------------------------------"
echo "Done! Converted files are in: $OUTPUT_DIR"