From 37d1745041e73be7fb0e5b8ec3d4bd6bed41f04a Mon Sep 17 00:00:00 2001
From: Antonio De Lucreziis <antonio.delucreziis@gmail.com>
Date: Thu, 16 Feb 2023 02:06:30 +0100
Subject: [PATCH] initial commit

---
 .gitignore   | 11 +++++++
 README.md    |  5 +++
 pdf-compress | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 108 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 README.md
 create mode 100755 pdf-compress

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..f3bcfa3
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,11 @@
+.env
+*.local*
+
+node_modules/
+
+bin/
+.out/
+out/
+dist/
+
+.vscode/
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..94315e3
--- /dev/null
+++ b/README.md
@@ -0,0 +1,5 @@
+# Scripts written with the help of ChatGPT
+
+- [`pdf-compress`](./pdf-compress)
+
+	A utility that uses convert to render each page of a PDF to a JPEG image and then merges them back into a single document.
\ No newline at end of file
diff --git a/pdf-compress b/pdf-compress
new file mode 100755
index 0000000..d63e5f7
--- /dev/null
+++ b/pdf-compress
@@ -0,0 +1,92 @@
+#!/bin/bash
+
+set -euo pipefail
+
+function show_usage {
+	cat <<-END
+	usage: $0 [OPTIONS...] input_file output_file
+
+	Converts a PDF file to a series of JPEG images using convert to
+	reduce the quality and then merges back the result in a single pdf 
+
+	options:
+		-q, --quality    Set the JPEG quality (default: 75)
+		-v, --verbose    Enable verbose output
+		-h, --help       Display this help message
+END
+	exit 1
+}
+
+quality=75
+verbose=false
+
+while [[ $# -gt 0 ]]
+do
+	key="$1"
+
+	case $key in
+		-q|--quality)
+			quality="$2"
+			shift # past argument
+			shift # past value
+			;;
+		-v|--verbose)
+			verbose=true
+			shift # past argument
+			;;
+		-h|--help)
+			show_usage
+			;;
+		-*)
+			echo "Unknown option: $key"
+			show_usage
+			;;
+		*)
+			break
+			;;
+	esac
+done
+
+if [ -z "$1" ] || [ -z "$2" ]; then
+	show_usage
+fi
+
+input_file="$1"
+output_file="$2"
+
+temp_pages_dir="$(mktemp -d)"
+
+function logf {
+	if [ "$verbose" = true ]; then
+		printf "$@"
+	fi
+}
+
+logf "Converting \"$input_file\" to \"$output_file\"\n"
+
+page_count=$(pdfinfo "$input_file" | grep Pages | awk '{print $2}')
+
+logf "Processing $page_count pages\n"
+
+start=$(date +%s.%N)
+for i in $(seq 0 $((page_count-1))); do
+	iter_start=$(date +%s.%N)
+
+	convert -density 300 -quality "$quality" "${input_file}[$i]" "$temp_pages_dir/$i.jpg"
+
+	# Compute estimated remaining time
+  end=$(date +%s.%N)
+  elapsed=$(echo "$end - $start" | bc)
+  iter_elapsed=$(echo "$end - $iter_start" | bc)
+  remaining=$(echo "($elapsed / ($i + 1)) * ($page_count - $i)" | bc)
+  remaining_fmt=$(printf "%02d:%02d:%02d" $((remaining/3600)) $((remaining/60)) $((remaining%60)))
+
+	logf "Compressed page $((i+1)) in $(printf '%.2f' "$iter_elapsed")s (estimated remaining time $remaining_fmt)\n"
+done
+
+logf "Merging compressed pages to a single PDF\n"
+convert "$temp_pages_dir"/*.jpg "$output_file"
+
+rm -r "$temp_pages_dir"
+
+logf "Done\n"