#! /usr/bin/env dash

# shellcheck source=/dev/null
SHELL_LIBRARY_VERSION="1.1.3" . %SHELL_LIBRARY_PATH


# needed for help() and version
# shellcheck disable=2034
AUTHORS="Soispha";
# shellcheck disable=2034
YEARS="2023";
# shellcheck disable=2034
VERSION="1.0.0";

help() {
cat << EOF
Scan images and turn them into a pdf.

Usage:
    $NAME [--help|--version|--out-dir|--num-pages|--method] --name --device

Options:
    --out-dir | -o
                            Path to place the generated pdf files (default: ./pdf).
    --name | -n
                            Name for the pdf files (e.g. "\$name"_1.pdf).
    --num-pages | -p
                            Number of pages to merge into one pdf (default: 1).
    --device | -d
                            Device used for scanning.
    --method | -m
                            Method to use for scanning (default: ADF).
    --help | -h
                            Display this help and exit.
    --version | -v
                            Display version and copyright information and exit.
EOF
}

scan() {
    number_of_pages="$1";
    device="$2";
    output_directory="$3";
    name="$4";
    method="$5";

    [ -z "$number_of_pages" ] && die "Parameter 'number_of_pages' is not set!"
    [ -z "$device" ] && die "Parameter 'device' is not set!"
    [ -z "$output_directory" ] && die "Parameter 'output_directory' is not set!"
    [ -z "$name" ] && die "Parameter 'name' is not set!"
    [ -z "$method" ] && die "Parameter 'method' is not set!"

    tiff_temp_path="$(mktmp -d)";
    cd "$tiff_temp_path" || die "Bug"

    msg "Started scanning...";
    if [ "$method" = "Flatbed" ]; then
        do_until_success \
            "scanimage --format=tiff --progress --source='$method' --device='$device' --output-file=1.tiff" \
            "warn 'Retrying scan, as we assume a network error!'"
    else
        for i in $(seq "$number_of_pages");do
            do_until_success \
                "scanimage --format=tiff --progress --source='$method' --device='$device' --batch=%d.tif --batch-increment='$number_of_pages' --batch-start='$i'" \
                "warn 'Retrying scan, as we assume a network error!'"


            if [ "$number_of_pages" -ne 1 ];then
                msg "Finished turn, please change side!";
                readp "Press enter to continue" noop
            fi
        done
    fi

    msg "Creating output directory...";
    mkdir "$output_directory";
    cd "$output_directory" || die "Bug"

    counter=0;
    msg "Converting images to pdfs...";
    while read -r scanned_image_a;do
        if [ "$number_of_pages" -ne 1 ];then
            scanned_image_b_set=false;
            if [ -z "$scanned_image_b" ];then
                scanned_image_b="$i"
                scanned_image_b_set=true;
                : $((counter += 1))
            fi

            if [ -n "$scanned_image_a" ] && [ "$scanned_image_b_set" = false ];then
                convert "$scanned_image_b" "$scanned_image_a" -compress jpeg -quality 100 "$name"_"$counter".pdf
            fi
        else
            : $((counter += 1))
            convert "$scanned_image_a" -compress jpeg -quality 100 "$name"_"$counter".pdf
        fi

    done < "$(tmp "fd . '$tiff_temp_path' | sort -n")"
}

for input in "$@"; do
    case "$input" in
        "--help" | "-h")
            help;
            exit 0;
            ;;
        "--version" | "-v")
            version;
            exit 0;
            ;;
    esac
done

number_of_pages="1";
unset device;
output_directory="$(pwd)/pdf";
unset name;
method="ADF";

while [ "$#" -ne 0 ]; do
    case "$1" in
        "--help" | "-h")
            ;;
        "--version" | "-v")
            ;;
        "--out-dir" | "-o")
            shift 1;
            output_directory="$1";
            ;;
        "--name" | "-n")
            shift 1;
            name="$1";
            ;;
        "--num-pages" | "-p")
            shift 1;
            number_of_pages="$1";
            ;;
        "--device" | "-d")
            shift 1;
            device="$1";
            ;;
        "--method" | "-m")
            shift 1;
            method="$1";
            ;;
        *)
            die "Command line arg $1 does not exist. See --help for a list.";
            ;;
    esac
    shift 1;
done
scan "$number_of_pages" "$device" "$output_directory" "$name" "$method";