scan

#!/usr/bin/env bash

set -e
set -o pipefail

# Usage: see below
#
# This is an interactive/noninteractive script for wrapping SANE and
# ImageMagick to interface with my ScanSnap scanner. You can pass a
# variety of different tokens defined in the argument parser below to
# choose a set of options (monochrome/color, letter-size/long-page,
# simplex/duplex), or alternatively you can specify interactive mode
# to let you enter any of those tokens, scan a document with them, and
# let you enter new options or press return to repeat the same. Don't
# forget about the option to open each document after scanning, like I
# forgot about it for several years after implementing.

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

color=""
duplex=""
open=""
interactive=""
long=""

for arg; do
    case "$arg" in
    -) ;;
    gray | g | m | monochrome | bw | b | w | -b | -g | -m) color= ;;
    color | c | rgb | -c) color=yes ;;
    1 | s | simplex | 1sided | ss | -s | -1) duplex= ;;
    duplex | double | 2 | 2sided | ds | -d | -2) duplex=yes ;;
    1page | page | p) long= ;;
    l | long) long=yes ;;
    1b)
        ;;
    1c)
        color=yes
        ;;
    2b)
        duplex=yes
        ;;
    2c)
        color=yes
        duplex=yes
        ;;
    1bl | 1l)
        long=yes
        ;;
    1cl)
        color=yes
        long=yes
        ;;
    2bl | 2l)
        duplex=yes
        long=yes
        ;;
    2cl)
        color=yes
        duplex=yes
        long=yes
        ;;
    open | o | -o) open=yes ;;
    interactive | i | int | -i | -int) interactive=yes ;;
    *) die "unknown argument: $arg" ;;
    esac
done

if [[ -n "$interactive" ]]; then
    last_cmd=
    while read -r cmd; do
        if [[ "$cmd" == q* ]]; then
            exit 0
        fi
        if [[ -n "$cmd" ]]; then
            last_cmd="$cmd"
        fi
        scan $last_cmd || true
    done
    exit 0
fi

scandir="$HOME/files/scans"
timestamp="$(date +%Y%m%d%H%M%S)"
target="${scandir}/${timestamp}.pdf"

if [[ ! -d "$scandir" ]]; then
    die "not a directory: $scandir"
fi

tmpdir="$(mktemp -d)"
trap 'rm -rf $tmpdir' EXIT
cd "$tmpdir"

args=(
    --device="fujitsu:ScanSnap iX500:1377846"
    # Note that if we don't override the batch filename format,
    # documents of 10 or more pages will get out of order due to
    # lexicographic sorting in the shell.
    --batch="out%05d.pnm" --format=pnm --resolution=300
)

if [[ -n "$color" ]]; then
    args=("${args[@]}" --mode=Color)
fi

if [[ -n "$duplex" ]]; then
    args=("${args[@]}" --source="ADF Duplex")
fi

if [[ -n "$long" ]]; then
    # What a mess. It's really unclear why these parameters are all
    # needed but they are. Output to PNG or JPEG also fails, but only
    # in ALD mode. For ALD you need to do PNM. See
    # <https://alioth-lists.debian.net/pipermail/sane-devel/2015-January/032999.html>.
    args=(
        "${args[@]}"
        --ald=yes --buffermode=On
        --page-height=1000mm -y 1000mm
    )
fi

scanimage "${args[@]}"

magick ./*.pnm scan.pdf

# If stdout is redirected to a file, write to it. Otherwise just save
# a file to the standard directory.
if [[ -t 1 ]]; then
    mv scan.pdf "$target"
    if [[ -n "$open" ]]; then
        if command -v open &>/dev/null; then
            open "$target"
        else
            xdg-open "$target" &>/dev/null
        fi
    fi
else
    cat scan.pdf
fi