#!/usr/bin/env sh
#
# Advanced nsxiv url opening script.
#
# Can open remote urls of individual images, galleries, and local files at the same time.
# Uses gallery-dl for remote gallery opening - so if gallery-dl can open it, so can nsxiv.
#
# Usage: simply add multiple urls/paths as arguments.
# nsxiv-rifle "https://linkto.my/image.png" my/local/relative-path.jpg /home/absolute.gif

cache_dir="$(mktemp -d)"

die() {
    [ -n "$1" ] && printf '%s\n' "$*" >&2
    exit 1
}

cleanup() {
    rm -f -- "$cache_dir"/*
}

from_local() {
    fpath="$(realpath -e "$1")"
    ln -s "$fpath" "$cache_dir"
}

# invokes single image downloading or gallery downloading depending on content type
from_remote() {
    link="$(dereference "$1")"
    if curl -sLI "$link" | grep -i '^Content-Type:' | grep -q image; then
        get_single_image "$link"
    else
        get_gallery "$link"
    fi
}

get_gallery() {
    command -v gallery-dl 1>/dev/null 2>&1 || return
    gallery-dl -q -D "$cache_dir" "$1"
}

get_single_image() {
    pwd="$PWD"
    cd "$cache_dir" && curl -sSLO "$1"
    cd "$pwd" || exit 1
}

# unaliases urls which will not be downloaded correctly otherwise
dereference() {
    # teddit
    if echo "$1" | grep -qe "https\?://w\?w\?w\?\.\?teddit\.net.\+"; then
        echo "$1" | sed -e 's|^.*pics/w:null_\(.\+\)$|https://i.redd.it/\1|'
    else
        echo "$1"
    fi
}

### main ###
command -v nsxiv 1>/dev/null 2>&1 || die "Requires nsxiv installed"

[ -z "$1" ] && nsxiv
trap cleanup EXIT
[ -d "$cache_dir" ] || mkdir -p -- "$cache_dir" || die
im_number=1
while [ -n "$1" ]; do
    case "$1" in
    *://*.*) from_remote "$1" ;;
    *) from_local "$1" ;;
    esac
    im_number=$((im_number + 1))
    shift
done

[ "$(find -L "$cache_dir" -type f -print | wc -l)" -ne 0 ] &&
    nsxiv -p "$cache_dir"