scripts: Add nsxiv-rifle script

Opens basically any path, local or remote in nsxiv.
Can take multiple paths to open all of them.

Additionally, alias whichever version of the image viewer is available
on the system as `iv`, using `nsxiv-rifle`, `nsxiv`, `sxiv` in order of
preference.

scripts/.local/bin/nsxiv-rifle

@@ -0,0 +1,75 @@
+#!/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 "$1")"
+    ln -s "$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
+
+[ "$(find "$cache_dir" -type f -print | wc -l)" -ne 0 ] &&
+    nsxiv -p "$cache_dir"

sh/.config/sh/alias

@@ -93,6 +93,17 @@ if exist vifm; then
     alias vmm='vifm ${PWD}'
 fi
 
+# nsxiv image viewer
+if exist nsxiv; then
+    if exist nsxiv-rifle; then
+        alias iv=nsxiv-rifle
+    else
+        alias iv=nsxiv
+    fi
+elif exist sxiv; then
+    alias iv=sxiv
+fi
+
 # python
 if exist ptipython; then
     alias py=ptipython