#!/bin/bash

# Searches the website for RSS feeds and adds them to newsboat url list. Can
# also find hidden RSS feeds on various websites, namely Youtube, Reddit,
# Vimeo, Github, Gitlab and Medium. Gets site url as $1 or (if not present)
# from X clipboard. Gets tags as $2. If it finds more than one feed, calls
# mew for the user to choose which one to add. I have bound it to a keyboard
# shortcut so i copy a site link and easily add its feed to the reader.

# Inspired by and based on the logic of this extension:
# https://github.com/shevabam/get-rss-feed-url-extension

# This script requires rssadd to add feeds to the list.

getlink () {
	local url="$1"
	feeds="$(curl -s "$url" | rg -x '.*type=.*(rss|rdf|atom).*' | sed 's/ //g')"
	url="$(echo $url | sed 's|^\(https://[^/]*/\).*|\1|')"

	for rsspath in $feeds; do
		rsspath="$(echo $rsspath | sed -n "s|.*href=['\"]\([^'\"]*\)['\"].*|\1|p")"
	if echo "$rsspath" | rg "http" > /dev/null; then
		link="$rsspath"
	elif echo "$rsspath" | rg "^/" > /dev/null; then
		link="$url$(echo $rsspath | sed 's|^/||')"
	else
		link="$url$rsspath"
	fi
	echo $link
	done
}

getRedditRss() {
	echo "${1%/}.rss"
}

getYoutubeRss() {
	local url="$1"
	path=$(echo "$url" | sed -e 's|^http[s]*://||')
	case "$path" in
		*"/channel/"*) channel_id="$(echo $path | sed -r 's|.*channel/([^/]*).*|\1|')" && feed="https://www.youtube.com/feeds/videos.xml?channel_id=${channel_id}" ;;
		*"/c/"*|*"/user/"*)
			feed=$(wget -q "$url" -O tmp_rssget_yt \
			&& sed -n 's|.*\("rssUrl":"[^"]*\).*|\1|; p' tmp_rssget_yt \
			| rg rssUrl \
			| sed 's|"rssUrl":"||') ;;
	esac
	echo "$feed"
}

getVimeoRss() {
    local url="$1"
        if echo "$url" | rg -q "/videos$"; then
            feed_url=$(echo "$url" | sed 's/\/videos$//' | sed 's/\/$/\/rss/')
        else
            feed_url="${url}/videos/rss"
        fi
    echo "$feed_url"
}

getGithubRss () {
	local url="${1%/}"
	if echo $url | rg "github.com/[^/]*/[a-zA-Z0-9].*" >/dev/null ; then
		echo "${url}/commits.atom"
		echo "${url}/releases.atom"
		echo "${url}/tags.atom"
	elif echo $url | rg "github.com/[^/]*(/)" >/dev/null ; then
		echo "${url}.atom"
	fi
}

getGitlabRss () {
	local url="${1%/}"
	echo "${url}.atom"
}

getMediumRss () {
	echo $1 | sed 's|/tag/|/feed/|'
}


if [ -n "$1" ] ; then
	url="$1"
else
	url="$(wl-paste)"
	[ -z "$url" ] && echo "usage: $0 url 'tag1 tag2 tag3'" && exit 1
fi

declare -a list=()

yt_regex="^(http(s)?://)?((w){3}\.)?(youtube\.com|invidio\.us|invidious\.flokinet\.to|invidious\.materialio\.us|iv\.datura\.network|invidious\.perennialte\.ch|invidious\.fdn\.fr|invidious\.private\.coffee|invidious\.protokolla\.fi|invidious\.privacyredirect\.com|yt\.artemislena\.eu|yt\.drgnz\.club|invidious\.incogniweb\.net|yewtu\.be|inv\.tux\.pizza|invidious\.reallyaweso\.me|iv\.melmac\.space|inv\.us\.projectsegfau\.lt|inv\.nadeko\.net|invidious\.darkness\.services|invidious\.jing\.rocks|invidious\.privacydev\.net|inv\.in\.projectsegfau\.lt|invidious\.drgns\.space)/(channel|user|c).+"
reddit_regex="^(http(s)?://)?((w){3}\.)?reddit\.com.*"
vimeo_regex="^(http(s)?://)?((w){3}.)?vimeo\.com.*"
if echo $url | rg -x "$yt_regex" >/dev/null ; then
	list="$(getYoutubeRss "$url")"
elif echo $url | rg -x "$reddit_regex" >/dev/null ; then
	list="$(getRedditRss "$url")"
# vimeo actually works with getlink
elif echo $url | rg "$vimeo_regex" >/dev/null ; then
	list="$(getVimeoRss "$url")"
elif echo $url | rg "github.com" >/dev/null ; then
	list="$(getGithubRss "$url")"
# gitlab also works with getlink
elif echo $url | rg "gitlab.com/[a-zA-Z0-9].*" >/dev/null ; then
	list="$(getGitlabRss "$url")"
elif echo $url | rg "medium.com/tag" >/dev/null ; then
	list="$(getMediumRss "$url")"
else
	list="$(getlink "$url")"
fi

[ "$(echo "$list" | wc -l)" -eq 1 ] && chosen_link="$list" || chosen_link=$(printf '%s\n' "${list[@]}" | mew -p "Choose a feed:")
tags="$2"
ifinstalled rssadd && rssadd "$chosen_link" "$tags"
echo "$chosen_link" "$tags"