#!/bin/sh
#―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――
# Name: bookmarks-dl: Mastodon
# Desc: A source for bookmarks-dl that fetches bookmarks from Mastodon/Pleroma.
# Auth: Jaidyn Ann <jadedctrl@posteo.at>
# Date: 2023-09-02
# Reqs: curl, jq
# Lisc: GPLv3
#―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――

usage() {
	1>&2 echo "usage: bookmarks-dl mastodon [-h] [-a USER_TOKEN] -u USERNAME -d DOMAIN"
	1>&2 echo ""
	1>&2 echo "  -h             print this message and exit"
	1>&2 echo "  -a             the authorization token for your account; see below"
	1>&2 echo "  -u             account username"
	1>&2 echo "  -d             the server’s domain name"
}


# Fetch all of a user’s Mastodon/Pleroma bookmarks.
fetch_bookmarks() {
	local auth="$1"
	local domain="$2"
	local url="$3"
	if test -z "$url"; then
		url="https://$domain/api/v1/bookmarks?limit=40"
	fi

	local header_file="$(mktemp)"
	curl -H "Authorization: Bearer $auth" \
		 -D "$header_file" \
		 "$url" \
		 | bookmarks_parse

	local next_url="$(header_next_link "$header_file")"
	rm "$header_file"
	if test -n "$next_url"; then
		fetch_bookmarks "$auth" "$domain" "$next_url"
	fi
}


source_start() {
	local auth=""
	local domain=""
	while getopts 'hf:a:u:d:' arg; do
		case $arg in
			h)
				usage
				exit 1
				;;
			a)
				auth="$OPTARG"
				;;
			d)
				domain="$OPTARG"
				;;
		esac
	done

	if test -z "$auth" -o -z "$domain"; then
		usage
		exit 5
	else
		fetch_bookmarks "$auth" "$domain"
	fi
}


# Given a page of /api/v1/bookmarks, parse into the simple bookmarks-dl format
bookmarks_parse() {
	local bookmark_lines="$(jq -r '.[] | "\(.url)\t\t\(@json "\(.content)")\t\(.created_at)"')"
	local IFS="
"
	for bookmark in $bookmark_lines; do
		local url="$(echo "$bookmark" | awk -F '\t' '{print $1}')"
		local date="$(echo "$bookmark" | awk -F '\t' '{print $4}')"
		local desc="$(echo "$bookmark" | bookmark_line_desc)"
		local title="$(echo "$desc" | head -c40)"
		printf '%s\t%s\t%s\t%s\n' "$url" "$title" "$desc" "$date"
    done
}


# If curl’s HTTP response contains a “link” header for pagination, return the
# “next” page’s URL.
header_next_link() {
	local header_file="$1"
	grep '^link:' "$header_file" \
		| tr -d ' ' \
		| tr '[A-Z]' '[a-z]' \
		| sed 's/>;rel="next",.*//' \
		| sed 's/link:<//'
}


# Given a tab-delimited bookmark line, process HTML description into plain-text.
bookmark_line_desc() {
	awk -F '\t' '{print $3}' \
		| sed 's%^"%%' \
		| sed 's%"$%%' \
		| html_text_deescape \
		| tr '\n\t' '  '
}