#!/bin/bash
#
# Generates an RSS feed from Git commit messages
#
#  Copyright (C) 2012  Mike Gerwitz
#
#  This file is part of repo2html.
#
#  This program is free software: you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation, either version 3 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program.  If not, see <http://www.gnu.org/licenses/>.
# #

repotype="${1?Missing repository type}"
url="${2?Missing URL}"
count="${3:-0}"

# provide default message formatter if necessary
msgfmt="${msgfmt:-./msgfmt}"

# rss header
cat <<EOH
<?xml version="1.0"?>
<rss version="2.0">
  <channel>
    <title>Mike Gerwitz's Thoughts and Ramblings</title>
    <link>$url</link>
    <description>
      The miscellaneous thoughts and ramblings of a free software hacker
    </description>
EOH


# output recent commits as entries (assuming no funny business in the output)
while read hash commit ts id subject; do
  # ignore commits that begin with ':'
  [[ "$subject" == :* ]] && {
    echo "[RSS] Ignoring $commit: $subject" >&2
    continue
  }

  echo "[RSS] Found $commit: $subject" >&2

  # TODO: avoid HTML entities where browsers may decide not to render them (e.g.
  # the title)
  cat <<EOE
    <item>
      <title><![CDATA[$( "$msgfmt" -n < <( echo "$subject"; echo ) )]]></title>
      <link>$(
        printf "%s/%s/%s.html" \
          "${url/%\/}" "$( ./tsdate "$ts" %Y/%m )" "$id"
        )
      </link>
      <pubDate>$( ./tsdate "$ts" %Y-%m-%d )</pubDate>
      <description>
        <![CDATA[
          $( ./"$repotype"/commit2html "$commit" )
        ]]>
      </description>
    </item>
EOE

  # continue until we reach the requested number (note that we increment before
  # the check, meaning that if the count is 0, then we will output every commit
  ((i++))
  [ "$i" -eq "$count" ] && break
done

# footer
cat <<EOF
  </channel>
</rss>
EOF