#!/bin/bash

# Generates a feed file for droid nation

# Feed base URL
feedbase="http://www.quadronyx.org/mirror/podcasts/droidnation/" # <filetype>.<feedtype>.xml

# Feed title and description
feedtitle="Droid Nation Audio Cast (UNOFFICIAL FEED)"
feeddesc="Droid Nation was an audio cast (also known as a podcast) about \
"'"'"rooting and hacking Android devices"'"'". There are 53 episodes in \
total, now hosted at the AMAZING archive.org."

# Author (us) name and email
authorname="Quadronyx (on behalf of Droid Nation)"
authoremail="droidnationfeed@quadronyx.org"

# File host URL and tag
filehost="https://archive.org/details/droidnation"
feedtag="archive.org,2015"

# File base URL
filebase="https://archive.org/download/droidnation/droidnation0" # <epnum>.<ext>

# Now
now="$(date -u)"



[ ${#} -ne 2 ] && {
    echo "Usage: $(basename "${0}") [ogg|mp3|all] [rss|atom|all]"
    exit 1
}

### types

[ "${1}" == "all" ] && {
    types=(ogg mp3)
} || {
    types=("${1}")
}
shift 1

[ "${types[0]}" != "ogg" ]\
&& [ "${types[0]}" != "mp3" ]\
&& {
    # Invalid type
    echo "Invalid type specified (${types[0]})" >&2
    exit 2
}

### feeds

[ "${1}" == "all" ] && {
    feeds=(rss atom)
} || {
    feeds=("${1}")
}
shift 1

[ "${feeds[0]}" != "rss" ]\
&& [ "${feeds[0]}" != "atom" ]\
&& {
    # Invalid feed
    echo "Invalid feed specified (${feeds[0]})" >&2
    exit 2
}



### START

for t in "${types[@]}"; do #{

    ### CREATE HEADERS

    for f in "${feeds[@]}"; do #{
        outfile="${t}.${f}.xml"
        >"${outfile}"

        [ "${f}" == "rss" ] && {

cat <<EOF >>"${outfile}"
<?xml version="1.0" encoding="iso-8859-1" ?>
<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel>
<atom:link href="${feedbase}${outfile}" rel="self" type="application/rss+xml" />

    <title>${feedtitle}</title>

<pubDate>$(date -uR)</pubDate>
<description>
${feeddesc}
</description>
<link>${filehost}</link>
EOF

        }

        [ "${f}" == "atom" ] && {

cat <<EOF >>"${outfile}"
<?xml version="1.0" encoding="iso-8859-1" ?>
<feed xmlns="http://www.w3.org/2005/Atom">
<link href="${feedbase}${outfile}" rel="self" type="application/rss+xml" />

    <title>${feedtitle}</title>

<author>
	<name>${authorname}</name>
	<email>${authoremail}</email>
</author>
<updated>$(date -u --rfc-3339=seconds|tr ' ' T)</updated>
<subtitle>
${feeddesc}
</subtitle>
<link href="${filehost}" />
<id>tag:${feedtag}:${filehost}</id>
EOF

        }

    done #}



    ### CREATE ENTRIES

    for e in $(seq -w 53 -1 1); do #{
        lastmod="${now}"
        contlen="0"

        while read line; do #{

            # Get the first bit
            firstbit="${line%% *}"

# NOTE: For this cast, the file dates are all borked :/
#            # Check if lowercase firstbit is last-modified
#            [ "${firstbit,,}" == "last-modified:" ] && {
#                # Last-Modified
#                lastmod="${line#* }"
#            }

            # Check if lowercase firstbit is content-length
            [ "${firstbit,,}" == "content-length:" ] && {
                # Content-Length
                contlen="${line#* }"
            }

        done < <(\
            curl -LIs ${filebase}${e}.${t}\
            |tr -d '\r'\
            |egrep 'Content-Length|Last-Modified'\
        ) #}

        for f in "${feeds[@]}"; do #{
            outfile="${t}.${f}.xml"

            [ "${f}" == "rss" ] && {

# NOTE: For some reason the w3c validator says the URL is invalid when it's
#       https :S ... hence the substitution below

cat <<EOF >>"${outfile}"
<item>
    <title>Episode ${e}</title>
    <description>Episode ${e}</description>
    <guid isPermaLink="false">tag:${feedtag}:${filebase}${e}.${t}</guid>
    <enclosure
        type="audio/${t/mp3/mpeg}"
        length="${contlen}"
        url="${filebase/https/http}${e}.${t}"
    />

    <pubDate>$(date -d "${lastmod}" -uR)</pubDate>
</item>
EOF

            }

            [ "${f}" == "atom" ] && {

cat <<EOF >>"${outfile}"
<entry>
    <title>Episode ${e}</title>
    <summary type="text">Episode ${e}</summary>
    <id>tag:${feedtag}:${filebase}${e}.${t}</id>
    <link
        rel="alternate"
        type="text/html"
        href="${filehost}"
    />
    <link
    	rel="enclosure"
    	type="audio/${t/mp3/mpeg}"
    	length="${contlen}"
    	href="${filebase}${e}.${t}"
    />

    <updated>$(date -d "${lastmod}" -u --rfc-3339=seconds|tr ' ' T)</updated>
</entry>
EOF

            }

        done #}

    done #}



    ### CREATE FOOTERS

    for f in "${feeds[@]}"; do #{
        outfile="${t}.${f}.xml"

        [ "${f}" == "rss" ] && {

cat <<EOF >>"${outfile}"
</channel>
</rss>
EOF

        }

        [ "${f}" == "atom" ] && {

cat <<EOF >>"${outfile}"
</feed>
EOF

        }

    done #}

done #}