#!/bin/sh
###     get-last-rss-post.sh
###     Usage: ./get-last-rss-post.sh [-t] URL
###
###     Downloads the RSS feed of the URL and checks the latest post.
###     It provides a simple way to copy/paste the Title and Link of the post.
###     Arguments:
###     -t | --today        Checks if the Publication Date of the post is Today.
###                         If not, it exits.

help() {
    sed -rn 's/^### ?//;T;p' "$0"
}
if [[ "$1" == "-h" ]] || [[ "$1" == "--help" ]] || [[ "$1" == "" ]]; then
    help
    exit 1
fi

if [[ "$1" == "-t" ]] || [[ "$1" == "--today" ]]; then
    TODAY=$(date +'%d %b %Y')
    echo "Checking if the post pubblication days is ${TODAY}…"
    set -- "$2" # Reset arguments - link becomes $1
    CHECK_TODAY=1
fi

today () {
    # Checks if pubDate is $TODAY
    echo $PUB_DATE | grep -q "$TODAY"
    if [[ "$?" == "0" ]]; then # pubDate is $TODAY
        echo "Published Date is today - good!"
    else
        echo "ERROR. Published Date is different than today. Exiting."
        cleanup 1
    fi
}

cleanup () {
    rm -f feed.xml
    exit $1
}

echo "Downloading latest XML feed…"
wget -q -O feed.xml $1
if ! [[ $? == "0" ]]; then echo "Error."; cleanup 1; else echo "Done."; fi

# Check if downloaded file has <rss> tag
grep -q '<rss' feed.xml
if ! [[ $? == "0" ]]; then echo "This is not a RSS feed. Exiting."; cleanup 1; fi


# Find 2nd clean title (1st post) and replaces / with \/
TITLE=$(awk '/<title>/{++n; if (n==2) {print; exit}}' feed.xml | sed 's/<title>//g; s/<\/title>//g; s/^ *//g')

# Find the link of the article
LINK=$(grep -A1 "$TITLE" feed.xml | tail -n 1 | sed 's/<link>//g; s/<\/link>//g; s/ //g')

# Replace / with \/ in the link
LINK_FIXED=$(echo $LINK | sed 's./.\\/.g')

# Print whole post until pubDate tag, saves the PUB_DATE
PUB_DATE=$(sed -n "/<link>$LINK_FIXED/,/pubDate/p" feed.xml | tail -n 1 | sed 's/<pubDate>//g; s/<\/pubDate>//g')

if [[ "$CHECK_TODAY" == "1" ]]; then today; fi

echo "\nCopy and Paste this:\n\n\
+++++\n\
Latest article from my blog: \"$TITLE\"\n\
$LINK
+++++"

cleanup 0