Helper script: fetch puzzle description

Extended the helper script to fetch the puzzle description. It will be
put into a README.md. The input will now be stored into a input folder
along with examples extracted from the puzzle description.

Adjusted the parsing of the day from the folder name. It will now take
any number that appears in the folder name. Previously: folder name must
be a number, leading zeros will be stripped (e.g 01, 02). Now: there can
be other characters as well (e.g day01, day02)

lib/aoc.sh

@@ -3,14 +3,34 @@
 PARENT_DIR=$(dirname $PWD)
 YEAR=${PARENT_DIR##*/}
 DAY_RAW=${PWD##*/}
-DAY=$((10#$DAY_RAW))
+DAY=$((10#${DAY_RAW//[^0-9]/}))
 
 SESSION_KEY=$(cat ~/.aocrc)
 
 echo "Fetching ${YEAR} ${DAY}"
 echo $SESSION_KEY
 
-curl -b session=$SESSION_KEY https://adventofcode.com/${YEAR}/day/${DAY}/input > input
+URL_DAY="https://adventofcode.com/${YEAR}/day/${DAY}"
+URL_INPUT="$URL_DAY/input"
 
-echo "Visit: https://adventofcode.com/${YEAR}/day/${DAY}"
+mkdir -p input
 
+echo -e "$URL_DAY\n" > README.md
+
+curl -b session=$SESSION_KEY $URL_DAY | sed -n '/<article class="day-desc">/,/<\/article>/p' | html2markdown --mark-code >> README.md
+curl -b session=$SESSION_KEY $URL_INPUT > input/input
+
+cat README.md
+
+echo "Extracting example code blocks..."
+# extract example code blocks
+cat README.md |
+  sed -n '/\[code\]/,/\[\/code\]/p' | # extract code blocks
+  sed '/^\s*$/d' | # remove empty lines
+  sed '/^\[\/code\]/d' | # remove closing bracket
+  sed 's/^    //' | # remove indentation
+  csplit - --suppress-matched --elide-empty-files --prefix='input/example' --suffix='%d' '/\[code\]/' '{*}'
+echo "done."
+
+echo
+echo "Visit: $URL_DAY"