init

aoc-inputdl

@@ -0,0 +1,48 @@
+#!/bin/bash
+set -euo pipefail
+
+AOC_DIR="${AOC_DIR:-$HOME/.aoc}"
+CACHE_DIR="$AOC_DIR/cache"
+SESSION_FILE="$AOC_DIR/session"
+
+usage() {
+    pname=$(basename "$0")
+    echo "Usage: $pname <year> <day>" >&2
+    exit 1
+}
+
+verify_int() {
+    if ! [[ "$1" =~ ^[0-9]+$ ]]; then
+        echo "'$1' is not an integer" >&2
+        usage
+    fi
+}
+
+if [ $# != 2 ]; then
+    usage
+fi
+
+year="$1"
+day="$2"
+
+verify_int "$year"
+verify_int "$day"
+
+year_cache_dir="$CACHE_DIR/$year"
+cache_file="$year_cache_dir/d$day.in"
+mkdir -p "$year_cache_dir"
+
+if [ ! -f "$cache_file" ]; then
+    echo "Input not cached, downloading..." >&2
+    if [ ! -f "$SESSION_FILE" ]; then
+        echo "Error: No session file available" >&2
+        exit 1
+    fi
+
+    session="$(cat "$SESSION_FILE")"
+    url="https://adventofcode.com/$year/day/$day/input"
+    curl -f "$url" -o "$cache_file" -b "session=$session"
+fi
+
+cat "$cache_file"
+