#! /usr/bin/bash

set -euo pipefail
IFS=$'\n\t'

API_KEY="${NASA_API_KEY:-DEMO_KEY}"
if [ "${API_KEY}" = "DEMO_KEY" ]; then
    echo "No API key set! using demo key."
fi

WALLPAPERS="$(systemd-path user)"/Pictures/nasa

mkdir --parents "${WALLPAPERS}"

APOD_URL="https://api.nasa.gov/planetary/apod?api_key=${API_KEY}"
response="$(curl --silent "${APOD_URL}")"
picture_date="$(printf '%s' "${response}" | jq --raw-output .date)"
picture_url="$(printf '%s' "${response}" | jq --raw-output .hdurl)"

extension="${picture_url##*.}"
filename="${picture_date}.${extension}"
outfile="${WALLPAPERS}/${filename}"

if [ -f "${outfile}" ]; then
    echo "Target file already exists"
    exit 0
fi

tempfile="$(mktemp)"
curl \
    --location \
    --output "${tempfile}" \
    --silent \
    "${picture_url}"
mv "${tempfile}" "${outfile}"
ln \
    --force \
    --symbolic \
    "${outfile}" \
    "${WALLPAPERS}/today"
swaymsg output "*" bg "${SWAY_WALLPAPER}" fill