#!/usr/bin/env bash
set -euo pipefail

subreddit="EarthPorn"
wallpaper_dir="$HOME/wallpapers"
min_width=1920
mkdir -p "$wallpaper_dir"

json=$(curl -sf -A "Mozilla/5.0 (X11; Linux x86_64) get-new-wallpaper/1.0" \
    "https://www.reddit.com/r/${subreddit}.json?limit=25")

# Keep posts where:
#   - preview source exists and is at least min_width wide
#   - aspect ratio is wider than 4:3
# For Reddit-hosted images use i.redd.it directly; for external images fall back
# to the signed preview.redd.it URL so hotlink protection doesn't bite us.
mapfile -t candidates < <(echo "$json" | jq -r \
  --argjson min "$min_width" '
  .data.children[].data |
  select(.preview.images[0].source != null) |
  select(.preview.images[0].source.width >= $min) |
  select((.preview.images[0].source.width / .preview.images[0].source.height) > (4/3)) |
  [
    .title,
    (if (.url | test("^https://i\\.redd\\.it/")) then .url
     else (.preview.images[0].source.url | gsub("&amp;"; "&"))
     end)
  ] | @tsv
')

if [[ ${#candidates[@]} -eq 0 ]]; then
    echo "No suitable images found." >&2
    exit 1
fi

selected="${candidates[$((RANDOM % ${#candidates[@]}))]}"
title=$(printf '%s' "$selected" | cut -f1)
img_url=$(printf '%s' "$selected" | cut -f2)

safe_name=$(printf '%s' "$title" \
    | tr '[:upper:]' '[:lower:]' \
    | sed 's/[^a-z0-9 ]//g' \
    | tr -s ' ' '-' \
    | sed 's/^-//; s/-$//' \
    | cut -c1-60)

ext=$(printf '%s' "$img_url" | grep -oP '\.(jpg|jpeg|png|webp)' | tail -1 | tr -d '.')
[[ -z "$ext" ]] && ext="jpg"

filename="${wallpaper_dir}/${safe_name}.${ext}"

echo "Downloading: $title"
curl -sfL \
    -A "Mozilla/5.0 (X11; Linux x86_64; rv:120.0) Gecko/20100101 Firefox/120.0" \
    --referer "https://www.reddit.com/" \
    -o "$filename" "$img_url" || { echo "Download failed." >&2; rm -f "$filename"; exit 1; }

echo "Saved: $filename"
set-wallpaper "$filename"