#!/usr/bin/env bash

set -euo pipefail

DOWNLOAD_DIR="/data/ubuntu"
mkdir -p "$DOWNLOAD_DIR"

ARCH="amd64"

# Supported:
# 24.04 desktop
# 24.04 server
# 26.04 desktop
# 26.04 server

declare -A URLS=(
  ["24-desktop"]="https://releases.ubuntu.com/24.04/"
  ["24-server"]="https://releases.ubuntu.com/24.04/"
  ["26-desktop"]="https://releases.ubuntu.com/resolute/"
  ["26-server"]="https://releases.ubuntu.com/resolute/"
)

download_if_newer() {
    local key="$1"
    local base_url="${URLS[$key]}"

    echo "Checking $key..."

    iso_name=$(curl -fsSL "$base_url" \
        | grep -oE 'ubuntu-[0-9.]+(-live-server|-desktop)-amd64\.iso' \
        | sort -Vu \
        | tail -1)

    if [[ -z "$iso_name" ]]; then
        echo "Could not determine latest ISO for $key"
        return 1
    fi

    latest_version=$(echo "$iso_name" | grep -oE '[0-9]+(\.[0-9]+)+')

    local_iso=$(find "$DOWNLOAD_DIR" -name "*$(basename "$iso_name" | sed 's/[0-9.]\+//')*" 2>/dev/null | sort | tail -1 || true)

    if [[ -n "$local_iso" ]]; then
        local_version=$(basename "$local_iso" | grep -oE '[0-9]+(\.[0-9]+)+' | head -1)

        if [[ "$local_version" == "$latest_version" ]]; then
            echo "Already up to date: $iso_name"
            return 0
        fi

        echo "Outdated local ISO found:"
        echo "  Local : $local_version"
        echo "  Latest: $latest_version"
    fi

    echo "Downloading $iso_name..."
    wget --limit-rate=4M -c -P "$DOWNLOAD_DIR" "${base_url}${iso_name}"

    echo "Done."
    echo
}

download_if_newer "24-desktop"
download_if_newer "24-server"
download_if_newer "26-desktop"
download_if_newer "26-server"

echo "Finished."