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

OUT_DIR="${WATERMAPS_GEOFABRIK_DIR:-${SEA_COMPASS_GEOFABRIK_DIR:-data/geofabrik}}"
GERMANY_BASE_URL="${WATERMAPS_GEOFABRIK_GERMANY_BASE_URL:-${SEA_COMPASS_GEOFABRIK_GERMANY_BASE_URL:-https://download.geofabrik.de/europe/germany}}"
EUROPE_BASE_URL="${WATERMAPS_GEOFABRIK_EUROPE_BASE_URL:-${SEA_COMPASS_GEOFABRIK_EUROPE_BASE_URL:-https://download.geofabrik.de/europe}}"

DEFAULT_REGIONS=(
  germany
  netherlands
)

regions=("$@")
if [[ "${#regions[@]}" -eq 0 ]]; then
  regions=("${DEFAULT_REGIONS[@]}")
fi

mkdir -p "$OUT_DIR"

for region in "${regions[@]}"; do
  file_name="${region}-latest.osm.pbf"
  case "$region" in
    germany|netherlands)
      url="${EUROPE_BASE_URL}/${file_name}"
      ;;
    *)
      url="${GERMANY_BASE_URL}/${file_name}"
      ;;
  esac
  target="${OUT_DIR}/${file_name}"
  checksum_target="${target}.md5"

  echo "Downloading $url.md5"
  curl --fail --location --retry 5 --retry-delay 5 --output "$checksum_target" "${url}.md5"

  expected_checksum="$(awk 'NR == 1 { print $1 }' "$checksum_target")"
  if [[ -f "$target" ]] && [[ "$(md5sum "$target" | awk '{ print $1 }')" == "$expected_checksum" ]]; then
    echo "$(basename "$target"): already current"
    continue
  fi

  echo "Downloading $url"
  curl --fail --location --continue-at - --retry 5 --retry-delay 5 --output "$target" "$url"

  actual_checksum="$(md5sum "$target" | awk '{ print $1 }')"
  if [[ -z "$expected_checksum" || "$actual_checksum" != "$expected_checksum" ]]; then
    echo "Checksum verification failed for $target" >&2
    exit 1
  fi
  echo "$(basename "$target"): OK"
done