#!/usr/bin/env bash

# Sync preview NuGet packages into the local offline feed.
# Reads package metadata from ops/devops/nuget-preview-packages.csv
# and ensures ./local-nuget holds the expected artefacts (with SHA-256 verification).
# Optional 4th CSV column can override the download base (e.g. dotnet-public flat container).

set -euo pipefail

repo_root="$(git -C "${BASH_SOURCE%/*}/.." rev-parse --show-toplevel 2>/dev/null || pwd)"
manifest="${repo_root}/ops/devops/nuget-preview-packages.csv"
dest="${repo_root}/local-nuget"
nuget_v2_base="${NUGET_V2_BASE:-https://www.nuget.org/api/v2/package}"

if [[ ! -f "$manifest" ]]; then
  echo "Manifest not found: $manifest" >&2
  exit 1
fi

mkdir -p "$dest"

fetch_package() {
  local package="$1"
  local version="$2"
  local expected_sha="$3"
  local source_base="$4"
  local target="$dest/${package}.${version}.nupkg"
  local url

  if [[ -n "$source_base" ]]; then
    local package_lower
    package_lower="${package,,}"
    url="${source_base%/}/${package_lower}/${version}/${package_lower}.${version}.nupkg"
  else
    url="${nuget_v2_base%/}/${package}/${version}"
  fi

  echo "[sync-nuget] Fetching ${package} ${version}"
  local tmp
  tmp="$(mktemp)"
  trap 'rm -f "$tmp"' RETURN
  curl -fsSL --retry 3 --retry-delay 1 "$url" -o "$tmp"
  local actual_sha
  actual_sha="$(sha256sum "$tmp" | awk '{print $1}')"
  if [[ "$actual_sha" != "$expected_sha" ]]; then
    echo "Checksum mismatch for ${package} ${version}" >&2
    echo "  expected: $expected_sha" >&2
    echo "  actual:   $actual_sha" >&2
    exit 1
  fi
  mv "$tmp" "$target"
  trap - RETURN
}

while IFS=',' read -r package version sha source_base; do
  [[ -z "$package" || "$package" == \#* ]] && continue

  local_path="$dest/${package}.${version}.nupkg"
  if [[ -f "$local_path" ]]; then
    current_sha="$(sha256sum "$local_path" | awk '{print $1}')"
    if [[ "$current_sha" == "$sha" ]]; then
      echo "[sync-nuget] OK ${package} ${version}"
      continue
    fi
    echo "[sync-nuget] SHA mismatch for ${package} ${version}, refreshing"
  else
    echo "[sync-nuget] Missing ${package} ${version}"
  fi

  fetch_package "$package" "$version" "$sha" "${source_base:-}"
done < "$manifest"