type CollectionMarkdownInput = {
  name: string;
  description: string | null;
  recipes: Array<{
    title: string;
    description: string | null;
    baseServings: number;
    prepMins: number | null;
    cookMins: number | null;
    difficulty: "easy" | "medium" | "hard" | null;
  }>;
};

export function collectionToMarkdown(collection: CollectionMarkdownInput): string {
  const lines: string[] = [`# ${collection.name}`, ""];

  if (collection.description) {
    lines.push(collection.description, "");
  }

  for (const recipe of collection.recipes) {
    lines.push(`## ${recipe.title}`, "");
    if (recipe.description) lines.push(recipe.description, "");
    const meta: string[] = [`Servings: ${recipe.baseServings}`];
    if (recipe.prepMins) meta.push(`Prep: ${recipe.prepMins} min`);
    if (recipe.cookMins) meta.push(`Cook: ${recipe.cookMins} min`);
    if (recipe.difficulty) meta.push(`Difficulty: ${recipe.difficulty}`);
    lines.push(meta.join(" · "), "");
  }

  return lines.join("\n").trim() + "\n";
}