type RecipeMarkdownInput = {
  title: string;
  description: string | null;
  baseServings: number;
  prepMins: number | null;
  cookMins: number | null;
  difficulty: "easy" | "medium" | "hard" | null;
  sourceUrl: string | null;
  ingredients: Array<{ rawName: string; quantity: string | null; unit: string | null; note: string | null }>;
  steps: Array<{ instruction: string; timerSeconds: number | null }>;
};

function formatQuantity(quantity: string | null, unit: string | null): string {
  return [quantity, unit].filter(Boolean).join(" ");
}

export function recipeToMarkdown(recipe: RecipeMarkdownInput): string {
  const lines: string[] = [`# ${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(" · "), "");

  if (recipe.ingredients.length > 0) {
    lines.push("## Ingredients", "");
    for (const ing of recipe.ingredients) {
      const qty = formatQuantity(ing.quantity, ing.unit);
      const note = ing.note ? ` (${ing.note})` : "";
      lines.push(`- ${qty ? `${qty} ` : ""}${ing.rawName}${note}`);
    }
    lines.push("");
  }

  if (recipe.steps.length > 0) {
    lines.push("## Instructions", "");
    recipe.steps.forEach((step, i) => {
      const timer = step.timerSeconds ? ` (${Math.round(step.timerSeconds / 60)} min)` : "";
      lines.push(`${i + 1}. ${step.instruction}${timer}`);
    });
    lines.push("");
  }

  if (recipe.sourceUrl) {
    lines.push(`Source: ${recipe.sourceUrl}`);
  }

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