import { NextRequest, NextResponse } from "next/server";
import { z } from "zod";
import { db, recipes, cookingHistory, pantryItems, recipeIngredients, eq, and } from "@epicure/db";
import { requireSession } from "@/lib/api-auth";

type Params = { params: Promise<{ id: string }> };

const Schema = z.object({
  servings: z.number().int().min(1).max(1000).optional(),
  notes: z.string().max(2000).optional(),
  deductFromPantry: z.boolean().default(true),
});

export async function POST(req: NextRequest, { params }: Params) {
  const { session, response } = await requireSession();
  if (response) return response;
  const { id } = await params;
  const userId = session!.user.id;

  const recipe = await db.query.recipes.findFirst({ where: eq(recipes.id, id) });
  if (!recipe || (recipe.visibility === "private" && recipe.authorId !== userId)) {
    return NextResponse.json({ error: "Not found" }, { status: 404 });
  }

  const body = await req.json().catch(() => ({})) as unknown;
  const parsed = Schema.safeParse(body);
  const data = parsed.success ? parsed.data : { deductFromPantry: true };

  await db.insert(cookingHistory).values({
    id: crypto.randomUUID(),
    userId,
    recipeId: id,
    servings: data.servings,
    notes: data.notes,
    cookedAt: new Date(),
  });

  if (data.deductFromPantry) {
    const ings = await db.query.recipeIngredients.findMany({
      where: eq(recipeIngredients.recipeId, id),
    });
    const scale = data.servings ? data.servings / recipe.baseServings : 1;
    const userPantry = await db.query.pantryItems.findMany({
      where: eq(pantryItems.userId, userId),
    });

    for (const ing of ings) {
      const key = ing.rawName.toLowerCase();
      const pantryItem = userPantry.find(
        (p) => p.rawName.toLowerCase() === key && (p.unit ?? "") === (ing.unit ?? "")
      );
      if (!pantryItem) continue;

      const pantryQty = pantryItem.quantity ? parseFloat(pantryItem.quantity) : null;
      const ingQty = ing.quantity ? parseFloat(ing.quantity) * scale : null;

      if (pantryQty !== null && ingQty !== null && !isNaN(pantryQty) && !isNaN(ingQty)) {
        const remaining = pantryQty - ingQty;
        if (remaining <= 0) {
          await db.delete(pantryItems).where(eq(pantryItems.id, pantryItem.id));
        } else {
          await db.update(pantryItems)
            .set({ quantity: String(Math.round(remaining * 10000) / 10000) })
            .where(eq(pantryItems.id, pantryItem.id));
        }
      } else {
        // no numeric quantity to deduct — remove the item entirely
        await db.delete(pantryItems).where(eq(pantryItems.id, pantryItem.id));
      }
    }
  }

  return NextResponse.json({ logged: true }, { status: 201 });
}