import { createClient } from "@supabase/supabase-js";

const SUPABASE_URL = process.env.SUPABASE_URL;
const SUPABASE_KEY = process.env.SUPABASE_KEY;
const supabase = createClient(SUPABASE_URL, SUPABASE_KEY);
const PAGE_SIZE = 1000;

const fetchAllBooks = async () => {
  let books = [];
  let rangeStart = 0;

  while (true) {
    const { data, error } = await supabase
      .from("optimized_books")
      .select("*")
      .order("date_finished", { ascending: false })
      .range(rangeStart, rangeStart + PAGE_SIZE - 1);

    if (error) {
      console.error("Error fetching books:", error);
      break;
    }

    books = books.concat(data);
    if (data.length < PAGE_SIZE) break;
    rangeStart += PAGE_SIZE;
  }

  return books;
};

const sortBooksByYear = (books) => {
  const years = {};
  books.forEach((book) => {
    const year = book["year"];
    if (!years[year]) {
      years[year] = { value: year, data: [book] };
    } else {
      years[year]["data"].push(book);
    }
  });
  return Object.values(years).filter((year) => year["value"] > 2017);
};

const currentYear = new Date().getFullYear();

export default async function () {
  const books = await fetchAllBooks();
  const sortedByYear = sortBooksByYear(books);
  const booksForCurrentYear =
    sortedByYear.find((yearGroup) => yearGroup.value === currentYear)?.data ||
    [];

  return {
    all: books,
    years: sortedByYear,
    currentYear: booksForCurrentYear,
    feed: books.filter((book) => book["feed"]),
  };
}