fetchTimetable.js

import { config } from "dotenv";
config();

const s3Endpoint = process.env.APU_TIMETABLE_S3;
const intakeCode = process.env.INTAKE_CODE;
const nonElectives = ["CT065-3-3-ALG",]; // Add MODID that is NOT your elective
const grouping = "G1"; // G1 is default, grouping to filter by

export async function fetchTimetable() {
  if (!s3Endpoint) {
    console.error("❌ Error: S3 endpoint not configured");
    return []; // Return empty array instead of Response
  }

  if (!intakeCode) {
    console.error("❌ Error: Intake Code not configured");
    return [];
  }

  try {
    const response = await fetch(s3Endpoint);

    if (!response.ok) {
      console.error("❌ Error: Unable to fetch data from S3");
      return [];
    }

    const data = await response.json();

    // Filter the entire S3 dataset by intake code
    const filteredData = filterByIntake(data, intakeCode);

    const filteredByGrouping = filterByGrouping(filteredData, grouping);

    // Filter the courses by the user's elective choices
    const result = filterByElective(filteredByGrouping, nonElectives);

    return result; // ✅ Return data directly as an array
  } catch (error) {
    console.error("❌ Error fetching data:", error.message);
    return []; // ✅ Return empty array on error
  }
}

const filterByIntake = (data, intakeCode) => {
  return data.filter((entry) => {
    const intakeValue = entry.INTAKE?.trim();
    const searchValue = intakeCode.trim();
    return intakeValue === searchValue;
  });
};

const filterByElective = (filteredData, nonElectives) => {
  if (nonElectives.length < 1) {
    return filteredData;
  }

  return filteredData.filter((entry) => {
    const modid = entry.MODID?.trim();
    const isNonElective = nonElectives.some((mod) => modid?.includes(mod));
    return !isNonElective; // Keep only those that are NOT nonElectives
  });
};

const filterByGrouping = (filteredData, grouping) => {
  return filteredData.filter((entry) => {
    const groupingValue = entry.GROUPING?.trim();
    const searchValue = grouping.trim();
    return groupingValue === searchValue;
  });
};