import { computed } from "@vue/reactivity";
import { ref, watch } from "vue";

export const substitutionFilter = ref(
  localStorage.getItem("substitutionFilter") || "all"
);
export const timetableClass = ref(
  localStorage.getItem("timetableClass") || "none"
);

watch(substitutionFilter, (newValue) => {
  if (newValue == "other") {
    newValue = prompt("Please enter a class to filter (e.g. 9C)");
  }
  localStorage.setItem("substitutionFilter", newValue);
  fetchData();
});
watch(timetableClass, (newValue) => {
  localStorage.setItem("timetableClass", newValue);
  fetchData();
});

export const timetable = ref([]);
export const substitutions = ref([]);
export const history = ref([]);
export const classList = ref([]);

export const historyOfDate = computed(() => {
  const dates = {};
  for (const entry of history.value) {
    const date = entry.date;
    if (!dates[date]) dates[date] = [];
    dates[entry.date].push(entry);
  }
  return dates;
});

export const substitutionsForDate = computed(() => {
  const dates = {};
  for (const substitution of substitutions.value) {
    const date = substitution.date;
    if (!dates[date]) dates[date] = [];
    dates[substitution.date].push(substitution);
  }
  return sortObject(dates);
});

export const parsedTimetable = computed(() => {
  return timetable.value.map((day) => {
    const newDay = [];
    for (const lesson of day) {
      const lessonLength = lesson.length || 1;
      delete lesson.length;
      for (var i = 0; i < lessonLength; i++) newDay.push(lesson);
    }
    return newDay;
  });
});

export async function fetchData() {
  const baseUrl = "http://localhost:3000/api";
  const timetableResponse = await fetch(
    `${baseUrl}/timetable?class=${timetableClass.value}`
  );
  const timetableData = await timetableResponse.json();
  if (timetableData.error) {
    console.warn("API Error: " + timetableData.error);
    timetable.value = [];
  } else timetable.value = timetableData;

  const substitutionResponse = await fetch(
    substitutionFilter.value == "all"
      ? `${baseUrl}/substitutions`
      : `${baseUrl}/substitutions?class=${substitutionFilter.value}`
  );
  const substitutionData = await substitutionResponse.json();
  substitutions.value = substitutionData;

  const historyResponse = await fetch(
    substitutionFilter.value == "all"
      ? `${baseUrl}/history`
      : `${baseUrl}/history?class=${substitutionFilter.value}`
  );
  const historyData = await historyResponse.json();
  if (historyData.error) console.warn("API Error: " + historyData.error);
  else history.value = historyData;

  const classListResponse = await fetch(`${baseUrl}/classes`);
  const classListData = await classListResponse.json();
  classList.value = classListData;
}

fetchData();

function sortObject(obj) {
  return Object.keys(obj)
    .sort()
    .reduce(function (result, key) {
      result[key] = obj[key];
      return result;
    }, {});
}