import * as cheerio from "cheerio";
const titleTranslations = {
  "Klasse(n)": "class",
  Datum: "date",
  Stunde: "lesson",
  "(Lehrer)": "teacher",
  Vertreter: "changedTeacher",
  Fach: "subject",
  Raum: "room",
  Art: "type",
  Text: "notes",
};

export function parseSubstitutionPlan(html) {
  const infos = {};
  const $ = cheerio.load(html);

  const data = [];
  const tables = $("table.mon_list");
  tables.each((tableIndex, tableElement) => {
    // Extract the date, weekday and a/b week from the title
    const title = $(tableElement)
      .parent()
      .siblings(".mon_title")
      .text()
      .split(" ");
    const rawDate = title[0];
    const date = rawDate
      .split(".")
      .reverse()
      .map((e) => e.padStart(2, 0))
      .join("-");

    if (tableIndex == 0) {
      infos.date = new Date(date).setUTCHours(0, 0, 0, 0);
      infos.week = title[3];

      // Get the export timestamp
      const rawTimestamp = $(".mon_head")
        .first()
        .find("td")
        .text()
        .split("Stand: ")[1]
        .replace(/[\s\n]*$/g, "");
      const exportDate = rawTimestamp
        .split(" ")[0]
        .split(".")
        .reverse()
        .join("-");
      const timestamp = exportDate + " " + rawTimestamp.split(" ")[1];
      infos.updatedAt = new Date(timestamp).getTime();
    } else {
      // If there are multiple days in one file,
      // ignore all except the first one
      if (new Date(date).setUTCHours(0, 0, 0, 0) != infos.date) {
        return;
      }
    }

    const titles = [];
    const titleElements = $(tableElement).find("tr.list th");
    titleElements.each((index, titleElement) => {
      const title = $(titleElement).text();
      titles[index] = titleTranslations[title];
    });

    const subsitutionTable = $(tableElement).find("tr.list");
    // Loop through each table row
    subsitutionTable.each((_rowcnt, row) => {
      const rowData = {};

      // Find the columns and ignore empty ones
      const columns = $(row).find("td");
      if (columns.text() == "") return;
      // Ignore columns that include "Keine Vertretungen"
      // to have an empty array if there are no substitutions
      if (columns.text().includes("Keine Vertretungen")) return;

      columns.each((columncnt, column) => {
        const text = $(column).text();
        // Clean the text by removing new lines, tabs, ...
        var cleantext = text.replace(/^\n\s*/g, "").replace(/\s*$/, "");
        if (cleantext == "" || cleantext == "---") cleantext = null;

        const columntitle = titles[columncnt];
        rowData[columntitle] = cleantext;
      });

      // Split change if it spans over multiple lessons
      const rawLesson = rowData.lesson || "0";
      const fromToLessons = rawLesson.match(/\d+/g).map(Number);
      const from = fromToLessons[0];
      const to = fromToLessons[1] || fromToLessons[0];

      // Generate numbers from `from` to `to`
      const lessons = Array(to - from + 1)
        .fill()
        .map((_e, i) => i + from);

      // Create new change for each lesson the change spans over
      for (const lesson of lessons) {
        rowData.lesson = lesson;
        data.push({ ...rowData });
      }
    });
  });

  infos.changes = data;
  return infos;
}