import { c } from './files.js'

const ctage = {
  "Mo": [],
  "Di": [],
  "Mi": [],
  "Do": [],
  "Fr": []
}

// returns time difference in 15-minute intervalls
function timediff(a, b) {
  const time = "1970-01-01 ";
  return (new Date(time + a) - new Date(time + b)) / 1000 / 60 / 15;
}

export function gettimefromintervalls(x) {
  let y = 15 * x / 60 + 8
  let z = y.toString().padStart(2, '0');

  if (Math.round(y) == y) return `<th rowspan="4">${z}:00</th>`;

  return ""
}

function sortTage(tage) {
  for (let tag in tage) {
    tage[tag].sort((a, b) => {
      return timediff(a.von, b.von)
    });
  }

  return tage;
}

function runtimes(tage, tage_runtimes) {
  for (let tag in tage) {
    for (let eintrag in tage[tag]) {
      // could be redundant
      if (eintrag == tage[tag].length) break;

      let a = tage[tag][eintrag];
      let runtime = timediff(a.bis, a.von)

      tage_runtimes[tag].push({
        "name": a.name,
        "raum": a.raum,
        "runtime": runtime,
      });
    }
  }

  return tage_runtimes;
}

function bufferUp(tage) {
  tage = sortTage(tage);

  for (let tag in tage) {
    if (tage[tag][0].von != "08:00") {
      tage[tag].splice(0, 0, {
          "name": "BUFFER",
          "raum": "BUFFER",
          "von": "08:00",
          "bis": tage[tag][0].von,
      })
    }

    if (tage[tag][tage[tag].length - 1].bis != "19:00") {
      tage[tag].push({
          "name": "BUFFER",
          "raum": "BUFFER",
          "von": tage[tag][tage[tag].length - 1].bis,
          "bis": "19:00",
      })
    }
  }

  for (let tag in tage) {
    for (let eintrag in tage[tag]) {
      if (eintrag == tage[tag].length - 1) break;

      let a = tage[tag][eintrag];
      let b = tage[tag][eintrag - -1];

      let runtime = timediff(b.von, a.bis)

      if (runtime > 0) {
        tage[tag].push({
          "name": "BUFFER",
          "raum": "BUFFER",
          "von": a.bis,
          "bis": b.von,
        });
      }
    }
  }

  return tage;
}

export function prepare(forICS = false) {
  let tage = structuredClone(ctage);
  let tage_runtimes = structuredClone(ctage);

  for (let eintrag of c.eintraege) {
    let eintragName = Object.keys(eintrag)[0];
    eintrag = eintrag[eintragName]

    for (let veranstaltung in eintrag) {
      for (let termin of eintrag[veranstaltung]) {
        tage[termin[0]].push({
          "name": `${eintragName.toString()} / ${veranstaltung.toString()}`,
          "raum": termin[3],
          "von": termin[1].replace("h", ":"),
          "bis": termin[2].replace("h", ":"),
        })
      }
    }
  }

  if (forICS) {
    return tage = sortTage(tage);
  }

  tage = bufferUp(tage, ctage);
  tage = sortTage(tage);

  return runtimes(tage, tage_runtimes)
}