import * as fs from "fs"
import * as html_to_pdf from "html-pdf-node"

import * as v from './variables.js'

let hinweise = "<ul>";
for (let hinweis of v.hinweise) {
  hinweise += `<li>${hinweis}</li>`;
}
hinweise += `</ul>`;

let date = new Date();
date = date.toLocaleDateString("de-DE", {
  weekday: 'long',
  year: 'numeric',
  month: 'long',
  day: 'numeric',
});

let options = {
  format: 'A4',
  landscape: true,
  margin: {
    top: "0.5cm",
    right: "1cm",
    bottom: "1cm",
    left: "2cm",
  },
};

// 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;
}

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;
}

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

function main() {
  let res = "";

  let tage = structuredClone(ctage);
  let tage_runtimes = structuredClone(ctage);

  for (let eintrag of v.eintraege) {
    for (let termin of eintrag.termine) {
      tage[termin.wochentag].push({
        "name": eintrag.name,
        "raum": termin.raum,
        "von": termin.von,
        "bis": termin.bis,
      })
    }
  }

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

  let timeout = {}

  // 1h has 4 15 minute intervalls: 08 to 19 means 44 intervalls
  for (let i = 0; i < 44; i++) {
    let mensa = "";

    if (11 < i && i < 25) mensa = "mensa1";
    if (25 < i && i < 27) mensa = "mensa2";

    res += `<tr class="${mensa}">` + gettimefromintervalls(i)

    for (let day in tage_runtimes) {
      if (timeout[day] > 0) {
        timeout[day]--;
        continue;
      }

      let el = tage_runtimes[day][0];

      if (el.name == "BLOCKED" && el.raum == "BLOCKED") {
        res += `<td rowspan="${el.runtime}" class="block"></td>`;
      } else {
        let name = el.name == "BUFFER" ? "" : `<div><span>${el.name}</span>`;
        let raum = el.raum == "BUFFER" ? "" : `<span>${el.raum}</span>`;

        res += `<td rowspan="${el.runtime}">${name}${raum}</td>`;
      }

      timeout[day] = el.runtime - 1;
      tage_runtimes[day].splice(0, 1);
    }

    res += "</tr>"
  }

  // console.log(res)

  return res
}

let html = `
${v.style}
<p>Persönlicher Stundenplan von ${v.student} für das ${v.semester}. Stand: ${date}.</p>
<table>
  <tr>
    <th> Uhrzeit </th>
    <th class="tag"> Montag </th>
    <th class="tag"> Dienstag </th>
    <th class="tag"> Mittwoch </th>
    <th class="tag"> Donnerstag </th>
    <th class="tag"> Freitag </th>
  </tr>
  ${main()}
</table>
<br>
<u> Hinweise: </u>
${hinweise}
`;

fs.writeFileSync("test.html", html)

html_to_pdf.generatePdf({content: html}, options).then(pdfBuffer => {
  fs.writeFileSync(v.filename, pdfBuffer);
});