/*
 * Copyright (C) 2025 Jakub Žitník
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

import ExcelJS from "exceljs"
import fs from "fs"
import parseAbsence from "../utils/parseAbsence.js"
import parseTeachers from "../utils/parseTeachers.js"

export default async function parseV1V2(downloadedFilePath) {
  const workbook = new ExcelJS.Workbook();
  await workbook.xlsx.readFile(downloadedFilePath);
  const teacherMap = await parseTeachers();

  const sheetNames = workbook.worksheets.map((sheet) => sheet.name);

  const dateRegex = /^(pondělí|úterý|středa|čtvrtek|pátek|po|út|ut|st|čt|ct|pa|pá)\s+(\d{1,2})\.\s*(\d{1,2})\.\s*(20\d{2})/i;

  // Get today's date for comparison
  function getCurrentDateObject() {
    const now = new Date();
    return new Date(now.getFullYear(), now.getMonth(), now.getDate());
  }

  const today = getCurrentDateObject();

  const upcomingSheets = sheetNames.filter((name) => {
    const match = name.match(dateRegex);
    if (!match) return false;

    const day = Number.parseInt(match[2], 10);
    const month = Number.parseInt(match[3], 10) - 1; // JavaScript months are 0-indexed
    const year = Number.parseInt(match[4], 10);

    const sheetDate = new Date(year, month, day);

    return sheetDate >= today;
  })

  const final = [];

  let finalIndex = 0
  for (const key of upcomingSheets) {
    const currentSheet = workbook.getWorksheet(key);
    final.push({});

    const regex = /[AEC][0-4][a-c]?\s*\/.*/s;
    const prefixRegex = /[AEC][0-4][a-c]?/;
    const classes = [];
    const matchingKeys = [];

    currentSheet.eachRow((row) => {
      row.eachCell((cell) => {
        const cellAddress = cell.address;
        const value = cell.value;

        if (value && typeof value === "string") {
          const testResult = regex.test(value);
          if (testResult && cellAddress.startsWith("A")) {
            const prefixMatch = value.match(prefixRegex);
            if (prefixMatch) {
              const prefix = prefixMatch[0];
              classes.push(prefix);
            }
            matchingKeys.push(cellAddress);
          }
        }
      })
    })

    function letterToNumber(letter) {
      return letter.toLowerCase().charCodeAt(0) - "a".charCodeAt(0);
    }

    // For each class
    let classI = 0;
    for (const matchingKey of matchingKeys) {
      const matchingCell = currentSheet.getCell(matchingKey);
      const rowNumber = matchingCell.row;
      const allKeys = [];

      // Get all cells in the same row
      const row = currentSheet.getRow(rowNumber);
      row.eachCell((cell) => {
        if (cell.address !== matchingKey) {
          allKeys.push(cell.address);
        }
      })

      let final2 = [];

      for (const key of allKeys) {
        const cell = currentSheet.getCell(key);
        const parsedKey = letterToNumber(key.replace(/[0-9]/gi, ""));
        let d = true;

        try {
          const regex = /^úklid\s+(?:\d+\s+)?[A-Za-z]{2}$/;
          const cellText = cell.text || "";
          if (regex.test(cellText.trim()) || cellText.trim().length == 0 || cell.fill?.fgColor === undefined) {
            d = false;
          }
        } catch {}

        if (d) {
          let text = cell.text;
          if (cell.fill?.fgColor?.argb == "FFFFFF00") {
            text += "\n(bude upřesněno)";
          }
          final2[parsedKey] = text || "";
        } else {
          final2[parsedKey] = null;
        }
      }

      final2 = Array.from(final2, (item) => (item === undefined ? null : item));
      while (final2.length < 10) {
        final2.push(null);
      }

      final[finalIndex][classes[classI]] = final2.slice(1, 11);

      classI++;
    }

    // ABSENCE
    final[finalIndex]["ABSENCE"] = [];
    let absenceKey = null;

    currentSheet.eachRow((row) => {
      row.eachCell((cell) => {
        const value = (typeof cell.value === "string" ? cell.value : "").trim().toLowerCase();
        if (value === "absence") {
          absenceKey = cell.address;
        }
      })
    });

    if (absenceKey) {
      const absenceCell = currentSheet.getCell(absenceKey);
      const rowNumber = absenceCell.row;
      const allAbsenceKeys = [];

      // Get all cells in the same row as absence
      const row = currentSheet.getRow(rowNumber);
      row.eachCell((cell) => {
        if (cell.address !== absenceKey) {
          allAbsenceKeys.push(cell.address);
        }
      })

      let i = 0;
      for (const absenceKeyCur of allAbsenceKeys) {
        if (i >= 10) {
          break; // stop once 10 items are added
        }
        i++;

        const cell = currentSheet.getCell(absenceKeyCur);
        const value = (cell.value || "").toString().trim();
        if (value.length === 0) {
          continue
        }

        const data = parseAbsence(value, teacherMap);
        final[finalIndex]["ABSENCE"].push(...data);
      }
    }

    finalIndex++;
  }

  const currentDate = new Date();
  const formattedDate = currentDate.getHours().toString().padStart(2, "0") + ":" + currentDate.getMinutes().toString().padStart(2, "0");

  const data = {
    schedule: final,
    props: upcomingSheets.map((str) => {
      const dateMatch = str.match(/(\d{1,2})\.\s*(\d{1,2})\.\s*(\d{4})/);

      let date = null;

      if (dateMatch) {
        const day = Number.parseInt(dateMatch[1], 10);
        const month = Number.parseInt(dateMatch[2], 10);
        const year = Number.parseInt(dateMatch[3], 10);

        date = new Date(year, month - 1, day);
      }

      const isPriprava = str
        .toLowerCase()
        .normalize("NFD")
        .replace(/[\u0300-\u036f]/g, "")
        .includes("priprava");

      return {
        date: date
          ? `${date.getFullYear()}-${String(date.getMonth() + 1).padStart(2, "0")}-${String(date.getDate()).padStart(2, "0")}`
          : null,
        priprava: isPriprava,
      };
    }),
    status: {
      lastUpdated: formattedDate,
    }
  }

  fs.writeFileSync("db/v2.json", JSON.stringify(data, null, 2));

  // Modify the data for v1
  const copy = JSON.parse(JSON.stringify(data));

  copy.schedule.forEach(day => {
    if (!Array.isArray(day.ABSENCE)) return;

    day.ABSENCE = day.ABSENCE.map(old => {
      if (old.type === "zastoupen") {
        return {
          type: "invalid",
          teacher: null,
          teacherCode: null,
          hours: null,
          original: `za ${old.teacherCode.toUpperCase()} zastupuje ${old.zastupuje.teacherCode.toUpperCase()}`
        };
      }
      return old;
    });
  });

  fs.writeFileSync("db/v1.json", JSON.stringify(copy, null, 2))
}

//parseV1V2("db/current.xlsx")