import * as XLSX from "xlsx";
import { ExcelColumnsName } from "../constants";

// Функция для разделения текста на документы
const splitDocuments = (text: string) => {
  const regex = /Документ: \[\d+\]/g;
  const matches = text.match(regex);
  if (!matches) return [text];

  const documents = [];
  let lastIndex = 0;

  matches.forEach((match, index) => {
    const startIndex = text.indexOf(match, lastIndex);
    if (index > 0) {
      documents.push(text.slice(lastIndex, startIndex));
    }
    lastIndex = startIndex;
  });

  documents.push(text.slice(lastIndex));
  return documents;
};

// Функция для группировки документов
const groupDocuments = (documents: string[], groupSize: number) => {
  const groups = [];
  for (let i = 0; i < documents.length; i += groupSize) {
    groups.push(documents.slice(i, i + groupSize).join("\n"));
  }
  return groups;
};

// Функция для разделения текста на части, не превышающие 32000 символов
const splitLongText = (text: string, maxLength: number) => {
  const parts = [];
  for (let i = 0; i < text.length; i += maxLength) {
    parts.push(text.slice(i, i + maxLength));
  }
  return parts;
};

// eslint-disable-next-line @typescript-eslint/no-explicit-any
export const downloadExcel = (data: any[]) => {
  let worksheet;

  if (data.length === 0) {
    worksheet = XLSX.utils.aoa_to_sheet([["No Data"]]);
  } else {
    const keys = Object.keys(data[0]);

    const rows = data.flatMap((obj) => {
      const row = keys.map((key) => obj[key]);
      const llmPrompt = obj.llmPrompt || "";
      const documents = splitDocuments(llmPrompt);
      const groupedDocuments = groupDocuments(documents, 10);

      // Сохраняем начало текста до первого документа
      const initialText = llmPrompt.slice(0, llmPrompt.indexOf(documents[0]));

      return groupedDocuments.flatMap((group, index) => {
        const textParts = splitLongText(group, 32000);
        return textParts.map((part, partIndex) => {
          if (index === 0 && partIndex === 0) {
            const newRow = [...row];
            newRow[keys.indexOf("llmPrompt")] = initialText + part;
            return newRow;
          } else {
            const emptyRow = new Array(keys.length).fill("");
            emptyRow[keys.indexOf("llmPrompt")] = part;
            return emptyRow;
          }
        });
      });
    });

    const renamedKeys = keys.map((key) => ExcelColumnsName[key] || key);

    worksheet = XLSX.utils.aoa_to_sheet([renamedKeys, ...rows]);
  }

  const columnWidth = 25; // Ширина в символах
  worksheet["!cols"] = new Array(Object.keys(data[0] || {}).length).fill({
    wch: columnWidth,
  });

  const workbook = XLSX.utils.book_new();
  XLSX.utils.book_append_sheet(workbook, worksheet, "Logs");

  // Генерация бинарных данных Excel-файла
  const wbout = XLSX.write(workbook, { bookType: "xlsx", type: "array" });

  // Создание ссылки для скачивания
  const blob = new Blob([wbout], { type: "application/octet-stream" });
  const url = URL.createObjectURL(blob);
  const a = document.createElement("a");
  a.href = url;
  a.download = "Журнал логов.xlsx";
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  URL.revokeObjectURL(url);
};