import { Document, Packer, Paragraph, TextRun, HeadingLevel, AlignmentType, Table, TableRow, TableCell, WidthType } from 'docx';
import PDFDocument from 'pdfkit';
import ExcelJS from 'exceljs';
// @ts-ignore
import officegen from 'officegen';
import fs from 'fs';
import path from 'path';

export interface DocumentContent {
  title?: string;
  content: string | any[];
  metadata?: Record<string, any>;
}

export interface TableData {
  headers: string[];
  rows: string[][];
}

export interface SlideContent {
  title: string;
  content: string | string[];
  bullets?: string[];
}

export class DocumentGenerator {
  // Generate DOCX file
  static async generateDOCX(content: DocumentContent): Promise<Buffer> {
    const doc = new Document({
      sections: [{
        properties: {},
        children: this.parseContentToParagraphs(content.content, content.title)
      }]
    });

    return await Packer.toBuffer(doc);
  }

  private static parseContentToParagraphs(content: string | any, title?: string): Paragraph[] {
    const paragraphs: Paragraph[] = [];

    // Add title if provided
    if (title) {
      paragraphs.push(new Paragraph({
        text: title,
        heading: HeadingLevel.HEADING_1,
        spacing: { after: 200 }
      }));
    }

    // Handle complex nested structures (like the letter example)
    if (typeof content === 'object' && content !== null) {
      // Check if it has sections array
      if (content.sections && Array.isArray(content.sections)) {
        for (const section of content.sections) {
          if (section.content) {
            // Add section content
            if (typeof section.content === 'string') {
              const lines = section.content.split('\n');
              for (const line of lines) {
                if (line.trim()) {
                  paragraphs.push(new Paragraph({
                    children: [new TextRun(line)],
                    spacing: { after: 100 }
                  }));
                }
              }
            }
          }

          // Handle paragraphs array in section
          if (section.paragraphs && Array.isArray(section.paragraphs)) {
            for (const para of section.paragraphs) {
              paragraphs.push(new Paragraph({
                children: [new TextRun(para)],
                spacing: { after: 100 }
              }));
            }
          }
        }
        return paragraphs;
      }

      // Handle direct content field
      if (content.content) {
        return this.parseContentToParagraphs(content.content, title);
      }
    }

    if (typeof content === 'string') {
      const lines = content.split('\n');
      for (const line of lines) {
        if (line.startsWith('# ')) {
          // H1 heading
          paragraphs.push(new Paragraph({
            text: line.substring(2),
            heading: HeadingLevel.HEADING_1
          }));
        } else if (line.startsWith('## ')) {
          // H2 heading
          paragraphs.push(new Paragraph({
            text: line.substring(3),
            heading: HeadingLevel.HEADING_2
          }));
        } else if (line.startsWith('### ')) {
          // H3 heading
          paragraphs.push(new Paragraph({
            text: line.substring(4),
            heading: HeadingLevel.HEADING_3
          }));
        } else if (line.startsWith('- ') || line.startsWith('* ')) {
          // Bullet point
          paragraphs.push(new Paragraph({
            text: line.substring(2),
            bullet: {
              level: 0
            }
          }));
        } else if (line.startsWith('1. ') || /^\d+\. /.test(line)) {
          // Numbered list
          paragraphs.push(new Paragraph({
            text: line.replace(/^\d+\. /, ''),
            numbering: {
              reference: "default-numbering",
              level: 0
            }
          }));
        } else {
          // Regular paragraph
          paragraphs.push(new Paragraph({
            children: [new TextRun(line)]
          }));
        }
      }
    } else if (Array.isArray(content)) {
      for (const item of content) {
        if (typeof item === 'string') {
          paragraphs.push(new Paragraph({
            children: [new TextRun(item)]
          }));
        } else if (item.type === 'heading') {
          paragraphs.push(new Paragraph({
            text: item.text,
            heading: item.level || HeadingLevel.HEADING_1
          }));
        } else if (item.type === 'paragraph') {
          paragraphs.push(new Paragraph({
            children: [new TextRun(item.text)]
          }));
        } else if (item.type === 'bullet') {
          paragraphs.push(new Paragraph({
            text: item.text,
            bullet: {
              level: item.level || 0
            }
          }));
        }
      }
    }

    return paragraphs;
  }

  // Generate PDF file
  static async generatePDF(content: DocumentContent): Promise<Buffer> {
    return new Promise((resolve, reject) => {
      const doc = new PDFDocument();
      const buffers: Buffer[] = [];

      doc.on('data', buffers.push.bind(buffers));
      doc.on('end', () => {
        const pdfData = Buffer.concat(buffers);
        resolve(pdfData);
      });
      doc.on('error', reject);

      // Add title if provided
      if (content.title) {
        doc.fontSize(20).text(content.title, { align: 'center' });
        doc.moveDown();
      }

      // Add content
      if (typeof content.content === 'string') {
        const lines = content.content.split('\n');
        for (const line of lines) {
          if (line.startsWith('# ')) {
            doc.fontSize(18).text(line.substring(2));
          } else if (line.startsWith('## ')) {
            doc.fontSize(16).text(line.substring(3));
          } else if (line.startsWith('### ')) {
            doc.fontSize(14).text(line.substring(4));
          } else if (line.startsWith('- ') || line.startsWith('* ')) {
            doc.fontSize(12).text(`• ${line.substring(2)}`, { indent: 20 });
          } else {
            doc.fontSize(12).text(line);
          }
          doc.moveDown(0.5);
        }
      }

      doc.end();
    });
  }

  // Generate PowerPoint file
  static async generatePowerPoint(slides: SlideContent[]): Promise<Buffer> {
    return new Promise((resolve, reject) => {
      const pptx = officegen('pptx');
      const buffers: Buffer[] = [];

      pptx.on('data', (data: Buffer) => buffers.push(data));
      pptx.on('end', () => {
        const pptData = Buffer.concat(buffers);
        resolve(pptData);
      });
      pptx.on('error', reject);

      // Add title slide
      if (slides.length > 0 && slides[0].title) {
        const titleSlide = pptx.makeNewSlide();
        titleSlide.title = slides[0].title;
        if (slides[0].content) {
          titleSlide.addText(slides[0].content.toString(), {
            x: 'c',
            y: 'c',
            cx: '80%',
            cy: '30%',
            font_size: 18
          });
        }
      }

      // Add content slides
      for (let i = 1; i < slides.length; i++) {
        const slide = pptx.makeNewSlide();
        slide.title = slides[i].title;

        if (slides[i].bullets && slides[i].bullets!.length > 0) {
          // Add bullet points
          const bullets = slides[i].bullets!.map(bullet => ({
            text: bullet,
            options: { font_size: 14 }
          }));
          slide.addText(bullets, {
            x: 0.5,
            y: 1.5,
            cx: '90%',
            cy: '70%'
          });
        } else if (slides[i].content) {
          // Add regular content
          slide.addText(slides[i].content.toString(), {
            x: 0.5,
            y: 1.5,
            cx: '90%',
            cy: '70%',
            font_size: 14
          });
        }
      }

      pptx.generate();
    });
  }

  // Generate Excel file
  static async generateExcel(data: { sheets: { name: string; data: TableData }[] }): Promise<Buffer> {
    const workbook = new ExcelJS.Workbook();

    workbook.creator = 'ReubenOS';
    workbook.created = new Date();
    workbook.modified = new Date();

    for (const sheetData of data.sheets) {
      const worksheet = workbook.addWorksheet(sheetData.name);

      // Add headers
      worksheet.addRow(sheetData.data.headers);

      // Style headers
      worksheet.getRow(1).font = { bold: true };
      worksheet.getRow(1).fill = {
        type: 'pattern',
        pattern: 'solid',
        fgColor: { argb: 'FFE0E0E0' }
      };

      // Add data rows
      for (const row of sheetData.data.rows) {
        worksheet.addRow(row);
      }

      // Auto-fit columns
      worksheet.columns.forEach((column) => {
        let maxLength = 0;
        if (column && column.eachCell) {
          column.eachCell({ includeEmpty: true }, (cell) => {
            const length = cell.value ? cell.value.toString().length : 10;
            if (length > maxLength) {
              maxLength = length;
            }
          });
          column.width = maxLength + 2;
        }
      });

      // Add borders to all cells with data
      const rowCount = worksheet.rowCount;
      const colCount = worksheet.columnCount;
      for (let row = 1; row <= rowCount; row++) {
        for (let col = 1; col <= colCount; col++) {
          const cell = worksheet.getCell(row, col);
          cell.border = {
            top: { style: 'thin' },
            left: { style: 'thin' },
            bottom: { style: 'thin' },
            right: { style: 'thin' }
          };
        }
      }
    }

    const buffer = await workbook.xlsx.writeBuffer();
    return Buffer.from(buffer);
  }

  // Generate LaTeX and compile to PDF (requires latex installation)
  static async generateLatexPDF(latexContent: string): Promise<Buffer> {
    // For now, we'll use PDFKit as LaTeX compilation requires external tools
    // In production, you'd use node-latex or similar with a LaTeX installation
    return this.generatePDF({
      content: this.convertLatexToPlainText(latexContent)
    });
  }

  private static convertLatexToPlainText(latex: string): string {
    // Basic LaTeX to plain text conversion
    return latex
      .replace(/\\documentclass{.*?}/g, '')
      .replace(/\\usepackage{.*?}/g, '')
      .replace(/\\begin{document}/g, '')
      .replace(/\\end{document}/g, '')
      .replace(/\\section{(.*?)}/g, '# $1')
      .replace(/\\subsection{(.*?)}/g, '## $1')
      .replace(/\\subsubsection{(.*?)}/g, '### $1')
      .replace(/\\textbf{(.*?)}/g, '**$1**')
      .replace(/\\textit{(.*?)}/g, '*$1*')
      .replace(/\\item/g, '- ')
      .replace(/\\begin{itemize}/g, '')
      .replace(/\\end{itemize}/g, '')
      .replace(/\\begin{enumerate}/g, '')
      .replace(/\\end{enumerate}/g, '')
      .replace(/\$/g, '')
      .replace(/\\/g, '\n')
      .trim();
  }

  // Convert markdown to structured content for document generation
  static parseMarkdown(markdown: string): any[] {
    const lines = markdown.split('\n');
    const content = [];

    for (const line of lines) {
      if (line.startsWith('# ')) {
        content.push({ type: 'heading', text: line.substring(2), level: HeadingLevel.HEADING_1 });
      } else if (line.startsWith('## ')) {
        content.push({ type: 'heading', text: line.substring(3), level: HeadingLevel.HEADING_2 });
      } else if (line.startsWith('### ')) {
        content.push({ type: 'heading', text: line.substring(4), level: HeadingLevel.HEADING_3 });
      } else if (line.startsWith('- ') || line.startsWith('* ')) {
        content.push({ type: 'bullet', text: line.substring(2) });
      } else if (line.trim() !== '') {
        content.push({ type: 'paragraph', text: line });
      }
    }

    return content;
  }
}