import { Document, Packer, Paragraph, TextRun, HeadingLevel, AlignmentType } from "docx";
import * as XLSX from "xlsx";
import { jsPDF } from "jspdf";
import pptxgen from "pptxgenjs";

export type DocType = "docx" | "xlsx" | "pdf" | "pptx";

export interface DocxOptions {
  title: string;
  subtitle?: string;
  sections: Array<{
    heading?: string;
    body: string | string[];
  }>;
}

export interface XlsxOptions {
  fileName: string;
  sheetName?: string;
  headers: string[];
  rows: Array<Array<string | number | boolean>>;
}

export interface PdfOptions {
  title: string;
  subtitle?: string;
  author?: string;
  content: Array<{
    heading?: string;
    text: string;
  }>;
}

export interface PptxSlide {
  title: string;
  bullets?: string[];
  content?: string;
  keyTakeaway?: string;
}

export interface PptxOptions {
  title: string;
  subtitle?: string;
  slides: PptxSlide[];
}

export interface GenerateDocResult {
  success: boolean;
  message: string;
  fileName?: string;
  fileUrl?: string;
}

// Check Tier Permissions for Document Creation
export function validateDocTierPermission(
  docType: DocType,
  userTier: "guest" | "free" | "pro" | "tiniagents",
  requestedSlidesCount: number = 1
): { allowed: boolean; reason?: string; maxSlidesAllowed?: number } {
  // Everything is 100% FREE for all users without charges or restrictions
  return { allowed: true, maxSlidesAllowed: 20 };
}

// 1. Generate Word Document (.docx)
export async function createWordDocument(options: DocxOptions): Promise<Blob> {
  const children: Paragraph[] = [];

  // Document Title
  if (options.title) {
    children.push(
      new Paragraph({
        text: options.title,
        heading: HeadingLevel.TITLE,
        alignment: AlignmentType.CENTER,
        spacing: { after: 200 }
      })
    );
  }

  // Subtitle
  if (options.subtitle) {
    children.push(
      new Paragraph({
        children: [
          new TextRun({
            text: options.subtitle,
            italics: true,
            size: 24,
            color: "555555"
          })
        ],
        alignment: AlignmentType.CENTER,
        spacing: { after: 400 }
      })
    );
  }

  // Sections
  options.sections.forEach((sec) => {
    if (sec.heading) {
      children.push(
        new Paragraph({
          text: sec.heading,
          heading: HeadingLevel.HEADING_1,
          spacing: { before: 300, after: 120 }
        })
      );
    }

    if (Array.isArray(sec.body)) {
      sec.body.forEach((paraText) => {
        children.push(
          new Paragraph({
            children: [new TextRun({ text: paraText, size: 22 })],
            spacing: { after: 150 }
          })
        );
      });
    } else if (sec.body) {
      // Split by newlines if paragraph string has breaks
      const lines = sec.body.split("\n");
      lines.forEach((line) => {
        if (line.trim().startsWith("- ") || line.trim().startsWith("* ")) {
          children.push(
            new Paragraph({
              text: line.trim().substring(2),
              bullet: { level: 0 },
              spacing: { after: 100 }
            })
          );
        } else if (line.trim()) {
          children.push(
            new Paragraph({
              children: [new TextRun({ text: line.trim(), size: 22 })],
              spacing: { after: 150 }
            })
          );
        }
      });
    }
  });

  const doc = new Document({
    sections: [
      {
        properties: {},
        children: children
      }
    ]
  });

  return await Packer.toBlob(doc);
}

// 2. Generate Excel Spreadsheet (.xlsx)
export function createExcelSpreadsheet(options: XlsxOptions): Blob {
  const wsData = [options.headers, ...options.rows];
  const worksheet = XLSX.utils.aoa_to_sheet(wsData);

  // Set header column formatting auto-width
  const colWidths = options.headers.map((h, i) => {
    let maxLen = h.length;
    options.rows.forEach((r) => {
      const valStr = String(r[i] ?? "");
      if (valStr.length > maxLen) maxLen = valStr.length;
    });
    return { wch: Math.min(Math.max(maxLen + 4, 12), 40) };
  });
  worksheet["!cols"] = colWidths;

  const workbook = XLSX.utils.book_new();
  XLSX.utils.book_append_sheet(workbook, worksheet, options.sheetName || "Sheet1");

  const wbout = XLSX.write(workbook, { bookType: "xlsx", type: "array" });
  return new Blob([wbout], { type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" });
}

// 3. Generate PDF Document (.pdf)
export function createPdfDocument(options: PdfOptions): Blob {
  const doc = new jsPDF({
    orientation: "portrait",
    unit: "mm",
    format: "a4"
  });

  const pageHeight = doc.internal.pageSize.getHeight();
  const pageWidth = doc.internal.pageSize.getWidth();
  const margin = 15;
  const maxLineWidth = pageWidth - margin * 2;
  let y = 20;

  // Primary Header Title
  doc.setFont("helvetica", "bold");
  doc.setFontSize(20);
  doc.setTextColor(30, 41, 59); // Slate-800
  doc.text(options.title || "Document Report", margin, y);
  y += 10;

  if (options.subtitle) {
    doc.setFont("helvetica", "normal");
    doc.setFontSize(12);
    doc.setTextColor(100, 116, 139); // Slate-500
    doc.text(options.subtitle, margin, y);
    y += 10;
  }

  // Divider Line
  doc.setDrawColor(226, 232, 240); // Slate-200
  doc.setLineWidth(0.5);
  doc.line(margin, y, pageWidth - margin, y);
  y += 10;

  options.content.forEach((sec) => {
    // Check page space for section header
    if (y > pageHeight - 25) {
      doc.addPage();
      y = 20;
    }

    if (sec.heading) {
      doc.setFont("helvetica", "bold");
      doc.setFontSize(14);
      doc.setTextColor(15, 23, 42); // Slate-900
      doc.text(sec.heading, margin, y);
      y += 7;
    }

    doc.setFont("helvetica", "normal");
    doc.setFontSize(10);
    doc.setTextColor(51, 65, 85); // Slate-700

    const lines = doc.splitTextToSize(sec.text || "", maxLineWidth);
    lines.forEach((line: string) => {
      if (y > pageHeight - 20) {
        doc.addPage();
        y = 20;
      }
      doc.text(line, margin, y);
      y += 5.5;
    });

    y += 6; // Spacing after section
  });

  // Footer Page Numbers
  const totalPages = doc.getNumberOfPages();
  for (let i = 1; i <= totalPages; i++) {
    doc.setPage(i);
    doc.setFont("helvetica", "italic");
    doc.setFontSize(8);
    doc.setTextColor(148, 163, 184);
    doc.text(`Page ${i} of ${totalPages} • Generated by Aura AI`, pageWidth / 2, pageHeight - 10, { align: "center" });
  }

  return doc.output("blob");
}

// 4. Generate PowerPoint Presentation (.pptx)
export async function createPptxPresentation(
  options: PptxOptions,
  maxAllowedSlides: number = 10
): Promise<Blob> {
  const pptx = new pptxgen();

  pptx.layout = "LAYOUT_16x9";
  pptx.author = "Aura AI";
  pptx.company = "Aura Cognitive Assistant";

  // Title Slide
  const titleSlide = pptx.addSlide();
  titleSlide.background = { color: "0F172A" }; // Dark Navy Blue

  titleSlide.addText(options.title || "Presentation", {
    x: 0.8,
    y: 2.0,
    w: "80%",
    h: 1.5,
    fontSize: 36,
    bold: true,
    color: "38BDF8", // Sky blue accent
    align: "left"
  });

  if (options.subtitle) {
    titleSlide.addText(options.subtitle, {
      x: 0.8,
      y: 3.6,
      w: "80%",
      h: 1.0,
      fontSize: 20,
      color: "94A3B8",
      align: "left"
    });
  }

  // Filter slides up to maximum allowed by tier (PRO: 5, TiniAgents: 10)
  const slidesToRender = (options.slides || []).slice(0, maxAllowedSlides);

  slidesToRender.forEach((slideData, idx) => {
    const slide = pptx.addSlide();
    slide.background = { color: "F8FAFC" }; // Slate 50 background

    // Header Title Bar
    slide.addText(slideData.title || `Slide ${idx + 2}`, {
      x: 0.8,
      y: 0.6,
      w: "85%",
      h: 0.8,
      fontSize: 24,
      bold: true,
      color: "0F172A"
    });

    // Content or Bullets
    if (slideData.bullets && slideData.bullets.length > 0) {
      const bulletItems = slideData.bullets.map((b) => ({
        text: b,
        options: { fontSize: 16, color: "334155", breakLine: true, bullet: true }
      }));

      slide.addText(bulletItems, {
        x: 0.8,
        y: 1.6,
        w: "85%",
        h: 4.2,
        margin: 10
      });
    } else if (slideData.content) {
      slide.addText(slideData.content, {
        x: 0.8,
        y: 1.6,
        w: "85%",
        h: 4.2,
        fontSize: 16,
        color: "334155"
      });
    }

    // Key Takeaway Box at bottom if present
    if (slideData.keyTakeaway) {
      slide.addText(`KEY TAKEAWAY: ${slideData.keyTakeaway}`, {
        x: 0.8,
        y: 6.0,
        w: "85%",
        h: 0.8,
        fontSize: 13,
        bold: true,
        color: "0369A1",
        fill: { color: "E0F2FE" },
        align: "center"
      });
    }
  });

  const blob = (await pptx.write({ outputType: "blob" })) as Blob;
  return blob;
}

// Download Helper
export function triggerFileDownload(blob: Blob, defaultFileName: string) {
  const url = URL.createObjectURL(blob);
  const a = document.createElement("a");
  a.href = url;
  a.download = defaultFileName;
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
  setTimeout(() => URL.revokeObjectURL(url), 1000);
}