(function (root, factory) {
  if (typeof module === 'object' && module.exports) {
    module.exports = factory();
  } else {
    root.ISMIStools = Object.assign(root.ISMIStools || {}, factory());
  }
})(typeof self !== 'undefined' ? self : this, function () {
  'use strict';

  function getPDFLib() {
    return (typeof self !== 'undefined' && self.PDFLib) ||
           (typeof globalThis !== 'undefined' && globalThis.PDFLib);
  }

  function wrapText(text, font, size, maxWidth) {
    const words = String(text).split(/\s+/).filter(Boolean);
    const lines = [];
    let line = '';
    for (const word of words) {
      const candidate = line ? line + ' ' + word : word;
      if (font.widthOfTextAtSize(candidate, size) <= maxWidth) {
        line = candidate;
      } else {
        if (line) lines.push(line);
        line = word;
      }
    }
    if (line) lines.push(line);
    return lines.length ? lines : [''];
  }

  async function buildStudyLoadPdf(data) {
    const PDFLib = getPDFLib();
    const { PDFDocument, StandardFonts, rgb } = PDFLib;
    const header = data.header || {};
    const courses = data.courses || [];

    const doc = await PDFDocument.create();
    let page = doc.addPage([612, 792]); // Letter
    const font = doc.embedStandardFont(StandardFonts.Helvetica);
    const bold = doc.embedStandardFont(StandardFonts.HelveticaBold);
    const margin = 50;
    const contentWidth = 612 - margin * 2;
    let y = 792 - 50;

    const black = rgb(0, 0, 0);
    const gray = rgb(0.3, 0.3, 0.3);

    function center(text, size, fontToUse, dy) {
      const w = fontToUse.widthOfTextAtSize(text, size);
      page.drawText(text, { x: (612 - w) / 2, y: y, size, font: fontToUse, color: black });
      y -= dy;
    }
    function left(text, size, fontToUse, x, dy) {
      page.drawText(text, { x, y, size, font: fontToUse, color: black });
      y -= dy;
    }

    // Header
    center(header.semester || '', 14, bold, 20);
    center("STUDENT'S STUDY LOAD", 16, bold, 24);
    center(header.dateRange || '', 11, font, 18);
    if (header.dateEnrolled) left('Date Enrolled: ' + header.dateEnrolled, 10, font, margin, 16);
    y -= 6;
    if (header.studentId) left('Student ID: ' + header.studentId, 10, font, margin, 14);
    if (header.fullName) left('Name: ' + header.fullName, 10, font, margin, 14);
    if (header.program) left('Program: ' + header.program, 10, font, margin, 14);
    if (header.yearLevel) left('Year Level: ' + header.yearLevel, 10, font, margin, 14);
    y -= 10;

    // Table columns: NOTE, UNITS, TEACHER, COURSE DESCRIPTION, COURSE, GROUP
    const cols = [
      { key: 'status', label: 'NOTE', x: margin, w: 50 },
      { key: 'units', label: 'UNITS', x: margin + 50, w: 45 },
      { key: 'teacher', label: 'TEACHER', x: margin + 95, w: 110 },
      { key: 'description', label: 'COURSE DESCRIPTION', x: margin + 205, w: 150 },
      { key: 'courseCode', label: 'COURSE', x: margin + 355, w: 70 },
      { key: 'groupSchedule', label: 'GROUP', x: margin + 425, w: 87 }
    ];
    const cellSize = 9;
    const headerSize = 9;

    function drawRow(cells, isHeader) {
      const f = isHeader ? bold : font;
      const size = isHeader ? headerSize : cellSize;
      const linesPerCol = cols.map((c) => wrapText(cells[c.key] || '', f, size, c.w - 6));
      const rowHeight = Math.max(...linesPerCol.map((l) => l.length)) * 11 + 8;
      if (!isHeader && y - rowHeight < 50) {
        // Row doesn't fit on the current page: start a new page and re-draw the header.
        page = doc.addPage([612, 792]);
        y = 792 - 50;
        drawHeaderRow();
      }
      if (isHeader) {
        page.drawRectangle({ x: margin, y: y - rowHeight, width: contentWidth, height: rowHeight, color: rgb(0.85, 0.9, 0.95) });
      }
      page.drawRectangle({ x: margin, y: y - rowHeight, width: contentWidth, height: rowHeight, borderColor: black, borderWidth: 0.5 });
      for (const c of cols) {
        page.drawRectangle({ x: c.x, y: y - rowHeight, width: c.w, height: rowHeight, borderColor: black, borderWidth: 0.5 });
      }
      for (let i = 0; i < cols.length; i++) {
        const c = cols[i];
        const lines = linesPerCol[i];
        let ty = y - 10;
        for (const line of lines) {
          page.drawText(line, { x: c.x + 3, y: ty, size, font: f, color: black });
          ty -= 11;
        }
      }
      y -= rowHeight;
      return true;
    }

    function drawHeaderRow() {
      const headerCells = {};
      cols.forEach((c) => { headerCells[c.key] = c.label; });
      drawRow(headerCells, true);
    }

    drawHeaderRow();

    for (const course of courses) {
      const cells = {
        status: course.status,
        units: course.units,
        teacher: course.teacher,
        description: course.description,
        courseCode: course.courseCode,
        groupSchedule: (course.group ? course.group + ' ' : '') + (course.schedule || '')
      };
      if (!drawRow(cells, false)) break;
    }

    y -= 12;
    if (data.totalUnits) {
      page.drawText('Total Units: ' + data.totalUnits, { x: margin, y: y, size: 11, font: bold, color: black });
      y -= 16;
    }
    const printedBy = 'Printed by: ' + (header.studentId || '') + ' on ' + new Date().toLocaleDateString();
    page.drawText(printedBy, { x: margin, y: y, size: 9, font, color: gray });

    return doc.save(); // returns Promise<Uint8Array>
  }

  return { buildStudyLoadPdf };
});