(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';

  // RFC-4180 field encoding: quote fields containing commas, quotes, or
  // newlines; double up embedded quotes.
  function csvField(value) {
    let s = String(value == null ? '' : value);
    if (/[",\r\n]/.test(s)) {
      s = '"' + s.replace(/"/g, '""') + '"';
    }
    return s;
  }

  function csvRow(cells) {
    return cells.map(csvField).join(',') + '\r\n';
  }

  // Build a CSV representation of the study load.
  // data: { header, courses, totalUnits }
  // header fields: program, studentName, studentId, semester, yearLevel
  function buildStudyLoadCsv(data) {
    const header = data.header || {};
    const lines = [];
    lines.push(csvRow(['ISMIS HELPER - STUDY LOAD']));
    lines.push(csvRow(['Program', header.program || '']));
    lines.push(csvRow(['Student Name', header.fullName || header.studentName || '']));
    lines.push(csvRow(['Student ID', header.studentId || '']));
    lines.push(csvRow(['Semester', header.semester || '']));
    lines.push(csvRow(['Year Level', header.yearLevel || '']));
    lines.push(csvRow(['Total Units', data.totalUnits || '']));
    lines.push(''); // blank separator line
    lines.push(csvRow(['Group', 'Course Code', 'Description', 'Schedule', 'Faculty', 'Units', 'Status']));
    for (const c of (data.courses || [])) {
      lines.push(csvRow([
        c.group, c.courseCode, c.description, c.schedule,
        c.faculty || c.teacher, c.units, c.status
      ]));
    }
    lines.push(csvRow(['Total', '', '', '', '', data.totalUnits || '']));
    lines.push(''); // final blank line, per RFC
    // UTF-8 BOM so Excel opens it without mojibake.
    return '\uFEFF' + lines.join('');
  }

  // Build a Next Up import CSV following the exact column contract in
  // raycast/nextup/src/lib/csv-utils.ts:
  //   title, courseCode, days, startTime, endTime, room, meetingLink,
  //   color, icon, units, classLink, professorName, professorEmail, groupName
  // One row per schedule block (a course may have multiple meeting segments).
  function buildNextUpCsv(data, parseSchedule) {
    const lines = [];
    lines.push(csvRow(['title', 'courseCode', 'days', 'startTime', 'endTime',
      'room', 'meetingLink', 'color', 'icon', 'units', 'classLink',
      'professorName', 'professorEmail', 'groupName']));
    const resolver = parseSchedule || parseScheduleBlocks;
    const groupName = (data.header && (data.header.semester || '')) || '';
    for (const c of (data.courses || [])) {
      const blocks = resolver(c.schedule);
      if (!blocks.length) {
        lines.push(csvRow([c.description || c.courseCode, c.courseCode, '',
          '', '', '', '', '', '', c.units, '', c.faculty || '', '', groupName]));
        continue;
      }
      for (const b of blocks) {
        lines.push(csvRow([
          c.description || c.courseCode,
          c.courseCode,
          b.days,
          b.startTime,
          b.endTime,
          b.room || '',
          '', '', '',
          c.units,
          '',
          c.faculty || '',
          '',
          groupName
        ]));
      }
    }
    return '\uFEFF' + lines.join('');
  }

  // Split a study-load schedule string like
  //   "F 01:30 PM - 04:30 PM LB486TC TC; T Th 03:00 PM - 04:30 PM LB468"
  // into [{ days: 'MO,TU', startTime: '01:30', endTime: '16:30', room }]
  // Day codes map to the 3-letter codes Next Up expects (MO,TU,WE,TH,FR).
  function parseScheduleBlocks(schedule) {
    const s = String(schedule || '').trim();
    if (!s) return [];
    const blocks = [];
    const segRe = /([A-Za-z]{1,3}(?:\s+[A-Za-z]{1,3})*)\s+(\d{1,2}):(\d{2})\s*(AM|PM)\s*-\s*(\d{1,2}):(\d{2})\s*(AM|PM)\s*([A-Za-z0-9]*)/gi;
    const dayMap = {
      M: 'MO', MO: 'MO', MON: 'MO',
      T: 'TU', TU: 'TU', TUE: 'TU',
      W: 'WE', WE: 'WE', WED: 'WE',
      TH: 'TH', THU: 'TH', THUR: 'TH', THURS: 'TH',
      F: 'FR', FR: 'FR', FRI: 'FR',
      SA: 'SA', SAT: 'SA',
      S: 'SU', SU: 'SU', SUN: 'SU', SUNDAY: 'SU'
    };
    let m;
    while ((m = segRe.exec(s)) !== null) {
      const dayToCode = (d) => dayMap[d.toUpperCase().replace(/\./g, '')] || '';
      const days = m[1].split(/\s+/).map(dayToCode).filter(Boolean);
      const to24 = (h, ampm, minute) => {
        let hour = parseInt(h, 10) % 12;
        if (/PM/i.test(ampm)) hour += 12;
        return String(hour).padStart(2, '0') + ':' + minute;
      };
      blocks.push({
        days: days.join(','),
        startTime: to24(m[2], m[4], m[3]),
        endTime: to24(m[5], m[7], m[6]),
        room: m[8] || ''
      });
    }
    return blocks;
  }

  return { buildStudyLoadCsv, buildNextUpCsv, parseScheduleBlocks, csvField };
});