function parseAbsence(str, teacherMap) {
  str = str.trim().replace(/\s+/g, " ");

  const result = {
    teacher: null, // String or null
    teacherCode: null, // String or null
    type: null,   // "wholeDay" | "range" | "single" | "invalid"
    hours: null // { from: number, to: number } or number
  };

  // Regex patterns (with flexible spaces)
  const wholeDayPattern = /^([A-Za-z]+)$/;                   
  const rangePattern = /^(\d+)\s*-\s*(\d+)\s+([A-Za-z]+)$/;  
  const singleHourPattern = /^(\d+)\s+([A-Za-z]+)$/;         

  if (rangePattern.test(str)) {
    const [, from, to, teacherCode] = str.match(rangePattern);
    result.teacher = teacherMap[teacherCode.toLowerCase()];
    result.teacherCode = teacherCode;
    result.type = "range";
    result.hours = { from: parseInt(from), to: parseInt(to) };
  } 
  else if (singleHourPattern.test(str)) {
    const [, hour, teacherCode] = str.match(singleHourPattern);
    result.teacher = teacherMap[teacherCode.toLowerCase()];
    result.teacherCode = teacherCode;
    result.type = "single";
    result.hours = parseInt(hour);
  } 
  else if (wholeDayPattern.test(str)) {
    const [, teacherCode] = str.match(wholeDayPattern);
    result.teacher = teacherMap[teacherCode.toLowerCase()];
    result.teacherCode = teacherCode;
    result.type = "wholeDay";
  } 
  else {
    result.type = "invalid";
    result.original = str;
  }

  return result;
}

module.exports = parseAbsence;