/*
 * Get a date object in a date format dd-mm-yyyy
 */
  export function formatDate(date) {
    var d = new Date(date),
        month = '' + (d.getMonth() + 1),
        day = '' + d.getDate(),
        year = d.getFullYear();

    if (month.length < 2) 
        month = '0' + month;
    if (day.length < 2) 
        day = '0' + day;

    return [day, month, year].join('-');
  }

/*
 * Get a date object in a date format yyyy-mm-dd
 */
  export function invertedFormatDate(date) {
    let d = new Date(date),
        month = '' + (d.getMonth() + 1),
        day = '' + d.getDate(),
        year = d.getFullYear();

    if (month.length < 2)
      month = '0' + month;
    if (day.length < 2)
      day = '0' + day;

    return [year, month, day].join('-');
  }

  /*
   * Create a string date via the hour and the date
   */
  export function createLessonEvent(date,hour){
    const str = date.concat(' ',hour);
    return new Date(str);
  }
/*
 * Get the duration of a lesson
 */
  export function durationCourse(element){
    const hour = element.lessonEnd.substring(3,5) -element.lessonStart.substring(3,5);
    
    
    return (element.lessonEnd - element.lessonStart)%2;
  }

/*
 * Help to sort lessons chronologically
 */
  export function sortByDate(a, b) {
    const nameA = new Date(a.lessonStart); // ignore upper and lowercase
    const nameB = new Date(b.lessonStart); // ignore upper and lowercase
      
    if (nameA < nameB) {
      return -1;
    }
    if (nameA > nameB) {
      return 1;
    }
    return 0; 
      }

/*
* Get the first day of the current month
*/
  export function getFirstDay(d){
    var date = new Date(d);
    return new Date(date.getFullYear(), date.getMonth(), 1);
  }

/*
 * Convert a list of lesson to a schedule in a week
 */
  export function weekFromList(list, weekMonday){
    const weekStart = new Date(weekMonday); 
    const matrix = new Array(7);
    for (let i = 0; i < matrix.length; i++) {
      matrix[i] = [];
    }
    for(let key in list){
      const temp = list[key];
      const day = new Date(list[key].lessonStart);
      if((((day.getTime()-weekStart.getTime())/60000)<10080) && (((day.getTime()-weekStart.getTime())/60000)>0)){
        matrix[day.getDay()].push(temp);
        matrix[day.getDay()].sort((a,b) => sortByDate(a,b));
      }
    }
      return matrix;
  }

  /*
   * Return the last date of a month
   */
  export function lastDateOfMonth(d){
    const date = new Date(d);
    const temp = new Date(date.getFullYear(), date.getMonth() + 1, 0);
    return temp.getDate();
  }
/*
 * Convert a list of lesson to a schedule in a month
 */

  export function monthFromList(list,month){
    const beginning = getFirstDay(month);
    const matrix = new Array(lastDateOfMonth(month))
    for (let i = 0; i < matrix.length; i++) {
      matrix[i] = [];
    }
    for(let key in list){
      const temp = list[key];
      const day = new Date(list[key].lessonStart);
      if(day.getMonth()==month){
      matrix[day.getDate()].push(temp);
      matrix[day.getDay()].sort((a,b) => sortByDate(a,b));
      }}
    
    
    return matrix;
  }


/*
 * Put the first element of a weekly schedule (corresponds to sunday) to the end of the list
 */
  export function sundayToTheEnd(list){
    const newlist = list;
    const sunday = newlist.shift();
    newlist.push(sunday);
    return newlist;
  }

  /*
   * Get the difference of time between 2 dates
   */
  export function getDifferenceTime(date1,date2){
    return Math.abs((new Date(date2).getTime() - new Date(date1).getTime())/60000);
  }

  /*
   * used to shift the lessons correctly
   */
  export function getMarginTop(list, index1, index2){
    if(index2 < 0){
      const temp = new Date(list[index1].lessonStart);
      temp.setHours(8,0,0);
      return Math.abs((new Date(list[index1].lessonStart).getTime()- temp.getTime())/60000);
    }
    if(new Date(list[index1].lessonStart).getTime() === new Date(list[index2].lessonEnd).getTime()){
      return Math.abs(getMarginTop(list,index2,index2-1));
    }
    return Math.abs((new Date(list[index1].lessonStart).getTime()- new Date(list[index2].lessonEnd).getTime())/60000)+getMarginTop(list,index2,index2-1);
  }

 /*
  * Get the hour and minutes of a date in the right format
  */
  export function getHoursMinutes(date){
    const d = new Date(date);
    let hours = [d.getHours().toString().length == 1 ? "0" + d.getHours().toString() : d.getHours()];
    return hours+ ":" + d.getMinutes();  
  }