import moment from 'moment';

export type CalendarEvent = {
  title: string;
  description: string;
  location: string;
  startDate: string;
  endDate: string;
};

class CalendarExport {
  public event: CalendarEvent;

  constructor(event: CalendarEvent) {
    this.event = event;
  }

  private getRandomKey() {
    let n = Math.floor(Math.random() * 999999999999).toString();
    return new Date().getTime().toString() + '_' + n;
  }

  private formatTime(date: string) {
    let formattedDate = moment.utc(date).format('YYYYMMDDTHHmmssZ');
    return formattedDate.replace('+00:00', 'Z');
  }

  private calculateDuration(
    startDate: CalendarEvent['startDate'],
    endDate: CalendarEvent['endDate'],
  ) {
    // snag parameters and format properly in UTC
    let end = moment.utc(endDate).format('DD/MM/YYYY HH:mm:ss');
    let start = moment.utc(startDate).format('DD/MM/YYYY HH:mm:ss');

    // calculate the difference in milliseconds between the start and end times
    let difference = moment(end, 'DD/MM/YYYY HH:mm:ss').diff(moment(start, 'DD/MM/YYYY HH:mm:ss'));

    // convert difference from above to a proper momentJs duration object
    let duration = moment.duration(difference);

    return Math.floor(duration.asHours()) + moment.utc(difference).format(':mm');
  }

  // determine if a mobile browser is being used
  private isMobile() {
    let mobile = false;

    (function (a) {
      if (
        /(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows ce|xda|xiino/i.test(
          a,
        ) ||
        /1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i.test(
          a.substr(0, 4),
        )
      )
        mobile = true;
      // @ts-ignore
    })(window.navigator.userAgent || window.navigator.vendor || window?.opera);

    return mobile;
  }

  private buildUrl(event: CalendarEvent, type: string, isIE: boolean) {
    let calendarUrl = '';

    // allow mobile browsers to open the gmail data URI within native calendar app
    // type = (type == "google" && this.isMobile()) ? "outlook" : type;

    switch (type) {
      case 'google':
        calendarUrl = 'https://calendar.google.com/calendar/render';
        calendarUrl += '?action=TEMPLATE';
        calendarUrl += '&dates=' + this.formatTime(event.startDate);
        calendarUrl += '/' + this.formatTime(event.endDate);
        calendarUrl += '&location=' + encodeURIComponent(event.location);
        calendarUrl += '&text=' + encodeURIComponent(event.title);
        calendarUrl += '&details=' + encodeURIComponent(event.description);
        break;

      case 'yahoo':
        // yahoo doesn't utilize endDate so we need to calulate duration
        let duration = this.calculateDuration(event.startDate, event.endDate);
        calendarUrl = 'https://calendar.yahoo.com/?v=60&view=d&type=20';
        calendarUrl += '&title=' + encodeURIComponent(event.title);
        calendarUrl += '&st=' + this.formatTime(event.startDate);
        calendarUrl += '&dur=' + duration;
        calendarUrl += '&desc=' + encodeURIComponent(event.description);
        calendarUrl += '&in_loc=' + encodeURIComponent(event.location);
        break;

      case 'outlookcom':
        calendarUrl = 'https://outlook.live.com/owa/?rru=addevent';
        calendarUrl += '&startdt=' + this.formatTime(event.startDate);
        calendarUrl += '&enddt=' + this.formatTime(event.endDate);
        calendarUrl += '&subject=' + encodeURIComponent(event.title);
        calendarUrl += '&location=' + encodeURIComponent(event.location);
        calendarUrl += '&body=' + encodeURIComponent(event.description);
        calendarUrl += '&allday=false';
        calendarUrl += '&uid=' + this.getRandomKey();
        calendarUrl += '&path=/calendar/view/Month';

        console.log(calendarUrl);
        break;

      default:
        calendarUrl = [
          'BEGIN:VCALENDAR',
          'VERSION:2.0',
          'BEGIN:VEVENT',
          'URL:' + document.URL,
          'DTSTART:' + this.formatTime(event.startDate),
          'DTEND:' + this.formatTime(event.endDate),
          'SUMMARY:' + event.title,
          'DESCRIPTION:' + event.description,
          'LOCATION:' + event.location,
          'END:VEVENT',
          'END:VCALENDAR',
        ].join('\n');

        if (!isIE && this.isMobile()) {
          calendarUrl = encodeURI('data:text/calendar;charset=utf8,' + calendarUrl);
        }
    }

    return calendarUrl;
  }

  public onExportEvent(type: string) {
    const isIE = !!(typeof window !== 'undefined' && window.navigator.msSaveOrOpenBlob && window.Blob);
    const url = this.buildUrl(this.event, type, isIE);

    if (!this.isMobile() && (url.startsWith('data') || url.startsWith('BEGIN'))) {
      let filename = `${this.event.title}.ics`;
      let blob = new Blob([url], { type: 'text/calendar;charset=utf-8' });

      if (isIE) {
        window.navigator.msSaveOrOpenBlob(blob, filename);
      } else {
        /****************************************************************
        // many browsers do not properly support downloading data URIs
        // (even with "download" attribute in use) so this solution
        // ensures the event will download cross-browser
        ****************************************************************/
        let link = document.createElement('a');
        link.href = window.URL.createObjectURL(blob);
        link.setAttribute('download', filename);
        document.body.appendChild(link);
        link.click();
        document.body.removeChild(link);
      }
    } else {
      window.open(url, '_blank');
    }
  }
}

export { CalendarExport };