const request = require('request');
const log4js = require('log4js');
const logger = log4js.getLogger('calHandler');
const STRING = require('string');
const util = require('util');
const Elapsed = require('elapsed');
const Sugar = require('sugar');
const { inRange } = require('lodash');
const moment = require('moment');

Sugar.extend();

logger.level = 'error';

moment.updateLocale('en', {
  'calendar' : {
    'lastDay' : '[Yesterday\n] HH:mm',
    'sameDay' : '[Today\n] HH:mm',
    'nextDay' : '[Tomorrow\n] HH:mm',
    'lastWeek' : '[last] dddd [at] HH:mm',
    'nextWeek' : 'dddd[\n] HH:mm',
    'sameElse' : 'YYYY-MM-DD'
  }
});

function processICAL(ical) {
  'use strict';
  logger.info('+ processICAL');
  let workingBlock = [];
  const segments = {
    'meetingStartID': 'DTSTART;TZID=Europe/London:',
    'meetingStartAlt': 'DTSTART:',
    'meetingStartAltOther': 'DTSTART;VALUE=DATE:',
    'meetingEndID': 'DTEND;TZID=Europe/London:',
    'meetingEndAlt': 'DTEND:',
    'meetingEndAltOther': 'DTEND;VALUE=DATE:',
    'meetingDescID': 'DESCRIPTION:',
    'summaryID': 'SUMMARY:',
    'begin': 'BEGIN:VEVENT',
    'end': 'END:VEVENT',
    'beginAlarm': 'BEGIN:VALARM',
    'endAlarm': 'END:VALARM',
    'recur': 'RRULE:'
  };

  const rules = ['FREQ', 'WKST', 'UNTIL', 'BYMONTH', 'BYMONTHDAY', 'INTERVAL', 'BYDAY'];

  function nThDayOfMonth(monthsAhead, wantedDay) {
    const now = new Date();

    for(let t = 0; t < monthsAhead; t++) {

    }
  }

  function processRecurrence(workBlock) {
    const _workBlock = Object.assign({}, workBlock);
    const dateLimit = new Date().reset('month').addMonths(2);
    const recurArray = [];
    logger.info('---===---');
    logger.debug('>> Processing recurrence...');
    logger.debug(`Expanding ${_workBlock.summary}`);
    logger.debug('DateLimit:', dateLimit);
    //  logger.debug('Processing recurrence...');
    const weekBits = { 'SU': 0, 'MO': 1, 'TU': 2, 'WE': 3, 'TH': 4, 'FR': 5, 'SA': 6 };

    const now = new Date();
    const day = now.getDate();
    const dayNum = now.getDay();
    const month = now.getMonth();
    const year = now.getFullYear();
    const byDayRegEx = /(\d)(\w.)/;

    const recurSettings = { 'freq': null, 'wkst': null, 'until': null, 'bymonth': null, 'bymonthday': null, 'interval': null, 'byday': null };

    const firstSplit = _workBlock.recur.split(';');

    for (let t = 0; t < firstSplit.length; t++) {
      const ws = firstSplit[t].split('=');
      if (rules.indexOf(ws[0]) > -1)
        recurSettings[ws[0].toLowerCase()] = ws[1];
    }

    // if all null discard..

    if (recurSettings.freq === null && recurSettings.wkst === null && recurSettings.until === null && recurSettings.byday === null && recurSettings.bymonth === null && recurSettings.bymonthday === null && recurSettings.interval === null)
      return null;

    if (recurSettings.until !== null) {
      // have we expired?
      const _until = Date.create(recurSettings.until).isPast();
      if (_until) {
        logger.warn('EXPIRED!!');

        return null;
      }
    }

    if (recurSettings.freq !== null) {
      //      logger.debug(_workBlock);
      let newStart, newEnd;

      const origStart = new Date(_workBlock.dtstart);
      const origEnd = new Date(_workBlock.dtend);

      const _dstart = new Date(_workBlock.dtstart);
      const _dend = new Date(_workBlock.dtend);
      logger.debug('>> origStart', origStart);

      const _d = origStart.getDate();
      const _m = origStart.getMonth();
      const _h = origStart.getHours();
      const _min = origStart.getMinutes();
      const _secs = origStart.getSeconds();
      const distance = origEnd - origStart;

      _workBlock.details = {
        _d,
        _m,
        _h,
        _min,
        _secs,
        distance
      };

      logger.debug('freq:', recurSettings.freq);
      if (recurSettings.freq === 'YEARLY') {
        logger.warn('YEARLY');
        if (recurSettings.bymonth !== null && recurSettings.bymonthday !== null) {
          let _yearCount = year;
          logger.debug('>> Yearly with specific month / day');
          let newBlock;
          newStart = new Date().set({ 'year':_yearCount, 'month': recurSettings.bymonth - 1, 'day': recurSettings.bymonthday, 'hour':_h, 'minutes':_min, 'seconds':_secs });
          newEnd = new Date(_dstart).addMilliseconds(distance);
          do {
            newBlock = Object.assign({}, _workBlock);
            newBlock.dstart = new Date(newStart);
            newBlock.dend = new Date(newEnd);

            recurArray.push(newBlock);
            _yearCount++;
            newStart = new Date().set({ 'year':_yearCount, 'month': recurSettings.bymonth - 1, 'day': recurSettings.bymonthday, 'hour':_h, 'minutes':_min, 'seconds':_secs });
            newEnd = new Date(_dstart).addMilliseconds(distance);
          }
          while(newStart < dateLimit);
        }
        else if (recurSettings.bymonth === null && recurSettings.bymonthday === null) {
          logger.debug('>> Yearly no specific month / day');
          // extract month and year from dtstart
          let newBlock;
          do {
            newBlock = Object.assign({}, _workBlock);
            newBlock.dtstart = new Date(_dstart);
            newBlock.dtend = new Date(_dend);
            //            logger.info(newBlock.dtstart.medium());
            recurArray.push(newBlock);

            _dstart.advance({ 'year':1 });
            _dend.advance({ 'year':1 });
          }
          while(_dstart < dateLimit);
        }

        //  logger.info('** recurArray', recurArray);

        return recurArray;
      }

      if (recurSettings.freq === 'MONTHLY' ) {
        const interval = parseInt(recurSettings.interval, 10) || 1;
        logger.warn(`MONTHLY - ${interval}`);
        let newBlock;
        if (recurSettings.byday === null)
          do {
            newBlock = Object.assign({}, _workBlock);
            newBlock.dtstart = new Date(_dstart);
            newBlock.dtend = new Date(_dend);
            //            logger.info(newBlock.dtstart.medium());
            recurArray.push(newBlock);

            _dstart.addMonths(interval);
            _dend.addMonths(interval);
          }
          while(_dstart < dateLimit);

        else {
          logger.warn('BYDAY!!! ', recurSettings.byday);
          _dstart.setUTC(true);
          const byday = byDayRegEx.exec(recurSettings.byday);
          const dayNumber = weekBits[byday[2]];
          const stepCount = parseInt(byday[1], 10) - 1;

          do {
            const _findSun = new Date.create(_dstart, { 'fromUTC': true } ).reset('month');

            const firstDay = _findSun.getDay();
            // find first occurance of the wanted day.

            if (firstDay !== dayNumber) {
              const add = (dayNumber - firstDay + 7) ;
              _findSun.addDays(add).addWeeks(stepCount);
            }
            else
              _findSun.addWeeks(stepCount);

            newBlock = Object.assign({}, _workBlock);
            newBlock.dtstart = new Date(_findSun).addMilliseconds(_workBlock.timeStartMS);
            newBlock.dtend = new Date(_findSun).addMilliseconds(_workBlock.timeEndMS);
            //            logger.info(newBlock.dtstart.medium());
            recurArray.push(newBlock);
            // all done, next.
            _dstart.reset('month').addDays(32);
            _dend.reset('month').addDays(32);
          }
          while(_dstart < dateLimit);

          // something
        }

        return recurArray;
      }

      if (recurSettings.freq === 'WEEKLY') {
        const interval = parseInt(recurSettings.interval, 10) || 1;
        logger.warn(`WEEKLY - ${interval}`);
        let newBlock;

        do {
          newBlock = Object.assign({}, _workBlock);
          newBlock.dtstart = new Date(_dstart);
          newBlock.dtend = new Date(_dend);
          //          logger.info(newBlock.dtstart.medium());
          recurArray.push(newBlock);

          _dstart.addWeeks(interval);
          _dend.addWeeks(interval);
        }
        while(_dstart < dateLimit);
      }

      return recurArray;
    }

    // if we get here we've skipped everything just return the _workblock

    return [];
  }

  function processBlock(block) {
    logger.debug('>> processBlock');
    let _wb;
    const workBlock = {
      'summary': '',
      'dtstart': null,
      'dtend': null,
      'description': '',
      'timeStart': null,
      'timeEnd': null,
      'duration': 0,
      'combined': '',
      'recur': null,
      'timeStartMS': null,
      'timeEndMS': null,
      'ts' : null,
      'allday' : false
    };
    let alarmFlag = false, ws, blockStep;
    for (let step = 0; step < block.length; step++) {
      blockStep = block[step];
      if (blockStep.indexOf(segments.recur) >= 0)
        workBlock.recur = STRING(block[step].split(segments.recur)[1]).collapseWhitespace().s;
      // logger.debug(workBlock.recur);

      if (blockStep.indexOf(segments.summaryID) >= 0)
        workBlock.summary = STRING(block[step].split(segments.summaryID)[1]).collapseWhitespace().s;

      if (blockStep.indexOf(segments.meetingStartID) >= 0) {
        ws = STRING(block[step].split(segments.meetingStartID)[1]).collapseWhitespace().s;
        // workBlock.dtstart = Date.create(ws);
        workBlock.dtstart = new Sugar.Date(ws).raw;
      }
      if (blockStep.indexOf(segments.meetingEndID) >= 0) {
        ws = STRING(block[step].split(segments.meetingEndID)[1]).collapseWhitespace().s;
        // workBlock.dtend = Date.create(ws);
        workBlock.dtend = new Sugar.Date(ws).raw;
      }
      if (blockStep.indexOf(segments.meetingStartAlt) >= 0) {
        ws = STRING(block[step].split(segments.meetingStartAlt)[1]).collapseWhitespace().s;
        // console.log('>> ws', ws);
        // workBlock.dtstart = Date.create(ws);
        // let d = new Sugar.Date();
        workBlock.dtstart = new Sugar.Date(ws).raw;
        // console.log('>> date', workBlock.dtstart);
      }
      if (blockStep.indexOf(segments.meetingEndAlt) >= 0) {
        ws = STRING(block[step].split(segments.meetingEndAlt)[1]).collapseWhitespace().s;
        // workBlock.dtend = Date.create(ws);
        workBlock.dtend = new Sugar.Date(ws).raw;
        // console.log('>> date', workBlock.dtend);
      }

      if (blockStep.indexOf(segments.meetingStartAltOther) >= 0) {
        ws = STRING(block[step].split(segments.meetingStartAltOther)[1]).collapseWhitespace().s;
        // workBlock.dtstart = Date.create(ws);
        workBlock.dtstart = new Sugar.Date(ws).raw;
      }
      if (blockStep.indexOf(segments.meetingEndAltOther) >= 0) {
        ws = STRING(block[step].split(segments.meetingEndAltOther)[1]).collapseWhitespace().s;
        // console.log('>> ws', ws);
        // workBlock.dtend = Date.create(ws);
        workBlock.dtend = new Sugar.Date(ws).raw;
      }

      if (blockStep.indexOf(segments.meetingDescID) >= 0)
        if (!alarmFlag) {
          workBlock.description = STRING(block[step].split(segments.meetingDescID)[1]).collapseWhitespace().s;
        }

      if (blockStep.indexOf(segments.beginAlarm) >= 0)
        alarmFlag = true;
    }

    workBlock.summary = workBlock.summary.replace(/\\/g, '');
    workBlock.description = workBlock.description.replace(/\\/g, '');

    if (workBlock.dtstart !== null) {
      // workBlock.timeStart = workBlock.dtstart.format('{24hr}:{mm}:{ss}');
      workBlock.timeStart = Sugar.Date(workBlock.dtstart).format('{24hr}:{mm}:{ss}').raw;

      workBlock.timeStartMS = ((workBlock.dtstart.getHours() * 60 * 60 ) + (workBlock.dtstart.getMinutes() * 60 ) + workBlock.dtstart.getSeconds()) * 1000;
      // console.log('>> workBlock.timeStart', workBlock.timeStart);
      workBlock.combined = `<em>${workBlock.timeStart}</em> - '`;
      workBlock.long = `<em>${Sugar.Date(workBlock.dtstart).format('{Weekday}').raw}, ${workBlock.timeStart}</em> - `;
      // console.log('>> workBlock.long', workBlock.long);
    }
    workBlock.combined = workBlock.combined + workBlock.summary;
    workBlock.longcombined = workBlock.long + workBlock.summary;
    if (workBlock.dtend !== null) {
      workBlock.timeEnd = Sugar.Date(workBlock.dtend).format('{24hr}:{mm}:{ss}').raw;
      workBlock.timeEndMS = ((workBlock.dtend.getHours() * 60 * 60 ) + (workBlock.dtend.getMinutes() * 60 ) + workBlock.dtend.getSeconds()) * 1000;
    }

    if (workBlock.dtstart !== null && workBlock.dtend !== null) {
      const elapsedTime = new Elapsed(workBlock.dtstart, workBlock.dtend);
      workBlock.duration = elapsedTime.optimal;
      workBlock.combined = `${workBlock.combined }, ${ elapsedTime.optimal}`;
      workBlock.longcombined = `${workBlock.longcombined }, ${ elapsedTime.optimal}`;
    }

    workBlock.allday = (workBlock.timeStart === '0:00:00' && workBlock.timeEnd === '0:00:00');

    return workBlock;
  }

  function buildRecurranceArray(wb) {
    const _wb = processRecurrence(wb);

    return _wb;
  }

  const lines = ical.split('\r\n'), l = lines.length;
  let counter = 0;

  let alarmed = false;
  while (counter < l)
    if (lines[counter].indexOf(segments.begin) < 0)
      counter++;
    else {
      let subcounter = 0;
      const subBlock = [];
      alarmed = false;
      while (subcounter < 75)
        if (lines[counter + subcounter].indexOf(segments.end) < 0) {
          if (lines[counter + subcounter].indexOf(segments.beginAlarm) > -1)
            alarmed = true;

          if (!alarmed)
            subBlock.push(lines[counter + subcounter]);

          if (lines[counter + subcounter].indexOf(segments.endAlarm) > -1)
            alarmed = false;

          subcounter++;
        }
        else
          break;

      counter = counter + subcounter;
      const b = processBlock(subBlock);

      if (!b.recur ) {
        if (Array.isArray(b))
          logger.error('!returned an array...');
        else
        if (b.dtstart !== null) {
          b.ts = b.dtstart.format('{X}');
          workingBlock.push(b);
        }
      }
      else {
        // logger.warn('We need to spread the recurrance!!');
        // logger.debug(b);
        let recurBlocks = buildRecurranceArray(b);

        if (recurBlocks)
          recurBlocks = recurBlocks.map((item) => {
            if (item.dtstart)
              item.ts = item.dtstart.format('{X}');

            return item;
          });

        if (recurBlocks && recurBlocks.length > 0)
          workingBlock = workingBlock.concat(recurBlocks);
      }
    }

  logger.info('- processICAL');
  // If (workingBlock.dtstart == null) return {};

  return workingBlock;
}

/*
['https://calendar.google.com/calendar/ical/martind2000%40gmail.com/private-40cfebc9f7dcfa7fde6b9bf2f0092c93/basic.ics',
    'https://calendar.google.com/calendar/ical/mt5pgdhknvgoc8usfnrso9vkv0%40group.calendar.google.com/private-58876002af9f302a593acfa6fa792dcf/basic.ics',
    'https://www.tripit.com/feed/ical/private/DB96E4BB-94A9BD8F9CC1CF51C6CC0D920840F4F5/tripit.ics',
    'https://calendar.google.com/calendar/ical/en.uk%23holiday%40group.v.calendar.google.com/public/basic.ics',
    'https://calendar.google.com/calendar/ical/i8dglj12p5nuv20sbjmun5s588%40group.calendar.google.com/private-c8adccb41e56d6a2f285078aaed313f5/basic.ics',
    'https://calendar.google.com/calendar/ical/qppj4ebvdur1qui4v0fdpl7l70%40group.calendar.google.com/private-b5071cb2c3fe49544ffbbd08645088f1/basic.ics',
    'https://calendar.google.com/calendar/ical/8h3vi3rd5rvpfe11klvgre0q4c%40group.calendar.google.com/private-e9df93163a7046658946be45fb08db6f/basic.ics',
  'https://calendar.google.com/calendar/embed?src=family18216414236505453132%40group.calendar.google.com&ctz=Europe%2FLondon']
 */
module.exports = {
  'calendars': ['https://calendar.google.com/calendar/ical/martind2000%40gmail.com/private-40cfebc9f7dcfa7fde6b9bf2f0092c93/basic.ics',
      'https://calendar.google.com/calendar/ical/mt5pgdhknvgoc8usfnrso9vkv0%40group.calendar.google.com/private-58876002af9f302a593acfa6fa792dcf/basic.ics',
      'https://www.tripit.com/feed/ical/private/DB96E4BB-94A9BD8F9CC1CF51C6CC0D920840F4F5/tripit.ics',
      'https://calendar.google.com/calendar/ical/en.uk%23holiday%40group.v.calendar.google.com/public/basic.ics',
      'https://calendar.google.com/calendar/ical/i8dglj12p5nuv20sbjmun5s588%40group.calendar.google.com/private-c8adccb41e56d6a2f285078aaed313f5/basic.ics',
      'https://calendar.google.com/calendar/ical/qppj4ebvdur1qui4v0fdpl7l70%40group.calendar.google.com/private-b5071cb2c3fe49544ffbbd08645088f1/basic.ics',
      'https://calendar.google.com/calendar/ical/8h3vi3rd5rvpfe11klvgre0q4c%40group.calendar.google.com/private-e9df93163a7046658946be45fb08db6f/basic.ics',
    'https://calendar.google.com/calendar/embed?src=family18216414236505453132%40group.calendar.google.com&ctz=Europe%2FLondon'],
  'jsonBlock': [],
  'getTodaysSimple': function() {
    'use strict';
    logger.info('+ getTodaysSimple');
    const today = {
      'entries': []
    };

    const _td = new Date.create('today');
    const _tm = new Date.create('tomorrow') - 1 ;

    today.entries = this.jsonBlock.filter((item) => {
      if (!item || !item.dtstart || !item.dtend) return false;

      return item.dtstart.isBetween(_td, _tm) || item.dtend.isBetween(_td, _tm);
    });

    logger.info('- getTodaysSimple');

    return today;
  },
  'getTomorrow': function() {
    'use strict';
    logger.info('+ getTomorrow');
    const today = {
      'entries': []
    };

    const _tm = new Date.create('tomorrow');
    const _da = new Date.create('tomorrow').addDays(1);
    today.entries = this.jsonBlock.filter((item) => {
      if (!item || !item.dtstart || !item.dtend) return false;

      return item.dtstart.isBetween(_tm, _da) || item.dtend.isBetween(_tm, _da);
    });

    logger.info('- getTomorrow');

    return today;
  },
  'getThreeDays': function() {
    logger.info('+ getThreeDays');
    const three = {
      'entries': []
    };

    const _tdms = new Date.create('today').getTime();
    const _tmms = new Date.create('tomorrow').addDays(2).getTime() - 1 ;

    three.entries = this.jsonBlock.filter((item) => {
      if (!item || !item.dtstart || !item.dtend) return false;
      return inRange(item.dtstart.getTime(), _tdms, _tmms) || inRange(item.dtend.getTime(), _tdms, _tmms);
    });


    three.entries = three.entries.map( obj => {
      obj.readDate = moment(obj.dtstart.getTime()).calendar();
      if (obj.allday) {
        let fixReadDate = obj.readDate.split('\n');
        if (fixReadDate.length === 2) {
          obj.readDate = `${fixReadDate[0]}\nAll Day`;
        }
      }
      return obj;
    });
    logger.info('- getThreeDays');

    return three;
  },
  'getWeek': function() {
    'use strict';
    logger.info('+ getWeek');
    const today = {
      'entries': []
    };

    const now = new Date.create('today');
    logger.debug('>> now', now);
    const twoDays = new Date.create('today').addDays(2).beginningOfDay();
    logger.debug('>> twoDays', twoDays);
    const sevenDays = new Date.create('today').addDays(7).beginningOfDay();
    logger.debug('>> sevenDays', sevenDays);
    logger.debug('>> trip', { now, twoDays, sevenDays });

    /* for (let t = 0; t < this.jsonBlock.length; t++)
      // logger.debug('>> between', Sugar.Date(this.jsonBlock[t].dtstart).raw, Sugar.Date(this.jsonBlock[t].dtstart).isBetween(twoDays, sevenDays));
      if (Date(this.jsonBlock[t].dtstart).isBetween(twoDays, sevenDays))
        today.entries.push(this.jsonBlock[t]);*/

    today.entries = this.jsonBlock.filter((item) => {
      if (!item || !item.dtstart || !item.dtend) return false;

      return item.dtstart.isBetween(twoDays, sevenDays) || item.dtend.isBetween(twoDays, sevenDays);
    });

    logger.info('- getWeek');

    return today;
  },
  'getTodaysMeetings': function() {
    'use strict';
    logger.info('+ getTodaysMeetings');
    const today = {
      'previous': [], 'upcoming': [], 'current': {}
    };
    const now = new Date();

    for (let t = 0; t < this.jsonBlock.length; t++)
      if (Sugar.Date(this.jsonBlock[t].dtstart).isToday().raw) {
        if (Sugar.Date(this.jsonBlock[t].dtstart).isAfter(now).raw)
          today.upcoming.push(this.jsonBlock[t]);
        else
          today.previous.push(this.jsonBlock[t]);

        if (now.isBetween(this.jsonBlock[t].dtstart, this.jsonBlock[t].dtend))
          today.current = this.jsonBlock[t];
      }

    //     logger.debug(today);
    logger.info('- getTodaysMeetings');

    return today;
  }, 'getSimpleCalV2': function(url, cb) {
    'use strict';
    const self = this;

    // Var calJson = [];
    try {
      request(url, function(err, res, body) {
        if (err) {
          logger.error('Get remote Calendar Request failed');
          // Callback.call(null, new Error('Request failed'));

          return;
        }

        self.jsonBlock = processICAL(body);

        // logger.debug(self.jsonBlock);
        const st = self.getTodaysSimple();

        if (typeof cb === 'function')
          cb(st);
      }, function(error, response, body) {
        if (response.statusCode !== 200) {
          logger.error(response.statusCode);
          logger.error(body);
        }
      });
    }
    catch (e) {
      logger.error(e);
    }
  }, 'getSimpleCalV3': function(url) {
    'use strict';
    const self = this;

    return new Promise(function(resolve, reject) {
      try {
        request(url, function(err, res, body) {
          if (err)
            //  logger.error(err);
            return reject(err);
          // Throw err;

          self.jsonBlock = processICAL(body);

          logger.debug(self.jsonBlock);
          const st = self.getTodaysSimple();

          return resolve(st);
        }, function(error, response, body) {
          if (response.statusCode !== 200) {
            logger.error(response.statusCode);
            // logger.error(body);

            return reject(error);
          }
        });
      }
      catch (e) {
        logger.error(e);

        return reject(e);
      }
    });

    // Var calJson = [];
  }, 'getAdvancedCalV3': function(url) {
    'use strict';
    const self = this;

    return new Promise(function(resolve, reject) {
      try {
        request(url, function(err, res, body) {
          if (err)
          //  logger.error(err);
            return reject(err);
          // Throw err;

          self.jsonBlock = processICAL(body);

          logger.debug('jsonBlock length', self.jsonBlock.length);
          // logger.debug(self.jsonBlock);
          const st = self.getTodaysSimple().entries;
          const tom = self.getTomorrow().entries;
          const week = self.getWeek().entries;
          const three = self.getThreeDays().entries;

          const obj = { 'today': st, 'tomorrow': tom, 'week': week, 'three':three };

          // logger.warn(obj);

          return resolve(obj);
        }, function(error, response, body) {
          if (response.statusCode !== 200) {
            logger.error(response.statusCode);
            // logger.error(body);

            return reject(error);
          }
        });
      }
      catch (e) {
        logger.error(e);

        return reject(e);
      }
    });

    // Var calJson = [];
  }

  /**
   * Created by Martin on 16/02/2016.
   */
};