import * as moment from 'moment';
import { Component, ViewChildren, QueryList, ElementRef, ViewChild, Input, Output, EventEmitter, SimpleChanges } from '@angular/core';
import { PickerController, PickerColumn, Picker } from 'ionic-angular';

const monthNames = ['January', 'February', 'March', 'April', 'May', 'June', 'July',
                    'August', 'September', 'October', 'November', 'December']

const monthShortNames = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul',
                    'Aug', 'Sept', 'Oct', 'Nov', 'Dec']

interface IEventYear {
  year: number;
  months: IEventMonth[];
  dates: Date[];
}

interface IEventMonth {
  month: number;
  monthName: string;
  days: number[];
  dates: Date[];
}

@Component({
  selector: 'ionic-conference-calendar-header',
  template: `
<div class="header-calendar-wrapper">

  <div (click)="openDatePicker()">
    <div *ngIf="viewType === 'days';else month_datepicker_view">
      <div class="datepicker-headline">{{getMonthName()}}</div>
      <div class="datepicker-subline">{{activeYear}}</div>
    </div>

    <ng-template #month_datepicker_view>
      <div class="datepicker-headline">{{activeYear}}</div>
    </ng-template>
  </div>

  <div #selectionWrapper class="selection-wrapper">

    <div #selectionSlider
         *ngIf="years.length"
         [style.width]="getSliderWidth() + 'px'"
         class="selection-slider">

      <div class="selection-slider-padding"></div>

      <div *ngIf="viewType === 'days';else month_selection_view">
        <div #selection 
            *ngFor="let d of getDaysInMonth()"
            [ngClass]="{active: d == activeDay}"
            (click)="setActiveDay(d)"
            class="selection">
            {{d}}
        </div>
      </div>

      <ng-template #month_selection_view>
        <div #selection
            *ngFor="let m of getMonthsInYear()"
            [ngClass]="{active: m == activeMonth}"
            (click)="setActiveMonth(m)"
            class="selection">
            {{getMonthShortName(m)}}
        </div>
      </ng-template>

      <div class="selection-slider-padding"></div>
            
    </div>

  </div>

</div>
`
})
export class IonicConferenceCalendarHeader {

  private margin: number = 0.5;

  private selectionWidth: number = 64;

  private years: IEventYear[] = [];

  private pickerYearColumn: PickerColumn;

  private pickerMonthColumn: PickerColumn;

  public sliderWidth: number;

  public activeYear: number;

  public activeMonth: number;

  public activeDay: number;

  @Output('change') change = new EventEmitter<string | Date>();

  @Input('dates') dates: Array<string | Date> = [];

  @Input('date') date: string | Date;

  @Input('view') viewType: 'days' | 'months' = 'days';

  @ViewChild('selectionWrapper') selectionWrapper: ElementRef;

  @ViewChild('selectionSlider') selectionSlider: ElementRef;

  @ViewChildren('selection') selections: QueryList<ElementRef>;

  constructor(private pickerController: PickerController) {}

  public ngOnChanges(changes: SimpleChanges) {
    var activeDateChanged = false;
    var datesChanged = false;

    if(!this.pickerMonthColumn) {
      this.pickerMonthColumn = {
        name: 'Month',
        align: 'center',
        options: []
      };

      this.pickerYearColumn = {
        name: 'Year',
        align: 'center',
        options: []
      };
    }

    if(changes.dates) {
      this.expandEvents();

      if(!changes.date) {
        this.setActiveYear(this.years[0].year, false);
      }
    }

    if(changes.date) {
      var dt = moment(this.date);
      this.setActiveDay(dt.utc().date(), dt.utc().month(), dt.utc().year(), false);
    }
  }

  public getSliderWidth(): number {
    var selectionWrapperWidth = (<HTMLDivElement>this.selectionWrapper.nativeElement).offsetWidth;

    let possibleSelections = 0;

    if(this.viewType === 'days') {
      possibleSelections = this.getDaysInMonth().length;
    } else {
      possibleSelections = this.getMonthsInYear().length;
    }
    

    return Math.max((selectionWrapperWidth + this.selectionWidth+(this.selectionWidth*this.margin)) * possibleSelections);
  }

  /**
   * Takes all this.dates and expands into years array
   */
  private expandEvents() {
    this.years = [];

    this.dates.forEach((dt) => {
      var date = moment(dt);

      var nDay = date.utc().date();
      var nYear = date.utc().year();
      var nMonth = date.utc().month();
      var monthName = monthNames[nMonth];

      var year = this.years.filter((yr) => {
        return yr.year === nYear;
      })[0];

      if(!year) {
        year = {
          year: nYear,
          dates: [],
          months: []
        };

        this.years.push(year);
      }

      year.dates.push(date.toDate());

      var month = year.months.filter(m => {
        return m.month === nMonth;
      })[0];

      if(!month) {
        month = {
          month: nMonth,
          monthName: monthName,
          dates: [],
          days: []
        };

        year.months.push(month);
      }

      month.dates.push(date.toDate());

      if(month.days.indexOf(nDay) == -1) {
        month.days.push(nDay);
      }

      month.days = month.days.sort((a, b) => {
        if(a > b) {
          return 1;
        } else if (b > a) {
          return -1;
        }

        return 0;
      });

      year.months = year.months.sort((a, b) => {
        if(a.month > b.month) {
          return 1;
        } else if (b.month > a.month) {
          return -1;
        }

        return 0;
      });

    });

    this.years = this.years.sort((a, b) => {
      if(a.year > b.year) {
          return 1;
      } else if (b.year > a.year) {
        return -1;
      }

      return 0;
    });

    this.years.forEach(yr => {
      this.pickerYearColumn.options.push({
        value: yr.year,
        text: yr.year.toString()
      });
    });
  }

  public getMonthsInYear(y: number = this.activeYear): number[] {
    return this.getYear(y).months.map(m => m.month);
  }

  public getDaysInMonth(m: number = this.activeMonth, y: number = this.activeYear) : number[] {
    return this.getMonth(m, y).days;
  }

  private getYear(y: number = this.activeYear) {
    return this.years.filter((yr) => {
      return yr.year === y;
    })[0];
  }

  private getMonth(m: number = this.activeMonth, y: number = this.activeYear) {
    var year = this.getYear(y);

    return year.months.filter((mn) => {
      return mn.month === m;
    })[0];
  }

  public setActiveMonth(m: number, y: number = this.activeYear, emitEvent: boolean = true) {
    this.activeYear = y;
    this.activeMonth = m;
    this.setActiveDay(this.getMonth(m, y).days[0], m, y, emitEvent);
  }

  public setActiveYear(y: number, emitEvent: boolean = true) {
    this.activeYear = y;
    var year = this.getYear(y);
    this.setActiveMonth(this.getYear(y).months[0].month, y, emitEvent);
  }

  public setActiveDay(d: number, m: number = this.activeMonth, y: number = this.activeYear, emitEvent: boolean = true) {
    this.activeYear = y;
    this.activeMonth = m;
    this.activeDay = d;

    this.updateSelectionScrollPosition();

    if(emitEvent) {
      let ds = this.getDateString();
      console.log(ds);
      this.change.emit(ds);
    }
  }

  public getSelectionIndex() {
    if(this.viewType === 'days') {
      return this.getDaysInMonth().indexOf(this.activeDay);
    } else {
      return this.getMonthsInYear().indexOf(this.activeMonth);
    }
  }

  public updateSelectionScrollPosition() {
    if(this.selections) {
      let idx = this.getSelectionIndex();
      var day = this.selections.toArray()[idx];
      let offset = (<HTMLDivElement>day.nativeElement).offsetLeft - this.selectionWrapper.nativeElement.offsetWidth/2 + this.selectionWidth/2;

      this.scrollTo(offset);
    }
  }

  public getMonthName(m: number = this.activeMonth) {
    return monthNames[m];
  }

  public getMonthShortName(m: number = this.activeMonth) {
    return monthShortNames[m];
  }

  public openDatePicker() {

    this.updatePickerMonthOptions(this.years[0].year);

    // Short circuit if no meaningful options exist
    if(this.viewType === 'days') {
      if(this.years.length < 2 && this.pickerMonthColumn.options.length < 2) {
        return;
      }
    } else {
      if(this.years.length < 2) {
        return;
      }
    }

    let columns: PickerColumn[] = [];

    if(this.years.length > 1) {
      columns.push(this.pickerYearColumn);
    }

    if(this.viewType === 'days') {
      columns.push(this.pickerMonthColumn);
    }

    var picker = this.pickerController.create({
      columns: columns,
      buttons: [
        {
          text: 'Cancel',
          role: 'cancel'
        },
        {
          text: 'Done',
          handler: (data: any) => {
            if(data.Month) {
              this.setActiveMonth(data.Month.value, data.Year ? data.Year.value : this.years[0].year);
            } else {
              this.setActiveMonth(this.getMonthsInYear(data.Year.value)[0], data.Year.value);
            }
          }
        }
      ]
    });

    if(this.viewType === 'days') {
      let yr = this.years[0].year;

      /**
       * July, 15 2017
       * 
       * Hacked the shit out of this. As of this date, current ControlPicker does not support dynamic column items.
       * If they update this, this should be unhacked.
       * 
       * Didn't mean to introduce lavaflow this early.
       */

      picker.ionChange.subscribe((change) => {
        if(change.Year && change.Year.value !== yr) {

          yr = change.Year.value;

          this.updatePickerMonthOptions(yr);

          setTimeout(() => {
            (<any>picker)._cmp._component._cols._results.forEach(r => {
              r.col.prevSelected = null
            });

            picker.refresh();
          });
        }
      });
    }

    picker.present();

    setTimeout(() => {
      (<any>picker)._cmp._component._cols._results.forEach(r => {
        r.lastIndex = 0;
        r.col.selectedIndex = 0;
        r.col.prevSelected = null
      });
      
      picker.refresh();
    });
  }

  private updatePickerMonthOptions(year: number) {
    this.pickerMonthColumn.options.length = 0;
    
    this.getYear(year).months.forEach((mn) => {
      this.pickerMonthColumn.options.push({
        value: mn.month,
        text: mn.monthName
      });
    });
  }

  private getDateString(date: string | Date = null) {
    if(!date) {
      return `${this.activeYear}-${this.padLeft(this.activeMonth+1)}-${this.padLeft(this.activeDay) }`;
    }

    var dt = moment(date);

    var day = dt.utc().date();
    var month = dt.utc().month();
    var year = dt.utc().year();

    return `${year}-${this.padLeft(month+1)}-${this.padLeft(day)}`;
  }

  private scrollTo(to) {
    var ele = <HTMLDivElement>this.selectionWrapper.nativeElement;

    ele.scrollLeft = to;
  }

  private padLeft(n: number) {
    let str = n.toString();
    let pad = '00';
    return pad.substr(0, pad.length - str.length) + str;
  }
}