import {Injectable} from '@angular/core';
import {NgbDateParserFormatter, NgbDateStruct} from '@ng-bootstrap/ng-bootstrap';


@Injectable()
export class NgbDateDEParserFormatter extends NgbDateParserFormatter {

    public parse(value: string): NgbDateStruct {

        if (!value) return null as any;

        const dateParts = value.trim().split('.');

        if (dateParts.length === 1 && this.isNumber(dateParts[0])) {
            return {
                year: this.toInteger(dateParts[0]),
                month: null,
                day: null
            } as any;
        } else if (dateParts.length === 2 && this.isNumber(dateParts[0]) && this.isNumber(dateParts[1])) {
            return {
                year: this.toInteger(dateParts[1]),
                month: this.toInteger(dateParts[0]),
                day: null
            } as any;
        } else if (dateParts.length === 3 && this.isNumber(dateParts[0]) && this.isNumber(dateParts[1])
            && this.isNumber(dateParts[2])) {
            return {
                year: this.toInteger(dateParts[2]),
                month: this.toInteger(dateParts[1]),
                day: this.toInteger(dateParts[0])
            };
        }

        return null as any;
    }


    public format(date: NgbDateStruct): string {

        let stringDate: string = '';

        if (date) {
            stringDate += this.isNumber(date.day) ? this.padNumber(date.day) + '.' : '';
            stringDate += this.isNumber(date.month) ? this.padNumber(date.month) + '.' : '';
            stringDate += date.year;
        }

        return stringDate;
    }


	private padNumber(value: number) {

	    return (this.isNumber(value)) ? `0${value}`.slice(-2) : '';
	}


	private isNumber(value: any): boolean {

	    return !isNaN(this.toInteger(value));
	}


	private toInteger(value: any): number {

	    return parseInt(`${value}`, 10);
	}
}