import {Injectable} from '@angular/core';
import {PersianService} from './persian-service';
import {InvalidServiceInputError} from './InvalidServiceInput.error';

@Injectable({
    providedIn: 'root'
})
export class PersianNumberService implements PersianService {
    static persianNumberPattern = '\u06F0-\u06F9';
    private static persianNumbersTable = ['\u06F0', '\u06F1', '\u06F2', '\u06F3', '\u06F4', '\u06F5', '\u06F6', '\u06F7', '\u06F8', '\u06F9'];
    private static englishNumbersTable = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];

    /**
     * Splits input value by persian letters and then returns length of matched array.
     *
     * @param value
     * @return 0 if input value has no persian letter, numbers of persian letters in the input value otherwise.
     */
    private static _getMatchedPatternLength(value: string): number {
        // Language=JSRegexp
        const matchResult = value.match(new RegExp(`[${PersianNumberService.persianNumberPattern}]`, 'g'));
        return matchResult ? matchResult.length : 0;
    }

    /**
     * Checks if input value contains any persian number or not.
     *
     * @param value
     * @return true if input value contains any persian number. false otherwise.
     */
    containsPersian(value: string): boolean {
        if (!value) {
            return false;
        }
        // Language=JSRegexp
        const persianRegex = new RegExp(`[${PersianNumberService.persianNumberPattern}]`);
        return persianRegex.test(value);
    }

    /**
     * Checks if input value contains only persian letters.
     *
     * @param value
     */
    isPersian(value: string): boolean {
        if (!value) {
            return false;
        }
        return value.length === PersianNumberService._getMatchedPatternLength(value);
    }

    /**
     * Converts arabic numbers to the persian ones.
     *
     * @param value
     */
    arabicToPersian(value: string): string {
        return value.replace(
            /٤/g,
            PersianNumberService.persianNumbersTable[4]
        ).replace(
            /٥/g,
            PersianNumberService.persianNumbersTable[5]
        ).replace(
            /٦/g,
            PersianNumberService.persianNumbersTable[6]
        );
    }

    /**
     * Converts all arabic and english numbers to the persian numbers.
     *
     * @param value
     */
    toPersian(value: string | number): string {
        if (value === undefined || value === null) {
            throw new InvalidServiceInputError();
        }
        let persianValue: string = value.toString();
        persianValue = this.arabicToPersian(persianValue);
        let regex: RegExp;
        for (let i = 0; i < PersianNumberService.persianNumbersTable.length; i++) {
            // Language=JSRegexp
            regex = new RegExp(`[${PersianNumberService.englishNumbersTable[i]}]`, 'g');
            persianValue = persianValue.replace(regex, PersianNumberService.persianNumbersTable[i]);
        }
        return persianValue;
    }

    /**
     * Convert persian numbers in input value to the english numbers.
     *
     * @param value
     */
    toEnglish(value: string): string {
        let englishValue: string = value;
        let regex: RegExp;
        for (let i = 0; i < PersianNumberService.englishNumbersTable.length; i++) {
            // Language=JSRegexp
            regex = new RegExp(`[${PersianNumberService.persianNumbersTable[i]}]`, 'g');
            englishValue = englishValue.replace(regex, PersianNumberService.englishNumbersTable[i]);
        }
        return englishValue;
    }
}