patrik-csak/license-plate-serial-generator

import arrayShuffle from 'array-shuffle';
import {random as randomBb26} from 'bb26';
import randomItem from 'random-item';
import {randomNumericString} from '../../lib';

/**
 * Generates random serial for [Idaho](https://en.wikipedia.org/wiki/Vehicle_registration_plates_of_Idaho#1968_to_present)
 *
 * **Serial formats**, where `XX` is a county code:
 *
 * - `X 123456`
 * - `XX 12345`
 * - `XX A1234`
 * - `XX A1234`
 * - `XX AB123`
 * - `XX 1A234`
 * - `XX 1234A`
 * - `XX 123AB`
 * - `XXX 1234`
 * - `XXX A123`
 *
 * ```
 * import { idaho } from 'license-plate-serial-generator'
 *
 * idaho() // 'K 066648'
 * ```
 */
export default function idaho(): string {
    interface County {
        letter: string;
        count: number;
    }

    const counties: County[] = [
        {letter: 'A', count: 2},
        {letter: 'B', count: 10},
        {letter: 'C', count: 7},
        {letter: 'E', count: 1},
        {letter: 'F', count: 2},
        {letter: 'G', count: 2},
        {letter: 'I', count: 1},
        {letter: 'J', count: 2},
        {letter: 'K', count: 1},
        {letter: 'L', count: 4},
        {letter: 'M', count: 2},
        {letter: 'N', count: 1},
        {letter: 'O', count: 2},
        {letter: 'P', count: 2},
        {letter: 'S', count: 1},
        {letter: 'T', count: 2},
        {letter: 'V', count: 1},
        {letter: 'W', count: 1}
    ];
    const countyCodes: string[] = [];
    let numbers: string;
    let right = '';

    for (const county of counties) {
        for (let i = 0; i < county.count; i++) {
            const number = county.count > 1 ? `${i + 1}` : '';

            countyCodes.push(number + county.letter);
        }
    }

    const countyCode = randomItem(countyCodes);

    switch (countyCode.length) {
        case 1: {
            // There's only one county character, so the format must be
            // `A 123456`

            right = randomNumericString(999999);

            break;
        }

        case 2: {
            // There are two county characters, so the format can be
            // `0A 12345`, `0A A1234`, `0A AB123`, `0A 1A234`, `0A 1234A`, or
            // `0A 123AB`

            numbers = randomNumericString(randomItem([999, 9999, 99999]));

            switch (numbers.length) {
                case 3: {
                    const letters = randomBb26('ZZ');
                    numbers = randomNumericString(999);

                    right =
                        letters.length === 1
                            ? randomNumericString(9) + letters + numbers
                            : arrayShuffle([letters, numbers]).join('');

                    break;
                }

                case 4: {
                    const letter = randomBb26('Z');
                    numbers = randomNumericString(9999);

                    right = arrayShuffle([letter, numbers]).join('');

                    break;
                }

                case 5: {
                    right = numbers;

                    break;
                }
                // No default
            }

            break;
        }

        case 3: {
            // There are three county characters, so the format can be
            // `CCC 1234` or `CCC A123`

            numbers = randomNumericString(randomItem([999, 9999]));

            right = numbers.length === 3 ? randomBb26('Z') + numbers : numbers;

            break;
        }
        // No default
    }

    return `${countyCode} ${right}`;
}