<?php

declare(strict_types=1);

namespace Uwil\ArcadiaApiPhpClient\Utils;

final readonly class DateUtils
{
    private const FRENCH_DATE_REGEX   = '/^\d{4}-\d{2}-\d{2}$/';

    private const ISO8601_REGEX       = '/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z$/';

    private const RFC3339_REGEX       = '/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d+)?(?:Z|[+\-]\d{2}:\d{2})$/';

    public function __construct()
    {
        throw new \Error('Abstract class');
    }

    public static function toRfc3339(\DateTimeInterface | string $datetime): string
    {
        $datetime = is_string($datetime) ? self::parseDateTime($datetime) : $datetime;

        return $datetime->format(\DATE_RFC3339);
    }

    public static function parseDateTime(string $datetime): \DateTimeInterface
    {
        $datetime = trim($datetime);

        /** @var \DateTimeInterface|null */
        $output = null;

        switch (true) {
            case (bool) preg_match(self::FRENCH_DATE_REGEX, $datetime):
                $output = self::parseFrench($datetime);
                break;
            case (bool) preg_match(self::RFC3339_REGEX, $datetime):
                $output = self::parseRfc3339($datetime);
                break;
            case (bool) preg_match(self::ISO8601_REGEX, $datetime):
                $output = self::parseIso8601($datetime);
                break;
            default:
                try {
                    $output = new \DateTimeImmutable($datetime);
                } catch (\Exception $e) {
                    throw new \InvalidArgumentException('Unrecognized date/time format: ' . $datetime);
                }
        }

        return $output;
    }

    protected static function parseFrench(string $datetime): \DateTimeInterface
    {
        $dt = \DateTimeImmutable::createFromFormat('Y-m-d H:i:s', $datetime . ' 00:00:00');

        return $dt ?: self::parseFallback($datetime);
    }

    protected static function parseRfc3339(string $datetime): \DateTimeInterface
    {
        $dt = \DateTimeImmutable::createFromFormat(\DateTime::RFC3339, $datetime);
        if ($dt !== false) {
            return $dt;
        }

        $dt = \DateTimeImmutable::createFromFormat('Y-m-d\TH:i:s.uP', $datetime);

        return $dt ?: self::parseFallback($datetime);
    }

    protected static function parseIso8601(string $datetime): \DateTimeInterface
    {
        $dt = \DateTimeImmutable::createFromFormat(\DateTimeInterface::ATOM, $datetime);

        return $dt ?: self::parseFallback($datetime);
    }

    protected static function parseFallback(string $datetime): \DateTimeInterface
    {
        try {
            return new \DateTimeImmutable($datetime);
        } catch (\Throwable $e) {
            throw new \InvalidArgumentException("Unrecognized date/time format: {$datetime}");
        }
    }
}