<?php

namespace KTXC\Db;

use MongoDB\BSON\UTCDateTime as MongoUTCDateTime;
use DateTimeInterface;

/**
 * Wrapper for MongoDB\BSON\UTCDateTime
 * Provides abstraction layer for MongoDB datetime handling
 */
class UTCDateTime
{
    private MongoUTCDateTime|string $dateTime;

    /**
     * Create a new UTCDateTime
     * 
     * @param int|DateTimeInterface|null $milliseconds Milliseconds since epoch, or DateTime object
     */
    public function __construct(int|DateTimeInterface|null $milliseconds = null)
    {
        // Check if MongoDB extension is loaded
        if (class_exists(MongoUTCDateTime::class)) {
            $this->dateTime = new MongoUTCDateTime($milliseconds);
        } else {
            // Fallback for environments without MongoDB extension (testing, linting)
            $this->dateTime = (new \DateTimeImmutable('now', new \DateTimeZone('UTC')))->format(DATE_ATOM);
        }
    }

    /**
     * Get the string representation
     */
    public function __toString(): string
    {
        if ($this->dateTime instanceof MongoUTCDateTime) {
            return $this->dateTime->toDateTime()->format(DATE_ATOM);
        }
        return $this->dateTime;
    }

    /**
     * Get the underlying MongoDB UTCDateTime or fallback string
     * Used internally when interacting with MongoDB driver
     */
    public function toBSON(): MongoUTCDateTime|string
    {
        return $this->dateTime;
    }

    /**
     * Convert to PHP DateTime
     */
    public function toDateTime(): \DateTimeImmutable
    {
        if ($this->dateTime instanceof MongoUTCDateTime) {
            return \DateTimeImmutable::createFromMutable($this->dateTime->toDateTime());
        }
        return new \DateTimeImmutable($this->dateTime);
    }

    /**
     * Get milliseconds since epoch
     */
    public function toMilliseconds(): int
    {
        if ($this->dateTime instanceof MongoUTCDateTime) {
            return (int) $this->dateTime;
        }
        return (int) ((new \DateTimeImmutable($this->dateTime))->getTimestamp() * 1000);
    }

    /**
     * Create from DateTime
     */
    public static function fromDateTime(DateTimeInterface $dateTime): self
    {
        return new self($dateTime);
    }

    /**
     * Create current timestamp
     */
    public static function now(): self
    {
        return new self();
    }
}