<?php
/**
 * Output size for the OpenAI image models.
 *
 * @package Fitzaro
 */

namespace Fitzaro\Provider\OpenAi;

defined( 'ABSPATH' ) || exit;

/**
 * Keeps the output in the photo's aspect ratio: when they differ, the model re-composes the scene
 * (pose, hands, background and face change, the frame gets cropped).
 *
 * The gpt-image-2 family accepts any WIDTHxHEIGHT with both sides divisible by 16 and a ratio
 * between 1:3 and 3:1. Older models only take 1024x1024, 1024x1536 and 1536x1024.
 */
final class OutputSize {

	/**
	 * Longest side of the output, in pixels.
	 */
	public const LONGEST = 1536;

	/**
	 * The size parameter for a photo of $width x $height.
	 *
	 * @param string $model  Model name.
	 * @param int    $width  Photo width.
	 * @param int    $height Photo height.
	 */
	public static function for( string $model, int $width, int $height ): string {
		if ( $width < 1 || $height < 1 ) {
			return '1024x1536';
		}

		if ( 0 !== strpos( $model, 'gpt-image-2' ) ) {
			$ratio = $width / $height;
			if ( $ratio < 0.83 ) {
				return '1024x1536';
			}

			return $ratio > 1.2 ? '1536x1024' : '1024x1024';
		}

		$ratio = max( 1 / 3, min( 3, $width / $height ) );
		$w     = $ratio <= 1 ? self::LONGEST * $ratio : self::LONGEST;
		$h     = $ratio <= 1 ? self::LONGEST : self::LONGEST / $ratio;

		return self::to16( $w ) . 'x' . self::to16( $h );
	}

	/**
	 * Nearest multiple of 16, at least 16.
	 *
	 * @param float $value Pixels.
	 */
	private static function to16( float $value ): int {
		return max( 16, (int) round( $value / 16 ) * 16 );
	}
}