<?php
namespace Vichan\Service\Media;

use Vichan\Data\{Exif, ImageMetadataResult};
use Vichan\Functions\Mime;


class MagickImageMetadataReader implements ImageMetadataReader {
	private string $prefix;


	private static function parseOrientation(string $str): ?int {
		switch ($str) {
			case 'Undefined':
				return Exif::EXIF_ORIENTATION_UNDEFINED;
			case 'TopLeft':
				return Exif::EXIF_ORIENTATION_0_UPRIGHT;
			case 'TopRight':
				return Exif::EXIF_ORIENTATION_0_FLIPPED;
			case 'BottomRight':
				return Exif::EXIF_ORIENTATION_180_UPRIGHT;
			case 'BottomLeft':
				return Exif::EXIF_ORIENTATION_180_FLIPPED;
			case 'LeftTop':
				return Exif::EXIF_ORIENTATION_90_UPRIGHT;
			case 'RightTop':
				return Exif::EXIF_ORIENTATION_90_FLIPPED;
			case 'RightBottom':
				return Exif::EXIF_ORIENTATION_270_UPRIGHT;
			case 'LeftBottom':
				return Exif::EXIF_ORIENTATION_270_FLIPPED;
			case 'Unrecognized':
			default:
				return null;
		}
	}

	public static function createImageMagickReader(): MagickImageMetadataReader {
		return new self('magick');
	}

	public static function createGraphicsMagickReader(): MagickImageMetadataReader {
		return new self('gm');
	}

	private function __construct(string $prefix) {
		$this->prefix = $prefix;
	}

	public function getMetadata(string $file_path): ImageMetadataResult {
		$arg = \escapeshellarg("$file_path[0]");
		$ret_exec = shell_exec_error("{$this->prefix} identify -format \"%w %h %m\" $arg");

		if (!\is_string($ret_exec)) {
			throw new \RuntimeException("Error while executing identify");
		}
		$ret_match = \preg_match('/^(\d+) (\d+) ([\w\d]+) ([\w]+)$/', $ret_exec, $m);
		if (!$ret_match) {
			throw new \RuntimeException("Could not parse identify output");
		}
		$width = $m[1];
		$height = $m[2];
		$ext = $m[3];
		$orientation_str = $m[4];

		$mime = Mime\ext_to_mime($ext) ?? 'application/octet-stream';
		$exif_orientation = self::parseOrientation($orientation_str);
		return new ImageMetadataResult($width, $height, $mime, $exif_orientation);
	}
}