<?php

namespace BookStack\Uploads;

use BookStack\Exceptions\ImageUploadException;
use GuzzleHttp\Psr7\Utils;
use Intervention\Image\Exception\NotSupportedException;
use Intervention\Image\Image as InterventionImage;
use Intervention\Image\ImageManager;

class ImageResizer
{
    public function __construct(
        protected ImageManager $intervention
    ) {
    }

    /**
     * Resize the image of given data to the specified size, and return the new image data.
     *
     * @throws ImageUploadException
     */
    protected function resizeImageData(string $imageData, ?int $width, ?int $height, bool $keepRatio): string
    {
        try {
            $thumb = $this->intervention->make($imageData);
        } catch (NotSupportedException $e) {
            throw new ImageUploadException(trans('errors.cannot_create_thumbs'));
        }

        $this->orientImageToOriginalExif($thumb, $imageData);

        if ($keepRatio) {
            $thumb->resize($width, $height, function ($constraint) {
                $constraint->aspectRatio();
                $constraint->upsize();
            });
        } else {
            $thumb->fit($width, $height);
        }

        $thumbData = (string) $thumb->encode();

        // Use original image data if we're keeping the ratio
        // and the resizing does not save any space.
        if ($keepRatio && strlen($thumbData) > strlen($imageData)) {
            return $imageData;
        }

        return $thumbData;
    }

    /**
     * Orientate the given intervention image based upon the given original image data.
     * Intervention does have an `orientate` method but the exif data it needs is lost before it
     * can be used (At least when created using binary string data) so we need to do some
     * implementation on our side to use the original image data.
     * Bulk of logic taken from: https://github.com/Intervention/image/blob/b734a4988b2148e7d10364b0609978a88d277536/src/Intervention/Image/Commands/OrientateCommand.php
     * Copyright (c) Oliver Vogel, MIT License.
     */
    protected function orientImageToOriginalExif(InterventionImage $image, string $originalData): void
    {
        if (!extension_loaded('exif')) {
            return;
        }

        $stream = Utils::streamFor($originalData)->detach();
        $exif = @exif_read_data($stream);
        $orientation = $exif ? ($exif['Orientation'] ?? null) : null;

        switch ($orientation) {
            case 2:
                $image->flip();
                break;
            case 3:
                $image->rotate(180);
                break;
            case 4:
                $image->rotate(180)->flip();
                break;
            case 5:
                $image->rotate(270)->flip();
                break;
            case 6:
                $image->rotate(270);
                break;
            case 7:
                $image->rotate(90)->flip();
                break;
            case 8:
                $image->rotate(90);
                break;
        }
    }
}