<?php
declare(strict_types=1);

namespace Esun\BlogImport\Model;

use Magento\Framework\Exception\LocalizedException;
use Symfony\Component\Process\Exception\ProcessFailedException;
use Symfony\Component\Process\Process;

class MediaNormalizer
{
    /** @var array<string, int> */
    private const EXPECTED_IMAGE_TYPES = [
        'gif' => IMAGETYPE_GIF,
        'jpeg' => IMAGETYPE_JPEG,
        'jpg' => IMAGETYPE_JPEG,
        'png' => IMAGETYPE_PNG,
    ];

    public function needsNormalization(string $path): bool
    {
        $expectedType = $this->getExpectedType($path);
        if ($expectedType === null) {
            return false;
        }

        return $this->getActualType($path) !== $expectedType;
    }

    /**
     * Convert image data in place so that its real format matches its filename extension.
     *
     * @throws LocalizedException
     */
    public function normalize(string $path): bool
    {
        $expectedType = $this->getExpectedType($path);
        if ($expectedType === null) {
            return false;
        }

        $actualType = $this->getActualType($path);
        if ($actualType === $expectedType) {
            return false;
        }

        $createCallback = match ($actualType) {
            IMAGETYPE_GIF => 'imagecreatefromgif',
            IMAGETYPE_JPEG => 'imagecreatefromjpeg',
            IMAGETYPE_PNG => 'imagecreatefrompng',
            IMAGETYPE_WEBP => 'imagecreatefromwebp',
            default => null,
        };
        if ($createCallback === null || !is_callable($createCallback)) {
            throw new LocalizedException(
                __('Cannot convert unsupported image data in %1.', $path)
            );
        }

        $sourceImage = @$createCallback($path);

        $temporaryPath = tempnam(dirname($path), '.esun-media-');
        if ($temporaryPath === false) {
            if ($sourceImage instanceof \GdImage) {
                imagedestroy($sourceImage);
            }
            throw new LocalizedException(__('Unable to create a temporary image beside %1.', $path));
        }

        try {
            $written = $sourceImage instanceof \GdImage
                ? $this->writeImage($sourceImage, $temporaryPath, $expectedType)
                : $this->writeAnimatedWebp($path, $temporaryPath, $actualType, $expectedType);
            if (!$written) {
                throw new LocalizedException(__('Unable to encode image %1.', $path));
            }
            $permissions = fileperms($path);
            if ($permissions !== false) {
                @chmod($temporaryPath, $permissions & 0777);
            }
            if (!@rename($temporaryPath, $path)) {
                throw new LocalizedException(__('Unable to replace image %1 after conversion.', $path));
            }
        } finally {
            if ($sourceImage instanceof \GdImage) {
                imagedestroy($sourceImage);
            }
            if (is_file($temporaryPath)) {
                @unlink($temporaryPath);
            }
        }

        return true;
    }

    private function getExpectedType(string $path): ?int
    {
        $extension = strtolower(pathinfo($path, PATHINFO_EXTENSION));

        return self::EXPECTED_IMAGE_TYPES[$extension] ?? null;
    }

    /** @throws LocalizedException */
    private function getActualType(string $path): int
    {
        $imageInfo = @getimagesize($path);
        if ($imageInfo === false || !isset($imageInfo[2])) {
            throw new LocalizedException(__('Unable to determine the real image format of %1.', $path));
        }

        return (int)$imageInfo[2];
    }

    private function writeImage(\GdImage $sourceImage, string $path, int $expectedType): bool
    {
        if ($expectedType === IMAGETYPE_JPEG) {
            $flattened = imagecreatetruecolor(imagesx($sourceImage), imagesy($sourceImage));
            if (!$flattened instanceof \GdImage) {
                return false;
            }
            $white = imagecolorallocate($flattened, 255, 255, 255);
            imagefill($flattened, 0, 0, $white);
            imagecopy(
                $flattened,
                $sourceImage,
                0,
                0,
                0,
                0,
                imagesx($sourceImage),
                imagesy($sourceImage)
            );
            $written = imagejpeg($flattened, $path, 90);
            imagedestroy($flattened);

            return $written;
        }
        if ($expectedType === IMAGETYPE_PNG) {
            imagealphablending($sourceImage, false);
            imagesavealpha($sourceImage, true);

            return imagepng($sourceImage, $path, 6);
        }

        return imagegif($sourceImage, $path);
    }

    /**
     * GD cannot decode animated WebP. Use ffmpeg as a fallback and keep animation when the target is GIF.
     *
     * @throws LocalizedException
     */
    private function writeAnimatedWebp(
        string $sourcePath,
        string $destinationPath,
        int $actualType,
        int $expectedType
    ): bool {
        if ($actualType !== IMAGETYPE_WEBP) {
            throw new LocalizedException(__('Unable to decode image %1.', $sourcePath));
        }

        $outputArguments = match ($expectedType) {
            IMAGETYPE_GIF => ['-f', 'gif'],
            IMAGETYPE_JPEG => ['-frames:v', '1', '-c:v', 'mjpeg', '-f', 'image2'],
            IMAGETYPE_PNG => ['-frames:v', '1', '-c:v', 'png', '-f', 'image2'],
            default => [],
        };
        $command = array_merge(
            ['ffmpeg', '-v', 'error', '-y', '-i', $sourcePath],
            $outputArguments,
            [$destinationPath]
        );
        $process = new Process($command);
        $process->setTimeout(60);
        try {
            $process->mustRun();
        } catch (ProcessFailedException $ffmpegException) {
            @unlink($destinationPath);
            try {
                return $this->writeFirstWebpFrame($sourcePath, $destinationPath, $expectedType);
            } catch (\Throwable $fallbackException) {
                throw new LocalizedException(
                    __(
                        'Unable to convert animated WebP image %1. Install ffmpeg or the WebP tools (webpmux and dwebp). %2',
                        $sourcePath,
                        trim($fallbackException->getMessage())
                    ),
                    $ffmpegException
                );
            }
        }

        return is_file($destinationPath) && filesize($destinationPath) > 0;
    }

    /**
     * Extract a static first frame when ffmpeg cannot decode the animated WebP stream.
     */
    private function writeFirstWebpFrame(string $sourcePath, string $destinationPath, int $expectedType): bool
    {
        $frameWebp = tempnam(dirname($sourcePath), '.esun-webp-frame-');
        $framePng = tempnam(dirname($sourcePath), '.esun-png-frame-');
        if ($frameWebp === false || $framePng === false) {
            if (is_string($frameWebp)) {
                @unlink($frameWebp);
            }
            if (is_string($framePng)) {
                @unlink($framePng);
            }
            throw new LocalizedException(__('Unable to create temporary WebP frame files.'));
        }

        $frameImage = null;
        try {
            (new Process(['webpmux', '-get', 'frame', '1', $sourcePath, '-o', $frameWebp]))
                ->setTimeout(60)
                ->mustRun();
            (new Process(['dwebp', $frameWebp, '-o', $framePng]))
                ->setTimeout(60)
                ->mustRun();
            $frameImage = @imagecreatefrompng($framePng);
            if (!$frameImage instanceof \GdImage) {
                throw new LocalizedException(__('Unable to decode the extracted WebP frame.'));
            }

            return $this->writeImage($frameImage, $destinationPath, $expectedType);
        } finally {
            if ($frameImage instanceof \GdImage) {
                imagedestroy($frameImage);
            }
            @unlink($frameWebp);
            @unlink($framePng);
        }
    }
}