<?php

namespace Kirby\Image\Darkroom;

use Exception;
use Kirby\Filesystem\F;
use Kirby\Image\Darkroom;
use Kirby\Image\Focus;

/**
 * ImageMagick
 *
 * @package   Kirby Image
 * @author    Bastian Allgeier <bastian@getkirby.com>
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier
 * @license   https://opensource.org/licenses/MIT
 */
class ImageMagick extends Darkroom
{
	/**
	 * Applies the blur settings
	 */
	protected function blur(string $file, array $options): string|null
	{
		if ($options['blur'] !== false) {
			return '-blur ' . escapeshellarg('0x' . $options['blur']);
		}

		return null;
	}

	/**
	 * Keep animated gifs
	 */
	protected function coalesce(string $file, array $options): string|null
	{
		if (F::extension($file) === 'gif') {
			return '-coalesce';
		}

		return null;
	}

	/**
	 * Creates the convert command with the right path to the binary file
	 */
	protected function convert(string $file, array $options): string
	{
		$command = escapeshellarg($options['bin']);

		// default is limiting to single-threading to keep CPU usage sane
		$command .= ' -limit thread ' . escapeshellarg($options['threads']);

		// append input file
		return $command . ' ' . escapeshellarg($file);
	}

	/**
	 * Returns additional default parameters for imagemagick
	 */
	protected function defaults(): array
	{
		return parent::defaults() + [
			'bin'       => 'convert',
			'interlace' => false,
			'threads'   => 1,
		];
	}

	/**
	 * Applies the correct settings for grayscale images
	 */
	protected function grayscale(string $file, array $options): string|null
	{
		if ($options['grayscale'] === true) {
			return '-colorspace gray';
		}

		return null;
	}

	/**
	 * Applies sharpening if activated in the options.
	 */
	protected function sharpen(string $file, array $options): string|null
	{
		if (is_int($options['sharpen']) === false) {
			return null;
		}

		$amount = max(1, min(100, $options['sharpen'])) / 100;
		return '-sharpen ' . escapeshellarg('0x' . $amount);
	}

	/**
	 * Applies the correct settings for interlaced JPEGs if
	 * activated via options
	 */
	protected function interlace(string $file, array $options): string|null
	{
		if ($options['interlace'] === true) {
			return '-interlace line';
		}

		return null;
	}

	/**
	 * Creates and runs the full imagemagick command
	 * to process the image
	 *
	 * @throws \Exception
	 */
	public function process(string $file, array $options = []): array
	{
		$options = $this->preprocess($file, $options);
		$command = [];

		$command[] = $this->convert($file, $options);
		$command[] = $this->strip($file, $options);
		$command[] = $this->interlace($file, $options);
		$command[] = $this->coalesce($file, $options);
		$command[] = $this->grayscale($file, $options);
		$command[] = '-auto-orient';
		$command[] = $this->resize($file, $options);
		$command[] = $this->quality($file, $options);
		$command[] = $this->blur($file, $options);
		$command[] = $this->sharpen($file, $options);
		$command[] = $this->save($file, $options);

		// remove all null values and join the parts
		$command = implode(' ', array_filter($command));

		// try to execute the command
		exec($command, $output, $return);

		// log broken commands
		if ($return !== 0) {
			throw new Exception(message: 'The imagemagick convert command could not be executed: ' . $command);
		}

		return $options;
	}

	/**
	 * Applies the correct JPEG compression quality settings
	 */
	protected function quality(string $file, array $options): string
	{
		return '-quality ' . escapeshellarg($options['quality']);
	}

	/**
	 * Creates the correct options to crop or resize the image
	 * and translates the crop positions for imagemagick
	 */
	protected function resize(string $file, array $options): string
	{
		// simple resize
		if ($options['crop'] === false) {
			return '-thumbnail ' . escapeshellarg(sprintf('%sx%s!', $options['width'], $options['height']));
		}

		// crop based on focus point
		if (Focus::isFocalPoint($options['crop']) === true) {
			if ($focus = Focus::coords(
				$options['crop'],
				$options['sourceWidth'],
				$options['sourceHeight'],
				$options['width'],
				$options['height']
			)) {
				return sprintf(
					'-crop %sx%s+%s+%s -resize %sx%s^',
					$focus['width'],
					$focus['height'],
					$focus['x1'],
					$focus['y1'],
					$options['width'],
					$options['height']
				);
			}
		}

		// translate the gravity option into something imagemagick understands
		$gravity = match ($options['crop'] ?? null) {
			'top left'     => 'NorthWest',
			'top'          => 'North',
			'top right'    => 'NorthEast',
			'left'         => 'West',
			'right'        => 'East',
			'bottom left'  => 'SouthWest',
			'bottom'       => 'South',
			'bottom right' => 'SouthEast',
			default        => 'Center'
		};

		$command  = '-thumbnail ' . escapeshellarg(sprintf('%sx%s^', $options['width'], $options['height']));
		$command .= ' -gravity ' . escapeshellarg($gravity);
		$command .= ' -crop ' . escapeshellarg(sprintf('%sx%s+0+0', $options['width'], $options['height']));

		return $command;
	}

	/**
	 * Creates the option for the output file
	 */
	protected function save(string $file, array $options): string
	{
		if ($options['format'] !== null) {
			$file = pathinfo($file, PATHINFO_DIRNAME) . '/' . pathinfo($file, PATHINFO_FILENAME) . '.' . $options['format'];
		}

		return escapeshellarg($file);
	}

	/**
	 * Removes all metadata from the image
	 */
	protected function strip(string $file, array $options): string
	{
		if (F::extension($file) === 'png') {
			// ImageMagick does not support keeping ICC profiles while
			// stripping other privacy- and security-related information,
			// such as GPS data; so discard all color profiles for PNG files
			// (tested with ImageMagick 7.0.11-14 Q16 x86_64 2021-05-31)
			return '-strip';
		}

		return '';
	}
}
