<?php
/**
 * @copyright Copyright (c) 2016 Julius Härtl <jus@bitgrid.net>
 *
 * @author Christoph Wurst <christoph@winzerhof-wurst.at>
 * @author Daniel Kesselberg <mail@danielkesselberg.de>
 * @author Joas Schilling <coding@schilljs.com>
 * @author Julien Veyssier <eneiluj@posteo.net>
 * @author Julius Haertl <jus@bitgrid.net>
 * @author Julius Härtl <jus@bitgrid.net>
 * @author Michael Weimann <mail@michael-weimann.eu>
 *
 * @license GNU AGPL version 3 or any later version
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 *
 */
namespace OCA\Theming;

use OCP\App\AppPathNotFoundException;
use OCP\App\IAppManager;
use OCP\Files\IAppData;
use OCP\Files\NotFoundException;
use OCP\Files\SimpleFS\ISimpleFile;
use OCP\IConfig;

class Util {

	/** @var IConfig */
	private $config;

	/** @var IAppManager */
	private $appManager;

	/** @var IAppData */
	private $appData;

	/**
	 * Util constructor.
	 *
	 * @param IConfig $config
	 * @param IAppManager $appManager
	 * @param IAppData $appData
	 */
	public function __construct(IConfig $config, IAppManager $appManager, IAppData $appData) {
		$this->config = $config;
		$this->appManager = $appManager;
		$this->appData = $appData;
	}

	/**
	 * @param string $color rgb color value
	 * @return bool
	 */
	public function invertTextColor($color) {
		$l = $this->calculateLuma($color);
		if ($l > 0.6) {
			return true;
		} else {
			return false;
		}
	}

	/**
	 * get color for on-page elements:
	 * theme color by default, grey if theme color is to bright
	 * @param string $color
	 * @param bool $brightBackground
	 * @return string
	 */
	public function elementColor($color, bool $brightBackground = true) {
		$luminance = $this->calculateLuminance($color);

		if ($brightBackground && $luminance > 0.8) {
			// If the color is too bright in bright mode, we fall back to a darker gray
			return '#aaaaaa';
		}

		if (!$brightBackground && $luminance < 0.2) {
			// If the color is too dark in dark mode, we fall back to a brighter gray
			return '#555555';
		}

		return $color;
	}

	/**
	 * Convert RGB to HSL
	 *
	 * Copied from cssphp, copyright Leaf Corcoran, licensed under MIT
	 *
	 * @param integer $red
	 * @param integer $green
	 * @param integer $blue
	 *
	 * @return array
	 */
	public function toHSL($red, $green, $blue) {
		$min = min($red, $green, $blue);
		$max = max($red, $green, $blue);
		$l = $min + $max;
		$d = $max - $min;

		if ((int) $d === 0) {
			$h = $s = 0;
		} else {
			if ($l < 255) {
				$s = $d / $l;
			} else {
				$s = $d / (510 - $l);
			}

			if ($red == $max) {
				$h = 60 * ($green - $blue) / $d;
			} elseif ($green == $max) {
				$h = 60 * ($blue - $red) / $d + 120;
			} else {
				$h = 60 * ($red - $green) / $d + 240;
			}
		}

		return [fmod($h, 360), $s * 100, $l / 5.1];
	}

	/**
	 * @param string $color rgb color value
	 * @return float
	 */
	public function calculateLuminance($color) {
		[$red, $green, $blue] = $this->hexToRGB($color);
		$hsl = $this->toHSL($red, $green, $blue);
		return $hsl[2] / 100;
	}

	/**
	 * @param string $color rgb color value
	 * @return float
	 */
	public function calculateLuma($color) {
		[$red, $green, $blue] = $this->hexToRGB($color);
		return (0.2126 * $red + 0.7152 * $green + 0.0722 * $blue) / 255;
	}

	/**
	 * @param string $color rgb color value
	 * @return int[]
	 * @psalm-return array{0: int, 1: int, 2: int}
	 */
	public function hexToRGB($color) {
		$hex = preg_replace("/[^0-9A-Fa-f]/", '', $color);
		if (strlen($hex) === 3) {
			$hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
		}
		if (strlen($hex) !== 6) {
			return [0, 0, 0];
		}
		return [
			hexdec(substr($hex, 0, 2)),
			hexdec(substr($hex, 2, 2)),
			hexdec(substr($hex, 4, 2))
		];
	}

	/**
	 * @param $color
	 * @return string base64 encoded radio button svg
	 */
	public function generateRadioButton($color) {
		$radioButtonIcon = '<svg xmlns="http://www.w3.org/2000/svg" height="16" width="16">' .
			'<path d="M8 1a7 7 0 0 0-7 7 7 7 0 0 0 7 7 7 7 0 0 0 7-7 7 7 0 0 0-7-7zm0 1a6 6 0 0 1 6 6 6 6 0 0 1-6 6 6 6 0 0 1-6-6 6 6 0 0 1 6-6zm0 2a4 4 0 1 0 0 8 4 4 0 0 0 0-8z" fill="'.$color.'"/></svg>';
		return base64_encode($radioButtonIcon);
	}


	/**
	 * @param $app string app name
	 * @return string|ISimpleFile path to app icon / file of logo
	 */
	public function getAppIcon($app) {
		$app = str_replace(['\0', '/', '\\', '..'], '', $app);
		try {
			$appPath = $this->appManager->getAppPath($app);
			$icon = $appPath . '/img/' . $app . '.svg';
			if (file_exists($icon)) {
				return $icon;
			}
			$icon = $appPath . '/img/app.svg';
			if (file_exists($icon)) {
				return $icon;
			}
		} catch (AppPathNotFoundException $e) {
		}

		if ($this->config->getAppValue('theming', 'logoMime', '') !== '') {
			$logoFile = null;
			try {
				$folder = $this->appData->getFolder('images');
				return $folder->getFile('logo');
			} catch (NotFoundException $e) {
			}
		}
		return \OC::$SERVERROOT . '/core/img/logo/logo.svg';
	}

	/**
	 * @param $app string app name
	 * @param $image string relative path to image in app folder
	 * @return string|false absolute path to image
	 */
	public function getAppImage($app, $image) {
		$app = str_replace(['\0', '/', '\\', '..'], '', $app);
		$image = str_replace(['\0', '\\', '..'], '', $image);
		if ($app === "core") {
			$icon = \OC::$SERVERROOT . '/core/img/' . $image;
			if (file_exists($icon)) {
				return $icon;
			}
		}

		try {
			$appPath = $this->appManager->getAppPath($app);
		} catch (AppPathNotFoundException $e) {
			return false;
		}

		$icon = $appPath . '/img/' . $image;
		if (file_exists($icon)) {
			return $icon;
		}
		$icon = $appPath . '/img/' . $image . '.svg';
		if (file_exists($icon)) {
			return $icon;
		}
		$icon = $appPath . '/img/' . $image . '.png';
		if (file_exists($icon)) {
			return $icon;
		}
		$icon = $appPath . '/img/' . $image . '.gif';
		if (file_exists($icon)) {
			return $icon;
		}
		$icon = $appPath . '/img/' . $image . '.jpg';
		if (file_exists($icon)) {
			return $icon;
		}

		return false;
	}

	/**
	 * replace default color with a custom one
	 *
	 * @param $svg string content of a svg file
	 * @param $color string color to match
	 * @return string
	 */
	public function colorizeSvg($svg, $color) {
		$svg = preg_replace('/#0082c9/i', $color, $svg);
		return $svg;
	}

	/**
	 * Check if a custom theme is set in the server configuration
	 *
	 * @return bool
	 */
	public function isAlreadyThemed() {
		$theme = $this->config->getSystemValue('theme', '');
		if ($theme !== '') {
			return true;
		}
		return false;
	}

	public function isBackgroundThemed() {
		$backgroundLogo = $this->config->getAppValue('theming', 'backgroundMime', '');
		return $backgroundLogo !== '' && $backgroundLogo !== 'backgroundColor';
	}
}