<?php

/**
 * A color utility that helps manipulate HEX colors
 *
 * @link https://github.com/mexitek/phpColors/blob/master/src/Mexitek/PHPColors/Color.php
 */
class gmColor {
	private $_hex;
	private $_hsl;
	private $_rgb;
	/**
	 * Auto darkens/lightens by 10% for sexily-subtle gradients.
	 * Set this to FALSE to adjust automatic shade to be between given color
	 * and black (for darken) or white (for lighten)
	 */
	const DEFAULT_ADJUST = 10;

	/**
	 * Instantiates the class with a HEX value
	 *
	 * @param bool|string $hex
	 */
	public function __construct( $hex = '#000000' ) {
		// Strip # sign is present.
		$color = str_replace( '#', '', $hex );
		// Make sure it's 6 digits.
		$color      = self::_checkHex( $color );
		$this->_hsl = self::hexToHsl( $color );
		$this->_hex = $color;
		$this->_rgb = self::hexToRgb( $color );
	}
	// ====================
	// = Public Interface =
	// ====================
	/**
	 * Given a HEX string returns a HSL array equivalent.
	 *
	 * @param string $color
	 *
	 * @return array HSL associative array
	 */
	public static function hexToHsl( $color ) {
		// Sanity check.
		$color = self::_checkHex( $color );
		// Convert HEX to DEC.
		$R       = hexdec( $color[0] . $color[1] );
		$G       = hexdec( $color[2] . $color[3] );
		$B       = hexdec( $color[4] . $color[5] );
		$HSL     = array();
		$var_R   = ( $R / 255 );
		$var_G   = ( $G / 255 );
		$var_B   = ( $B / 255 );
		$var_Min = min( $var_R, $var_G, $var_B );
		$var_Max = max( $var_R, $var_G, $var_B );
		$del_Max = $var_Max - $var_Min;
		$L       = ( $var_Max + $var_Min ) / 2;
		if ( $del_Max == 0 ) {
			$H = 0;
			$S = 0;
		} else {
			if ( $L < 0.5 ) {
				$S = $del_Max / ( $var_Max + $var_Min );
			} else {
				$S = $del_Max / ( 2 - $var_Max - $var_Min );
			}
			$del_R = ( ( ( $var_Max - $var_R ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;
			$del_G = ( ( ( $var_Max - $var_G ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;
			$del_B = ( ( ( $var_Max - $var_B ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;
			if ( $var_R == $var_Max ) {
				$H = $del_B - $del_G;
			} else if ( $var_G == $var_Max ) {
				$H = ( 1 / 3 ) + $del_R - $del_B;
			} else if ( $var_B == $var_Max ) {
				$H = ( 2 / 3 ) + $del_G - $del_R;
			}
			if ( $H < 0 ) {
				$H ++;
			}
			if ( $H > 1 ) {
				$H --;
			}
		}
		$HSL['H'] = ( $H * 360 );
		$HSL['S'] = $S;
		$HSL['L'] = $L;

		return $HSL;
	}

	/**
	 *  Given a HSL associative array returns the equivalent HEX string
	 *
	 * @param array $hsl
	 *
	 * @return string HEX string
	 * @throws Exception "Bad HSL Array"
	 */
	public static function hslToHex( $hsl = array() ) {
		// Make sure it's HSL
		if (empty($hsl) || !isset($hsl["H"], $hsl["S"], $hsl["L"])) {
			throw new Exception("Param was not an HSL array");
		}

		list($H, $S, $L) = array($hsl['H'] / 360, $hsl['S'], $hsl['L']);

		if ($S == 0) {
			$r = $L * 255;
			$g = $L * 255;
			$b = $L * 255;
		} else {
			if ($L < 0.5) {
				$var_2 = $L * (1 + $S);
			} else {
				$var_2 = ($L + $S) - ($S * $L);
			}

			$var_1 = 2 * $L - $var_2;

			$r = 255 * self::_huetorgb($var_1, $var_2, $H + (1 / 3));
			$g = 255 * self::_huetorgb($var_1, $var_2, $H);
			$b = 255 * self::_huetorgb($var_1, $var_2, $H - (1 / 3));
		}

		// Convert to hex
		$r = dechex(round($r));
		$g = dechex(round($g));
		$b = dechex(round($b));

		// Make sure we get 2 digits for decimals
		$r = (strlen("" . $r) === 1) ? "0" . $r : $r;
		$g = (strlen("" . $g) === 1) ? "0" . $g : $g;
		$b = (strlen("" . $b) === 1) ? "0" . $b : $b;

		return $r . $g . $b;
	}

	/**
	 * Given a HEX string returns a RGB array equivalent.
	 *
	 * @param string $color
	 *
	 * @return array RGB associative array
	 */
	public static function hexToRgb( $color ) {
		// Sanity check.
		$color = self::_checkHex( $color );
		// Convert HEX to DEC.
		$R        = hexdec( $color[0] . $color[1] );
		$G        = hexdec( $color[2] . $color[3] );
		$B        = hexdec( $color[4] . $color[5] );
		$RGB['R'] = $R;
		$RGB['G'] = $G;
		$RGB['B'] = $B;

		return $RGB;
	}

	/**
	 *  Given an RGB associative array returns the equivalent HEX string
	 *
	 * @param array $rgb
	 *
	 * @return string RGB string
	 * @throws Exception "Bad RGB Array"
	 */
	public static function rgbToHex( $rgb = array() ) {
		// Make sure it's RGB.
		if ( empty( $rgb ) || ! isset( $rgb['R'] ) || ! isset( $rgb['G'] ) || ! isset( $rgb['B'] ) ) {
			throw new Exception( 'Param was not an RGB array' );
		}
		// https://github.com/mexitek/phpColors/issues/25#issuecomment-88354815
		// Convert RGB to HEX.
		$hex[0] = str_pad( dechex( $rgb['R'] ), 2, '0', STR_PAD_LEFT );
		$hex[1] = str_pad( dechex( $rgb['G'] ), 2, '0', STR_PAD_LEFT );
		$hex[2] = str_pad( dechex( $rgb['B'] ), 2, '0', STR_PAD_LEFT );

		return implode( '', $hex );
	}

	/**
	 * Given a HEX value, returns a darker color. If no desired amount provided, then the color halfway between
	 * given HEX and black will be returned.
	 *
	 * @param int $amount
	 *
	 * @return string Darker HEX value
	 */
	public function darken( $amount = self::DEFAULT_ADJUST ) {
		// Darken.
		$darkerHSL = $this->_darken( $this->_hsl, $amount );

		// Return as HEX.
		return self::hslToHex( $darkerHSL );
	}

	/**
	 * Given a HEX value, returns a lighter color. If no desired amount provided, then the color halfway between
	 * given HEX and white will be returned.
	 *
	 * @param int $amount
	 *
	 * @return string Lighter HEX value
	 */
	public function lighten( $amount = self::DEFAULT_ADJUST ) {
		// Lighten.
		$lighterHSL = $this->_lighten( $this->_hsl, $amount );

		// Return as HEX.
		return self::hslToHex( $lighterHSL );
	}

	/**
	 * Given a HEX value, returns a mixed color. If no desired amount provided, then the color mixed by this ratio
	 *
	 * @param string $hex2   Secondary HEX value to mix with.
	 * @param int    $amount = -100..0..+100.
	 *
	 * @return string mixed HEX value
	 */
	public function mix( $hex2, $amount = 0 ) {
		$rgb2  = self::hexToRgb( $hex2 );
		$mixed = $this->_mix( $this->_rgb, $rgb2, $amount );

		// Return as HEX.
		return self::rgbToHex( $mixed );
	}

	/**
	 * Creates an array with two shades that can be used to make a gradient
	 *
	 * @param int $amount Optional percentage amount you want your contrast color.
	 *
	 * @return array An array with a 'light' and 'dark' index
	 */
	public function makeGradient( $amount = self::DEFAULT_ADJUST ) {
		// Decide which color needs to be made.
		if ( $this->isLight() ) {
			$lightColor = $this->_hex;
			$darkColor  = $this->darken( $amount );
		} else {
			$lightColor = $this->lighten( $amount );
			$darkColor  = $this->_hex;
		}

		// Return our gradient array.
		return array( 'light' => $lightColor, 'dark' => $darkColor );
	}

	/**
	 * Returns whether or not given color is considered "light"
	 *
	 * @param string|Boolean $color
	 * @param int            $lighterThan
	 *
	 * @return boolean
	 */
	public function isLight( $color = false, $lighterThan = 130 ) {
		// Get our color.
		$color = ( $color ) ? $color : $this->_hex;
		// Calculate straight from rbg.
		$r = hexdec( $color[0] . $color[1] );
		$g = hexdec( $color[2] . $color[3] );
		$b = hexdec( $color[4] . $color[5] );

		return ( ( $r * 299 + $g * 587 + $b * 114 ) / 1000 > $lighterThan );
	}

	/**
	 * Returns whether or not a given color is considered "dark"
	 *
	 * @param string|Boolean $color
	 * @param int            $darkerThan
	 *
	 * @return boolean
	 */
	public function isDark( $color = false, $darkerThan = 130 ) {
		// Get our color.
		$color = ( $color ) ? $color : $this->_hex;
		// Calculate straight from rbg.
		$r = hexdec( $color[0] . $color[1] );
		$g = hexdec( $color[2] . $color[3] );
		$b = hexdec( $color[4] . $color[5] );

		return ( ( $r * 299 + $g * 587 + $b * 114 ) / 1000 <= $darkerThan );
	}

	/**
	 * Returns the complimentary color
	 *
	 * @return string Complementary hex color
	 *
	 */
	public function complementary() {
		// Get our HSL.
		$hsl = $this->_hsl;
		// Adjust Hue 180 degrees.
		$hsl['H'] += ( $hsl['H'] > 180 ) ? - 180 : 180;

		// Return the new value in HEX.
		return self::hslToHex( $hsl );
	}

	/**
	 * Returns your color's HSL array
	 */
	public function getHsl() {
		return $this->_hsl;
	}

	/**
	 * Returns your original color
	 */
	public function getHex() {
		return $this->_hex;
	}

	/**
	 * Returns your color's RGB array
	 */
	public function getRgb() {
		return $this->_rgb;
	}

	/**
	 * Returns the cross browser CSS3 gradient
	 *
	 * @param int     $amount          Optional: percentage amount to light/darken the gradient.
	 * @param boolean $vintageBrowsers Optional: include vendor prefixes for browsers that almost died out already.
	 * @param string  $prefix          Optional: prefix for every lines.
	 * @param string  $suffix          Optional: suffix for every lines.
	 *
	 * @return string CSS3 gradient for chrome, safari, firefox, opera and IE10
	 * @link  http://caniuse.com/css-gradients Resource for the browser support
	 */
	public function getCssGradient( $amount = self::DEFAULT_ADJUST, $vintageBrowsers = false, $suffix = '', $prefix = '' ) {
		// Get the recommended gradient.
		$g   = $this->makeGradient( $amount );
		$css = '';
		/* fallback/image non-cover color */
		$css .= "{$prefix}background-color: #" . $this->_hex . ";{$suffix}";
		/* IE Browsers */
		$css .= "{$prefix}filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#" . $g['light'] . "', endColorstr='#" . $g['dark'] . "');{$suffix}";
		/* Safari 4+, Chrome 1-9 */
		if ( $vintageBrowsers ) {
			$css .= "{$prefix}background-image: -webkit-gradient(linear, 0% 0%, 0% 100%, from(#" . $g['light'] . '), to(#' . $g['dark'] . "));{$suffix}";
		}
		/* Safari 5.1+, Mobile Safari, Chrome 10+ */
		$css .= "{$prefix}background-image: -webkit-linear-gradient(top, #" . $g['light'] . ', #' . $g['dark'] . ");{$suffix}";
		/* Firefox 3.6+ */
		if ( $vintageBrowsers ) {
			$css .= "{$prefix}background-image: -moz-linear-gradient(top, #" . $g['light'] . ', #' . $g['dark'] . ");{$suffix}";
		}
		/* Opera 11.10+ */
		if ( $vintageBrowsers ) {
			$css .= "{$prefix}background-image: -o-linear-gradient(top, #" . $g['light'] . ', #' . $g['dark'] . ");{$suffix}";
		}
		/* Unprefixed version (standards): FF 16+, IE10+, Chrome 26+, Safari 7+, Opera 12.1+ */
		$css .= "{$prefix}background-image: linear-gradient(to bottom, #" . $g['light'] . ', #' . $g['dark'] . ");{$suffix}";

		// Return our CSS.
		return $css;
	}
	// ===========================
	// = Private Functions Below =
	// ===========================
	/**
	 * Darkens a given HSL array
	 *
	 * @param array $hsl
	 * @param int   $amount
	 *
	 * @return array $hsl
	 */
	private function _darken( $hsl, $amount = self::DEFAULT_ADJUST ) {
		// Check if we were provided a number.
		if ( $amount ) {
			if ( is_string( $amount ) && strpos( $amount, '%' ) ) {
				$amount = (float) str_replace( '%', '', $amount );
				$amount = $hsl['L'] * $amount;
			}
			$hsl['L'] = ( $hsl['L'] * 100 ) - $amount;
			$hsl['L'] = ( $hsl['L'] < 0 ) ? 0 : $hsl['L'] / 100;
		} else {
			// We need to find out how much to darken.
			$hsl['L'] = $hsl['L'] / 2;
		}

		return $hsl;
	}

	/**
	 * Lightens a given HSL array
	 *
	 * @param array $hsl
	 * @param int   $amount
	 *
	 * @return array $hsl
	 */
	private function _lighten( $hsl, $amount = self::DEFAULT_ADJUST ) {
		// Check if we were provided a number.
		if ( $amount ) {
			if ( is_string( $amount ) && strpos( $amount, '%' ) ) {
				$amount = (float) str_replace( '%', '', $amount );
				$amount = $hsl['L'] * $amount;
			}
			$hsl['L'] = ( $hsl['L'] * 100 ) + $amount;
			$hsl['L'] = ( $hsl['L'] > 100 ) ? 1 : $hsl['L'] / 100;
		} else {
			// We need to find out how much to lighten.
			$hsl['L'] += ( 1 - $hsl['L'] ) / 2;
		}

		return $hsl;
	}

	/**
	 * Mix 2 rgb colors and return an rgb color
	 *
	 * @param array $rgb1
	 * @param array $rgb2
	 * @param int   $amount ranged -100..0..+100.
	 *
	 * @return array $rgb
	 *
	 *    ported from http://phpxref.pagelines.com/nav.html?includes/class.colors.php.source.html
	 */
	private function _mix( $rgb1, $rgb2, $amount = 0 ) {
		$r1   = ( $amount + 100 ) / 100;
		$r2   = 2 - $r1;
		$rmix = ( ( $rgb1['R'] * $r1 ) + ( $rgb2['R'] * $r2 ) ) / 2;
		$gmix = ( ( $rgb1['G'] * $r1 ) + ( $rgb2['G'] * $r2 ) ) / 2;
		$bmix = ( ( $rgb1['B'] * $r1 ) + ( $rgb2['B'] * $r2 ) ) / 2;

		return array( 'R' => $rmix, 'G' => $gmix, 'B' => $bmix );
	}

	/**
	 * Given a Hue, returns corresponding RGB value
	 *
	 * @param int $v1
	 * @param int $v2
	 * @param int $vH
	 *
	 * @return int
	 */
	private static function _huetorgb( $v1, $v2, $vH ) {
		if ($vH < 0) {
			++$vH;
		}

		if ($vH > 1) {
			--$vH;
		}

		if ((6 * $vH) < 1) {
			return ($v1 + ($v2 - $v1) * 6 * $vH);
		}

		if ((2 * $vH) < 1) {
			return $v2;
		}

		if ((3 * $vH) < 2) {
			return ($v1 + ($v2 - $v1) * ((2 / 3) - $vH) * 6);
		}

		return $v1;
	}

	/**
	 * You need to check if you were given a good hex string
	 *
	 * @param string $hex
	 *
	 * @return string Color
	 * @throws Exception "Bad color format".
	 */
	private static function _checkHex( $hex ) {
		// Strip # sign is present.
		$color = str_replace( '#', '', $hex );
		// Make sure it's 6 digits.
		if ( strlen( $color ) == 3 ) {
			$color = $color[0] . $color[0] . $color[1] . $color[1] . $color[2] . $color[2];
		}
		//		else if( strlen($color) != 6 ) {
		//			throw new Exception("HEX color needs to be 6 or 3 digits long");
		//		}
		return $color;
	}
}