<?php
/**
 * Handles CSS output for fields.
 *
 * @package     Kirki
 * @subpackage  Controls
 * @copyright   Copyright (c) 2016, Aristeides Stathopoulos
 * @license     http://opensource.org/licenses/https://opensource.org/licenses/MIT
 * @since       2.2.0
 */

if ( ! class_exists( 'Kirki_Output' ) ) {

	/**
	 * Handles field CSS output.
	 */
	class Kirki_Output {

		/**
		 * The Kirki configuration used in the field.
		 *
		 * @access protected
		 * @var string
		 */
		protected $config_id = 'global';

		/**
		 * The field's `output` argument.
		 *
		 * @access protected
		 * @var array
		 */
		protected $output = array();

		/**
		 * An array of the generated styles.
		 *
		 * @access protected
		 * @var array
		 */
		protected $styles = array();

		/**
		 * The value.
		 *
		 * @access protected
		 * @var string|array
		 */
		protected $value;

		/**
		 * The class constructor.
		 *
		 * @access public
		 * @param string       $config_id The config ID.
		 * @param array        $output    The output argument.
		 * @param string|array $value     The value.
		 */
		public function __construct( $config_id, $output, $value ) {

			$this->config_id = $config_id;
			$this->value     = $value;
			$this->output    = $output;

			$this->parse_output();
		}

		/**
		 * If we have a sanitize_callback defined, apply it to the value.
		 *
		 * @param array        $output The output args.
		 * @param string|array $value  The value.
		 *
		 * @return string|array
		 */
		protected function apply_sanitize_callback( $output, $value ) {

			if ( isset( $output['sanitize_callback'] ) && null !== $output['sanitize_callback'] ) {

				// If the sanitize_callback is invalid, return the value.
				if ( ! is_callable( $output['sanitize_callback'] ) ) {
					return $value;
				}
				return call_user_func( $output['sanitize_callback'], $this->value );
			}

			return $value;

		}

		/**
		 * If we have a value_pattern defined, apply it to the value.
		 *
		 * @param array        $output The output args.
		 * @param string|array $value  The value.
		 *
		 * @return string|array
		 */
		protected function apply_value_pattern( $output, $value ) {

			if ( isset( $output['value_pattern'] ) && ! empty( $output['value_pattern'] ) ) {
				if ( is_string( $output['value_pattern'] ) ) {
					return str_replace( '$', $value, $output['value_pattern'] );
				}
			}

			return $value;

		}

		/**
		 * Parses the output arguments.
		 * Calls the process_output method for each of them.
		 *
		 * @access protected
		 */
		protected function parse_output() {
			foreach ( $this->output as $output ) {
				$skip = false;

				// Apply any sanitization callbacks defined.
				$value = $this->apply_sanitize_callback( $output, $this->value );

				// Skip if value is empty.
				if ( '' === $this->value ) {
					$skip = true;
				}

				// No need to proceed this if the current value is the same as in the "exclude" value.
				if ( isset( $output['exclude'] ) && false !== $output['exclude'] && is_array( $output['exclude'] ) ) {
					foreach ( $output['exclude'] as $exclude ) {
						if ( $skip ) {
							continue;
						}

						// Skip if value is defined as excluded.
						if ( $exclude === $value ) {
							$skip = true;
						}
					}
				}
				if ( $skip ) {
					continue;
				}

				// Apply any value patterns defined.
				$value = $this->apply_value_pattern( $output, $value );

				if ( isset( $output['element'] ) && is_array( $output['element'] ) ) {
					$output['element'] = array_unique( $output['element'] );
					sort( $output['element'] );
					$output['element'] = implode( ',', $output['element'] );
				}

				$value = $this->process_value( $value, $output );
				$this->process_output( $output, $value );
			}
		}

		/**
		 * Parses an output and creates the styles array for it.
		 *
		 * @access protected
		 * @param array  $output The field output.
		 * @param string $value  The value.
		 *
		 * @return void
		 */
		protected function process_output( $output, $value ) {
			if ( ! isset( $output['element'] ) || ! isset( $output['property'] ) ) {
				return;
			}
			$output['media_query'] = ( isset( $output['media_query'] ) ) ? $output['media_query'] : 'global';
			$output['prefix']      = ( isset( $output['prefix'] ) )      ? $output['prefix']      : '';
			$output['units']       = ( isset( $output['units'] ) )       ? $output['units']       : '';
			$output['suffix']      = ( isset( $output['suffix'] ) )      ? $output['suffix']      : '';

			$this->styles[ $output['media_query'] ][ $output['element'] ][ $output['property'] ] = $output['prefix'] . $value . $output['units'] . $output['suffix'];
		}

		/**
		 * Some CSS properties are unique.
		 * We need to tweak the value to make everything works as expected.
		 *
		 * @access protected
		 * @param string $property The CSS property.
		 * @param string $value    The value.
		 *
		 * @return array
		 */
		protected function process_property_value( $property, $value ) {
			$properties = apply_filters( 'kirki/' . $this->config_id . '/output/property-classnames', array(
				'font-family'         => 'Kirki_Output_Property_Font_Family',
				'background-image'    => 'Kirki_Output_Property_Background_Image',
				'background-position' => 'Kirki_Output_Property_Background_Position',
			) );
			if ( array_key_exists( $property, $properties ) ) {
				$classname = $properties[ $property ];
				$obj = new $classname( $property, $value );
				return $obj->get_value();
			}
			return $value;
		}

		/**
		 * Returns the value.
		 *
		 * @access protected
		 * @param string|array $value The value.
		 * @param array        $output The field "output".
		 * @return string|array
		 */
		protected function process_value( $value, $output ) {
			if ( isset( $output['property'] ) ) {
				return $this->process_property_value( $output['property'], $value );
			}
			return $value;
		}

		/**
		 * Exploses the private $styles property to the world
		 *
		 * @access protected
		 * @return array
		 */
		public function get_styles() {
			return $this->styles;
		}
	}
}