<?php
/**
 * Reports API - Chart Endpoint Handler
 *
 * @package     EDD
 * @subpackage  Reports
 * @copyright   Copyright (c) 2018, Easy Digital Downloads, LLC
 * @license     http://opensource.org/licenses/gpl-2.0.php GNU Public License
 * @since       3.0
 */
namespace EDD\Reports\Data;

use EDD\Reports\Data\Charts\v2 as Chart;

/**
 * Handler for building a chart endpoint in the Reports API.
 *
 * @since 3.0
 */
class Chart_Endpoint extends Endpoint {

	/**
	 * Endpoint view (type).
	 *
	 * @since 3.0
	 * @var   string
	 */
	protected $view = 'chart';

	/**
	 * Represents the chart type.
	 *
	 * @since 3.0
	 * @var   string
	 */
	private $type;

	/**
	 * Represents the PHP manifestation of the chart data and options.
	 *
	 * @since 3.0
	 * @var   Chart\Manifest
	 */
	private $manifest;

	/**
	 * Represents the ChartJS options passed to the chart endpoint.
	 *
	 * @since 3.0
	 * @var   array
	 */
	private $options = array();

	/**
	 * Call to override JS output for the chart.
	 *
	 * Completely overrides the manifest process for the current chart..
	 *
	 * @since 3.0
	 * @var   callable
	 */
	private $js_callback;

	/**
	 * Sets up the chart endpoint.
	 *
	 * @since 3.0
	 *
	 * @param array $args Chart endpoint attributes.
	 */
	public function __construct( $args ) {
		$this->errors = new \WP_Error();

		// ID and Label.
		$this->set_props( $args );

		$args = $this->parse_display_props( $args );

		// Common values set last to account for overrides.
		parent::__construct( $args );

		// Chart props.
		$this->setup_chart( $args );

	}

	/**
	 * Sets up the chart props needed for rendering.
	 *
	 * @since 3.0
	 *
	 * @param array $atts Endpoint attributes.
	 */
	private function setup_chart( $atts ) {
		$view_type = $this->get_view();

		if ( ! empty( $atts['views'][ $view_type ] ) ) {

			$view_atts = $atts['views'][ $view_type ];

			if ( ! empty( $view_atts['type'] ) ) {
				$this->set_type( $view_atts['type'] );
			} else {
				$this->errors->add(
					'missing_chart_type',
					sprintf( 'The chart type for \'%1$s\' endpoint is missing.', $this->get_id() )
				);
			}

			if ( ! empty( $view_atts['options'] ) ) {
				$this->set_options( $view_atts['options'] );
			} else {
				$this->errors->add(
					'missing_chart_options',
					sprintf( 'The chart options for the \'%1$s\' endpoint is missing.', $this->get_id() )
				);
			}

			if ( isset( $view_atts['render_js'] ) && is_callable( $view_atts['render_js'] ) ) {
				$this->js_callback = $atts['render_js'];
			}

		}

		if ( null === $this->js_callback ) {
			// Due to the parent constructor firing last, make sure the report gets set for the benefit of the manifest.
			if ( ! empty( $atts['report'] ) ) {
				parent::set_report_id( $atts['report'] );
			}

			$this->build_manifest();
		}

	}

	/**
	 * Sets display-related properties for the Endpoint.
	 *
	 * @since 3.0
	 *
	 * @param array $atts Endpoint attributes.
	 */
	private function parse_display_props( $atts ) {

		$view_type = $this->get_view();

		if ( ! empty( $atts['views'][ $view_type ] ) ) {

			$atts['views'][ $view_type ] = $this->maybe_convert_callbacks_to_methods( $atts['views'][ $view_type ] );

		}

		return $atts;
	}

	/**
	 * Retrieves the graphing library options set for the current endpoint.
	 *
	 * @since 3.0
	 *
	 * @return array Options set for the current graph endpoint.
	 */
	public function get_options() {
		return $this->options;
	}

	/**
	 * Sets options for displaying the graph.
	 *
	 * @since 3.0
	 *
	 * @param array $options Options for displaying the graph via the graphing library.
	 */
	protected function set_options( $options ) {
		$this->options = $options;
	}

	/**
	 * Retrieves the value of a graph option if set.
	 *
	 * @since 3.0
	 *
	 * @param string $key Option key to retrieve a value for.
	 * @return mixed Value of the option key if set, otherwise an empty string.
	 */
	public function get( $key ) {
		if ( isset( $this->options[ $key ] ) ) {
			$value = $this->options[ $key ];
		} else {
			$value = '';
		}

		return $value;
	}

	/**
	 * Retrieves the chart type.
	 *
	 * @since 3.0
	 *
	 * @return string Chart type.
	 */
	public function get_type() {
		return $this->type;
	}

	/**
	 * Sets the chart type.
	 *
	 * @since 3.0
	 *
	 * @param string $type Chart type to set.
	 */
	private function set_type( $type ) {
		$this->type = sanitize_key( $type );
	}

	/**
	 * Retrieves the manifest instance.
	 *
	 * @since 3.0
	 *
	 * @return Chart\Manifest Chart manifest.
	 */
	public function get_manifest() {
		return $this->manifest;
	}

	/**
	 * Instantiates the manifest based on chart type and options.
	 *
	 * @since 3.0
	 */
	private function build_manifest() {
		$this->manifest = new Chart\Manifest( $this );
	}

	/**
	 * Retrieves a specific axis' data if set.
	 *
	 * @since 3.0
	 *
	 * @param string $set Dataset to retrieve corresponding data for.
	 * @return array Data corresponding to `$set` if it's set, otherwise an empty array.
	 */
	public function get_data_by_set( $set ) {
		$data = $this->get_data();

		if ( isset( $data[ $set ] ) ) {
			return $data[ $set ];
		} else {
			return array();
		}
	}

	/**
	 * Builds and outputs the graph JS to the page.
	 *
	 * @since 3.0
	 */
	public function display() {
		// JS callback override.
		if ( is_callable( $this->js_callback ) ) {
			call_user_func( $this->js_callback, $this->get_display_args() );

			return;
		}

		// Start parsing the manifest for output as JS.
		$manifest = $this->get_manifest();

		$manifest->render();
	}

}