<?php

if( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

if( ! class_exists('ACF_Local_Meta') ) :

class ACF_Local_Meta {
	
	/** @var array Storage for meta data. */
	var $meta = array();
	
	/** @var mixed Storage for the current post_id. */
	var $post_id = 0;
	
	/**
	 * __construct
	 *
	 * Sets up the class functionality.
	 *
	 * @date	8/10/18
	 * @since	5.8.0
	 *
	 * @param	void
	 * @return	void
	 */
	function __construct() {
		
		// add filters
		add_filter( 'acf/pre_load_post_id', 	array($this, 'pre_load_post_id'), 	1, 2 );
		add_filter( 'acf/pre_load_meta', 		array($this, 'pre_load_meta'), 		1, 2 );
		add_filter( 'acf/pre_load_metadata', 	array($this, 'pre_load_metadata'), 	1, 4 );
	}
	
	/**
	 * add
	 *
	 * Adds postmeta to storage.
	 * Accepts data in either raw or request format.
	 *
	 * @date	8/10/18
	 * @since	5.8.0
	 *
	 * @param	array $meta An array of metdata to store.
	 * @param	mixed $post_id The post_id for this data.
	 * @param	bool $is_main Makes this postmeta visible to get_field() without a $post_id value.
	 * @return	array
	 */
	function add( $meta = array(), $post_id = 0, $is_main = false ) {
		
		// Capture meta if supplied meta is from a REQUEST.
		if( $this->is_request($meta) ) {
			$meta = $this->capture( $meta, $post_id );
		}
		
		// Add to storage.
		$this->meta[ $post_id ] = $meta;
		
		// Set $post_id reference when is the "main" postmeta.
		if( $is_main ) {
			$this->post_id = $post_id;
		}
		
		// Return meta.
		return $meta;
	}
	
	/**
	 * is_request
	 *
	 * Returns true if the supplied $meta is from a REQUEST (serialized <form> data).
	 *
	 * @date	11/3/19
	 * @since	5.7.14
	 *
	 * @param	array $meta An array of metdata to check.
	 * @return	bool
	 */
	function is_request( $meta = array() ) {
		return acf_is_field_key( key( $meta ) );
	}
	
	/**
	 * capture
	 *
	 * Returns a flattened array of meta for the given postdata.
	 * This is achieved by simulating a save whilst capturing all meta changes.
	 *
	 * @date	26/2/19
	 * @since	5.7.13
	 *
	 * @param	array $values An array of raw values.
	 * @param	mixed $post_id The post_id for this data.
	 * @return	array
	 */
	function capture( $values = array(), $post_id = 0 ) {
		
		// Reset meta.
		$this->meta[ $post_id ] = array();
		
		// Listen for any added meta.
		add_filter('acf/pre_update_metadata', array($this, 'capture_update_metadata'), 1, 5);
		
		// Simulate update.
		if( $values ) {
			acf_update_values( $values, $post_id );
		}
		
		// Remove listener filter.
		remove_filter('acf/pre_update_metadata', array($this, 'capture_update_metadata'), 1, 5);
		
		// Return meta.
		return $this->meta[ $post_id ];
	}
	
	/**
	 * capture_update_metadata
	 *
	 * Records all meta activity and returns a non null value to bypass DB updates.
	 *
	 * @date	26/2/19
	 * @since	5.7.13
	 *
	 * @param	null $null .
	 * @param	(int|string) $post_id The post id.
	 * @param	string $name The meta name.
	 * @param	mixed $value The meta value.
	 * @param	bool $hidden If the meta is hidden (starts with an underscore).
	 * @return	false.
	 */
	function capture_update_metadata( $null, $post_id, $name, $value, $hidden ) {
		$name = ($hidden ? '_' : '') . $name;
		$this->meta[ $post_id ][ $name ] = $value;
		
		// Return non null value to escape update process.
		return true;
	}
	
	/**
	 * remove
	 *
	 * Removes postmeta from storage.
	 *
	 * @date	8/10/18
	 * @since	5.8.0
	 *
	 * @param	mixed $post_id The post_id for this data.
	 * @return	void
	 */
	function remove( $post_id = 0 ) {
		
		// unset meta
		unset( $this->meta[ $post_id ] );
		
		// reset post_id
		if( $post_id === $this->post_id ) {
			$this->post_id = 0;
		}
	}
	
	/**
	 * pre_load_meta
	 *
	 * Injects the local meta.
	 *
	 * @date	8/10/18
	 * @since	5.8.0
	 *
	 * @param	null $null An empty parameter. Return a non null value to short-circuit the function.
	 * @param	mixed $post_id The post_id for this data.
	 * @return	mixed
	 */
	function pre_load_meta( $null, $post_id ) {
		if( isset($this->meta[ $post_id ]) ) {
			return $this->meta[ $post_id ];
		}
		return $null;
	}
	
	/**
	 * pre_load_metadata
	 *
	 * Injects the local meta.
	 *
	 * @date	8/10/18
	 * @since	5.8.0
	 *
	 * @param	null $null An empty parameter. Return a non null value to short-circuit the function.
	 * @param	(int|string) $post_id The post id.
	 * @param	string $name The meta name.
	 * @param	bool $hidden If the meta is hidden (starts with an underscore).
	 * @return	mixed
	 */
	function pre_load_metadata( $null, $post_id, $name, $hidden ) {
		$name = ($hidden ? '_' : '') . $name;
		if( isset($this->meta[ $post_id ]) ) {
			if( isset($this->meta[ $post_id ][ $name ]) ) {
				return $this->meta[ $post_id ][ $name ];
			}
			return '__return_null';
		}
		return $null;
	}
		
	/**
	 * pre_load_post_id
	 *
	 * Injects the local post_id.
	 *
	 * @date	8/10/18
	 * @since	5.8.0
	 *
	 * @param	null $null An empty parameter. Return a non null value to short-circuit the function.
	 * @param	mixed $post_id The post_id for this data.
	 * @return	mixed
	 */
	function pre_load_post_id( $null, $post_id ) {
		if( !$post_id && $this->post_id ) {
			return $this->post_id;
		}
		return $null;
	}
}

endif; // class_exists check

/**
 * acf_setup_meta
 *
 * Adds postmeta to storage.
 *
 * @date	8/10/18
 * @since	5.8.0
 * @see		ACF_Local_Meta::add() for list of parameters.
 *
 * @return	array
 */
function acf_setup_meta( $meta = array(), $post_id = 0, $is_main = false ) {
	return acf_get_instance('ACF_Local_Meta')->add( $meta, $post_id, $is_main );
}

/**
 * acf_reset_meta
 *
 * Removes postmeta to storage.
 *
 * @date	8/10/18
 * @since	5.8.0
 * @see		ACF_Local_Meta::remove() for list of parameters.
 *
 * @return	void
 */
function acf_reset_meta( $post_id = 0 ) {
	return acf_get_instance('ACF_Local_Meta')->remove( $post_id );
}