array An array of fields definitions.
	 */
	public function get_fields_for_location( $location ) {
		if ( in_array( $location, array_keys( $this->fields_locations ), true ) ) {
			$order_fields_keys = $this->fields_locations[ $location ];

			return array_filter(
				$this->get_additional_fields(),
				function( $key ) use ( $order_fields_keys ) {
					return in_array( $key, $order_fields_keys, true );
				},
				ARRAY_FILTER_USE_KEY
			);
		}
		return [];
	}

	/**
	 * Validates a set of fields for a given location against custom validation rules.
	 *
	 * @param array  $fields Array of key value pairs of field values to validate.
	 * @param string $location The location being validated (address|contact|additional).
	 * @param string $group The group to get the field value for (shipping|billing|'') in which '' refers to the additional group.
	 * @return WP_Error
	 */
	public function validate_fields_for_location( $fields, $location, $group = '' ) {
		$errors = new WP_Error();

		try {
			/**
			 * Pass an error object to allow validation of an additional field.
			 *
			 * @param WP_Error $errors  A WP_Error object that extensions may add errors to.
			 * @param mixed    $fields  List of fields (key value pairs) in this location.
			 * @param string   $group   The group of this location (shipping|billing|'').
			 *
			 * @since 8.7.0
			 */
			do_action( '__experimental_woocommerce_blocks_validate_location_' . $location . '_fields', $errors, $fields, $group );

		} catch ( \Throwable $e ) {

			// One of the filters errored so skip them. This allows the checkout process to continue.
			// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error
			trigger_error(
				sprintf(
					'The action %s encountered an error. The field location %s may not have any custom validation applied to it. %s',
					esc_html( 'woocommerce_blocks_validate_' . $location . '_fields' ),
					esc_html( $location ),
					esc_html( $e->getMessage() )
				),
				E_USER_WARNING
			);
		}

		return $errors;
	}

	/**
	 * Validates a field to check it belongs to the given location and is valid according to its registration.
	 *
	 * This does not apply any custom validation rules on the value.
	 *
	 * @param string $key The field key.
	 * @param mixed  $value The field value.
	 * @param string $location The location to validate the field for (address|contact|additional).
	 *
	 * @return true|WP_Error True if the field is valid, a WP_Error otherwise.
	 */
	public function validate_field_for_location( $key, $value, $location ) {
		if ( ! $this->is_field( $key ) ) {
			return new WP_Error(
				'woocommerce_blocks_checkout_field_invalid',
				\sprintf(
					// translators: % is field key.
					__( 'The field %s is invalid.', 'woocommerce' ),
					$key
				)
			);
		}

		if ( ! in_array( $key, $this->fields_locations[ $location ], true ) ) {
			return new WP_Error(
				'woocommerce_blocks_checkout_field_invalid_location',
				\sprintf(
					// translators: %1$s is field key, %2$s location.
					__( 'The field %1$s is invalid for the location %2$s.', 'woocommerce' ),
					$key,
					$location
				)
			);
		}

		$field = $this->additional_fields[ $key ];
		if ( ! empty( $field['required'] ) && empty( $value ) ) {
			return new WP_Error(
				'woocommerce_blocks_checkout_field_required',
				\sprintf(
					// translators: %s is field key.
					__( 'The field %s is required.', 'woocommerce' ),
					$key
				)
			);
		}

		return true;
	}

	/**
	 * Returns true if the given key is a valid field.
	 *
	 * @param string $key The field key.
	 *
	 * @return bool True if the field is valid, false otherwise.
	 */
	public function is_field( $key ) {
		return array_key_exists( $key, $this->additional_fields );
	}

	/**
	 * Persists a field value for a given order. This would also optionally set the field value on the customer object if the order is linked to a registered customer.
	 *
	 * @param string   $key The field key.
	 * @param mixed    $value The field value.
	 * @param WC_Order $order The order to persist the field for.
	 * @param bool     $set_customer Whether to set the field value on the customer or not.
	 *
	 * @return void
	 */
	public function persist_field_for_order( $key, $value, $order, $set_customer = true ) {
		$this->set_array_meta( $key, $value, $order );
		if ( $set_customer && $order->get_customer_id() ) {
			$customer = new WC_Customer( $order->get_customer_id() );
			$this->persist_field_for_customer( $key, $value, $customer );
		}
	}

	/**
	 * Persists a field value for a given customer.
	 *
	 * @param string      $key The field key.
	 * @param mixed       $value The field value.
	 * @param WC_Customer $customer The customer to persist the field for.
	 *
	 * @return void
	 */
	public function persist_field_for_customer( $key, $value, $customer ) {
		$this->set_array_meta( $key, $value, $customer );
	}

	/**
	 * Sets a field value in an array meta, supporting routing things to billing, shipping, or additional fields, based on a prefix for the key.
	 *
	 * @param string               $key The field key.
	 * @param mixed                $value The field value.
	 * @param WC_Customer|WC_Order $object The object to set the field value for.
	 *
	 * @return void
	 */
	private function set_array_meta( $key, $value, $object ) {
		$meta_key = '';

		if ( 0 === strpos( $key, '/billing/' ) ) {
			$meta_key = self::BILLING_FIELDS_KEY;
			$key      = str_replace( '/billing/', '', $key );
		} elseif ( 0 === strpos( $key, '/shipping/' ) ) {
			$meta_key = self::SHIPPING_FIELDS_KEY;
			$key      = str_replace( '/shipping/', '', $key );
		} else {
			$meta_key = self::ADDITIONAL_FIELDS_KEY;
		}

		$meta_data = $object->get_meta( $meta_key, true );

		if ( ! is_array( $meta_data ) ) {
			$meta_data = array();
		}

		$meta_data[ $key ] = $value;

		// Replacing all meta using `add_meta_data`. For some reason `update_meta_data` causes duplicate keys.
		$object->add_meta_data( $meta_key, $meta_data, true );
	}

	/**
	 * Returns a field value for a given object.
	 *
	 * @param string      $key The field key.
	 * @param WC_Customer $customer The customer to get the field value for.
	 * @param string      $group The group to get the field value for (shipping|billing|'') in which '' refers to the additional group.
	 *
	 * @return mixed The field value.
	 */
	public function get_field_from_customer( $key, $customer, $group = '' ) {
		return $this->get_field_from_object( $key, $customer, $group );
	}

	/**
	 * Returns a field value for a given order.
	 *
	 * @param string   $field The field key.
	 * @param WC_Order $order The order to get the field value for.
	 * @param string   $group The group to get the field value for (shipping|billing|'') in which '' refers to the additional group.
	 *
	 * @return mixed The field value.
	 */
	public function get_field_from_order( $field, $order, $group = '' ) {
		return $this->get_field_from_object( $field, $order, $group );
	}

	/**
	 * Returns a field value for a given object.
	 *
	 * @param string               $key The field key.
	 * @param WC_Customer|WC_Order $object The customer to get the field value for.
	 * @param string               $group The group to get the field value for (shipping|billing|'') in which '' refers to the additional group.
	 *
	 * @return mixed The field value.
	 */
	private function get_field_from_object( $key, $object, $group = '' ) {
		$meta_key = '';
		if ( 0 === strpos( $key, '/billing/' ) || 'billing' === $group ) {
			$meta_key = self::BILLING_FIELDS_KEY;
			$key      = str_replace( '/billing/', '', $key );
		} elseif ( 0 === strpos( $key, '/shipping/' ) || 'shipping' === $group ) {
			$meta_key = self::SHIPPING_FIELDS_KEY;
			$key      = str_replace( '/shipping/', '', $key );
		} else {
			$meta_key = self::ADDITIONAL_FIELDS_KEY;
		}

		$meta_data = $object->get_meta( $meta_key, true );

		if ( ! is_array( $meta_data ) ) {
			return '';
		}

		if ( ! isset( $meta_data[ $key ] ) ) {
			return '';
		}

		return $meta_data[ $key ];
	}

	/**
	 * Returns an array of all fields values for a given customer.
	 *
	 * @param WC_Customer $customer The customer to get the fields for.
	 * @param bool        $all Whether to return all fields or only the ones that are still registered. Default false.
	 *
	 * @return array An array of fields.
	 */
	public function get_all_fields_from_customer( $customer, $all = false ) {
		$meta_data = array(
			'billing'    => array(),
			'shipping'   => array(),
			'additional' => array(),
		);
		if ( $customer instanceof WC_Customer ) {
			$meta_data['billing']    = $customer->get_meta( self::BILLING_FIELDS_KEY, true );
			$meta_data['shipping']   = $customer->get_meta( self::SHIPPING_FIELDS_KEY, true );
			$meta_data['additional'] = $customer->get_meta( self::ADDITIONAL_FIELDS_KEY, true );
		}
		return $this->format_meta_data( $meta_data, $all );
	}

	/**
	 * Returns an array of all fields values for a given order.
	 *
	 * @param WC_Order $order The order to get the fields for.
	 * @param bool     $all Whether to return all fields or only the ones that are still registered. Default false.
	 *
	 * @return array An array of fields.
	 */
	public function get_all_fields_from_order( $order, $all = false ) {
		$meta_data = array(
			'billing'    => array(),
			'shipping'   => array(),
			'additional' => array(),
		);
		if ( $order instanceof WC_Order ) {
			$meta_data['billing']    = $order->get_meta( self::BILLING_FIELDS_KEY, true );
			$meta_data['shipping']   = $order->get_meta( self::SHIPPING_FIELDS_KEY, true );
			$meta_data['additional'] = $order->get_meta( self::ADDITIONAL_FIELDS_KEY, true );
		}
		return $this->format_meta_data( $meta_data, $all );
	}

	/**
	 * Returns an array of all fields values for a given meta object. It would add the billing or shipping prefix to the keys.
	 *
	 * @param array $meta The meta data to format.
	 * @param bool  $all Whether to return all fields or only the ones that are still registered. Default false.
	 *
	 * @return array An array of fields.
	 */
	private function format_meta_data( $meta, $all = false ) {
		$billing_fields    = $meta['billing'] ?? array();
		$shipping_fields   = $meta['shipping'] ?? array();
		$additional_fields = $meta['additional'] ?? array();

		$fields = array();

		if ( is_array( $billing_fields ) ) {
			foreach ( $billing_fields as $key => $value ) {
				if ( ! $all && ! $this->is_field( $key ) ) {
					continue;
				}
				$fields[ '/billing/' . $key ] = $value;
			}
		}

		if ( is_array( $shipping_fields ) ) {
			foreach ( $shipping_fields as $key => $value ) {
				if ( ! $all && ! $this->is_field( $key ) ) {
					continue;
				}
				$fields[ '/shipping/' . $key ] = $value;
			}
		}

		if ( is_array( $additional_fields ) ) {
			foreach ( $additional_fields as $key => $value ) {
				if ( ! $all && ! $this->is_field( $key ) ) {
					continue;
				}
				$fields[ $key ] = $value;
			}
		}

		return $fields;
	}

	/**
	 * From a set of fields, returns only the ones that should be saved to the customer.
	 * For now, this only supports fields in address location.
	 *
	 * @param array $fields The fields to filter.
	 * @return array The filtered fields.
	 */
	public function filter_fields_for_customer( $fields ) {
		$customer_fields_keys = array_merge(
			$this->get_address_fields_keys(),
			$this->get_contact_fields_keys(),
		);
		return array_filter(
			$fields,
			function( $key ) use ( $customer_fields_keys ) {
				if ( 0 === strpos( $key, '/billing/' ) ) {
					$key = str_replace( '/billing/', '', $key );
				} elseif ( 0 === strpos( $key, '/shipping/' ) ) {
					$key = str_replace( '/shipping/', '', $key );
				}
				return in_array( $key, $customer_fields_keys, true );
			},
			ARRAY_FILTER_USE_KEY
		);
	}

	/**
	 * From a set of fields, returns only the ones for a given location.
	 *
	 * @param array  $fields The fields to filter.
	 * @param string $location The location to validate the field for (address|contact|additional).
	 * @return array The filtered fields.
	 */
	public function filter_fields_for_location( $fields, $location ) {
		return array_filter(
			$fields,
			function( $key ) use ( $location ) {
				if ( 0 === strpos( $key, '/billing/' ) ) {
					$key = str_replace( '/billing/', '', $key );
				} elseif ( 0 === strpos( $key, '/shipping/' ) ) {
					$key = str_replace( '/shipping/', '', $key );
				}
				return $this->is_field( $key ) && $this->get_field_location( $key ) === $location;
			},
			ARRAY_FILTER_USE_KEY
		);
	}

	/**
	 * Filter fields for order confirmation.
	 *
	 * @param array $fields The fields to filter.
	 * @return array The filtered fields.
	 */
	public function filter_fields_for_order_confirmation( $fields ) {
		return array_filter(
			$fields,
			function( $field ) {
				return ! empty( $field['show_in_order_confirmation'] );
			}
		);
	}

	/**
	 * Get additional fields for an order.
	 *
	 * @param WC_Order $order Order object.
	 * @param string   $location The location to get fields for (address|contact|additional).
	 * @param string   $group The group to get the field value for (shipping|billing|'') in which '' refers to the additional group.
	 * @param string   $context The context to get the field value for (edit|view).
	 * @return array An array of fields definitions as well as their values formatted for display.
	 */
	public function get_order_additional_fields_with_values( $order, $location, $group = '', $context = 'edit' ) {
		$fields             = $this->get_fields_for_location( $location );
		$fields_with_values = array();

		foreach ( $fields as $field_key => $field ) {
			$value = $this->get_field_from_order( $field_key, $order, $group );

			if ( '' === $value || null === $value ) {
				continue;
			}

			if ( 'view' === $context ) {
				$value = $this->format_additional_field_value( $value, $field );
			}

			$field['value']                   = $value;
			$fields_with_values[ $field_key ] = $field;
		}

		return $fields_with_values;
	}

	/**
	 * Formats a raw field value for display based on its type definition.
	 *
	 * @param string $value Value to format.
	 * @param array  $field Additional field definition.
	 * @return string
	 */
	public function format_additional_field_value( $value, $field ) {
		if ( 'checkbox' === $field['type'] ) {
			$value = $value ? __( 'Yes', 'woocommerce' ) : __( 'No', 'woocommerce' );
		}

		if ( 'select' === $field['type'] ) {
			$options = array_column( $field['options'], 'label', 'value' );
			$value   = isset( $options[ $value ] ) ? $options[ $value ] : $value;
		}

		return $value;
	}
}