<?php
/**
 * State field keys.
 *
 * @package Recast\WCS
 */

namespace Recast\WCS\State;

defined( 'ABSPATH' ) || exit;

/**
 * The allow-listed subscription fields Recast can read, fingerprint and write.
 *
 * Keys: scalar fields, 'date:{type}', 'item:{id}:{prop}' (or 'item:*:{prop}' as a pattern that
 * expands to every product line item), and 'meta:{key}'.
 */
final class Fields {

	const STATUS                  = 'status';
	const REQUIRES_MANUAL_RENEWAL = 'requires_manual_renewal';
	const PAYMENT_METHOD          = 'payment_method';
	const PAYMENT_METHOD_TITLE    = 'payment_method_title';
	const BILLING_PERIOD          = 'billing_period';
	const BILLING_INTERVAL        = 'billing_interval';
	const CURRENCY                = 'currency';
	const TOTAL                   = 'total';
	const TOTAL_TAX               = 'total_tax';

	const DATE_TYPES = array( 'start', 'trial_end', 'next_payment', 'end', 'last_order_date_created', 'cancelled' );
	const ITEM_PROPS = array( 'subtotal', 'total', 'tax_class', 'quantity', 'product_id', 'variation_id', 'name', 'attributes', 'taxes' );

	/**
	 * Context fields included in every fingerprint on top of an operation's own fields.
	 */
	const CONTEXT = array(
		self::STATUS,
		'date:next_payment',
		'date:last_order_date_created',
		self::PAYMENT_METHOD,
		self::REQUIRES_MANUAL_RENEWAL,
		self::TOTAL,
		self::CURRENCY,
	);

	/**
	 * Scalar field keys.
	 *
	 * @return string[]
	 */
	public static function scalars() {
		return array(
			self::STATUS,
			self::REQUIRES_MANUAL_RENEWAL,
			self::PAYMENT_METHOD,
			self::PAYMENT_METHOD_TITLE,
			self::BILLING_PERIOD,
			self::BILLING_INTERVAL,
			self::CURRENCY,
			self::TOTAL,
			self::TOTAL_TAX,
		);
	}

	/**
	 * Builds a date key.
	 *
	 * @param string $type Date type.
	 * @return string
	 */
	public static function date( $type ) {
		return 'date:' . $type;
	}

	/**
	 * Builds an item key.
	 *
	 * @param int|string $item_id Item ID or '*'.
	 * @param string     $prop    Property.
	 * @return string
	 */
	public static function item( $item_id, $prop ) {
		return 'item:' . $item_id . ':' . $prop;
	}

	/**
	 * Builds a meta key.
	 *
	 * @param string $key Meta key.
	 * @return string
	 */
	public static function meta( $key ) {
		return 'meta:' . $key;
	}

	/**
	 * Parses a key into its parts.
	 *
	 * @param string $field Field key.
	 * @return array{kind: string, type?: string, item_id?: string, prop?: string, key?: string}|null
	 */
	public static function parse( $field ) {
		if ( in_array( $field, self::scalars(), true ) ) {
			return array( 'kind' => 'scalar' );
		}
		if ( preg_match( '/^date:([a-z_]+)$/', $field, $m ) && in_array( $m[1], self::DATE_TYPES, true ) ) {
			return array(
				'kind' => 'date',
				'type' => $m[1],
			);
		}
		if ( preg_match( '/^item:(\*|\d+):([a-z_]+)$/', $field, $m ) && in_array( $m[2], self::ITEM_PROPS, true ) ) {
			return array(
				'kind'    => 'item',
				'item_id' => $m[1],
				'prop'    => $m[2],
			);
		}
		if ( preg_match( '/^meta:(.+)$/', $field, $m ) ) {
			return array(
				'kind' => 'meta',
				'key'  => $m[1],
			);
		}
		return null;
	}

	/**
	 * Whether a key is valid.
	 *
	 * @param string $field Field key.
	 * @return bool
	 */
	public static function is_valid( $field ) {
		return null !== self::parse( $field );
	}

	/**
	 * Human label for a key.
	 *
	 * @param string $field Field key.
	 * @return string
	 */
	public static function label( $field ) {
		$labels = array(
			self::STATUS                   => __( 'Status', 'recast-subscriptions' ),
			self::REQUIRES_MANUAL_RENEWAL  => __( 'Manual renewal', 'recast-subscriptions' ),
			self::PAYMENT_METHOD           => __( 'Payment method', 'recast-subscriptions' ),
			self::PAYMENT_METHOD_TITLE     => __( 'Payment method title', 'recast-subscriptions' ),
			self::BILLING_PERIOD           => __( 'Billing period', 'recast-subscriptions' ),
			self::BILLING_INTERVAL         => __( 'Billing interval', 'recast-subscriptions' ),
			self::CURRENCY                 => __( 'Currency', 'recast-subscriptions' ),
			self::TOTAL                    => __( 'Recurring total', 'recast-subscriptions' ),
			self::TOTAL_TAX                => __( 'Recurring tax', 'recast-subscriptions' ),
			'date:start'                   => __( 'Start date', 'recast-subscriptions' ),
			'date:trial_end'               => __( 'Trial end', 'recast-subscriptions' ),
			'date:next_payment'            => __( 'Next payment', 'recast-subscriptions' ),
			'date:end'                     => __( 'End date', 'recast-subscriptions' ),
			'date:last_order_date_created' => __( 'Last order', 'recast-subscriptions' ),
			'date:cancelled'               => __( 'Cancelled', 'recast-subscriptions' ),
		);
		if ( isset( $labels[ $field ] ) ) {
			return $labels[ $field ];
		}
		if ( 0 === strpos( $field, 'display:' ) ) {
			return __( 'Unit price', 'recast-subscriptions' );
		}
		$parsed = self::parse( $field );
		if ( $parsed && 'item' === $parsed['kind'] ) {
			$props = array(
				'subtotal'     => __( 'Line price before discounts', 'recast-subscriptions' ),
				'total'        => __( 'Line price after discounts', 'recast-subscriptions' ),
				'tax_class'    => __( 'Tax class', 'recast-subscriptions' ),
				'quantity'     => __( 'Quantity', 'recast-subscriptions' ),
				'product_id'   => __( 'Product', 'recast-subscriptions' ),
				'variation_id' => __( 'Variation', 'recast-subscriptions' ),
				'name'         => __( 'Line item name', 'recast-subscriptions' ),
				'attributes'   => __( 'Attributes', 'recast-subscriptions' ),
				'taxes'        => __( 'Line tax', 'recast-subscriptions' ),
			);
			return isset( $props[ $parsed['prop'] ] ) ? $props[ $parsed['prop'] ] : ucfirst( str_replace( '_', ' ', $parsed['prop'] ) );
		}
		if ( $parsed && 'meta' === $parsed['kind'] ) {
			/* translators: %s: meta key */
			return sprintf( __( 'Custom field %s', 'recast-subscriptions' ), $parsed['key'] );
		}
		return ucfirst( str_replace( array( '_', ':' ), ' ', $field ) );
	}

	/**
	 * Value type of a key, for diff rendering.
	 *
	 * @param string $field Field key.
	 * @return string money|date|string|int|bool|meta|json
	 */
	public static function type( $field ) {
		$parsed = self::parse( $field );
		if ( ! $parsed ) {
			return 'string';
		}
		switch ( $parsed['kind'] ) {
			case 'date':
				return 'date';
			case 'meta':
				return 'meta';
			case 'item':
				if ( in_array( $parsed['prop'], array( 'subtotal', 'total' ), true ) ) {
					return 'money';
				}
				if ( in_array( $parsed['prop'], array( 'quantity', 'product_id', 'variation_id' ), true ) ) {
					return 'int';
				}
				return in_array( $parsed['prop'], array( 'taxes', 'attributes' ), true ) ? 'json' : 'string';
		}
		switch ( $field ) {
			case self::TOTAL:
			case self::TOTAL_TAX:
				return 'money';
			case self::BILLING_INTERVAL:
				return 'int';
			case self::REQUIRES_MANUAL_RENEWAL:
				return 'bool';
		}
		return 'string';
	}
}