<?php
/**
 * Payment gateways: the common shape and the registry.
 *
 * The free plugin ships the manual bank transfer gateway. PAYGRAB Pro adds Stripe
 * through the `paygrab_gateways` filter.
 *
 * @package PAYGRAB
 */

defined( 'ABSPATH' ) || exit;

/**
 * A way to pay.
 */
abstract class Paygrab_Gateway {

	/**
	 * Unique ID (stored on orders).
	 *
	 * @return string
	 */
	abstract public function id();

	/**
	 * Name shown to buyers.
	 *
	 * @return string
	 */
	abstract public function label();

	/**
	 * Short explanation shown on the checkout screen.
	 *
	 * @return string
	 */
	public function description() {
		return '';
	}

	/**
	 * Short explanation of one method, shown on the checkout screen.
	 *
	 * @param string $method Method.
	 * @return string
	 */
	public function method_description( $method ) {
		return $this->description();
	}

	/**
	 * Whether the gateway confirms payments and refunds by itself (no manual buttons in the admin).
	 *
	 * @return bool
	 */
	public function confirms_payments() {
		return false;
	}

	/**
	 * Whether the gateway is set up and can take orders.
	 *
	 * @return bool
	 */
	abstract public function is_available();

	/**
	 * Start the payment for a new order.
	 *
	 * @param Paygrab_Order $order Order (awaiting payment).
	 * @return array{redirect:string}|WP_Error Where to send the buyer next.
	 */
	abstract public function start( Paygrab_Order $order );

	/**
	 * Methods the buyer can pick within this gateway: [ method => label ].
	 *
	 * @return array<string,string>
	 */
	public function methods() {
		return array( $this->id() => $this->label() );
	}

	/**
	 * Label of one method.
	 *
	 * @param string $method Method.
	 * @return string
	 */
	public function method_label( $method ) {
		$methods = $this->methods();
		return $methods[ $method ] ?? $this->label();
	}

	/**
	 * Payment instructions for an order awaiting payment (HTML for screens).
	 *
	 * @param Paygrab_Order $order Order.
	 * @return string
	 */
	public function instructions_html( Paygrab_Order $order ) {
		return '';
	}

	/**
	 * Payment instructions for an order awaiting payment (plain text for mail).
	 *
	 * @param Paygrab_Order $order Order.
	 * @return string
	 */
	public function instructions_text( Paygrab_Order $order ) {
		return '';
	}

	/**
	 * When the buyer pays, for the checkout screen and the legal notice.
	 *
	 * @return string
	 */
	public function payment_timing() {
		return '';
	}

	/**
	 * Methods and payment timing in one line, for the buy box.
	 *
	 * @return string
	 */
	public function summary() {
		return implode( paygrab_sep(), $this->methods() ) . ( $this->payment_timing() ? paygrab_open() . $this->payment_timing() . paygrab_close() : '' );
	}

	/**
	 * Fees other than the price, for the legal notice.
	 *
	 * @return string
	 */
	public function extra_fees() {
		return '';
	}

	/**
	 * The note under the payment instructions on the completion screen.
	 *
	 * @param Paygrab_Order $order Order.
	 * @return string Plain text.
	 */
	public function complete_note( Paygrab_Order $order ) {
		return __( 'We email you when we have confirmed your payment (usually within 1–2 business days).', 'paygrab' );
	}

	/**
	 * Whether a buyer may cancel an order awaiting payment by themselves.
	 *
	 * @return bool
	 */
	public function buyer_can_cancel() {
		return true;
	}
}

/**
 * Registry of gateways.
 */
class Paygrab_Gateways {

	/**
	 * Request cache.
	 *
	 * @var Paygrab_Gateway[]|null
	 */
	private static $all = null;

	/**
	 * Every registered gateway, keyed by ID.
	 *
	 * @return Paygrab_Gateway[]
	 */
	public static function all() {
		if ( null === self::$all ) {
			/**
			 * Filters the payment gateways.
			 *
			 * @param Paygrab_Gateway[] $gateways Gateways.
			 */
			$list      = apply_filters( 'paygrab_gateways', array( new Paygrab_Gateway_Bank_Manual() ) );
			self::$all = array();
			foreach ( $list as $gateway ) {
				if ( $gateway instanceof Paygrab_Gateway ) {
					self::$all[ $gateway->id() ] = $gateway;
				}
			}
		}
		return self::$all;
	}

	/**
	 * One gateway.
	 *
	 * @param string $id Gateway ID.
	 * @return Paygrab_Gateway|null
	 */
	public static function get( $id ) {
		$all = self::all();
		return $all[ $id ] ?? null;
	}

	/**
	 * Gateways that can take orders now.
	 *
	 * @return Paygrab_Gateway[]
	 */
	public static function available() {
		return array_filter( self::all(), static fn( $g ) => $g->is_available() );
	}

	/**
	 * Whether buyers can pay at least one way (the bank account is entered, or a gateway that PAYGRAB Pro adds is set up).
	 *
	 * @return bool
	 */
	public static function ready() {
		return (bool) self::available();
	}

	/**
	 * Whether bank transfer is the only way to pay that the site offers (PAYGRAB without Pro).
	 *
	 * @return bool
	 */
	public static function bank_only() {
		return array( 'bank_manual' ) === array_keys( self::all() );
	}
}