<?php
/**
 * Condition registry.
 *
 * @package BlockSieve
 */

namespace BlockSieve\Conditions;

use BlockSieve\Conditions\Contracts\ConditionInterface;
use BlockSieve\Exception\ConditionException;

/**
 * Registry of available condition types.
 *
 * Acts as the single source of truth for condition metadata, read by the
 * evaluator (later phase) and the REST controller. Duplicate ids are rejected.
 */
final class ConditionRegistry {

	/**
	 * Registered conditions, keyed by id.
	 *
	 * @var array<string, ConditionInterface>
	 */
	private array $conditions = array();

	/**
	 * Registers a condition type.
	 *
	 * @param ConditionInterface $condition Condition to register.
	 * @return void
	 *
	 * @throws ConditionException When a condition with the same id is already registered.
	 */
	public function register( ConditionInterface $condition ): void {
		$id = $condition->id();

		if ( $this->has( $id ) ) {
			throw new ConditionException( esc_html( "Condition [$id] is already registered." ) );
		}

		$this->conditions[ $id ] = $condition;
	}

	/**
	 * Gets a registered condition by id.
	 *
	 * @param string $id Condition id.
	 * @return ConditionInterface
	 *
	 * @throws ConditionException When the id is not registered.
	 */
	public function get( string $id ): ConditionInterface {
		if ( ! isset( $this->conditions[ $id ] ) ) {
			throw new ConditionException( esc_html( "Condition [$id] is not registered." ) );
		}

		return $this->conditions[ $id ];
	}

	/**
	 * Reports whether a condition is registered.
	 *
	 * @param string $id Condition id.
	 * @return bool
	 */
	public function has( string $id ): bool {
		return isset( $this->conditions[ $id ] );
	}

	/**
	 * Gets all registered conditions keyed by id.
	 *
	 * @return array<string, ConditionInterface>
	 */
	public function all(): array {
		return $this->conditions;
	}

	/**
	 * Counts registered conditions.
	 *
	 * @return int
	 */
	public function count(): int {
		return count( $this->conditions );
	}
}