<?php
/**
 * The list of available AI providers.
 *
 * @package Fitzaro
 */

namespace Fitzaro\Provider;

defined( 'ABSPATH' ) || exit;

/**
 * Built in: OpenAI (once a key is configured) and the mock (local and development sites only).
 * Other providers are added with the `fitzaro/providers` filter (id => Provider).
 */
final class Registry {

	/**
	 * Available providers, keyed by ID.
	 *
	 * @return array<string, Provider>
	 */
	public static function all(): array {
		$providers = array();

		if ( self::mock_allowed( wp_get_environment_type(), defined( 'FITZARO_ENABLE_MOCK' ) && (bool) constant( 'FITZARO_ENABLE_MOCK' ) ) ) {
			$providers['mock'] = new MockProvider();
		}

		if ( '' !== OpenAi\OpenAiKey::get() ) {
			$providers[ OpenAi\OpenAiProvider::ID ] = self::openai();
		}

		/**
		 * Filters the available try-on providers.
		 *
		 * @since 1.0.0
		 *
		 * @param array<string, Provider> $providers Providers keyed by ID.
		 */
		return self::only_valid( apply_filters( 'fitzaro/providers', $providers ) );
	}

	/**
	 * Keeps entries that are real providers registered under their own ID.
	 *
	 * The hook documents an array of providers, but any plugin can return anything from a filter,
	 * so the result is checked at runtime rather than trusted.
	 *
	 * @param mixed $candidates Filter result.
	 * @return array<string, Provider>
	 */
	public static function only_valid( $candidates ): array {
		$valid = array();

		foreach ( is_array( $candidates ) ? $candidates : array() as $id => $provider ) {
			if ( is_string( $id ) && $provider instanceof Provider && $provider->id() === $id ) {
				$valid[ $id ] = $provider;
			}
		}

		return $valid;
	}

	/**
	 * A provider by ID, or null.
	 *
	 * @param string $id Provider ID.
	 */
	public static function get( string $id ): ?Provider {
		return self::all()[ $id ] ?? null;
	}

	/**
	 * Whether the mock may be offered: only on local/development sites, or when the site owner
	 * explicitly sets FITZARO_ENABLE_MOCK (for demos).
	 *
	 * @param string $environment_type wp_get_environment_type().
	 * @param bool   $forced           FITZARO_ENABLE_MOCK.
	 */
	public static function mock_allowed( string $environment_type, bool $forced ): bool {
		return $forced || in_array( $environment_type, array( 'local', 'development' ), true );
	}

	/**
	 * The OpenAI provider with the site's key and model, whether or not a key is set.
	 */
	public static function openai(): OpenAi\OpenAiProvider {
		return new OpenAi\OpenAiProvider( array( OpenAi\OpenAiKey::class, 'get' ), \Fitzaro\Settings::openai_model(), new OpenAi\WpHttp() );
	}
}