<?php
/**
 * Builds the provider chosen in the settings (Factory): picks the class,
 * passes it the key, model, glossary and instructions.
 */

declare( strict_types = 1 );

namespace AddBlack\Lang\MachineTranslation;

defined( 'ABSPATH' ) || exit;

use AddBlack\Lang\Settings\Defaults;
use AddBlack\Lang\Settings\SettingsRepository;
use WP_Error;

final class ProviderFactory {

	/** Provider id => class. */
	private const CLASSES = array(
		'google'    => Providers\Google::class,
		'deepl'     => Providers\Deepl::class,
		'gemini'    => Providers\Gemini::class,
		'claude'    => Providers\Claude::class,
		'wordpress' => Providers\WordPressAi::class,
		'pseudo'    => Providers\Pseudo::class,
	);

	public function __construct(
		private readonly SettingsRepository $settings,
		private readonly Defaults $defaults,
		private readonly HttpClient $http = new HttpClient()
	) {}

	/**
	 * The provider with this id, or the one saved in the settings.
	 * Filter blocklingo_pre_provider supplies a custom Provider (own engine, tests).
	 * $key and $model: typed in the settings form but not saved yet ("Load
	 * models", "Test connection"); empty means the saved ones.
	 */
	public function make( ?string $id = null, string $key = '', string $model = '' ): Provider|WP_Error {
		$settings = $this->settings->get();
		$id       = $id ? $id : $settings->provider();

		/**
		 * Supply your own machine translation engine.
		 *
		 * @param Provider|null $provider Return a Provider to use it.
		 * @param string        $id       Provider id from the settings.
		 */
		$custom = apply_filters( 'blocklingo_pre_provider', null, $id );
		if ( $custom instanceof Provider ) {
			return $custom;
		}
		if ( '' === $id ) {
			return new WP_Error( 'blocklingo_mt_off', __( 'Machine translation is not configured. Choose a provider in Settings > Blocklingo.', 'blocklingo' ) );
		}
		$available = $this->defaults->providers();
		if ( ! isset( $available[ $id ], self::CLASSES[ $id ] ) ) {
			return new WP_Error( 'blocklingo_mt_unknown', __( 'Unknown translation provider.', 'blocklingo' ) );
		}
		$key = '' !== trim( $key ) ? trim( $key ) : $settings->api_key( $id );
		if ( '' === $key ) {
			return new WP_Error( 'blocklingo_mt_nokey', sprintf( /* translators: %s: provider name. */ __( 'API key for %s is missing.', 'blocklingo' ), $available[ $id ]['label'] ) );
		}
		$model  = trim( $model );
		$config = new ProviderConfig(
			$key,
			'' !== $model ? $model : $settings->model( $id ),
			(array) preg_split( '/\r\n|\r|\n/', $settings->glossary() ),
			$settings->instructions()
		);
		$class  = self::CLASSES[ $id ];
		return new $class( $config, $this->http );
	}
}