sa-orchestration/includes/class-sa-llm-providers.php

<?php
defined( 'ABSPATH' ) || exit;

/**
 * Provider registry + active-provider resolver.
 *
 * v0.5 ships with the `simulated` provider only. Future providers attach by
 * extending the provider catalog — `get_provider_choices()` for the dropdown,
 * `instantiate()` for the factory branch.
 *
 * If the saved provider id is not enabled or is unknown, the registry falls
 * back to `simulated`. This guarantees Strategy Review always returns a result
 * even if the operator's configured provider is unreachable.
 */
class SA_Orch_LLM_Providers {

    /**
     * Catalog of provider id → human label, for the settings dropdown.
     * Only the simulated provider is wired up in v0.5; the others are listed
     * as inert placeholders so the operator can see the seam.
     */
    public static function get_provider_choices(): array {
        return [
            'simulated' => 'Simulated (no API call) — heuristic expansion of deterministic audit',
            'openai'    => 'OpenAI (Chat Completions; works with any OpenAI-compatible endpoint)',
            'anthropic' => 'Anthropic (not implemented yet)',
            'local'     => 'Local model endpoint (not implemented yet)',
            'custom'    => 'Custom HTTP endpoint (not implemented yet)',
        ];
    }

    /**
     * Resolve the active provider. Falls back to simulated when:
     *   - settings.enabled is false
     *   - settings.provider is unknown
     *   - the configured provider's class is not yet implemented
     */
    public static function get_active_provider(): SA_Orch_LLM_Provider_Interface {
        $settings = SA_Orch_LLM_Settings::get();

        if ( empty( $settings['enabled'] ) ) {
            return new SA_Orch_LLM_Provider_Simulated();
        }

        $instance = self::instantiate( (string) ( $settings['provider'] ?? '' ) );
        if ( $instance instanceof SA_Orch_LLM_Provider_Interface ) {
            return $instance;
        }

        // Fallback
        return new SA_Orch_LLM_Provider_Simulated();
    }

    private static function instantiate( $id ): ?SA_Orch_LLM_Provider_Interface {
        switch ( $id ) {
            case 'simulated':
                return new SA_Orch_LLM_Provider_Simulated();
            case 'openai':
                return new SA_Orch_LLM_Provider_OpenAI();
            // Future: add cases here as providers land.
            // case 'anthropic': return new SA_Orch_LLM_Provider_Anthropic();
            // case 'local':     return new SA_Orch_LLM_Provider_Local();
            // case 'custom':    return new SA_Orch_LLM_Provider_Custom();
        }
        return null;
    }
}