<?php

declare(strict_types=1);

namespace WordPress\PerplexityAiProvider\Provider;

use WordPress\AiClient\AiClient;
use WordPress\AiClient\Common\Exception\RuntimeException;
use WordPress\AiClient\Providers\ApiBasedImplementation\AbstractApiProvider;
use WordPress\AiClient\Providers\Contracts\ModelMetadataDirectoryInterface;
use WordPress\AiClient\Providers\Contracts\ProviderAvailabilityInterface;
use WordPress\AiClient\Providers\DTO\ProviderMetadata;
use WordPress\AiClient\Providers\Enums\ProviderTypeEnum;
use WordPress\AiClient\Providers\Http\Enums\RequestAuthenticationMethod;
use WordPress\AiClient\Providers\Models\Contracts\ModelInterface;
use WordPress\AiClient\Providers\Models\DTO\ModelMetadata;
use WordPress\PerplexityAiProvider\Metadata\PerplexityModelMetadataDirectory;
use WordPress\PerplexityAiProvider\Models\PerplexityTextGenerationModel;

/**
 * Class for the AI Provider for Perplexity.
 *
 * @since 1.0.0
 */
class PerplexityProvider extends AbstractApiProvider
{
    /**
     * The model used to verify provider availability (the cheapest Sonar model).
     *
     * @since 1.0.0
     *
     * @var string
     */
    private const AVAILABILITY_MODEL_ID = 'sonar';

    /**
     * {@inheritDoc}
     *
     * @since 1.0.0
     */
    protected static function baseUrl(): string
    {
        return 'https://api.perplexity.ai';
    }

    /**
     * {@inheritDoc}
     *
     * @since 1.0.0
     */
    protected static function createModel(
        ModelMetadata $modelMetadata,
        ProviderMetadata $providerMetadata
    ): ModelInterface {
        $capabilities = $modelMetadata->getSupportedCapabilities();
        foreach ($capabilities as $capability) {
            if ($capability->isTextGeneration()) {
                return new PerplexityTextGenerationModel($modelMetadata, $providerMetadata);
            }
        }

        // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Internal exception message, never rendered as HTML output.
        throw new RuntimeException(
            'Unsupported model capabilities: ' . implode(', ', $capabilities)
        );
    }

    /**
     * {@inheritDoc}
     *
     * @since 1.0.0
     */
    protected static function createProviderMetadata(): ProviderMetadata
    {
        $providerMetadataArgs = [
            'perplexity',
            'Perplexity',
            ProviderTypeEnum::cloud(),
            'https://www.perplexity.ai/account/api/keys',
            RequestAuthenticationMethod::apiKey()
        ];
        // Provider description support was added in 1.2.0.
        if (version_compare(AiClient::VERSION, '1.2.0', '>=')) {
            // For WordPress, we should translate the description.
            if (function_exists('__')) {
                $providerMetadataArgs[] = __('Web-grounded text generation with Sonar.', 'ai-provider-for-perplexity');
            } else {
                $providerMetadataArgs[] = 'Web-grounded text generation with Sonar.';
            }
        }
        // Provider logoPath support was added in 1.3.0.
        if (version_compare(AiClient::VERSION, '1.3.0', '>=')) {
            $providerMetadataArgs[] = dirname(__DIR__, 2) . '/assets/images/perplexity.svg';
        }
        return new ProviderMetadata(...$providerMetadataArgs);
    }

    /**
     * {@inheritDoc}
     *
     * Perplexity has no model listing endpoint for its Sonar chat models, so availability
     * is verified with a minimal text generation request instead of a list-models request.
     *
     * @since 1.0.0
     */
    protected static function createProviderAvailability(): ProviderAvailabilityInterface
    {
        $modelMetadata = static::modelMetadataDirectory()->getModelMetadata(self::AVAILABILITY_MODEL_ID);
        $model = static::createModel($modelMetadata, static::metadata());

        return new PerplexityProviderAvailability($model);
    }

    /**
     * {@inheritDoc}
     *
     * @since 1.0.0
     */
    protected static function createModelMetadataDirectory(): ModelMetadataDirectoryInterface
    {
        return new PerplexityModelMetadataDirectory();
    }
}