<?php
if ( ! defined( 'ABSPATH' ) ) exit;

class LLMSTXT_API_Client {

    private string $key;
    private string $base_url;

    public function __construct( string $pro_key ) {
        $this->key      = $pro_key;
        $this->base_url = LLMSTXT_API_URL;
    }

    /**
     * Verify a Pro licence key against the API.
     * Returns array with 'valid', 'plan', 'expires' or WP_Error.
     */
    public function verify_key(): array|WP_Error {
        $response = wp_remote_get(
            $this->base_url . 'license.php?action=verify&key=' . urlencode( $this->key ),
            [ 'timeout' => 15, 'sslverify' => true ]
        );

        if ( is_wp_error( $response ) ) return $response;

        $code = wp_remote_retrieve_response_code( $response );
        $body = json_decode( wp_remote_retrieve_body( $response ), true );

        if ( $code !== 200 || empty( $body ) ) {
            return new WP_Error( 'api_error', __( 'API unreachable', 'aiready-llms-txt-generator' ) );
        }
        return $body;
    }

    /**
     * Generate llms.txt via API for a given URL.
     * Returns array ['llms.txt' => '...', 'llms-full.txt' => '...'] or WP_Error.
     */
    public function generate( string $url ): array|WP_Error {
        $response = wp_remote_post(
            $this->base_url . 'wp-generate.php',
            [
                'timeout'   => 60,
                'sslverify' => true,
                'headers'   => [
                    'Content-Type'     => 'application/json',
                    'X-LLMSTXT-Key'    => $this->key,
                    'X-LLMSTXT-Source' => 'wp-plugin/' . LLMSTXT_VERSION,
                ],
                'body' => wp_json_encode( [
                    'url'     => $url,
                    'lang'    => get_locale(),
                    'formats' => [ 'llms.txt', 'llms-full.txt' ],
                    'source'  => 'wordpress',
                ] ),
            ]
        );

        if ( is_wp_error( $response ) ) return $response;

        $code = wp_remote_retrieve_response_code( $response );
        $body = json_decode( wp_remote_retrieve_body( $response ), true );

        if ( $code === 401 ) {
            return new WP_Error( 'invalid_key', __( 'Invalid or expired Pro key.', 'aiready-llms-txt-generator' ) );
        }
        if ( $code === 429 ) {
            return new WP_Error( 'rate_limit', __( 'Rate limit reached. Please try again later.', 'aiready-llms-txt-generator' ) );
        }
        if ( $code !== 200 || empty( $body['files'] ) ) {
            $msg = $body['error'] ?? __( 'Unknown API error.', 'aiready-llms-txt-generator' );
            return new WP_Error( 'api_error', $msg );
        }

        return $body['files']; // ['llms.txt' => '...', 'llms-full.txt' => '...']
    }

    /**
     * Get usage stats for the connected Pro account.
     */
    public function get_usage(): array|WP_Error {
        $response = wp_remote_get(
            $this->base_url . 'license.php?action=usage&key=' . urlencode( $this->key ),
            [ 'timeout' => 10 ]
        );

        if ( is_wp_error( $response ) ) return $response;
        $body = json_decode( wp_remote_retrieve_body( $response ), true );
        return $body ?: new WP_Error( 'api_error', 'Could not fetch usage data.' );
    }
}