<?php
/**
 * Generates /.well-known/agents.json for AI Agent Discovery.
 *
 * @see https://docs.google.com/document/d/18PbLFOg-x3E91RxQFkIQhjQzh0YWKucMm6BbJwVfx9k
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

class AIREWP_Agents_JSON {

    public function __construct() {
        // Generation triggered by main plugin
    }

    /**
     * Generate agents.json from settings and site content.
     */
    public static function generate( array $settings ): void {
        $dir = AI_Ready_WP::get_well_known_dir();
        AI_Ready_WP::write_file(
            $dir . 'agents.json',
            wp_json_encode( self::build( $settings ), JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE )
        );
    }

    /**
     * Serve agents.json straight from memory, without touching the filesystem.
     *
     * The fallback for every site that cannot write into .well-known/. A
     * certbot-owned directory is the common case, and before this existed the
     * URL answered 404 while the plugin had the content in hand the whole time.
     */
    public static function serve(): void {
        AIREWP_Rewrite::send_json( self::build( AI_Ready_WP::get_settings() ) );
    }

    /**
     * Build the agents.json data structure.
     *
     * Both the written file and the dynamic response come through here, so the
     * two can never drift apart, filters included.
     */
    public static function build( array $settings ): array {
        $tools = self::build_tools( $settings );

        $agents_json = [
            'schema_version' => '1.0.0',
            'name'           => $settings['company_name'],
            'description'    => $settings['company_desc'],
            'url'            => home_url(),
            'provider'       => [
                'organization' => $settings['company_name'],
                'url'          => home_url(),
                'contact'      => $settings['company_email'],
            ],
            'capabilities'   => [
                'data_formats' => [ 'application/json', 'text/plain', 'text/html' ],
                'protocols'    => [ 'https' ],
                'a2a'          => ! empty( $settings['enable_agent_card'] ),
                'languages'    => $settings['languages'] ?? [ get_locale() ],
            ],
            'tools'          => $tools,
            'authentication' => [
                'type' => 'none',
            ],
            'metadata'       => [
                'generated_by' => 'AI-Ready WP ' . AIREWP_VERSION,
                'generated_at' => gmdate( 'c' ),
                'language'     => get_locale(),
            ],
        ];

        return apply_filters( 'airewp_agents_json', $agents_json, $settings );
    }

    /**
     * Build tools array based on site capabilities.
     */
    private static function build_tools( array $settings ): array {
        $tools = [];

        // Always available: business info
        $tools[] = [
            'name'        => 'get_business_info',
            'description' => sprintf(
                'Get information about %s — services, contact details, and company overview.',
                $settings['company_name']
            ),
            'endpoint'    => home_url( '/wp-json/airewp/v1/info' ),
            'method'      => 'GET',
            'parameters'  => [],
        ];

        // Pages/content tool
        $tools[] = [
            'name'        => 'get_pages',
            'description' => 'Get a list of all public pages with titles, URLs, and descriptions.',
            'endpoint'    => home_url( '/wp-json/wp/v2/pages?per_page=100&_fields=id,title,link,excerpt' ),
            'method'      => 'GET',
            'parameters'  => [],
        ];

        // Posts/blog tool
        $post_count = wp_count_posts();
        if ( $post_count->publish > 0 ) {
            $tools[] = [
                'name'        => 'get_posts',
                'description' => 'Get blog posts and articles. Supports search and category filtering.',
                'endpoint'    => home_url( '/wp-json/wp/v2/posts' ),
                'method'      => 'GET',
                'parameters'  => [
                    [
                        'name'        => 'search',
                        'type'        => 'string',
                        'description' => 'Search term to filter posts.',
                        'required'    => false,
                    ],
                    [
                        'name'        => 'per_page',
                        'type'        => 'integer',
                        'description' => 'Number of results (max 100).',
                        'required'    => false,
                    ],
                ],
            ];
        }

        // Services tool (if services defined)
        if ( ! empty( $settings['services'] ) ) {
            $tools[] = [
                'name'        => 'get_services',
                'description' => sprintf(
                    'Get the services offered by %s.',
                    $settings['company_name']
                ),
                'endpoint'    => home_url( '/wp-json/airewp/v1/services' ),
                'method'      => 'GET',
                'parameters'  => [],
            ];
        }

        // Contact form tool
        if ( self::has_contact_form() ) {
            $tools[] = [
                'name'        => 'submit_contact',
                'description' => 'Submit a contact inquiry.',
                'endpoint'    => home_url( '/wp-json/airewp/v1/contact' ),
                'method'      => 'POST',
                'parameters'  => [
                    [
                        'name'        => 'name',
                        'type'        => 'string',
                        'description' => 'Name of the person making the inquiry.',
                        'required'    => true,
                    ],
                    [
                        'name'        => 'email',
                        'type'        => 'string',
                        'description' => 'Email address.',
                        'required'    => true,
                    ],
                    [
                        'name'        => 'message',
                        'type'        => 'string',
                        'description' => 'The inquiry message.',
                        'required'    => true,
                    ],
                ],
            ];
        }

        // WooCommerce tools
        if ( class_exists( 'WooCommerce' ) ) {
            $tools[] = [
                'name'        => 'get_products',
                'description' => 'Browse products in the shop. Supports search and category filtering.',
                'endpoint'    => home_url( '/wp-json/wc/store/v1/products' ),
                'method'      => 'GET',
                'parameters'  => [
                    [
                        'name'        => 'search',
                        'type'        => 'string',
                        'description' => 'Search term.',
                        'required'    => false,
                    ],
                    [
                        'name'        => 'category',
                        'type'        => 'string',
                        'description' => 'Category slug to filter by.',
                        'required'    => false,
                    ],
                ],
            ];
        }

        return $tools;
    }

    /**
     * Check if a contact form plugin is active.
     */
    private static function has_contact_form(): bool {
        if ( ! function_exists( 'is_plugin_active' ) ) {
            require_once ABSPATH . 'wp-admin/includes/plugin.php';
        }
        return is_plugin_active( 'contact-form-7/wp-contact-form-7.php' )
            || is_plugin_active( 'wpforms-lite/wpforms.php' )
            || is_plugin_active( 'wpforms/wpforms.php' )
            || is_plugin_active( 'forminator/forminator.php' );
    }
}