<?php
/**
 * Registers AltTextLab abilities for WordPress Abilities API.
 *
 */

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

class AltTextLab_Ability {

    private $attachment;

    public function __construct() {
        $this->attachment = new AltTextLab_Attachment();
    }

    /**
     * Registers the AltTextLab ability category.
     */
    public function register_categories() {
        if ( ! function_exists( 'wp_register_ability_category' ) ) {
            return;
        }

        wp_register_ability_category(
            'alttextlab',
            array(
                'label'       => __( 'AltTextLab', 'alttextlab' ),
                'description' => __( 'Abilities for generating image alt text with AltTextLab.', 'alttextlab' ),
            )
        );
    }

    /**
     * Registers AltTextLab abilities.
     */
    public function register_abilities() {
        if ( ! function_exists( 'wp_register_ability' ) ) {
            return;
        }

        wp_register_ability(
            'alttextlab/generate-alt-text',
            array(
                'label'               => __( 'Generate Alt Text', 'alttextlab' ),
                'description'         => __( 'Generates alt text for a single WordPress media attachment. Use this when the user wants to add or fix alt text for one specific image.', 'alttextlab' ),
                'category'            => 'alttextlab',
                'input_schema'        => array(
                    'type'       => 'object',
                    'properties' => array(
                        'attachment_id' => array(
                            'type' => 'integer',
                            'description' => __( 'The WordPress media attachment ID to generate alt text for.', 'alttextlab' ),
                        ),
                        'keywords'      => array(
                            'type'  => 'array',
                            'description' => __( 'Optional SEO key phrase(s) to target in the generated alt text (e.g. main search term for this image).', 'alttextlab' ),
                            'items' => array(
                                'type' => 'string',
                            ),
                        ),
                    ),
                    'required' => array( 'attachment_id' ),
                ),
                'execute_callback'    => array( $this, 'generate_alt_text' ),
                'permission_callback' => array( $this, 'can_generate_alt_text' ),
                'meta'                => array(
                    'show_in_rest' => true,
                    'mcp'          => array(
                        'public' => true,
                    ),
                ),
            )
        );

        wp_register_ability(
            'alttextlab/scan-missing-alt-text',
            array(
                'label'               => __( 'Scan Missing Alt Text', 'alttextlab' ),
                'description'         => __( 'Finds WordPress media images that have no alt text or empty alt text. Returns their attachment IDs, which can then be passed to bulk-generate-alt-text to fill them in.', 'alttextlab' ),
                'category'            => 'alttextlab',
                'input_schema'        => array(
                    'type'       => 'object',
                    'properties' => array(
                        'limit' => array(
                            'type' => 'integer',
                            'description' => __( 'Maximum number of images to return. Defaults to 20.', 'alttextlab' ),
                        ),
                    ),
                ),
                'execute_callback'    => array( $this, 'scan_missing_alt' ),
                'permission_callback' => array( $this, 'can_scan_missing_alt' ),
                'meta'                => array(
                    'show_in_rest' => true,
                    'mcp'          => array(
                        'public' => true,
                    ),
                ),
            )
        );

        wp_register_ability(
            'alttextlab/bulk-generate-alt-text',
            array(
                'label'               => __( 'Bulk Generate Alt Text', 'alttextlab' ),
                'description'         => __( 'Generates alt text for multiple WordPress media attachments at once. Typically used after scan-missing-alt-text to fill in alt text for all images that are missing it.', 'alttextlab' ),
                'category'            => 'alttextlab',
                'input_schema'        => array(
                    'type'       => 'object',
                    'properties' => array(
                        'attachment_ids' => array(
                            'type'  => 'array',
                            'description' => __( 'List of WordPress media attachment IDs to generate alt text for.', 'alttextlab' ),
                            'items' => array(
                                'type' => 'integer',
                            ),
                        )
                    ),
                    'required' => array( 'attachment_ids' ),
                ),
                'execute_callback'    => array( $this, 'bulk_generate_alt_text' ),
                'permission_callback' => array( $this, 'can_bulk_generate_alt_text' ),
                'meta'                => array(
                    'show_in_rest' => true,
                    'mcp'          => array(
                        'public' => true,
                    ),
                ),
            )
        );
    }

    public function can_generate_alt_text( $input ) {
        return current_user_can( 'upload_files' );
    }

    public function can_scan_missing_alt( $input ) {
        return current_user_can( 'upload_files' );
    }

    public function can_bulk_generate_alt_text( $input ) {
        return current_user_can( 'upload_files' );
    }

    /**
     * Generates alt text for a single media attachment.
     */
    public function generate_alt_text( $input ) {
        $attachment_id = isset( $input['attachment_id'] ) ? absint( $input['attachment_id'] ) : 0;

        if ( ! $attachment_id ) {
            return $this->ability_error_response(
                $attachment_id,
                'alttextlab_invalid_attachment_id',
                __( 'Invalid attachment ID.', 'alttextlab' )
            );
        }

        $keywords = $this->sanitize_keywords( $input['keywords'] ?? array() );

        $alt_text = $this->attachment->generate_alt(
            $attachment_id,
            null,
            array(
                'keywords' => $keywords,
            )
        );

        if ( $alt_text === AltTextLab_Attachment::ERROR_NO_CREDITS ) {
            return $this->ability_error_response(
                $attachment_id,
                'alttextlab_no_credits',
                __( 'No AltTextLab credits available.', 'alttextlab' )
            );
        }

        if ( $alt_text === AltTextLab_Attachment::ERROR_INVALID_API_KEY ) {
            return $this->ability_error_response(
                $attachment_id,
                'alttextlab_invalid_api_key',
                __( 'The AltTextLab API key is invalid.', 'alttextlab' )
            );
        }

        if ( $alt_text === AltTextLab_Attachment::ERROR_MONTHLY_LIMIT ) {
            return $this->ability_error_response(
                $attachment_id,
                'alttextlab_monthly_limit',
                __( 'Monthly credit limit reached for this API key. Update it anytime in your AltTextLab account settings.', 'alttextlab' )
            );
        }

        if ( ! is_string( $alt_text ) || $alt_text === '' ) {
            return $this->ability_error_response(
                $attachment_id,
                'alttextlab_generation_failed',
                __( 'Alt text generation failed.', 'alttextlab' )
            );
        }

        return array(
            'success'       => true,
            'attachment_id' => $attachment_id,
            'alt_text'      => $alt_text,
        );
    }

    /**
     * Finds media images that have missing or empty alt text.
     */
    public function scan_missing_alt( $input ) {
        $limit  = isset( $input['limit'] ) ? absint( $input['limit'] ) : 20;
        $images = $this->attachment->get_images_without_alt_text( $limit );

        return array(
            'success'       => true,
            'total_missing' => $this->attachment->get_images_without_alt_text_count(),
            'count'         => count( $images ),
            'images'        => $images,
        );
    }

    /**
     * Generates alt text for multiple media attachments.
     */
    public function bulk_generate_alt_text( $input ) {
        $attachment_ids = ! empty( $input['attachment_ids'] ) && is_array( $input['attachment_ids'] )
            ? array_map( 'absint', $input['attachment_ids'] )
            : array();

        if ( empty( $attachment_ids ) ) {
            return $this->bulk_error_response(
                'alttextlab_empty_attachment_ids',
                __( 'No attachment IDs provided.', 'alttextlab' )
            );
        }

        $api_key = AltTextLab_Utility::get_api_key();
        if ( empty( $api_key ) ) {
            return $this->bulk_error_response(
                'alttextlab_missing_api_key',
                __( 'AltTextLab API key is missing.', 'alttextlab' )
            );
        }

        return $this->attachment->bulk_generate_alt_text_for_attachments(
            $attachment_ids,
            array(
                'run_id' => uniqid( 'ability_', true ),
            )
        );
    }

    private function sanitize_keywords( $keywords ) {
        if ( empty( $keywords ) || ! is_array( $keywords ) ) {
            return array();
        }

        return array_values( array_filter( array_map( 'sanitize_text_field', $keywords ) ) );
    }

    private function ability_error_response( $attachment_id, $error_code, $message ) {
        return array(
            'success'       => false,
            'attachment_id' => absint( $attachment_id ),
            'error_code'    => $error_code,
            'message'       => $message,
        );
    }

    private function bulk_error_response( $error_code, $message ) {
        return array(
            'success'       => false,
            'processed'     => 0,
            'success_count' => 0,
            'error_count'   => 1,
            'error_code'    => $error_code,
            'message'       => $message,
            'results'       => array(),
        );
    }

}