<?php
class AIT_IAT_Alt_Generator {

    public function __construct() {
        add_filter('ait_iat_generate_alt_text', [ $this, 'generate_alt_text' ], 10, 3);
    }

    public static function generate_alt_text($alt, $attachment_id, $metadata = null, $post_id = 0) {
        $file_path      = get_attached_file($attachment_id);
        $api_key        = AIT_IAT_Settings::get('openai_api_key');
        $model          = AIT_IAT_Settings::get('openai_model');
        $model_override = AIT_IAT_Settings::get('force_model_override');
        $timeout        = AIT_IAT_Settings::get('request_timeout');
        $prefix         = AIT_IAT_Settings::get('alt_text_prefix');
        $suffix         = AIT_IAT_Settings::get('alt_text_suffix');
        $seo_keyword    = class_exists( 'AIT_IAT_SEO_Scoring_Pro' ) ? AIT_IAT_SEO_Scoring_Pro::get_focus_keyword($post_id, $attachment_id): '';
        $max_length     = intval(AIT_IAT_Settings::get('max_alt_text_length'));

        if (empty($file_path) || !file_exists($file_path)) {
            return $alt;
        }

        if (self::is_monthly_limit_exceeded()) {
            return $alt;
        }

        $allowed = apply_filters( 'ait_iat_should_generate', true, (int) $attachment_id );
        if ( ! $allowed ) {
            return $alt;
        }

        $model = $model_override ?: $model;

        do_action( 'ait_iat_before_generation', $alt, $attachment_id );

        $prompt = AIT_IAT_Prompt_Builder::build_prompt($attachment_id, $seo_keyword);

        $mime = mime_content_type($file_path);
        $image_data = base64_encode(file_get_contents($file_path));
        $image_data_uri = "data:{$mime};base64,{$image_data}";
        $api_url = 'https://api.openai.com/v1/chat/completions';
        $headers = [
            'Authorization' => 'Bearer ' . $api_key,
            'Content-Type'  => 'application/json',
        ];

        $body = [
            'model'    => $model,
            'messages' => [
                [
                    'role'    => 'user',
                    'content' => [
                        ['type' => 'text', 'text' => $prompt],
                        ['type' => 'image_url', 'image_url' => [ 'url' => $image_data_uri ]]
                    ]
                ]
            ]
        ];
        $response = wp_remote_post($api_url, [
            'headers' => $headers,
            'body'    => json_encode($body),
            'timeout' => $timeout,
        ]);

        $generated          = '';
        $api_response_json  = null;
        $json_fields        = null;

        if (!is_wp_error($response) && !empty($response['body'])) {
            $api_response_json = json_decode($response['body'], true);

            if (!empty($api_response_json['choices'][0]['message']['content'])) {
                // Raw content from the model
                $raw_content = trim($api_response_json['choices'][0]['message']['content']);
                $raw_content = trim($raw_content, "\"' \t\n\r\0\x0B");

                // Try to interpret the content itself as JSON containing "alt_text"
                $json_fields = json_decode($raw_content, true);
                if (json_last_error() !== JSON_ERROR_NONE || ! is_array($json_fields) || empty($json_fields['alt_text'])) {
                    // Backwards-compatible behavior: treat the content as plain alt text
                    $json_fields['alt_text'] = $raw_content;
                }
            }
            elseif ( isset( $api_response_json['error'] ) ) { 
                if (AIT_IAT_Settings::get('enable_debug_mode')) {
                    error_log(
                        '[AI Image Alt Text] OpenAI API error: ' .
                        $api_response_json['error']['code'] . ' - ' .
                        $api_response_json['error']['message']
                    );
                }
            }
        } else {
            if (AIT_IAT_Settings::get('enable_debug_mode')) {
                error_log('[AI Image Alt Text] OpenAI API error: ' . print_r($response, true));
            }

            return $alt;
        }


        if ($max_length && strlen($json_fields['alt_text']) > $max_length) {
            $json_fields['alt_text'] = mb_substr($json_fields['alt_text'], 0, $max_length);
        }

        $json_fields['alt_text'] = $prefix . $json_fields['alt_text'] . $suffix;

        $json_fields['alt_text'] = apply_filters('ait_iat_after_generate_alt_text', $json_fields['alt_text'], $attachment_id, $api_response_json);

        $accept = apply_filters('ait_iat_should_accept_alt', true, $json_fields['alt_text'], $attachment_id);
        
        if ( $accept && $json_fields['alt_text'] ) { self::record_generation(); }

        return ( $accept && ! empty( $json_fields['alt_text'] ) ) ? $json_fields : $alt;
    }

    public static function is_monthly_limit_exceeded() {

        $timestamps = get_option('ait_iat_generation_timestamps', []);
        $cutoff = time() - (30 * DAY_IN_SECONDS);
    
        // Keep only timestamps from the last 30 days
        $timestamps = array_filter($timestamps, function($t) use ($cutoff) {
            return $t >= $cutoff;
        });
    
        // Save cleaned list
        update_option('ait_iat_generation_timestamps', $timestamps);
        
        $limit = apply_filters( 'ait_iat/generation_limit', 25 );

        return count($timestamps) >= $limit;
    }
    
    public static function record_generation() {

        $timestamps = get_option('ait_iat_generation_timestamps', []);
        $timestamps[] = time();

        update_option('ait_iat_generation_timestamps', $timestamps);
    }

    /**
     * Rename an attachment's main file using a new filename slug.
     *
     * @param int    $attachment_id Attachment ID.
     * @param string $new_slug      New filename slug (without extension).
     * @return string|null          New basename (e.g. "my-file-name.jpg") on success, null on failure.
     */
    public static function maybe_rename_attachment_file( $attachment_id, $new_slug ) {
        $new_slug = sanitize_title( $new_slug );
        if ( ! $attachment_id || ! $new_slug ) {
            return null;
        }
    
        $old_path = get_attached_file( $attachment_id );
        if ( ! $old_path || ! file_exists( $old_path ) ) {
            return null;
        }
    
        $pathinfo = pathinfo( $old_path );
        $dir      = $pathinfo['dirname'];
        $ext      = isset( $pathinfo['extension'] ) ? $pathinfo['extension'] : '';
        $old_base = $pathinfo['basename'];
    
        // Build new basename and make sure it's unique within the directory.
        $proposed_basename = $new_slug . ( $ext ? '.' . $ext : '' );
        $new_basename      = wp_unique_filename( $dir, $proposed_basename );
        $new_path          = trailingslashit( $dir ) . $new_basename;
    
        // Actually move the main file.
        if ( ! @rename( $old_path, $new_path ) ) { // phpcs:ignore WordPress.PHP.NoSilencedErrors.Discouraged
            return null;
        }
    
        // Update attached file path.
        update_attached_file( $attachment_id, $new_path );
    
        // Update attachment metadata to reflect the new main file path.
        $meta = wp_get_attachment_metadata( $attachment_id );
        if ( ! empty( $meta ) && is_array( $meta ) && ! empty( $meta['file'] ) ) {
            // $meta['file'] is a path relative to uploads base dir, like "2025/12/old-name.jpg".
            $upload_dir = wp_get_upload_dir();
    
            if ( ! empty( $upload_dir['basedir'] ) && is_string( $upload_dir['basedir'] ) ) {
                $uploads_basedir = trailingslashit( $upload_dir['basedir'] );
    
                // Derive the relative directory from the old meta file.
                $meta_pathinfo = pathinfo( $meta['file'] );
                $rel_dir       = ! empty( $meta_pathinfo['dirname'] ) && '.' !== $meta_pathinfo['dirname']
                    ? trailingslashit( $meta_pathinfo['dirname'] )
                    : '';
    
                $meta['file'] = $rel_dir . $new_basename;
                wp_update_attachment_metadata( $attachment_id, $meta );
            }
        }
    
        return $new_basename;
    }
}