<?php

namespace AiChatbotBuilder\Frontend;

if (! defined('ABSPATH')) {
    exit; // Exit if accessed directly.
}

/**
 * Class Frontend.
 *
 * Handles the chat UI, shortcode, and AJAX requests.
 *
 * @package AiChatbotBuilder\Frontend
 */
class Frontend
{

    /**
     * Settings option name.
     *
     * @var string
     */
    private string $option_name = 'aichatbotbuilder_options';

    /**
     * Constructor.
     */
    public function __construct()
    {
        add_shortcode('aichatbot_chat', array($this, 'render_chat_shortcode'));
        // Backward compatibility for old shortcode
        add_shortcode('aichatbot_chat', array($this, 'render_chat_shortcode'));
        add_action('wp_enqueue_scripts', array($this, 'enqueue_assets'));
        add_action('wp_ajax_aichatbotbuilder_send_message', array($this, 'handle_ajax_send_message'));
        add_action('wp_ajax_nopriv_aichatbotbuilder_send_message', array($this, 'handle_ajax_send_message'));
    }

    /**
     * Enqueues frontend scripts and styles.
     */
    public function enqueue_assets(): void
    {
        wp_enqueue_style(
            'aichatbotbuilder-style',
            AICHATBOTBUILDER_URL . 'assets/css/aichatbotbuilder-style.css',
            array(),
            AICHATBOTBUILDER_VERSION
        );
        wp_enqueue_script(
            'aichatbotbuilder-chat',
            AICHATBOTBUILDER_URL . 'assets/js/aichatbotbuilder-chat.js',
            array('jquery'),
            AICHATBOTBUILDER_VERSION,
            true
        );
        $opts        = get_option($this->option_name);
        $daily_limit = isset($opts['daily_token_limit']) ? intval($opts['daily_token_limit']) : \AiChatbotBuilder\Admin\Settings::DEFAULT_DAILY_TOKEN_LIMIT;
        $daily_usage = $this->get_daily_usage();

        wp_localize_script(
            'aichatbotbuilder-chat',
            'aichatbotbuilderChatSettings',
            array(
                'ajax_url'    => admin_url('admin-ajax.php'),
                'nonce'       => wp_create_nonce('aichatbotbuilder_send_message_nonce'),
                'daily_limit' => $daily_limit,
                'daily_usage' => $daily_usage,
            )
        );
    }

    // Add daily usage helper methods.
    /**
     * Gets the current daily token usage.
     *
     * @return int Number of tokens used today.
     */
    private function get_daily_usage(): int
    {
        $usage_data = get_option('aichatbotbuilder_daily_usage', array('date' => '', 'count' => 0));
        $today = current_time('Y-m-d');
        if (! isset($usage_data['date']) || $usage_data['date'] !== $today) {
            return 0;
        }
        return intval($usage_data['count']);
    }

    /**
     * Increments the daily token usage count.
     *
     * @param int $tokens Number of tokens to add.
     * @return void
     */
    private function increment_daily_usage(int $tokens): void
    {
        $today = current_time('Y-m-d');
        $usage_data = get_option('aichatbotbuilder_daily_usage', array('date' => '', 'count' => 0));
        if (! isset($usage_data['date']) || $usage_data['date'] !== $today) {
            $usage_data = array(
                'date' => $today,
                'count' => 0,
            );
        }
        $usage_data['count'] = intval($usage_data['count']) + $tokens;
        update_option('aichatbotbuilder_daily_usage', $usage_data, false);
    }

    /**
     * Renders the chat UI via shortcode.
     *
     * @param array $atts Shortcode attributes.
     * @return string HTML markup for chat.
     */
    public function render_chat_shortcode($atts): string
    {
        $atts    = shortcode_atts(array('id' => 0), $atts, 'aichatbot_chat');
        $chat_id = absint($atts['id']);
        // If no chat ID provided, use the first published chat instance
        if (! $chat_id) {
            $all_chats = get_posts(
                array(
                    'post_type'      => 'aichatbot_chat',
                    'numberposts'    => 1,
                    'post_status'    => 'publish',
                    'fields'         => 'ids',
                )
            );
            if (! empty($all_chats)) {
                $chat_id = absint($all_chats[0]);
            }
        }
        // Fetch configuration and metadata.
        $initial_prompt             = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_initial_prompt', true) : '';
        $bg_color                   = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_bg_color', true) : '';
        $user_color                 = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_user_color', true) : '';
        $bot_color                  = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_bot_color', true) : '';
        // Determine chat position; respect explicit inline (empty) if set in meta
        if ($chat_id && metadata_exists('post', $chat_id, 'aichatbotbuilder_position')) {
            $position = sanitize_text_field(get_post_meta($chat_id, 'aichatbotbuilder_position', true));
        } else {
            $position = 'bottom-right';
        }
        $z_index_raw = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_z_index', true) : '';
        $z_index = '' === $z_index_raw ? 9999 : intval($z_index_raw);
        // Context memory settings
        $memory_enabled             = $chat_id && get_post_meta($chat_id, 'aichatbotbuilder_memory_enabled', true) === '1' ? '1' : '0';
        $memory_length              = $chat_id ? absint(get_post_meta($chat_id, 'aichatbotbuilder_memory_length', true)) : 0;
        // Style fields
        $container_border_color     = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_container_border_color', true) : '';
        $container_border_width     = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_container_border_width', true) : '';
        $container_border_radius    = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_container_border_radius', true) : '';
        // Container max width setting
        $container_max_width        = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_container_max_width', true) : '';
        $container_min_height       = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_container_min_height', true) : '';
        $container_min_height       = $container_min_height ?: 450;
        $input_bg_color             = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_input_bg_color', true) : '';
        $input_text_color           = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_input_text_color', true) : '';
        $input_border_color         = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_input_border_color', true) : '';
        $input_border_radius        = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_input_border_radius', true) : '';
        $input_border_width         = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_input_border_width', true) : '';
        $button_bg_color            = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_button_bg_color', true) : '';
        $button_text_color          = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_button_text_color', true) : '';
        $button_border_color        = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_button_border_color', true) : '';
        $button_border_radius       = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_button_border_radius', true) : '';
        $button_border_width        = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_button_border_width', true) : '';
        // Clear button styles
        $clear_bg_color            = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_clear_bg_color', true) : '';
        $clear_text_color          = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_clear_text_color', true) : '';
        $clear_border_color        = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_clear_border_color', true) : '';
        $clear_border_width        = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_clear_border_width', true) : '';
        $clear_border_radius       = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_clear_border_radius', true) : '';
        // Launcher button meta and defaults
        $launcher_bg_color   = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_launcher_bg_color', true) : '';
        $launcher_icon_color = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_launcher_icon_color', true) : '';
        // Launcher enabled flag
        $launcher_enabled   = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_launcher_enabled', true) : '';
        $launcher_enabled   = $launcher_enabled === '' ? '1' : $launcher_enabled;
        // Launcher position is fixed above the chat container
        $launcher_position  = 'above';
        // Disable floating button for inline embeds
        if ('inline' === $position) {
            $launcher_enabled = '0';
        }
        // Text labels
        $placeholder_text = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_placeholder_text', true) : '';
        $send_button_text = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_send_button_text', true) : '';
        $clear_button_text = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_clear_button_text', true) : '';
        // Greeting message and styles
        $greeting_message   = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_greeting_message', true) : '';
        $greeting_message   = $greeting_message ?: __('How can we help you?', 'ai-chatbot-builder');
        $greeting_bg_color      = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_greeting_bg_color', true) : '';
        $greeting_text_color    = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_greeting_text_color', true) : '';
        $greeting_border_color  = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_greeting_border_color', true) : '';
        $greeting_border_width  = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_greeting_border_width', true) : '';
        $greeting_border_radius = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_greeting_border_radius', true) : '';
        // Apply default greeting styles if empty
        $greeting_bg_color      = $greeting_bg_color ?: '#f1f1f1';
        $greeting_text_color    = $greeting_text_color ?: '#000000';
        $greeting_border_color  = $greeting_border_color ?: '#ccc';
        $greeting_border_width  = '' !== $greeting_border_width ? absint($greeting_border_width) : 1;
        $greeting_border_radius = '' !== $greeting_border_radius ? absint($greeting_border_radius) : 4;
        // Apply defaults if empty
        $placeholder_text = $placeholder_text ?: __('Type a message...', 'ai-chatbot-builder');
        $send_button_text = $send_button_text ?: __('Send', 'ai-chatbot-builder');
        $clear_button_text = $clear_button_text ?: __('Clear', 'ai-chatbot-builder');
        // Header Title and Subtitle
        $header_title    = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_header_title', true) : '';
        $header_title    = $header_title ?: __('Send a message', 'ai-chatbot-builder');
        $header_subtitle = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_header_subtitle', true) : '';
        $header_subtitle = $header_subtitle ?: __('We usually respond in a few hours', 'ai-chatbot-builder');
        // Typing indicator color setting
        $typing_color = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_typing_color', true) : '';
        $typing_color = $typing_color ?: $bot_color ?: '#333333';
        // Apply appearance presets or custom CSS vars
        $style_preset = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_style_preset', true) : 'apple';
        $style_preset = $style_preset ?: 'apple';
        $css_vars = '';
        if ('custom' !== $style_preset) {
            switch ($style_preset) {
                case 'google':
                    $css_vars = '--aichatbotbuilder-bg-color:#f1f3f4;--aichatbotbuilder-container-border-color:transparent;--aichatbotbuilder-container-border-width:1px;--aichatbotbuilder-container-border-radius:8px;--aichatbotbuilder-user-color:#cfe8fd;--aichatbotbuilder-user-text-color:#000000;--aichatbotbuilder-bot-color:#f1f3f4;--aichatbotbuilder-bot-text-color:#000000;--aichatbotbuilder-input-bg-color:#ffffff;--aichatbotbuilder-input-text-color:#202124;--aichatbotbuilder-input-border-color:#dadce0;--aichatbotbuilder-input-border-width:1px;--aichatbotbuilder-input-border-radius:24px;--aichatbotbuilder-button-bg-color:#1a73e8;--aichatbotbuilder-button-text-color:#ffffff;--aichatbotbuilder-button-border-color:#1a73e8;--aichatbotbuilder-button-border-width:1px;--aichatbotbuilder-button-border-radius:24px;--aichatbotbuilder-clear-bg-color:#e0e0e0;--aichatbotbuilder-clear-text-color:#000000;--aichatbotbuilder-clear-border-color:#dadce0;--aichatbotbuilder-clear-border-width:1px;--aichatbotbuilder-clear-border-radius:24px;--aichatbotbuilder-button-bg-hover:#1765c1;--aichatbotbuilder-input-border-hover:#1765c1;';
                    break;
                case 'apple':
                    $css_vars = '--aichatbotbuilder-bg-color:#ffffff;--aichatbotbuilder-container-border-color:#e0e0e0;--aichatbotbuilder-container-border-width:1px;--aichatbotbuilder-container-border-radius:8px;--aichatbotbuilder-user-color:#007aff;--aichatbotbuilder-user-text-color:#ffffff;--aichatbotbuilder-bot-color:#f2f2f2;--aichatbotbuilder-bot-text-color:#000000;--aichatbotbuilder-input-bg-color:#f2f2f2;--aichatbotbuilder-input-text-color:#000000;--aichatbotbuilder-input-border-color:#d1d1d6;--aichatbotbuilder-input-border-width:1px;--aichatbotbuilder-input-border-radius:18px;--aichatbotbuilder-button-bg-color:#007aff;--aichatbotbuilder-button-text-color:#ffffff;--aichatbotbuilder-button-border-color:#007aff;--aichatbotbuilder-button-border-width:1px;--aichatbotbuilder-button-border-radius:18px;--aichatbotbuilder-clear-bg-color:#d1d1d6;--aichatbotbuilder-clear-text-color:#000000;--aichatbotbuilder-clear-border-color:#d1d1d6;--aichatbotbuilder-clear-border-width:1px;--aichatbotbuilder-clear-border-radius:18px;--aichatbotbuilder-button-bg-hover:#005ecb;--aichatbotbuilder-input-border-hover:#005ecb;';
                    break;
                case 'whatsapp':
                    $css_vars = '--aichatbotbuilder-bg-color:#ece5dd;--aichatbotbuilder-container-border-color:transparent;--aichatbotbuilder-container-border-width:1px;--aichatbotbuilder-container-border-radius:0;--aichatbotbuilder-user-color:#daf8cb;--aichatbotbuilder-user-text-color:#000000;--aichatbotbuilder-bot-color:#ece5dd;--aichatbotbuilder-bot-text-color:#000000;--aichatbotbuilder-input-bg-color:#ffffff;--aichatbotbuilder-input-text-color:#000000;--aichatbotbuilder-input-border-color:#cccccc;--aichatbotbuilder-input-border-width:1px;--aichatbotbuilder-input-border-radius:16px;--aichatbotbuilder-button-bg-color:#075e54;--aichatbotbuilder-button-text-color:#ffffff;--aichatbotbuilder-button-border-color:#075e54;--aichatbotbuilder-button-border-width:1px;--aichatbotbuilder-button-border-radius:16px;--aichatbotbuilder-clear-bg-color:#e0e0e0;--aichatbotbuilder-clear-text-color:#000000;--aichatbotbuilder-clear-border-color:#cccccc;--aichatbotbuilder-clear-border-width:1px;--aichatbotbuilder-clear-border-radius:16px;--aichatbotbuilder-button-bg-hover:#064c47;--aichatbotbuilder-input-border-hover:#064c47;';
                    break;
                case 'facebook':
                    $css_vars = '--aichatbotbuilder-bg-color:#f0f2f5;--aichatbotbuilder-container-border-color:transparent;--aichatbotbuilder-container-border-width:1px;--aichatbotbuilder-container-border-radius:6px;--aichatbotbuilder-user-color:#0084ff;--aichatbotbuilder-user-text-color:#ffffff;--aichatbotbuilder-bot-color:#e4e6eb;--aichatbotbuilder-bot-text-color:#000000;--aichatbotbuilder-input-bg-color:#ffffff;--aichatbotbuilder-input-text-color:#050505;--aichatbotbuilder-input-border-color:#ccd0d5;--aichatbotbuilder-input-border-width:1px;--aichatbotbuilder-input-border-radius:20px;--aichatbotbuilder-button-bg-color:#0084ff;--aichatbotbuilder-button-text-color:#ffffff;--aichatbotbuilder-button-border-color:#0084ff;--aichatbotbuilder-button-border-width:1px;--aichatbotbuilder-button-border-radius:20px;--aichatbotbuilder-clear-bg-color:#e4e6eb;--aichatbotbuilder-clear-text-color:#050505;--aichatbotbuilder-clear-border-color:#ccd0d5;--aichatbotbuilder-clear-border-width:1px;--aichatbotbuilder-clear-border-radius:20px;--aichatbotbuilder-button-bg-hover:#006fd6;--aichatbotbuilder-input-border-hover:#006fd6;';
                    break;
                case 'telegram':
                    $css_vars = '--aichatbotbuilder-bg-color:#f7f7f7;--aichatbotbuilder-container-border-color:transparent;--aichatbotbuilder-container-border-width:1px;--aichatbotbuilder-container-border-radius:12px;--aichatbotbuilder-user-color:#dcf8c6;--aichatbotbuilder-user-text-color:#000000;--aichatbotbuilder-bot-color:#f7f7f7;--aichatbotbuilder-bot-text-color:#000000;--aichatbotbuilder-input-bg-color:#ffffff;--aichatbotbuilder-input-text-color:#000000;--aichatbotbuilder-input-border-color:#dcdcdc;--aichatbotbuilder-input-border-width:1px;--aichatbotbuilder-input-border-radius:20px;--aichatbotbuilder-button-bg-color:#0088cc;--aichatbotbuilder-button-text-color:#ffffff;--aichatbotbuilder-button-border-color:#0088cc;--aichatbotbuilder-button-border-width:1px;--aichatbotbuilder-button-border-radius:20px;--aichatbotbuilder-clear-bg-color:#e0e0e0;--aichatbotbuilder-clear-text-color:#000000;--aichatbotbuilder-clear-border-color:#dcdcdc;--aichatbotbuilder-clear-border-width:1px;--aichatbotbuilder-clear-border-radius:20px;--aichatbotbuilder-button-bg-hover:#007ab8;--aichatbotbuilder-input-border-hover:#007ab8;';
                    break;
                case 'slack':
                    $css_vars = '--aichatbotbuilder-bg-color:#f8f8f8;--aichatbotbuilder-container-border-color:transparent;--aichatbotbuilder-container-border-width:1px;--aichatbotbuilder-container-border-radius:4px;--aichatbotbuilder-user-color:#e01e5a;--aichatbotbuilder-user-text-color:#ffffff;--aichatbotbuilder-bot-color:#e1e1e1;--aichatbotbuilder-bot-text-color:#000000;--aichatbotbuilder-input-bg-color:#ffffff;--aichatbotbuilder-input-text-color:#000000;--aichatbotbuilder-input-border-color:#dddddd;--aichatbotbuilder-input-border-width:1px;--aichatbotbuilder-input-border-radius:4px;--aichatbotbuilder-button-bg-color:#3e5aac;--aichatbotbuilder-button-text-color:#ffffff;--aichatbotbuilder-button-border-color:#3e5aac;--aichatbotbuilder-button-border-width:1px;--aichatbotbuilder-button-border-radius:4px;--aichatbotbuilder-clear-bg-color:#e0e0e0;--aichatbotbuilder-clear-text-color:#000000;--aichatbotbuilder-clear-border-color:#dddddd;--aichatbotbuilder-clear-border-width:1px;--aichatbotbuilder-clear-border-radius:4px;--aichatbotbuilder-button-bg-hover:#2d417a;--aichatbotbuilder-input-border-hover:#2d417a;';
                    break;
                case 'chatgpt':
                    $css_vars = '--aichatbotbuilder-bg-color:#ffffff;--aichatbotbuilder-container-border-color:#e5e7eb;--aichatbotbuilder-container-border-width:1px;--aichatbotbuilder-container-border-radius:8px;--aichatbotbuilder-user-color:#f9fafb;--aichatbotbuilder-user-text-color:#000000;--aichatbotbuilder-bot-color:#f3f4f6;--aichatbotbuilder-bot-text-color:#000000;--aichatbotbuilder-input-bg-color:#ffffff;--aichatbotbuilder-input-text-color:#000000;--aichatbotbuilder-input-border-color:#d1d5db;--aichatbotbuilder-input-border-width:1px;--aichatbotbuilder-input-border-radius:6px;--aichatbotbuilder-button-bg-color:#000000;--aichatbotbuilder-button-text-color:#ffffff;--aichatbotbuilder-button-border-color:#000000;--aichatbotbuilder-button-border-width:1px;--aichatbotbuilder-button-border-radius:6px;--aichatbotbuilder-clear-bg-color:#f3f4f6;--aichatbotbuilder-clear-text-color:#555555;--aichatbotbuilder-clear-border-color:#d1d5db;--aichatbotbuilder-clear-border-width:1px;--aichatbotbuilder-clear-border-radius:6px;--aichatbotbuilder-button-bg-hover:#333333;--aichatbotbuilder-input-border-hover:#a0a0a0;--aichatbotbuilder-header-bg-color:#000000;--aichatbotbuilder-header-text-color:#ffffff;--aichatbotbuilder-typing-color:#555555;';
                    break;
                case 'gemini':
                    $css_vars = '--aichatbotbuilder-bg-color:#f0f4f9;--aichatbotbuilder-container-border-color:transparent;--aichatbotbuilder-container-border-width:0px;--aichatbotbuilder-container-border-radius:12px;--aichatbotbuilder-user-color:#e8e8f0;--aichatbotbuilder-user-text-color:#1f1f1f;--aichatbotbuilder-bot-color:#dde3ea;--aichatbotbuilder-bot-text-color:#1f1f1f;--aichatbotbuilder-input-bg-color:#ffffff;--aichatbotbuilder-input-text-color:#1f1f1f;--aichatbotbuilder-input-border-color:#c4c7c5;--aichatbotbuilder-input-border-width:1px;--aichatbotbuilder-input-border-radius:24px;--aichatbotbuilder-button-bg-color:#1a73e8;--aichatbotbuilder-button-text-color:#ffffff;--aichatbotbuilder-button-border-color:#1a73e8;--aichatbotbuilder-button-border-width:1px;--aichatbotbuilder-button-border-radius:24px;--aichatbotbuilder-clear-bg-color:#e0e0e0;--aichatbotbuilder-clear-text-color:#444746;--aichatbotbuilder-clear-border-color:#c4c7c5;--aichatbotbuilder-clear-border-width:1px;--aichatbotbuilder-clear-border-radius:24px;--aichatbotbuilder-button-bg-hover:#0b57d0;--aichatbotbuilder-input-border-hover:#0b57d0;--aichatbotbuilder-header-bg-color:#1f1f1f;--aichatbotbuilder-header-text-color:#e3e3e3;--aichatbotbuilder-typing-color:#444746;';
                    break;
                default:
                    $style_preset = 'custom';
                    break;
            }
        }
        // Apply custom CSS var declarations only when in 'custom' preset
        if ('custom' === $style_preset) {
            if ($bg_color) {
                $css_vars .= '--aichatbotbuilder-bg-color:' . esc_attr($bg_color) . ';';
            }
            if ($container_border_color) {
                $css_vars .= '--aichatbotbuilder-container-border-color:' . esc_attr($container_border_color) . ';';
            }
            if ($container_border_width !== '') {
                $css_vars .= '--aichatbotbuilder-container-border-width:' . intval($container_border_width) . 'px;';
            }
            if ($container_border_radius !== '') {
                $css_vars .= '--aichatbotbuilder-container-border-radius:' . intval($container_border_radius) . 'px;';
            }
            if ($container_max_width !== '') {
                $css_vars .= '--aichatbotbuilder-container-max-width:' . intval($container_max_width) . 'px;';
            }
            if ($container_min_height !== '') {
                $css_vars .= '--aichatbotbuilder-container-min-height:' . intval($container_min_height) . 'px;';
            }
            if ($user_color) {
                $css_vars .= '--aichatbotbuilder-user-color:' . esc_attr($user_color) . ';';
            }
            if ($bot_color) {
                $css_vars .= '--aichatbotbuilder-bot-color:' . esc_attr($bot_color) . ';';
            }
            if ($input_bg_color) {
                $css_vars .= '--aichatbotbuilder-input-bg-color:' . esc_attr($input_bg_color) . ';';
            }
            if ($input_text_color) {
                $css_vars .= '--aichatbotbuilder-input-text-color:' . esc_attr($input_text_color) . ';';
            }
            if ($input_border_color) {
                $css_vars .= '--aichatbotbuilder-input-border-color:' . esc_attr($input_border_color) . ';';
            }
            if ($input_border_width !== '') {
                $css_vars .= '--aichatbotbuilder-input-border-width:' . intval($input_border_width) . 'px;';
            }
            if ($input_border_radius !== '') {
                $css_vars .= '--aichatbotbuilder-input-border-radius:' . intval($input_border_radius) . 'px;';
            }
            if ($button_bg_color) {
                $css_vars .= '--aichatbotbuilder-button-bg-color:' . esc_attr($button_bg_color) . ';';
            }
            if ($button_text_color) {
                $css_vars .= '--aichatbotbuilder-button-text-color:' . esc_attr($button_text_color) . ';';
            }
            if ($button_border_color) {
                $css_vars .= '--aichatbotbuilder-button-border-color:' . esc_attr($button_border_color) . ';';
            }
            if ($button_border_width !== '') {
                $css_vars .= '--aichatbotbuilder-button-border-width:' . intval($button_border_width) . 'px;';
            }
            if ($button_border_radius !== '') {
                $css_vars .= '--aichatbotbuilder-button-border-radius:' . intval($button_border_radius) . 'px;';
            }
            // Add hover state variable based on button bg color
            if ($button_bg_color) {
                // Simple darken function placeholder - adjust logic if needed
                $hover_color = $button_bg_color; // TODO: Implement a real darken function if needed
                $css_vars .= '--aichatbotbuilder-button-bg-hover:' . esc_attr($hover_color) . ';';
            }
            if ($clear_bg_color) {
                $css_vars .= '--aichatbotbuilder-clear-bg-color:' . esc_attr($clear_bg_color) . ';';
            }
            if ($clear_text_color) {
                $css_vars .= '--aichatbotbuilder-clear-text-color:' . esc_attr($clear_text_color) . ';';
            }
            if ($clear_border_color) {
                $css_vars .= '--aichatbotbuilder-clear-border-color:' . esc_attr($clear_border_color) . ';';
            }
            if ($clear_border_width !== '') {
                $css_vars .= '--aichatbotbuilder-clear-border-width:' . intval($clear_border_width) . 'px;';
            }
            if ($clear_border_radius !== '') {
                $css_vars .= '--aichatbotbuilder-clear-border-radius:' . intval($clear_border_radius) . 'px;';
            }
            // Greeting style vars
            if ($greeting_bg_color) {
                $css_vars .= '--aichatbotbuilder-greeting-bg-color:' . esc_attr($greeting_bg_color) . ';';
            }
            if ($greeting_text_color) {
                $css_vars .= '--aichatbotbuilder-greeting-text-color:' . esc_attr($greeting_text_color) . ';';
            }
            if ($greeting_border_color) {
                $css_vars .= '--aichatbotbuilder-greeting-border-color:' . esc_attr($greeting_border_color) . ';';
            }
            if ($greeting_border_width !== '') {
                $css_vars .= '--aichatbotbuilder-greeting-border-width:' . intval($greeting_border_width) . 'px;';
            }
            if ($greeting_border_radius !== '') {
                $css_vars .= '--aichatbotbuilder-greeting-border-radius:' . intval($greeting_border_radius) . 'px;';
            }
            // Launcher style vars
            if ($launcher_bg_color) {
                $css_vars .= '--aichatbotbuilder-launcher-bg-color:' . esc_attr($launcher_bg_color) . ';';
            }
            // Header color from custom button color or fallback
            if ($button_bg_color) {
                $css_vars .= '--aichatbotbuilder-header-bg-color:' . esc_attr($button_bg_color) . ';';
            } else {
                $css_vars .= '--aichatbotbuilder-header-bg-color:#de4452;';
            }
            $css_vars .= '--aichatbotbuilder-header-text-color:#fff;';
            // Typing indicator color
            $css_vars .= '--aichatbotbuilder-typing-color:' . esc_attr($typing_color) . ';';
        }
        // Add default greeting vars for non-custom presets
        if ('custom' !== $style_preset) {
            $css_vars .= '--aichatbotbuilder-greeting-bg-color:var(--aichatbotbuilder-bg-color);';
            $css_vars .= '--aichatbotbuilder-greeting-text-color:var(--aichatbotbuilder-bot-text-color);';
            $css_vars .= '--aichatbotbuilder-greeting-border-color:var(--aichatbotbuilder-container-border-color);';
            $css_vars .= '--aichatbotbuilder-greeting-border-width:var(--aichatbotbuilder-container-border-width);';
            $css_vars .= '--aichatbotbuilder-greeting-border-radius:var(--aichatbotbuilder-container-border-radius);';
            // Launcher defaults for non-custom presets
            $css_vars .= '--aichatbotbuilder-launcher-bg-color:var(--aichatbotbuilder-button-bg-color);';
            // Header color from button color
            $css_vars .= '--aichatbotbuilder-header-bg-color:var(--aichatbotbuilder-button-bg-color,#de4452);';
            $css_vars .= '--aichatbotbuilder-header-text-color:#fff;';
            // Typing indicator fallback to bot text color
            $css_vars .= '--aichatbotbuilder-typing-color:var(--aichatbotbuilder-bot-text-color);';
        }

        if ($container_max_width) {
            $css_vars .= '--aichatbotbuilder-container-max-width:' . intval($container_max_width) . 'px;';
        }
        if ($container_min_height) {
            $css_vars .= '--aichatbotbuilder-container-min-height:' . intval($container_min_height) . 'px;';
        }
        if ($z_index) {
            $css_vars .= '--aichatbotbuilder-z-index:' . esc_attr($z_index) . ';';
        }

        // Container classes and styles
        $position_class = $position ? ' aichatbotbuilder-position-' . esc_attr($position) : '';
        // Escape late: $css_vars is output in an HTML attribute context.
        $style_attr = $css_vars ? ' style="' . esc_attr($css_vars) . '"' : '';

        // Add unique instance class for custom CSS targeting
        $instance_class = ' aichatbotbuilder-chat-instance-' . esc_attr($chat_id);
        // Wrap chat in launcher-enabled wrapper
        $open_class = '1' === $launcher_enabled ? '' : ' open';
        if ('inline' === $position) {
            $launcher_pos_class = '';
        } else {
            $launcher_pos_class = ' aichatbotbuilder-launcher-pos-' . esc_attr($launcher_position);
        }
        $html  = '<div class="aichatbotbuilder-widget-wrapper' . $instance_class . $position_class . $launcher_pos_class . ' aichatbotbuilder-preset-' . esc_attr($style_preset) . $open_class . '"' . $style_attr . '>';
        if ('inline' !== $position && '1' === $launcher_enabled && $launcher_position === 'above') {
            $html .= '<button class="aichatbotbuilder-launcher" type="button" aria-label="' . esc_attr__('Open Chat', 'ai-chatbot-builder') . '">';
            $html .= '<svg width="24" height="24" viewBox="0 0 24 24" fill="' . esc_attr($launcher_icon_color) . '" xmlns="http://www.w3.org/2000/svg">';
            $html .= '<path d="M2 2h20v14H6l-4 4V2z"/>';
            $html .= '</svg>';
            $html .= '</button>';
        }
        $html .= '<div class="aichatbotbuilder-chat-container" data-chat-id="' . esc_attr($chat_id) . '" data-memory-enabled="' . esc_attr($memory_enabled) . '" data-memory-length="' . esc_attr($memory_length) . '">';
        // Header section
        $html .= '<div class="aichatbotbuilder-header">';
        $html .= '<div class="aichatbotbuilder-header-title">' . esc_html($header_title) . '</div>';
        $html .= '<div class="aichatbotbuilder-header-subtitle">' . esc_html($header_subtitle) . '</div>';
        $html .= '</div>';

        // Close button inside chat - only show if floating button is enabled
        if ('1' === $launcher_enabled) {
            $html .= '<button type="button" class="aichatbotbuilder-close" aria-label="' . esc_attr__('Close Chat', 'ai-chatbot-builder') . '">&times;</button>';
        }

        // Initial greeting displayed as first message
        $html .= '<div class="aichatbotbuilder-messages">';
        $html .= '<div class="aichatbotbuilder-message aichatbotbuilder-message--bot aichatbotbuilder-greeting">' . esc_html($greeting_message) . '</div>';
        $html .= '</div>';
        $html .= '<form class="aichatbotbuilder-form">';
        $html .= '<input type="text" class="aichatbotbuilder-input" placeholder="' . esc_attr($placeholder_text) . '" required />';
        $html .= '<button type="submit" class="aichatbotbuilder-send" title="' . esc_attr__('Send', 'ai-chatbot-builder') . '">&#10148;</button>';
        $html .= '<button type="button" class="aichatbotbuilder-clear" title="' . esc_attr__('Clear', 'ai-chatbot-builder') . '">&times;</button>';
        $html .= '</form>';
        $html .= '</div>';
        $html .= '</div>'; // close widget-wrapper
        return $html;
    }

    /**
     * Handles AJAX request to send message to OpenAI.
     */
    public function handle_ajax_send_message(): void
    {
        check_ajax_referer('aichatbotbuilder_send_message_nonce', 'nonce');

        $message = isset($_POST['message']) ? sanitize_text_field(wp_unslash($_POST['message'])) : '';
        if (empty($message)) {
            wp_send_json_error(array('message' => esc_html__('Message cannot be empty.', 'ai-chatbot-builder')));
        }

        $opts          = get_option($this->option_name);
        $api_key       = $opts['openai_api_key'] ?? '';
        $model         = $opts['openai_model'] ?? 'gpt-4o';
        // Determine initial prompt from chat instance.
        $chat_id       = isset($_POST['chat_id']) ? absint(wp_unslash($_POST['chat_id'])) : 0;
        $initial_prompt = $chat_id ? get_post_meta($chat_id, 'aichatbotbuilder_initial_prompt', true) : '';
        $system_content = $initial_prompt ? $initial_prompt : 'You are a helpful assistant.';
        // Collect history if provided and sanitize each entry.
        $history = array();
        if (isset($_POST['history']) && $opts) {
            // Unsplash and sanitize JSON input
            $history_json = sanitize_textarea_field(wp_unslash($_POST['history']));
            $decoded = json_decode($history_json, true);
            if (is_array($decoded)) {
                foreach ($decoded as $entry) {
                    $role_raw    = $entry['role'] ?? '';
                    $content_raw = $entry['content'] ?? '';
                    $role    = sanitize_key($role_raw);
                    $content = sanitize_text_field($content_raw);
                    if (in_array($role, array('user', 'assistant'), true)) {
                        $history[] = array(
                            'role'    => $role,
                            'content' => $content,
                        );
                    }
                }
            }
        }

        // Enforce daily token limit
        $daily_limit   = isset($opts['daily_token_limit']) ? intval($opts['daily_token_limit']) : 0;
        $current_usage = $this->get_daily_usage();
        if ($daily_limit > 0 && $current_usage >= $daily_limit) {
            wp_send_json_error(array('message' => esc_html__('Daily token limit reached.', 'ai-chatbot-builder')), 429);
        }

        if (empty($api_key)) {
            wp_send_json_error(array('message' => esc_html__('API key is not set in the settings page.', 'ai-chatbot-builder')));
        }

        // Build chat messages array with memory
        $messages = array(array('role' => 'system', 'content' => $system_content));
        if (! empty($history)) {
            $messages = array_merge($messages, $history);
        }
        $messages[] = array('role' => 'user', 'content' => $message);
        $args       = array(
            'headers' => array(
                'Authorization' => 'Bearer ' . $api_key,
                'Content-Type'  => 'application/json',
            ),
            'body'    => wp_json_encode(array('model' => $model, 'messages' => $messages)),
            'timeout' => 60,
        );

        $response = wp_remote_post('https://api.openai.com/v1/chat/completions', $args);
        if (is_wp_error($response)) {
            wp_send_json_error(array('message' => $response->get_error_message()));
        }

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

        if (200 !== $code || empty($data['choices'][0]['message']['content'])) {
            wp_send_json_error(array('message' => esc_html__('Error retrieving response from API.', 'ai-chatbot-builder')));
        }

        // Update daily usage count
        if (isset($data['usage']['total_tokens'])) {
            $this->increment_daily_usage(intval($data['usage']['total_tokens']));
        }

        $reply = $data['choices'][0]['message']['content'];
        // Prepare usage data for response
        $current_usage = $this->get_daily_usage();
        $daily_limit   = isset($opts['daily_token_limit']) ? intval($opts['daily_token_limit']) : 0;
        wp_send_json_success(
            array(
                'reply' => wp_kses_post($reply),
                'usage' => array(
                    'used'  => $current_usage,
                    'limit' => $daily_limit,
                ),
            )
        );
    }
}