<?php
/**
 * Frontend Shortcode & Script Registry.
 *
 * @package AISupportAssistant\Frontend
 */

namespace AISupportAssistant\Frontend;

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

/**
 * Class Shortcode
 */
class Shortcode {

	/**
	 * Single instance of the class.
	 *
	 * @var Shortcode|null
	 */
	private static ?Shortcode $instance = null;

	/**
	 * Get active instance of the class.
	 *
	 * @return Shortcode
	 */
	public static function get_instance(): Shortcode {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Constructor.
	 */
	private function __construct() {
		add_shortcode( 'ai_support_assistant', array( $this, 'render_shortcode' ) );
		add_shortcode( 'ai_support', array( $this, 'render_shortcode' ) );
		add_shortcode( 'support_assistant', array( $this, 'render_shortcode' ) );
		add_action( 'wp_enqueue_scripts', array( $this, 'enqueue_assets' ) );
	}

	/**
	 * Enqueue frontend assets on wp_enqueue_scripts.
	 *
	 * @return void
	 */
	public function enqueue_assets(): void {
		if ( is_admin() ) {
			return;
		}

		wp_enqueue_style( 'dashicons' );

		$css_ver = file_exists( AI_SUPPORT_ASSISTANT_PATH . 'assets/css/frontend.css' ) ? (string) filemtime( AI_SUPPORT_ASSISTANT_PATH . 'assets/css/frontend.css' ) : AI_SUPPORT_ASSISTANT_VERSION;
		$js_ver  = file_exists( AI_SUPPORT_ASSISTANT_PATH . 'assets/js/frontend.js' ) ? (string) filemtime( AI_SUPPORT_ASSISTANT_PATH . 'assets/js/frontend.js' ) : AI_SUPPORT_ASSISTANT_VERSION;

		wp_enqueue_style(
			'ai-support-assistant-frontend-style',
			AI_SUPPORT_ASSISTANT_URL . 'assets/css/frontend.css',
			array(),
			$css_ver
		);

		wp_enqueue_script(
			'ai-support-assistant-frontend-js',
			AI_SUPPORT_ASSISTANT_URL . 'assets/js/frontend.js',
			array( 'jquery' ),
			$js_ver,
			true
		);

		$settings     = \AISupportAssistant\Admin\Settings::get_instance();
		$widget_title = $settings->get( 'chat_widget_title', __( 'AI Support Assistant', 'ai-support-assistant' ) );
		if ( empty( $widget_title ) ) {
			$widget_title = __( 'AI Support Assistant', 'ai-support-assistant' );
		}

		// Localize parameters for the frontend JS.
		wp_localize_script(
			'ai-support-assistant-frontend-js',
			'AISupportAssistant',
			array(
				'restUrl'   => esc_url_raw( get_rest_url( null, 'ai-support-assistant/v1/chat' ) ),
				'nonce'     => wp_create_nonce( 'ai_support_assistant_action' ),
				'restNonce' => wp_create_nonce( 'wp_rest' ),
				'title'           => esc_html( $widget_title ),
				'greeting'        => esc_html( $settings->get( 'chat_widget_greeting', __( 'Hello! I am your documentation assistant. Ask me anything, and I will search our guide files to help you.', 'ai-support-assistant' ) ) ),
				'enableStreaming' => ! empty( $settings->get( 'enable_streaming', 1 ) ) ? 1 : 0,
				'i18n'            => array(
					'typing'      => __( 'Assistant is typing...', 'ai-support-assistant' ),
					'error'       => __( 'Sorry, unable to fetch response. Try again.', 'ai-support-assistant' ),
					'placeholder' => __( 'Type your question...', 'ai-support-assistant' ),
					'ready'       => __( 'AI Assistant Ready', 'ai-support-assistant' ),
					'chat_hint'   => __( 'Ask a question to start chatting', 'ai-support-assistant' ),
				),
			)
		);
	}

	/**
	 * Render AI Support Assistant Shortcode.
	 *
	 * @param array $atts Shortcode attributes.
	 * @return string Output HTML.
	 */
	public function render_shortcode( $atts = array() ): string {
		// Enqueue the registered assets.
		wp_enqueue_style( 'ai-support-assistant-frontend-style' );
		wp_enqueue_style( 'dashicons' );
		wp_enqueue_script( 'ai-support-assistant-frontend-js' );

		$settings      = \AISupportAssistant\Admin\Settings::get_instance();
		$default_title = $settings->get( 'chat_widget_title', __( 'AI Support Assistant', 'ai-support-assistant' ) );
		if ( empty( $default_title ) ) {
			$default_title = __( 'AI Support Assistant', 'ai-support-assistant' );
		}

		// Merge attributes.
		$attributes = shortcode_atts(
			array(
				'theme'             => 'light',
				'title'             => $default_title,
				'height'            => '600px',
				'width'             => '450px',
				'provider_override' => '',
			),
			$atts,
			'ai_support_assistant'
		);

		// If title attribute is passed as empty or whitespace, fallback to default title from settings.
		if ( empty( trim( (string) $attributes['title'] ) ) ) {
			$attributes['title'] = $default_title;
		}

		// Buffer template output.
		ob_start();
		$template = AI_SUPPORT_ASSISTANT_PATH . 'templates/frontend-chat.php';
		if ( file_exists( $template ) ) {
			$theme           = esc_attr( $attributes['theme'] );
			$title           = esc_html( $attributes['title'] );
			$height          = esc_attr( $this->sanitize_dimension( $attributes['height'], '600px' ) );
			$width           = esc_attr( $this->sanitize_dimension( $attributes['width'], '450px' ) );
			$greeting        = esc_html( $settings->get( 'chat_widget_greeting', __( 'Hello! I am your documentation assistant. Ask me anything, and I will search our guide files to help you.', 'ai-support-assistant' ) ) );
			$show_powered_by = (int) $settings->get( 'show_powered_by', 0 );
			include $template;
		}
		return ob_get_clean();
	}

	/**
	 * Sanitize CSS dimension attribute (e.g. 600px, 80vh, 100%, or numeric 600).
	 *
	 * @param mixed  $val User input dimension.
	 * @param string $default Default fallback dimension.
	 * @return string
	 */
	private function sanitize_dimension( $val, string $default ): string {
		$val = trim( (string) $val );
		if ( '' === $val ) {
			return $default;
		}
		if ( is_numeric( $val ) ) {
			return $val . 'px';
		}
		if ( preg_match( '/^\d+(\.\d+)?(px|%|vh|vw|em|rem)$/i', $val ) ) {
			return $val;
		}
		return $default;
	}
}