<?php
class CAZ_Chatbot_Context {

    public static function build_system_prompt(): string {
        $store_name = get_bloginfo( 'name' );
        $currency   = get_woocommerce_currency();

        $base = "You are a helpful customer support assistant for {$store_name}, a WooCommerce store.
You help customers with orders, shipping, returns, and product questions.
Always be polite and concise. Currency is {$currency}.

STORE POLICIES:
- Returns: 30 days for unused items in original packaging.
- Shipping: UK standard 3-5 business days. Express 1-2 days.
- Contact: support@{$store_name}.com for escalations.

IMPORTANT: You are a WooCommerce AI chatbot. Do not make up order details.
Only report order information provided to you in this prompt.";

        // Add customer order history for logged-in users
        if ( is_user_logged_in() ) {
            $customer_id = get_current_user_id();
            $orders = wc_get_orders([
                'customer_id' => $customer_id,
                'limit'       => 5,
                'orderby'     => 'date',
                'order'       => 'DESC',
            ]);

            if ( $orders ) {
                $base .= "nnCUSTOMER'S RECENT ORDERS (use for order status queries):";
                foreach ( $orders as $order ) {
                    $base .= sprintf(
                        "n- Order #%s | Status: %s | Total: %s | Date: %s",
                        $order->get_order_number(),
                        wc_get_order_status_name( $order->get_status() ),
                        $order->get_formatted_order_total(),
                        $order->get_date_created()->date( 'd M Y' )
                    );
                }
            }
        }

        return $base;
    }
}

add_action( 'wp_ajax_caz_chatbot_message',        'caz_chatbot_handle_message' );
add_action( 'wp_ajax_nopriv_caz_chatbot_message', 'caz_chatbot_handle_message' );

function caz_chatbot_handle_message(): void {
    check_ajax_referer( 'caz-chatbot-nonce', 'nonce' );

    $user_message = sanitize_text_field( $_POST['message'] ?? '' );
    if ( ! $user_message ) wp_send_json_error( 'Empty message', 400 );

    // Load conversation history from WooCommerce session for this chatbot
    WC()->session->set_customer_session_cookie( true );
    $history = WC()->session->get( 'caz_chatbot_history', [] );

    // Limit history to last 10 turns to control token costs
    if ( count( $history ) > 20 ) {
        $history = array_slice( $history, -20 );
    }

    // Append user message to WooCommerce AI chatbot history
    $history[] = [ 'role' => 'user', 'content' => $user_message ];

    $api_key  = CAZ_AI_KeyManager::get();
    $response = wp_remote_post( 'https://api.openai.com/v1/chat/completions', [
        'timeout' => 30,
        'headers' => [
            'Authorization' => 'Bearer ' . $api_key,
            'Content-Type'  => 'application/json',
        ],
        'body' => wp_json_encode([
            'model'       => 'gpt-4o-mini',
            'max_tokens'  => 400,
            'temperature' => 0.5,
            'messages'    => array_merge(
                [[ 'role' => 'system', 'content' => CAZ_Chatbot_Context::build_system_prompt() ]],
                $history
            ),
        ]),
    ]);

    if ( is_wp_error( $response ) ) wp_send_json_error( 'API error', 500 );

    $body       = json_decode( wp_remote_retrieve_body( $response ), true );
    $assistant  = $body['choices'][0]['message']['content'] ?? '';

    if ( ! $assistant ) wp_send_json_error( 'No response from AI', 500 );

    // Save assistant reply to WooCommerce AI chatbot history
    $history[] = [ 'role' => 'assistant', 'content' => $assistant ];
    WC()->session->set( 'caz_chatbot_history', $history );

    wp_send_json_success([
        'message'    => $assistant,
        'turn_count' => count( $history ) / 2,
    ]);
}

async function sendMessage( message ) {
  appendMessage( 'user', message );
  setLoading( true );

  const body = new URLSearchParams({
    action:  'caz_chatbot_message',
    nonce:   cazChatbot.nonce,
    message: message,
  });

  try {
    const res  = await fetch( cazChatbot.ajaxUrl, { method: 'POST', body });
    const data = await res.json();

    if ( data.success ) {
      appendMessage( 'assistant', data.data.message );
    } else {
      appendMessage( 'assistant', 'Sorry, I am having trouble responding. Please try again.' );
    }
  } catch {
    appendMessage( 'assistant', 'Connection error. Please check your internet and try again.' );
  } finally {
    setLoading( false );
  }
}

function appendMessage( role, text ) {
  const el = document.createElement( 'div' );
  el.className = 'caz-chat-message caz-chat-message--' + role;
  el.textContent = text;
  document.querySelector( '.caz-chat-messages' ).appendChild( el );
  el.scrollIntoView({ behavior: 'smooth' });
}