-- Migration 004: Pending notifications table
-- Creates a queue for native-app notifications that the customer
-- device picks up via GET /customer/poll and acknowledges via
-- POST /customer/notifications/{id}/ack.
--
-- Usage: mysql -u root -p yourdb < migrations/004_pending_notifications.sql

SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO";
SET time_zone = "+00:00";

CREATE TABLE `pending_notifications` (
  `id` int(11) NOT NULL,
  `customer_id` int(11) NOT NULL,
  `title` varchar(255) NOT NULL,
  `body` text DEFAULT NULL,
  `created_at` timestamp NOT NULL DEFAULT current_timestamp(),
  `read_at` timestamp NULL DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;

ALTER TABLE `pending_notifications`
  ADD PRIMARY KEY (`id`),
  ADD KEY `customer_id` (`customer_id`),
  ADD KEY `idx_unread` (`customer_id`, `read_at`);

ALTER TABLE `pending_notifications`
  MODIFY `id` int(11) NOT NULL AUTO_INCREMENT;

ALTER TABLE `pending_notifications`
  ADD CONSTRAINT `pending_notifications_ibfk_1` FOREIGN KEY (`customer_id`) REFERENCES `customers` (`customer_id`) ON DELETE CASCADE;