<?php
require_once 'conn.php';

checkLogin();

$employee_id = $_SESSION['employee_id'];
$action = $_POST['action'] ?? '';
$message_id = isset($_POST['message_id']) ? intval($_POST['message_id']) : 0;

if ($message_id <= 0) {
    header('Content-Type: application/json');
    echo json_encode(['success' => false, 'message' => '无效的消息ID']);
    exit;
}

// 检查消息存在且用户有权限
$check_sql = "SELECT m.id, m.target_type 
              FROM messages m 
              LEFT JOIN message_recipients mr ON m.id = mr.message_id AND mr.employee_id = $employee_id
              WHERE m.id = $message_id AND (m.target_type = 2 OR mr.employee_id = $employee_id)";
$check_result = mysqli_query($conn, $check_sql);

if (mysqli_num_rows($check_result) == 0) {
    header('Content-Type: application/json');
    echo json_encode(['success' => false, 'message' => '消息不存在或无权操作']);
    exit;
}

$message = mysqli_fetch_assoc($check_result);

switch ($action) {
    case 'mark_read':
        $check_recipient_sql = "SELECT id FROM message_recipients WHERE message_id = $message_id AND employee_id = $employee_id";
        $check_recipient_result = mysqli_query($conn, $check_recipient_sql);

        if (mysqli_num_rows($check_recipient_result) > 0) {
            // 更新已有记录
            $update_sql = "UPDATE message_recipients SET is_read = 1, read_time = NOW() WHERE message_id = $message_id AND employee_id = $employee_id";
            $result = mysqli_query($conn, $update_sql);
        } else if ($message['target_type'] == 2) {
            // 全体公告，创建新的接收记录
            $insert_sql = "INSERT INTO message_recipients (message_id, employee_id, is_read, read_time, created_at) 
                          VALUES ($message_id, $employee_id, 1, NOW(), NOW())";
            $result = mysqli_query($conn, $insert_sql);
        }

        if ($result) {
            header('Content-Type: application/json');
            echo json_encode(['success' => true]);
        } else {
            header('Content-Type: application/json');
            echo json_encode(['success' => false, 'message' => '操作失败: ' . mysqli_error($conn)]);
        }
        break;

    case 'delete':
        $check_recipient_sql = "SELECT id FROM message_recipients WHERE message_id = $message_id AND employee_id = $employee_id";
        $check_recipient_result = mysqli_query($conn, $check_recipient_sql);

        if (mysqli_num_rows($check_recipient_result) > 0) {
            // 更新已有记录，标记为删除
            $update_sql = "UPDATE message_recipients SET is_deleted = 1 WHERE message_id = $message_id AND employee_id = $employee_id";
            $result = mysqli_query($conn, $update_sql);
        } else if ($message['target_type'] == 2) {
            // 全体公告，创建已删除的接收记录
            $insert_sql = "INSERT INTO message_recipients (message_id, employee_id, is_read, is_deleted, created_at) 
                          VALUES ($message_id, $employee_id, 1, 1, NOW())";
            $result = mysqli_query($conn, $insert_sql);
        }

        if ($result) {
            header('Content-Type: application/json');
            echo json_encode(['success' => true]);
        } else {
            header('Content-Type: application/json');
            echo json_encode(['success' => false, 'message' => '操作失败: ' . mysqli_error($conn)]);
        }
        break;

    default:
        header('Content-Type: application/json');
        echo json_encode(['success' => false, 'message' => '未知操作']);
}
?>