/* ========================================================================
 * Copyright (c) 2005-2025 The OPC Foundation, Inc. All rights reserved.
 *
 * OPC Foundation MIT License 1.00
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * The complete license agreement can be found here:
 * http://opcfoundation.org/License/MIT/1.00/
 * ======================================================================*/

using System.Collections.Generic;
using System.IO;
using System.Threading;
using System.Threading.Tasks;

namespace Opc.Ua.Di.Server.SoftwareUpdate
{
    /// <summary>
    /// Multi-version software repository for one DI topology element
    /// (typically a device). Models OPC 10000-100 §10.3.5
    /// <c>SoftwareFolderType</c> — the folder under
    /// <c>SoftwareType</c> that lists every known software version
    /// (current, previous, future) and tracks which one is currently
    /// active on the device.
    /// </summary>
    /// <remarks>
    /// <para>
    /// Implementations are scoped to a single topology element. Use
    /// one folder instance per device that supports the
    /// <c>SoftwareFolderType</c> facet.
    /// </para>
    /// <para>
    /// All operations must be safe for concurrent calls.
    /// </para>
    /// </remarks>
    public interface ISoftwareFolder
    {
        /// <summary>
        /// The topology element this folder belongs to (typically a
        /// device NodeId).
        /// </summary>
        NodeId ElementId { get; }

        /// <summary>
        /// Streams every software version known to the folder.
        /// </summary>
        IAsyncEnumerable<SoftwarePackage> ListVersionsAsync(
            CancellationToken cancellationToken = default);

        /// <summary>
        /// Returns the version currently marked as active on the
        /// device, or <see langword="null"/> when no version is
        /// active.
        /// </summary>
        ValueTask<SoftwarePackage?> GetCurrentVersionAsync(
            CancellationToken cancellationToken = default);

        /// <summary>
        /// Returns the package with the supplied
        /// <paramref name="version"/> identifier; or
        /// <see langword="null"/> when no such version exists.
        /// </summary>
        ValueTask<SoftwarePackage?> GetVersionAsync(
            string version,
            CancellationToken cancellationToken = default);

        /// <summary>
        /// Opens the binary payload of the version for reading.
        /// </summary>
        ValueTask<Stream> OpenVersionAsync(
            string version,
            CancellationToken cancellationToken = default);

        /// <summary>
        /// Adds a new software version. If a version with the same
        /// identifier already exists it is replaced.
        /// </summary>
        ValueTask<SoftwarePackage> AddVersionAsync(
            SoftwarePackage metadata,
            Stream payload,
            CancellationToken cancellationToken = default);

        /// <summary>
        /// Removes the version with the supplied identifier. Returns
        /// <see langword="true"/> when a version was removed.
        /// </summary>
        ValueTask<bool> RemoveVersionAsync(
            string version,
            CancellationToken cancellationToken = default);

        /// <summary>
        /// Marks the supplied version as the currently active one on
        /// the device. Throws <see cref="System.ArgumentException"/>
        /// when the version is unknown.
        /// </summary>
        ValueTask SetCurrentVersionAsync(
            string version,
            CancellationToken cancellationToken = default);
    }
}