// Copyright (c) Arlo Godfrey. All Rights Reserved.
// Licensed under the GNU Lesser General Public License, Version 3.0 with additional terms.
// See the LICENSE, LICENSE.LESSER and LICENSE.ADDITIONAL files in the project root for more information.

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using OwlCore.AbstractStorage;
using OwlCore.Provisos;
using StrixMusic.Sdk.FileMetadata.Models;

namespace StrixMusic.Sdk.FileMetadata.Repositories
{
    /// <summary>
    /// A repository that provides access to metadata scanned from a file.
    /// </summary>
    public interface IMetadataRepository<TFileMetadata> : IAsyncInit, IDisposable
        where TFileMetadata : class, IFileMetadata
    {
        /// <summary>
        /// Sets the root folder to operate in when saving data.
        /// </summary>
        /// <param name="rootFolder">The root folder to save data in.</param>
        public void SetDataFolder(IFolderData rootFolder);

        /// <summary>
        /// Returns the number of items currently loaded in the repository.
        /// </summary>
        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
        public Task<int> GetItemCount();

        /// <summary>
        /// Adds a metadata to the repo, or updates an existing metadata.
        /// </summary>
        /// <param name="metadata">The metadata to add.</param>
        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
        public Task AddOrUpdateAsync(params TFileMetadata[] metadata);

        /// <summary>
        /// Removes metadata from the repository.
        /// </summary>
        /// <param name="metadata">The metadata to remove.</param>
        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
        /// <exception cref="ArgumentException">The specified <paramref name="metadata"/> does not exist in the repository.</exception>
        public Task RemoveAsync(TFileMetadata metadata);

        /// <summary>
        /// Gets metadata by the given <paramref name="id"/>.
        /// </summary>
        /// <param name="id">The id of some metadata in the repository..</param>
        /// <returns>A <see cref="Task"/> representing the asynchronous operation. Value is the metadata if found, otherwise null.</returns>
        public Task<TFileMetadata?> GetByIdAsync(string id);

        /// <summary>
        /// Gets all <see cref="TrackMetadata"/> over the file system.
        /// </summary>
        /// <param name="offset">The starting index for retrieving items.</param>
        /// <param name="limit">The maximum number of items to return.</param>
        /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
        public Task<IReadOnlyList<TFileMetadata>> GetItemsAsync(int offset, int limit);

        /// <summary>
        /// Raised when metadata is updated.
        /// </summary>
        public event EventHandler<IEnumerable<TFileMetadata>>? MetadataUpdated;

        /// <summary>
        /// Raised metadata is removed.
        /// </summary>
        public event EventHandler<IEnumerable<TFileMetadata>>? MetadataRemoved;

        /// <summary>
        /// Raised when new metadata is added.
        /// </summary>
        public event EventHandler<IEnumerable<TFileMetadata>>? MetadataAdded;
    }
}