// Copyright (c) Nate McMaster.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Diagnostics;
using System.IO;

namespace BTCPayServer.Plugins.Dotnet.LibraryModel
{
    /// <summary>
    /// Represents an unmanaged library, such as `libsqlite3`, which may need to be loaded
    /// for P/Invoke to work.
    /// </summary>
    [DebuggerDisplay("{Name} = {AdditionalProbingPath}")]
    public class NativeLibrary
    {
        private NativeLibrary(string name, string appLocalPath, string additionalProbingPath)
        {
            Name = name ?? throw new ArgumentNullException(nameof(name));
            AppLocalPath = appLocalPath ?? throw new ArgumentNullException(nameof(appLocalPath));
            AdditionalProbingPath = additionalProbingPath ?? throw new ArgumentNullException(nameof(additionalProbingPath));
        }

        /// <summary>
        /// Name of the native library. This should match the name of the P/Invoke call.
        /// <para>
        /// For example, if specifying `[DllImport("sqlite3")]`, <see cref="Name" /> should be <c>sqlite3</c>.
        /// This may not match the exact file name as loading will attempt variations on the name according
        /// to OS convention. On Windows, P/Invoke will attempt to load `sqlite3.dll`. On macOS, it will
        /// attempt to find `sqlite3.dylib` and `libsqlite3.dylib`. On Linux, it will attempt to find
        /// `sqlite3.so` and `libsqlite3.so`.
        /// </para>
        /// </summary>
        public string Name { get; private set; }

        /// <summary>
        /// Contains path to file within a deployed, framework-dependent application
        /// <para>
        /// For example, <c>runtimes/linux-x64/native/libsqlite.so</c>
        /// </para>
        /// </summary>
        public string AppLocalPath { get; private set; }

        /// <summary>
        /// Contains path to file within an additional probing path root. This is typically a combination
        /// of the NuGet package ID (lowercased), version, and path within the package.
        /// <para>
        /// For example, <c>sqlite/3.13.3/runtimes/linux-x64/native/libsqlite.so</c>
        /// </para>
        /// </summary>
        public string AdditionalProbingPath { get; private set; }

        /// <summary>
        /// Create an instance of <see cref="NativeLibrary" /> from a NuGet package.
        /// </summary>
        /// <param name="packageId">The name of the package.</param>
        /// <param name="packageVersion">The version of the package.</param>
        /// <param name="assetPath">The path within the NuGet package.</param>
        /// <returns></returns>
        public static NativeLibrary CreateFromPackage(string packageId, string packageVersion, string assetPath)
        {
            return new NativeLibrary(
                Path.GetFileNameWithoutExtension(assetPath),
                assetPath,
                Path.Combine(packageId.ToLowerInvariant(), packageVersion, assetPath)
            );
        }
    }
}