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

namespace Aetherium.Interface.ImGuiFileDialog;

/// <summary>
/// A drive list loader. Thread-safety guaranteed.
/// </summary>
internal class DriveListLoader
{
    /// <summary>
    /// Initializes a new instance of the <see cref="DriveListLoader"/> class.
    /// </summary>
    public DriveListLoader()
    {
        this.Drives = Array.Empty<DriveInfo>();
    }

    /// <summary>
    /// Gets the drive list. This may be incomplete if the loader is still loading.
    /// </summary>
    public IReadOnlyList<DriveInfo> Drives { get; private set; }

    /// <summary>
    /// Gets a value indicating whether or not the loader is loading.
    /// </summary>
    public bool Loading { get; private set; }

    /// <summary>
    /// Loads the drive list, asynchronously.
    /// </summary>
    /// <returns>A <see cref="Task"/> representing the asynchronous operation.</returns>
    public async Task LoadDrivesAsync()
    {
        this.Loading = true;
        try
        {
            await this.InitDrives();
        }
        finally
        {
            this.Loading = false;
        }
    }

    private async Task InitDrives()
    {
        // Force async to avoid this being invoked synchronously unless it's awaited.
        await Task.Yield();
        this.Drives = DriveInfo.GetDrives();
    }
}
