// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using System.Collections.Generic;
using System.ComponentModel.Composition;
using Microsoft.CodeAnalysis.ExternalAccess.Razor;
using Microsoft.CodeAnalysis.Razor.Settings;
using Microsoft.CodeAnalysis.Razor.Workspaces.Settings;
using Microsoft.VisualStudio.Threading;
 
namespace Microsoft.VisualStudio.Razor.Settings;
 
[Export(typeof(IClientSettingsManager))]
internal sealed class ClientSettingsManager : IClientSettingsManager
{
    public event EventHandler<EventArgs>? ClientSettingsChanged;
 
    private readonly object _settingsUpdateLock = new();
    private readonly IAdvancedSettingsStorage? _advancedSettingsStorage;
    private readonly RazorGlobalOptions? _globalOptions;
    private ClientSettings _settings;
 
    [ImportingConstructor]
    public ClientSettingsManager(
        [ImportMany] IEnumerable<IClientSettingsChangedTrigger> changeTriggers,
        [Import(AllowDefault = true)] IAdvancedSettingsStorage? advancedSettingsStorage = null,
        RazorGlobalOptions? globalOptions = null)
    {
        _settings = ClientSettings.Default;
 
        // update Roslyn's global options (null in tests):
        if (globalOptions is not null)
        {
            globalOptions.TabSize = _settings.ClientSpaceSettings.IndentSize;
            globalOptions.UseTabs = _settings.ClientSpaceSettings.IndentWithTabs;
        }
 
        foreach (var changeTrigger in changeTriggers)
        {
            changeTrigger.Initialize(this);
        }
 
        _advancedSettingsStorage = advancedSettingsStorage;
        _globalOptions = globalOptions;
 
        if (_advancedSettingsStorage is not null)
        {
            Update(_advancedSettingsStorage.GetAdvancedSettings());
            _advancedSettingsStorage.OnChangedAsync(Update).Forget();
        }
    }
 
    public ClientSettings GetClientSettings() => _settings;
 
    public void Update(ClientSpaceSettings updatedSettings)
    {
        if (updatedSettings is null)
        {
            throw new ArgumentNullException(nameof(updatedSettings));
        }
 
        // update Roslyn's global options (null in tests):
        if (_globalOptions is not null)
        {
            _globalOptions.TabSize = updatedSettings.IndentSize;
            _globalOptions.UseTabs = updatedSettings.IndentWithTabs;
        }
 
        lock (_settingsUpdateLock)
        {
            UpdateSettings_NoLock(_settings with { ClientSpaceSettings = updatedSettings });
        }
    }
 
    public void Update(ClientCompletionSettings updatedSettings)
    {
        if (updatedSettings is null)
        {
            throw new ArgumentNullException(nameof(updatedSettings));
        }
 
        lock (_settingsUpdateLock)
        {
            UpdateSettings_NoLock(_settings with { ClientCompletionSettings = updatedSettings });
        }
    }
 
    public void Update(ClientAdvancedSettings advancedSettings)
    {
        if (advancedSettings is null)
        {
            throw new ArgumentNullException(nameof(advancedSettings));
        }
 
        lock (_settingsUpdateLock)
        {
            UpdateSettings_NoLock(_settings with { AdvancedSettings = advancedSettings });
        }
    }
 
    private void UpdateSettings_NoLock(ClientSettings settings)
    {
        if (!_settings.Equals(settings))
        {
            _settings = settings;
 
            ClientSettingsChanged?.Invoke(this, EventArgs.Empty);
        }
    }
}