using System;
using System.Threading;
using Microsoft.Extensions.Logging;
using StellaOps.Plugin.Hosting;

namespace StellaOps.Notify.WebService.Plugins;

internal interface INotifyPluginRegistry
{
    Task<int> WarmupAsync(CancellationToken cancellationToken = default);
}

internal sealed class NotifyPluginRegistry : INotifyPluginRegistry
{
    private readonly PluginHostOptions _hostOptions;
    private readonly ILogger<NotifyPluginRegistry> _logger;

    public NotifyPluginRegistry(
        PluginHostOptions hostOptions,
        ILogger<NotifyPluginRegistry> logger)
    {
        _hostOptions = hostOptions ?? throw new ArgumentNullException(nameof(hostOptions));
        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
    }

    public Task<int> WarmupAsync(CancellationToken cancellationToken = default)
    {
        cancellationToken.ThrowIfCancellationRequested();

        var result = PluginHost.LoadPlugins(_hostOptions, _logger);

        if (result.Plugins.Count == 0)
        {
            _logger.LogWarning(
                "No Notify plug-ins discovered under '{PluginDirectory}'.",
                result.PluginDirectory);
        }
        else
        {
            _logger.LogInformation(
                "Loaded {PluginCount} Notify plug-in(s) from '{PluginDirectory}'.",
                result.Plugins.Count,
                result.PluginDirectory);
        }

        if (result.MissingOrderedPlugins.Count > 0)
        {
            _logger.LogWarning(
                "Configured plug-ins missing from disk: {Missing}.",
                string.Join(", ", result.MissingOrderedPlugins));
        }

        return Task.FromResult(result.Plugins.Count);
    }
}