using Microsoft.Extensions.DependencyInjection;
using StellaOps.AdvisoryAI.Remediation.ScmConnector;
using StellaOps.Plugin.Abstractions;
using StellaOps.Plugin.Abstractions.Capabilities;

namespace StellaOps.AdvisoryAI.Scm.Plugin.Unified;


/// <summary>
/// Factory for creating unified SCM plugin adapters from existing connectors.
/// </summary>
public sealed class ScmPluginAdapterFactory
{
    private readonly ScmConnectorCatalog _catalog;
    private readonly Dictionary<string, ScmPluginAdapter> _adapters = new(StringComparer.OrdinalIgnoreCase);
    private readonly object _lock = new();

    /// <summary>
    /// Creates a new factory instance.
    /// </summary>
    /// <param name="catalog">The SCM connector catalog.</param>
    public ScmPluginAdapterFactory(ScmConnectorCatalog catalog)
    {
        _catalog = catalog ?? throw new ArgumentNullException(nameof(catalog));
    }

    /// <summary>
    /// Gets all available unified SCM plugins.
    /// </summary>
    /// <param name="options">Connector options.</param>
    /// <returns>List of unified SCM plugins.</returns>
    public IReadOnlyList<IPlugin> GetAllPlugins(ScmConnectorOptions options)
    {
        var result = new List<IPlugin>();

        foreach (var plugin in _catalog.Plugins)
        {
            if (plugin.IsAvailable(options))
            {
                var adapter = GetOrCreateAdapter(plugin.ScmType, options);
                if (adapter != null)
                {
                    result.Add(adapter);
                }
            }
        }

        return result;
    }

    /// <summary>
    /// Gets a unified SCM plugin by SCM type.
    /// </summary>
    /// <param name="scmType">SCM type identifier.</param>
    /// <param name="options">Connector options.</param>
    /// <returns>Unified SCM plugin, or null if not found.</returns>
    public IPlugin? GetPlugin(string scmType, ScmConnectorOptions options)
    {
        return GetOrCreateAdapter(scmType, options);
    }

    /// <summary>
    /// Gets a unified SCM plugin that can handle the given repository URL.
    /// </summary>
    /// <param name="repositoryUrl">Repository URL to handle.</param>
    /// <param name="options">Connector options.</param>
    /// <returns>Unified SCM plugin, or null if not found.</returns>
    public IPlugin? GetPluginForRepository(string repositoryUrl, ScmConnectorOptions options)
    {
        var plugin = _catalog.Plugins.FirstOrDefault(p => p.CanHandle(repositoryUrl));
        if (plugin == null)
            return null;

        return GetOrCreateAdapter(plugin.ScmType, options);
    }

    /// <summary>
    /// Gets the SCM capability for a connector.
    /// </summary>
    /// <param name="scmType">SCM type identifier.</param>
    /// <param name="options">Connector options.</param>
    /// <returns>SCM capability, or null if not found.</returns>
    public IScmCapability? GetCapability(string scmType, ScmConnectorOptions options)
    {
        return GetOrCreateAdapter(scmType, options);
    }

    private ScmPluginAdapter? GetOrCreateAdapter(string scmType, ScmConnectorOptions options)
    {
        lock (_lock)
        {
            if (_adapters.TryGetValue(scmType, out var existing))
            {
                return existing;
            }

            var plugin = _catalog.Plugins.FirstOrDefault(
                p => p.ScmType.Equals(scmType, StringComparison.OrdinalIgnoreCase));

            if (plugin == null || !plugin.IsAvailable(options))
            {
                return null;
            }

            var connector = _catalog.GetConnector(scmType, options);
            if (connector == null)
            {
                return null;
            }

            var adapter = new ScmPluginAdapter(connector, plugin, options);
            _adapters[scmType] = adapter;

            return adapter;
        }
    }
}

/// <summary>
/// Extension methods for registering unified SCM plugin services.
/// </summary>
public static class ScmPluginAdapterExtensions
{
    /// <summary>
    /// Adds unified SCM plugin adapter services to the service collection.
    /// </summary>
    /// <param name="services">Service collection.</param>
    /// <returns>Service collection for chaining.</returns>
    public static IServiceCollection AddUnifiedScmPlugins(this IServiceCollection services)
    {
        services.AddSingleton<ScmPluginAdapterFactory>();

        return services;
    }
}