using Microsoft.Extensions.Logging;
using Microsoft.Win32;
using PatchProbe.Shared.Contracts;
using PatchProbe.Shared.Models;

namespace PatchProbe.Cli.Collectors;

public sealed class WindowsUpdatePolicyCollector(ILogger<WindowsUpdatePolicyCollector> logger) : ICollector<WindowsUpdatePolicy>
{
    private const string WuPolicyKey = @"SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate";
    private const string AuPolicyKey = @"SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU";
    private const string WuUxKey = @"SOFTWARE\Microsoft\WindowsUpdate\UX\Settings";

    public Task<WindowsUpdatePolicy> CollectAsync(CancellationToken cancellationToken = default)
    {
        logger.LogInformation("Collecting Windows Update policy");

        using var wuKey = Registry.LocalMachine.OpenSubKey(WuPolicyKey);
        using var auKey = Registry.LocalMachine.OpenSubKey(AuPolicyKey);
        using var uxKey = Registry.LocalMachine.OpenSubKey(WuUxKey);

        var wsusServer = wuKey?.GetValue("WUServer")?.ToString();
        var policy = new WindowsUpdatePolicy
        {
            WsusConfigured = !string.IsNullOrEmpty(wsusServer),
            WsusServer = wsusServer,
            WsusStatusServer = wuKey?.GetValue("WUStatusServer")?.ToString(),
            WufbConfigured = wuKey?.GetValue("ManagePreviewBuilds") != null
                          || uxKey?.GetValue("BranchReadinessLevel") != null,
            DeferFeatureUpdatesDays = GetInt(wuKey, "DeferFeatureUpdatesPeriodInDays")
                                   ?? GetInt(uxKey, "DeferFeatureUpdatesPeriodInDays"),
            DeferQualityUpdatesDays = GetInt(wuKey, "DeferQualityUpdatesPeriodInDays")
                                   ?? GetInt(uxKey, "DeferQualityUpdatesPeriodInDays"),
            AutoUpdateEnabled = GetInt(auKey, "NoAutoUpdate") != 1,
            AuOptions = GetInt(auKey, "AUOptions"),
            TargetGroupEnabled = GetInt(wuKey, "TargetGroupEnabled") == 1,
            TargetGroup = wuKey?.GetValue("TargetGroup")?.ToString(),
            BranchReadinessLevel = uxKey?.GetValue("BranchReadinessLevel")?.ToString(),
        };

        return Task.FromResult(policy);
    }

    private static int? GetInt(RegistryKey? key, string name)
    {
        if (key?.GetValue(name) is int v) return v;
        return null;
    }
}