using System.Globalization;
using System.Security.Cryptography;
using System.Text;
using System.Text.RegularExpressions;

namespace SQLInsight.Core.Servers;

/// <summary>Task Scheduler's result codes (LastTaskResult) in Danish, and which of them mean the task failed.</summary>
public static partial class TaskResults
{
    public const uint Success = 0;
    public const uint Ready = 0x41300;
    public const uint Running = 0x41301;
    public const uint Disabled = 0x41302;
    public const uint HasNotRun = 0x41303;
    public const uint NoMoreRuns = 0x41304;
    public const uint TerminatedByUser = 0x41306;
    public const uint Queued = 0x41325;
    public const uint AlreadyRunning = 0x8004131F;

    /// <summary>Whether the last run ended badly. Running, queued, never run and "already running" are not failures.</summary>
    public static bool IsFailure(uint? result) => result is { } r && r is not (Success or Ready or Running or Disabled or HasNotRun or NoMoreRuns or Queued or AlreadyRunning);

    public static string Hex(uint result) => "0x" + result.ToString("X", CultureInfo.InvariantCulture);

    public static string Describe(uint result) => result switch
    {
        Success => "Fuldført (0x0)",
        Ready => "Klar (0x41300)",
        Running => "Kører nu (0x41301)",
        Disabled => "Deaktiveret (0x41302)",
        HasNotRun => "Har ikke kørt endnu (0x41303)",
        NoMoreRuns => "Ingen flere planlagte kørsler (0x41304)",
        TerminatedByUser => "Afbrudt af en bruger eller fordi den kørte for længe (0x41306)",
        Queued => "I kø (0x41325)",
        AlreadyRunning => "Kørte allerede, en ny kørsel blev ikke startet (0x8004131F)",
        0x1 => "Programmet sluttede med fejlkode 1 (typisk en fejl i scriptet eller programmet) (0x1)",
        0x2 => "Filen blev ikke fundet (0x2)",
        0xC000013A => "Programmet blev afbrudt (Ctrl+C eller nedlukning) (0xC000013A)",
        0x80070002 => "Filen blev ikke fundet (0x80070002)",
        0x80070005 => "Adgang nægtet: kontoen, opgaven kører som, mangler rettigheder (0x80070005)",
        0x8007052E => "Logon fejlede: forkert brugernavn eller adgangskode til opgavens konto (0x8007052E)",
        0x800710E0 => "Opgaven blev afvist (fx fordi computeren kørte på batteri eller kontoen ikke var logget på) (0x800710E0)",
        0x80041326 => "Opgaven er deaktiveret (0x80041326)",
        _ => "Sluttede med fejlkode " + Hex(result),
    };

    /// <summary>Whether a task is Microsoft's own (\Microsoft\…), which is not watched unless asked for.</summary>
    public static bool IsMicrosoftTask(string path)
    {
        ArgumentNullException.ThrowIfNull(path);
        return path.StartsWith(@"\Microsoft\", StringComparison.OrdinalIgnoreCase);
    }

    /// <summary>
    /// Tasks that programs create per user or to update themselves, in the root folder rather than under \Microsoft\:
    /// they are not the server's own work, and their failures are rarely anyone's business. A name, or a prefix ending in *.
    /// </summary>
    public static readonly IReadOnlyList<string> DefaultIgnoredNames =
    [
        "OneDrive Standalone Update Task*",
        "OneDrive Per-Machine Standalone Update Task*",
        "OneDrive Reporting Task*",
        "OneDrive Startup Task*",
        "MicrosoftEdgeUpdateTask*",
        "GoogleUpdateTask*",
        "GoogleUpdaterTask*",
        "User_Feed_Synchronization-*",
    ];

    /// <summary>
    /// Whether a task belongs to one user (its name carries the user's SID, S-1-5-21-…) or is a program's own updater
    /// (<see cref="DefaultIgnoredNames"/>). Such tasks are not watched unless asked for.
    /// </summary>
    public static bool IsUserOrUpdaterTask(string path)
    {
        ArgumentNullException.ThrowIfNull(path);
        if (path.Contains("S-1-5-21-", StringComparison.OrdinalIgnoreCase))
        {
            return true;
        }

        var name = path[(path.LastIndexOf('\\') + 1)..];
        return DefaultIgnoredNames.Any(p => p.EndsWith('*')
            ? name.StartsWith(p[..^1], StringComparison.OrdinalIgnoreCase)
            : name.Equals(p, StringComparison.OrdinalIgnoreCase));
    }

    /// <summary>Whether the task's path names a user by SID.</summary>
    public static bool HasUserSid(string path)
    {
        ArgumentNullException.ThrowIfNull(path);
        return Sid().IsMatch(path);
    }

    /// <summary>
    /// The task's path for titles and subjects: a user's SID is replaced by "bruger-" and a short hash of it, which tells
    /// two users' tasks apart without naming the user.
    /// </summary>
    public static string Display(string path)
    {
        ArgumentNullException.ThrowIfNull(path);
        return Sid().Replace(path, m => "bruger-" + Convert.ToHexString(SHA256.HashData(Encoding.UTF8.GetBytes(m.Value.ToUpperInvariant())))[..8].ToLowerInvariant());
    }

    [GeneratedRegex(@"S-1-5-21(-[0-9]+)+", RegexOptions.IgnoreCase | RegexOptions.CultureInvariant)]
    private static partial Regex Sid();
}