using System.Diagnostics;
using System.Text;

namespace SQLInsight.Servers.Tests;

/// <summary>
/// The security descriptor logic of db/permissions/grant-windows-server.ps1, run in Windows PowerShell against real
/// default SDDLs (Service Control Manager, a WMI namespace, WinRM's RootSDDL): exactly one ACE is added in canonical
/// order, an account that already has the right or has a Deny ACE is left alone, and removing gives back the original
/// SDDL character for character. Nothing on this computer is read or changed.
/// </summary>
public sealed class GrantScriptTests
{
    private const string Harness = """
        param([string] $Script)
        $ErrorActionPreference = 'Stop'
        $ast = [System.Management.Automation.Language.Parser]::ParseFile($Script, [ref] $null, [ref] $null)
        foreach ($f in $ast.FindAll({ $args[0] -is [System.Management.Automation.Language.FunctionDefinitionAst] }, $true)) {
            if ('Get-Aces', 'Test-Denied', 'Test-Allowed', 'Remove-Ace', 'Add-Ace' -contains $f.Name) { . ([scriptblock]::Create($f.Extent.Text)) }
        }
        $accessAllowed = [Security.AccessControl.AceQualifier]::AccessAllowed
        $accessDenied = [Security.AccessControl.AceQualifier]::AccessDenied
        $allSections = [Security.AccessControl.AccessControlSections]::All

        $sidObj = New-Object Security.Principal.SecurityIdentifier('S-1-5-20')
        $scm = 'D:(A;;CC;;;AU)(A;;CCLCRPRC;;;IU)(A;;CCLCRPRC;;;SU)(A;;CCLCRPWPRC;;;SY)(A;;KA;;;BA)(A;;CC;;;AC)S:(AU;FA;KA;;;WD)(AU;OIIOFA;GA;;;WD)'
        $new = Add-Ace $scm 0x20015
        "scm-new=$new"
        "scm-allowed=$(Test-Allowed $new 0x20015)"
        "scm-back=$((Remove-Ace $new 0x20015) -eq $scm)"

        $sidObj = New-Object Security.Principal.SecurityIdentifier('S-1-5-21-1-2-3-1105')
        $wmi = 'O:BAG:BAD:(A;CIID;CCDCLCSWRPWPRCWD;;;BA)(A;CIID;CCDCRP;;;NS)(A;CIID;CCDCRP;;;LS)(A;CIID;CCDCRP;;;AU)'
        $w = Add-Ace $wmi 0x21
        "wmi-new=$w"
        "wmi-back=$((Remove-Ace $w 0x21) -eq $wmi)"

        $root = 'O:NSG:BAD:P(A;;GA;;;BA)(A;;GR;;;IU)S:P(AU;FA;GA;;;WD)(AU;SA;GXGW;;;WD)'
        $r = Add-Ace $root ([int] 0x80000000)
        "root-new=$r"
        "root-back=$((Remove-Ace $r ([int] 0x80000000)) -eq $root)"

        $pre = 'D:(A;;CCLCRPRC;;;S-1-5-21-1-2-3-1105)(A;;CC;;;AU)'
        "pre-allowed=$(Test-Allowed $pre 0x20015)"
        "pre-remove-other-mask=$((Remove-Ace $pre 0x21) -eq $pre)"
        "deny=$(Test-Denied 'D:(D;;CC;;;S-1-5-21-1-2-3-1105)(A;;CC;;;AU)')"
        "no-deny=$(Test-Denied $scm)"
        """;

    [Fact]
    public async Task Exactly_one_ace_is_added_and_removing_it_restores_the_original()
    {
        var output = await RunAsync();

        Assert.Equal("D:(A;;CC;;;AU)(A;;CCLCRPRC;;;IU)(A;;CCLCRPRC;;;SU)(A;;CCLCRPWPRC;;;SY)(A;;KA;;;BA)(A;;CC;;;AC)(A;;CCLCRPRC;;;NS)S:(AU;FA;KA;;;WD)(AU;OIIOFA;GA;;;WD)", output["scm-new"]);
        Assert.Equal("True", output["scm-allowed"]);
        Assert.Equal("True", output["scm-back"]);

        // WMI: Enable Account (CC) + Remote Enable (WP), not inherited, before the inherited ACEs.
        Assert.Equal("O:BAG:BAD:(A;;CCWP;;;S-1-5-21-1-2-3-1105)(A;CIID;CCDCLCSWRPWPRCWD;;;BA)(A;CIID;CCDCRP;;;NS)(A;CIID;CCDCRP;;;LS)(A;CIID;CCDCRP;;;AU)", output["wmi-new"]);
        Assert.Equal("True", output["wmi-back"]);

        // WinRM: read (GR), never execute (GX).
        Assert.Equal("O:NSG:BAD:P(A;;GA;;;BA)(A;;GR;;;IU)(A;;GR;;;S-1-5-21-1-2-3-1105)S:P(AU;FA;GA;;;WD)(AU;SA;GXGW;;;WD)", output["root-new"]);
        Assert.Equal("True", output["root-back"]);

        Assert.Equal("True", output["pre-allowed"]);            // already there: the script adds nothing (and -Remove takes nothing)
        Assert.Equal("True", output["pre-remove-other-mask"]);  // only the script's own ACE is ever removed
        Assert.Equal("True", output["deny"]);                   // a Deny ACE stops the script
        Assert.Equal("False", output["no-deny"]);
    }

    private static async Task<Dictionary<string, string>> RunAsync()
    {
        var script = Path.Combine(RepositoryRoot(), "db", "permissions", "grant-windows-server.ps1");
        var harness = Path.Combine(Path.GetTempPath(), $"sqlinsight-grant-{Guid.NewGuid():N}.ps1");
        await File.WriteAllTextAsync(harness, Harness, new UTF8Encoding(true));
        try
        {
            var start = new ProcessStartInfo("powershell.exe")
            {
                RedirectStandardOutput = true,
                RedirectStandardError = true,
                UseShellExecute = false,
                StandardOutputEncoding = Encoding.UTF8,
            };
            foreach (var argument in new[] { "-NoProfile", "-NonInteractive", "-ExecutionPolicy", "Bypass", "-File", harness, "-Script", script })
            {
                start.ArgumentList.Add(argument);
            }

            using var process = Process.Start(start)!;
            using var timeout = new CancellationTokenSource(TimeSpan.FromMinutes(2));
            var stdout = process.StandardOutput.ReadToEndAsync(timeout.Token);
            var stderr = process.StandardError.ReadToEndAsync(timeout.Token);
            await process.WaitForExitAsync(timeout.Token);
            Assert.True(process.ExitCode == 0, await stderr);
            return (await stdout).Split('\n', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
                .Select(l => l.Split('=', 2))
                .Where(p => p.Length == 2)
                .ToDictionary(p => p[0], p => p[1], StringComparer.Ordinal);
        }
        finally
        {
            File.Delete(harness);
        }
    }

    private static string RepositoryRoot()
    {
        for (var directory = new DirectoryInfo(AppContext.BaseDirectory); directory is not null; directory = directory.Parent)
        {
            if (File.Exists(Path.Combine(directory.FullName, "SQLInsight.slnx")))
            {
                return directory.FullName;
            }
        }

        throw new DirectoryNotFoundException("SQLInsight.slnx blev ikke fundet over testens mappe.");
    }
}