#Requires -Modules @{ ModuleName = 'Pester'; ModuleVersion = '5.0' }
# Pester 5 tests for Request-VsqlServerCertificate.ps1. Run on Windows PowerShell 5.1 and PowerShell 7:
#   Invoke-Pester -Path scripts\tests -Output Detailed
# The host (registry, services, certreq, icacls, machine store) is a fake. The certificates are
# real, made with New-SelfSignedCertificate in Cert:\CurrentUser\My under the friendly name
# below, and removed in AfterAll. Nothing touches the machine store, the registry or a CA.

BeforeAll {
    . (Join-Path $PSScriptRoot '..\Request-VsqlServerCertificate.ps1')

    $script:TestFriendlyName = 'PS2-VSQL-CERT-TEST'
    $script:Root = 'HKLM:\SOFTWARE\Microsoft\Microsoft SQL Server'
    $script:KeyDefault = "$Root\MSSQL16.MSSQLSERVER\MSSQLServer\SuperSocketNetLib"
    $script:KeyDev = "$Root\MSSQL16.DEV\MSSQLServer\SuperSocketNetLib"
    $script:HostSans = 'DNS=vsql.pesco.com&DNS=vsql&DNS=sqlhost.pesco.com&DNS=SQLHOST'
    $script:Required = @('vsql.pesco.com', 'vsql', 'sqlhost.pesco.com', 'SQLHOST')

    Get-ChildItem Cert:\CurrentUser\My | Where-Object { $_.FriendlyName -eq $TestFriendlyName } | ForEach-Object { Remove-Item -LiteralPath "Cert:\CurrentUser\My\$($_.Thumbprint)" -DeleteKey }

    function New-TestCert {
        param(
            [string]$Sans = $HostSans,
            [string]$Provider = 'Microsoft RSA SChannel Cryptographic Provider',
            [string]$KeySpec = 'KeyExchange',
            [int]$KeyLength = 2048,
            [string]$Hash = 'SHA256',
            [string]$Eku = '1.3.6.1.5.5.7.3.1',
            [string[]]$KeyUsage = @('DigitalSignature', 'KeyEncipherment'),
            [datetime]$NotBefore = (Get-Date).AddDays(-1),
            [datetime]$NotAfter = (Get-Date).AddYears(1)
        )
        $a = @{
            Subject           = 'CN=vsql.pesco.com'
            CertStoreLocation = 'Cert:\CurrentUser\My'
            FriendlyName      = $TestFriendlyName
            Provider          = $Provider
            KeyLength         = $KeyLength
            HashAlgorithm     = $Hash
            KeyUsage          = $KeyUsage
            NotBefore         = $NotBefore
            NotAfter          = $NotAfter
            TextExtension     = @("2.5.29.17={text}$Sans", "2.5.29.37={text}$Eku")
        }
        if ($KeySpec) { $a.KeySpec = $KeySpec }
        $c = New-SelfSignedCertificate @a
        Get-Item "Cert:\CurrentUser\My\$($c.Thumbprint)"
    }

    $script:Good = New-TestCert
    $script:Good2 = New-TestCert
    $script:Evil = New-TestCert -Sans 'DNS=vsql.pesco.com.evil.example&DNS=vsql.evil.example&DNS=sqlhost.pesco.com&DNS=SQLHOST'
    $script:Cased = New-TestCert -Sans 'DNS=VSQL.PESCO.COM&DNS=Vsql&DNS=SqlHost.Pesco.Com&DNS=sqlhost'
    $script:Ksp = New-TestCert -Provider 'Microsoft Software Key Storage Provider' -KeySpec ''
    # The SChannel CSP cannot hold a signature key, so these use the Enhanced RSA and AES CSP (type 24).
    $script:SigSpec = New-TestCert -Provider 'Microsoft Enhanced RSA and AES Cryptographic Provider' -KeySpec 'Signature' -KeyUsage 'DigitalSignature'
    $script:AesCsp = New-TestCert -Provider 'Microsoft Enhanced RSA and AES Cryptographic Provider'
    $script:Weak = New-TestCert -KeyLength 1024
    $script:Sha1 = New-TestCert -Hash 'SHA1'
    $script:NoServerAuth = New-TestCert -Eku '1.3.6.1.5.5.7.3.2'
    $script:Expired = New-TestCert -NotBefore (Get-Date).AddDays(-60) -NotAfter (Get-Date).AddDays(-1)

    $script:Mutating = '^(certreq -new|certreq -submit|certreq -accept|icacls|SetReg|RemoveReg|Restart)'

    # A fake SQL host: default instance and DEV, service accounts, registry, machine store,
    # certreq and icacls. $Fake.Calls records every operation in order.
    function New-FakeHost {
        param([string]$Work)
        $fake = @{
            Admin        = $true
            Calls        = New-Object System.Collections.ArrayList
            Log          = New-Object System.Collections.ArrayList
            Instances    = [ordered]@{ MSSQLSERVER = 'MSSQL16.MSSQLSERVER'; DEV = 'MSSQL16.DEV' }
            Services     = @{
                'MSSQLSERVER' = [pscustomobject]@{ Name = 'MSSQLSERVER'; StartName = 'NT Service\MSSQLSERVER' }
                'MSSQL$DEV'   = [pscustomobject]@{ Name = 'MSSQL$DEV'; StartName = 'PESCO\svc-sqldev' }
            }
            Registry     = @{
                $KeyDefault = @{ Certificate = ''; ForceEncryption = '0' }
                $KeyDev     = @{ Certificate = ''; ForceEncryption = '0' }
            }
            Store        = @{}
            Submit       = 'Issued'      # Issued, Pending, Failure
            IssueCert    = $Good
            IcaclsFail   = $false
            SetFails     = @{}           # regKey -> $true: Set-ItemProperty throws
            SetIgnored   = @{}           # regKey -> $true: the write does not stick
            ReadFails    = @{}           # regKey -> $true: reading throws (access denied)
            Dependents   = @{ 'MSSQLSERVER' = @('SQLSERVERAGENT'); 'MSSQL$DEV' = @('SQLAgent$DEV') }
            Running      = New-Object 'System.Collections.Generic.HashSet[string]' ([StringComparer]::OrdinalIgnoreCase)
            RestartFails = @{}           # service -> $true: stops it and its dependents, then fails to start
            KeyFile      = Join-Path $Work 'machinekey.bin'
            ShouldProcess = $null
        }
        New-Item -ItemType Directory -Force -Path $Work | Out-Null
        Set-Content -Path $fake.KeyFile -Value 'key'
        $realKeyInfo = ${function:Get-CertificateKeyInfo}
        $p = @{
            WorkDir        = $Work
            InstanceRoot   = $Root
            IsAdmin        = { [void]$fake.Calls.Add('IsAdmin'); $fake.Admin }.GetNewClosure()
            GetInstanceMap = { param($r) $fake.Instances }.GetNewClosure()
            GetService     = { param($n) [void]$fake.Calls.Add("GetService $n"); $fake.Services[$n] }.GetNewClosure()
            TestRegKey     = { param($k) $fake.Registry.ContainsKey($k) }.GetNewClosure()
            GetRegValue    = {
                param($k, $n)
                if ($fake.ReadFails[$k]) { throw "Requested registry access is not allowed: $k" }
                $v = $fake.Registry[$k]; if ($v.ContainsKey($n)) { [string]$v[$n] } else { $null }
            }.GetNewClosure()
            SetRegValue    = {
                param($k, $n, $v)
                [void]$fake.Calls.Add("SetReg $k $n=$v")
                if ($fake.SetFails[$k]) { throw "Access to $k is denied" }
                if (-not $fake.SetIgnored[$k]) { $fake.Registry[$k][$n] = $v }
            }.GetNewClosure()
            RemoveRegValue = { param($k, $n) [void]$fake.Calls.Add("RemoveReg $k $n"); if ($fake.SetFails[$k]) { throw "Access to $k is denied" }; $fake.Registry[$k].Remove($n) }.GetNewClosure()
            GetHostNames   = { @('sqlhost.pesco.com', 'SQLHOST') }
            GetMachineCert = { param($t) $fake.Store[$t] }.GetNewClosure()
            Certreq        = {
                param([string[]]$a)
                [void]$fake.Calls.Add("certreq $($a[0]) $($a[1..($a.Count - 1)] -join ' ')")
                switch ($a[0]) {
                    '-new' { return [pscustomobject]@{ ExitCode = 0; Output = @('CertReq: Request Created') } }
                    '-submit' {
                        $cer = $a[-1]
                        switch ($fake.Submit) {
                            'Issued' { [IO.File]::WriteAllBytes($cer, $fake.IssueCert.Export('Cert')); return [pscustomobject]@{ ExitCode = 0; Output = @('RequestId: 42', 'RequestId: "42"', 'Certificate retrieved(Issued) Issued') } }
                            'Pending' { return [pscustomobject]@{ ExitCode = 0; Output = @('RequestId: 43', 'RequestId: "43"', 'Certificate request is pending: Taken Under Submission (0)') } }
                            default { return [pscustomobject]@{ ExitCode = -2146877436; Output = @('RequestId: 44', 'Certificate not issued (Denied) Denied by Policy Module') } }
                        }
                    }
                    '-accept' {
                        $c = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2 (, [IO.File]::ReadAllBytes($a[-1]))
                        $fake.Store[$c.Thumbprint] = Get-Item "Cert:\CurrentUser\My\$($c.Thumbprint)"
                        return [pscustomobject]@{ ExitCode = 0; Output = @('Installed Certificate') }
                    }
                }
            }.GetNewClosure()
            Icacls         = {
                param([string[]]$a)
                [void]$fake.Calls.Add("icacls $($a -join ' ')")
                if ($fake.IcaclsFail) { return [pscustomobject]@{ ExitCode = 5; Output = @('Access is denied.') } }
                [pscustomobject]@{ ExitCode = 0; Output = @('processed file') }
            }.GetNewClosure()
            ResolveSid     = { param($acct) @{ 'NT Service\MSSQLSERVER' = 'S-1-5-80-1'; 'PESCO\svc-sqldev' = 'S-1-5-21-9-1105' }[$acct] }
            # The real key reader on the real test certificate; only the store location is faked,
            # since the test keys live in the user store and vsql's in the machine store.
            GetKeyInfo     = { param($c) $k = & $realKeyInfo $c; if ($k) { $k.Machine = $true }; $k }.GetNewClosure()
            KeyFilePath    = { param($k) $fake.KeyFile }.GetNewClosure()
            TestFile       = { param($f) Test-Path -LiteralPath $f -PathType Leaf }
            GetRunningDependents = { param($n) @($fake.Dependents[$n] | Where-Object { $fake.Running.Contains($_) }) }.GetNewClosure()
            RestartService = {
                param($n)
                [void]$fake.Calls.Add("Restart $n")
                foreach ($d in $fake.Dependents[$n]) { [void]$fake.Running.Remove($d) }
                [void]$fake.Running.Remove($n)
                if ($fake.RestartFails[$n]) { throw "Service '$n' cannot be started" }
                [void]$fake.Running.Add($n)
            }.GetNewClosure()
            StartService   = { param($n) [void]$fake.Calls.Add("Start $n"); [void]$fake.Running.Add($n) }.GetNewClosure()
            Now            = { Get-Date }
            Log            = { param($m) [void]$fake.Log.Add("$m") }.GetNewClosure()
            ShouldProcess  = $null
        }
        foreach ($svc in 'MSSQLSERVER', 'MSSQL$DEV', 'SQLSERVERAGENT', 'SQLAgent$DEV') { [void]$fake.Running.Add($svc) }
        $fake.Provider = $p
        return $fake
    }

    function Get-MutatingCalls($Fake) { @($Fake.Calls | Where-Object { $_ -match $Mutating }) }
    function Get-Snapshots($Fake) { @(Get-ChildItem -LiteralPath $Fake.Provider.WorkDir -Filter 'deploy-*.json' -File -ErrorAction SilentlyContinue | Sort-Object Name) }
    function Add-ToStore($Fake, $Cert) { $Fake.Store[$Cert.Thumbprint] = $Cert }
}

AfterAll {
    Get-ChildItem Cert:\CurrentUser\My | Where-Object { $_.FriendlyName -eq $TestFriendlyName } | ForEach-Object { Remove-Item -LiteralPath "Cert:\CurrentUser\My\$($_.Thumbprint)" -DeleteKey }
}

Describe 'Finding 1: administrator check' {
    BeforeEach { $f = New-FakeHost (Join-Path $TestDrive ([guid]::NewGuid())); Add-ToStore $f $Good }

    It 'refuses an unelevated session before any lookup or change' {
        $f.Admin = $false
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint } | Should -Throw '*elevated*'
        $f.Calls | Should -Be @('IsAdmin')
    }
    It 'refuses an unelevated rollback too' {
        $f.Admin = $false
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback } | Should -Throw '*elevated*'
    }
    It 'lets an elevated session through' {
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint
        $r.Bound | Should -Be @('MSSQLSERVER', 'DEV')
    }
    It 'no longer calls Test-Admin with stray arguments' {
        $text = Get-Content (Join-Path $PSScriptRoot '..\Request-VsqlServerCertificate.ps1') -Raw
        $text | Should -Not -Match 'Test-Admin\s+-eq'
        $text | Should -Match 'if \(-not \(& \$P\.IsAdmin\)\)'
    }
}

Describe 'Finding 2: named instance service lookup' {
    It 'builds a WQL filter that keeps $ unescaped' {
        Get-ServiceFilter 'MSSQL$DEV' | Should -BeExactly "Name='MSSQL`$DEV'"
        Get-SqlServiceName 'DEV' | Should -BeExactly 'MSSQL$DEV'
        Get-SqlServiceName 'MSSQLSERVER' | Should -BeExactly 'MSSQLSERVER'
    }
    It 'runs that filter against real WMI without error (the old escaped form is an invalid query)' {
        { Get-CimInstance Win32_Service -Filter (Get-ServiceFilter 'MSSQL$DEV') -ErrorAction Stop } | Should -Not -Throw
        { Get-CimInstance Win32_Service -Filter "Name='MSSQL\`$DEV'" -ErrorAction Stop } | Should -Throw
    }
    It 'discovers the default and DEV instances with their accounts' {
        $f = New-FakeHost (Join-Path $TestDrive 'disc')
        $t = Get-SqlInstances $f.Provider $null
        $t.Name | Should -Be @('MSSQLSERVER', 'DEV')
        ($t | Where-Object Name -eq 'DEV').Service | Should -BeExactly 'MSSQL$DEV'
        ($t | Where-Object Name -eq 'DEV').Account | Should -Be 'PESCO\svc-sqldev'
        ($t | Where-Object Name -eq 'DEV').RegKey | Should -Be $KeyDev
        $f.Calls | Should -Contain 'GetService MSSQL$DEV'
    }
    It 'fails loudly when a service is missing' {
        $f = New-FakeHost (Join-Path $TestDrive 'nosvc')
        $f.Services.Remove('MSSQL$DEV')
        { Get-SqlInstances $f.Provider @('DEV') } | Should -Throw '*MSSQL$DEV*not found*'
    }
}

Describe 'Unknown instance names' {
    It 'rejects them before any change' {
        $f = New-FakeHost (Join-Path $TestDrive 'unknown')
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Instances 'DEV', 'PROD' } | Should -Throw '*Unknown instance(s): PROD*'
        Get-MutatingCalls $f | Should -BeNullOrEmpty
        @($f.Calls | Where-Object { $_ -like 'certreq*' }) | Should -BeNullOrEmpty
        Test-Path (Join-Path $f.Provider.WorkDir '*.inf') | Should -BeFalse
    }
}

Describe 'Finding 3: SAN decoding and matching' {
    It 'decodes the DNS names from the raw extension' {
        $ext = $Good.Extensions | Where-Object { $_.Oid.Value -eq '2.5.29.17' }
        Get-SanDnsNames $ext.RawData | Should -Be @('vsql.pesco.com', 'vsql', 'sqlhost.pesco.com', 'SQLHOST')
    }
    It 'agrees with .NET where .NET can decode SANs (PowerShell 7)' {
        $ext = $Good.Extensions | Where-Object { $_.Oid.Value -eq '2.5.29.17' }
        if (-not ($ext.PSObject.Methods.Name -contains 'EnumerateDnsNames')) { Set-ItResult -Skipped -Because 'this .NET has no X509SubjectAlternativeNameExtension'; return }
        Get-SanDnsNames $ext.RawData | Should -Be @($ext.EnumerateDnsNames())
    }
    It 'skips non-DNS entries and handles long-form lengths' {
        # SEQUENCE { [7] 4 bytes IP, [2] 130 bytes name }
        $name = 'a' * 126 + '.com'
        $dns = [byte[]](0x82, 0x81, 130) + [Text.Encoding]::ASCII.GetBytes($name)
        $ip = [byte[]](0x87, 4, 192, 168, 1, 1)
        $body = $ip + $dns
        $raw = [byte[]](0x30, 0x81, $body.Length) + $body
        Get-SanDnsNames $raw | Should -Be @($name)
    }
    It 'rejects malformed data' {
        { Get-SanDnsNames ([byte[]](0x30, 0x05, 0x82, 0x09, 0x61)) } | Should -Throw
        { Get-SanDnsNames ([byte[]](0x31, 0x00)) } | Should -Throw
    }
    It 'rejects vsql.pesco.com.evil.example for vsql.pesco.com and vsql' {
        $c = Test-ServerCertificate -Certificate $Evil -RequiredNames $Required
        $c.Problems | Should -Contain 'subject alternative name vsql.pesco.com missing'
        $c.Problems | Should -Contain 'subject alternative name vsql missing'
        @($c.Problems | Where-Object { $_ -like '*sqlhost*' -or $_ -like '*SQLHOST*' }) | Should -BeNullOrEmpty
    }
    It 'accepts case variants' {
        (Test-ServerCertificate -Certificate $Cased -RequiredNames $Required).Problems | Should -BeNullOrEmpty
    }
}

Describe 'Certificate validation on real keys' {
    It 'accepts a CSP exchange key, RSA 2048, SHA-256, Server Authentication, all SANs' {
        $c = Test-ServerCertificate -Certificate $Good -RequiredNames $Required
        $c.Problems | Should -BeNullOrEmpty
        $c.KeyInfo.ProviderType | Should -Be 12
        $c.KeyInfo.KeySpec | Should -Be 1
        $c.KeyInfo.UniqueName | Should -Not -BeNullOrEmpty
    }
    It 'rejects a KSP (CNG) key' {
        (Test-ServerCertificate -Certificate $Ksp -RequiredNames $Required).Problems -join " | " | Should -Match 'Key Storage Provider'
    }
    It 'rejects a CSP signature key' {
        $p = (Test-ServerCertificate -Certificate $SigSpec -RequiredNames $Required).Problems
        $p -join " | " | Should -Match 'AT_KEYEXCHANGE'
        $p | Should -Contain 'key usage lacks key encipherment'
    }
    It 'rejects a CSP other than the SChannel provider' {
        $p = (Test-ServerCertificate -Certificate $AesCsp -RequiredNames $Required).Problems
        @($p) | Should -HaveCount 1
        $p -join " | " | Should -Match 'provider type 24'
    }
    It 'rejects a key under 2048 bits' {
        (Test-ServerCertificate -Certificate $Weak -RequiredNames $Required).Problems -join " | " | Should -Match 'key size 1024'
    }
    It 'rejects SHA-1' {
        (Test-ServerCertificate -Certificate $Sha1 -RequiredNames $Required).Problems -join " | " | Should -Match 'not SHA-256'
    }
    It 'rejects a certificate without Server Authentication' {
        (Test-ServerCertificate -Certificate $NoServerAuth -RequiredNames $Required).Problems | Should -Contain 'Server Authentication EKU missing'
    }
    It 'rejects an expired certificate' {
        (Test-ServerCertificate -Certificate $Expired -RequiredNames $Required).Problems -join " | " | Should -Match 'not valid now'
    }
    It 'rejects one that expires within 30 days' {
        (Test-ServerCertificate -Certificate $Good -RequiredNames $Required -Now $Good.NotAfter.AddDays(-10)).Problems -join " | " | Should -Match 'within 30 days'
    }
    It 'binds nothing when the issued certificate fails validation' {
        $f = New-FakeHost (Join-Path $TestDrive 'invalid')
        Add-ToStore $f $Ksp
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Ksp.Thumbprint } | Should -Throw '*not usable*'
        Get-MutatingCalls $f | Should -BeNullOrEmpty
        Get-Snapshots $f | Should -BeNullOrEmpty
    }
}

Describe 'Certificate request INF' {
    It 'asks for exactly what SQL Server needs' {
        $inf = New-CertRequestInf 'vsql.pesco.com' $Required 'WebServer' '20261018-090000-000'
        $inf | Should -Match 'Subject = "CN=vsql.pesco.com"'
        $inf | Should -Match 'ProviderName = "Microsoft RSA SChannel Cryptographic Provider"'
        $inf | Should -Match 'ProviderType = 12'
        $inf | Should -Match 'KeySpec = 1'
        $inf | Should -Match 'KeyLength = 2048'
        $inf | Should -Match 'KeyAlgorithm = RSA'
        $inf | Should -Match 'HashAlgorithm = SHA256'
        $inf | Should -Match 'KeyUsage = 0xA0'
        $inf | Should -Match 'MachineKeySet = TRUE'
        $inf | Should -Match 'OID = 1\.3\.6\.1\.5\.5\.7\.3\.1'
        $inf | Should -Match 'CertificateTemplate = WebServer'
        $inf | Should -Match 'Signature = "\$Windows NT\$"'
        foreach ($n in $Required) { $inf | Should -Match ([regex]::Escape("_continue_ = `"dns=$n&`"")) }
    }
}

Describe 'A full request, issued' {
    It 'requests, accepts with -machine, validates, grants each account, snapshots and binds' {
        $f = New-FakeHost (Join-Path $TestDrive 'issued')
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider
        $r.Thumbprint | Should -Be $Good.Thumbprint.ToLowerInvariant()
        $r.Bound | Should -Be @('MSSQLSERVER', 'DEV')
        $order = @($f.Calls | Where-Object { $_ -match $Mutating } | ForEach-Object { ($_ -split ' ')[0..1] -join ' ' })
        $order[0..2] | Should -Be @('certreq -new', 'certreq -submit', 'certreq -accept')
        @($f.Calls | Where-Object { $_ -like 'certreq -accept*' })[0] | Should -Match '-machine -q'
        @($f.Calls | Where-Object { $_ -like 'icacls*' }) | Should -Be @("icacls $($f.KeyFile) /grant *S-1-5-80-1:(R)", "icacls $($f.KeyFile) /grant *S-1-5-21-9-1105:(R)")
        $f.Registry[$KeyDev].Certificate | Should -Be $r.Thumbprint
        $f.Registry[$KeyDev].ForceEncryption | Should -Be '0'
        @(Get-ChildItem $f.Provider.WorkDir -Filter 'request-*.json').Count | Should -Be 1
        (Get-Content (Get-Snapshots $f)[0].FullName -Raw | ConvertFrom-Json).instances.previous | Should -Be @('', '')
        @($f.Calls | Where-Object { $_ -like 'Restart*' }) | Should -BeNullOrEmpty
        $f.Log | Should -Contain "  Restart-Service -Name 'MSSQL`$DEV' -Force"
    }
    It 'restarts only with -RestartInstances' {
        $f = New-FakeHost (Join-Path $TestDrive 'restart')
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Instances DEV -RestartInstances
        $r.Bound | Should -Be @('DEV')
        $f.Calls | Should -Contain 'Restart MSSQL$DEV'
        $f.Calls | Should -Not -Contain 'Restart MSSQLSERVER'
        $f.Registry[$KeyDefault].Certificate | Should -Be ''
    }
    It 'fails cleanly when the CA denies the request' {
        $f = New-FakeHost (Join-Path $TestDrive 'denied')
        $f.Submit = 'Failure'
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider } | Should -Throw '*did not issue*request id 44*'
        @($f.Calls | Where-Object { $_ -match '^(icacls|SetReg|certreq -accept)' }) | Should -BeNullOrEmpty
    }
}

Describe 'Pending request' {
    It 'saves the request id, binds nothing, and resumes with -CerFile' {
        $f = New-FakeHost (Join-Path $TestDrive 'pending')
        $f.Submit = 'Pending'
        $err = $null
        try { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Instances DEV } catch { $err = $_.Exception.Message }
        $err | Should -Match 'pending on the CA \(request id 43'
        $err | Should -Match 'certreq -retrieve -config "DC-02.PESCO.COM\\PESCO-PSYLOCKE-CA" 43'
        $err | Should -Match '-Instances DEV'
        @($f.Calls | Where-Object { $_ -match '^(icacls|SetReg|certreq -accept)' }) | Should -BeNullOrEmpty
        $req = Get-Content (Get-ChildItem $f.Provider.WorkDir -Filter 'request-*.json')[0].FullName -Raw | ConvertFrom-Json
        $req.id | Should -Be '43'
        $req.instances | Should -Be @('DEV')

        # The CA admin issues it; certreq -retrieve writes the .cer the record names.
        [IO.File]::WriteAllBytes($req.cer, $Good.Export('Cert'))
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -CerFile $req.cer -Instances DEV
        @($f.Calls | Where-Object { $_ -like 'certreq -accept*' })[0] | Should -Be "certreq -accept -machine -q $($req.cer)"
        $r.Bound | Should -Be @('DEV')
        $f.Registry[$KeyDev].Certificate | Should -Be $Good.Thumbprint.ToLowerInvariant()
    }
}

Describe 'Finding 5: declined or failed prerequisites' {
    BeforeEach { $f = New-FakeHost (Join-Path $TestDrive ([guid]::NewGuid())); Add-ToStore $f $Good }

    It 'a declined ACL grant cancels the run and binds nothing' {
        $f.Provider.ShouldProcess = { param($t, $a) $a -notlike 'grant read*' }
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint 3>$null
        $r.Cancelled | Should -BeTrue
        @($f.Calls | Where-Object { $_ -match '^(SetReg|RemoveReg|Restart|icacls)' }) | Should -BeNullOrEmpty
        Get-Snapshots $f | Should -BeNullOrEmpty
    }
    It 'a declined second grant cancels after the first, still binding nothing' {
        $count = @{ n = 0 }
        $f.Provider.ShouldProcess = { param($t, $a) if ($a -like 'grant read*') { $count.n++; return ($count.n -lt 2) }; $true }.GetNewClosure()
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint 3>$null
        $r.Cancelled | Should -BeTrue
        @($f.Calls | Where-Object { $_ -match '^(SetReg|RemoveReg|Restart)' }) | Should -BeNullOrEmpty
    }
    It 'a failed icacls stops the run and binds nothing' {
        $f.IcaclsFail = $true
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint } | Should -Throw '*Could not grant*Nothing was bound*'
        @($f.Calls | Where-Object { $_ -match '^(SetReg|RemoveReg|Restart)' }) | Should -BeNullOrEmpty
        Get-Snapshots $f | Should -BeNullOrEmpty
    }
    It 'declining certreq -new, -submit or -accept cancels before the next step' {
        foreach ($step in 'certreq -new', 'certreq -submit', 'certreq -accept') {
            $g = New-FakeHost (Join-Path $TestDrive ([guid]::NewGuid()))
            $g.Provider.ShouldProcess = { param($t, $a) $a -notlike "*$step*" }.GetNewClosure()
            $r = Invoke-VsqlCertificateDeployment -Provider $g.Provider 3>$null
            $r.Cancelled | Should -BeTrue
            @($g.Calls | Where-Object { $_ -like "$step*" }) | Should -BeNullOrEmpty
            @($g.Calls | Where-Object { $_ -match '^(icacls|SetReg)' }) | Should -BeNullOrEmpty
        }
    }
    It 'declining one instance binding leaves that instance out of the snapshot' {
        $f.Provider.ShouldProcess = { param($t, $a) $t -ne 'instance MSSQLSERVER' }
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint
        $r.Bound | Should -Be @('DEV')
        (Get-Content (Get-Snapshots $f)[0].FullName -Raw | ConvertFrom-Json).instances.name | Should -Be @('DEV')
    }
}

Describe 'Finding 4: snapshots per deployment' {
    It 'keeps the useful snapshot when the bound certificate is run again, and rolls back to it' {
        $f = New-FakeHost (Join-Path $TestDrive 'rerun')
        Add-ToStore $f $Good; Add-ToStore $f $Good2
        $a = $Good.Thumbprint.ToLowerInvariant(); $b = $Good2.Thumbprint.ToLowerInvariant()
        $f.Registry[$KeyDefault].Certificate = $a; $f.Registry[$KeyDev].Certificate = $a

        $r1 = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good2.Thumbprint
        $r1.Bound | Should -Be @('MSSQLSERVER', 'DEV')
        $snap = Get-Snapshots $f
        $snap.Count | Should -Be 1
        $before = Get-FileHash $snap[0].FullName

        Start-Sleep -Milliseconds 20
        $f.Calls.Clear()
        $r2 = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good2.Thumbprint -RestartInstances
        $r2.Bound | Should -BeNullOrEmpty
        $r2.AlreadyBound | Should -Be @('MSSQLSERVER', 'DEV')
        $r2.Snapshot | Should -BeNullOrEmpty
        @($f.Calls | Where-Object { $_ -like 'SetReg*' }) | Should -BeNullOrEmpty
        $f.Calls | Should -Contain 'Restart MSSQL$DEV'
        (Get-Snapshots $f).Count | Should -Be 1
        (Get-FileHash $snap[0].FullName).Hash | Should -Be $before.Hash

        $rb = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback
        $rb.Restored | Should -Be @('MSSQLSERVER', 'DEV')
        $f.Registry[$KeyDefault].Certificate | Should -Be $a
        $f.Registry[$KeyDev].Certificate | Should -Be $a
        $b | Should -Not -Be $a
    }
    It 'never replaces an existing snapshot file' {
        $path = Join-Path $TestDrive 'immutable.json'
        Write-NewJsonFile $path @{ a = 1 }
        { Write-NewJsonFile $path @{ a = 2 } } | Should -Throw
        (Get-Content $path -Raw | ConvertFrom-Json).a | Should -Be 1
    }
    It 'records an absent value as null and an empty value as empty' {
        $f = New-FakeHost (Join-Path $TestDrive 'nullempty')
        Add-ToStore $f $Good
        $f.Registry[$KeyDefault].Remove('Certificate')
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint | Out-Null
        $s = Get-Content (Get-Snapshots $f)[0].FullName -Raw | ConvertFrom-Json
        $null -eq ($s.instances | Where-Object name -eq 'MSSQLSERVER').previous | Should -BeTrue
        ($s.instances | Where-Object name -eq 'DEV').previous | Should -BeExactly ''
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback | Out-Null
        $f.Registry[$KeyDefault].ContainsKey('Certificate') | Should -BeFalse
        $f.Registry[$KeyDev].Certificate | Should -BeExactly ''
    }
}

Describe 'Finding 6: rollback restores each instance on its own and verifies' {
    BeforeEach {
        $f = New-FakeHost (Join-Path $TestDrive ([guid]::NewGuid()))
        Add-ToStore $f $Good
        $f.Registry[$KeyDefault].Certificate = 'aaaa'; $f.Registry[$KeyDev].Certificate = 'bbbb'
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint | Out-Null
        $f.Calls.Clear()
    }

    It 'restores and verifies every instance' {
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback
        $r.Restored | Should -Be @('MSSQLSERVER', 'DEV')
        $f.Registry[$KeyDefault].Certificate | Should -Be 'aaaa'
        $f.Registry[$KeyDev].Certificate | Should -Be 'bbbb'
        $f.Log | Should -Contain 'Restored DEV to bbbb (verified)'
    }
    It 'keeps going past a failed instance and reports it' {
        $f.SetFails[$KeyDefault] = $true
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback } | Should -Throw '*Rollback incomplete*MSSQLSERVER*denied*'
        $f.Registry[$KeyDev].Certificate | Should -Be 'bbbb'
        $f.Log | Should -Not -Contain 'Restored MSSQLSERVER to aaaa (verified)'
    }
    It 'reports a write that does not stick instead of claiming success' {
        $f.SetIgnored[$KeyDev] = $true
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback } | Should -Throw "*DEV: reads*after restoring 'bbbb'*"
        $f.Registry[$KeyDefault].Certificate | Should -Be 'aaaa'
    }
    It 'restores only the named instances and rejects names not in the snapshot' {
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -Instances PROD } | Should -Throw '*not in any snapshot*'
        @($f.Calls | Where-Object { $_ -like 'SetReg*' }) | Should -BeNullOrEmpty
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -Instances DEV -RestartInstances
        $r.Restored | Should -Be @('DEV')
        $f.Calls | Should -Contain 'Restart MSSQL$DEV'
        $f.Registry[$KeyDefault].Certificate | Should -Be $Good.Thumbprint.ToLowerInvariant()
        # The next default rollback finishes the same snapshot with the instance left.
        $f.Calls.Clear()
        (Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback).Restored | Should -Be @('MSSQLSERVER')
        @($f.Calls | Where-Object { $_ -like "SetReg $KeyDev*" }) | Should -BeNullOrEmpty
        $f.Registry[$KeyDefault].Certificate | Should -Be 'aaaa'
    }
    It 'retries an instance whose restore failed' {
        $f.SetFails[$KeyDefault] = $true
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback } | Should -Throw '*Rollback incomplete*'
        $f.SetFails.Clear()
        (Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback).Restored | Should -Be @('MSSQLSERVER')
        $f.Registry[$KeyDefault].Certificate | Should -Be 'aaaa'
    }
    It 'defaults to the newest snapshot not yet rolled back; -Snapshot picks one' {
        Add-ToStore $f $Good2
        Start-Sleep -Milliseconds 20
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good2.Thumbprint | Out-Null
        $snaps = Get-Snapshots $f
        $snaps.Count | Should -Be 2
        (Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback).Snapshot | Should -Be $snaps[1].FullName
        $f.Registry[$KeyDev].Certificate | Should -Be $Good.Thumbprint.ToLowerInvariant()
        (Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback).Snapshot | Should -Be $snaps[0].FullName
        $f.Registry[$KeyDev].Certificate | Should -Be 'bbbb'
        # Both rolled back: a third run does nothing, it does not re-apply the newer snapshot.
        $f.Calls.Clear()
        (Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback).Snapshot | Should -BeNullOrEmpty
        @($f.Calls | Where-Object { $_ -like 'SetReg*' }) | Should -BeNullOrEmpty
        $f.Registry[$KeyDev].Certificate | Should -Be 'bbbb'
        (Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -Snapshot $snaps[1].Name).Snapshot | Should -Be $snaps[1].FullName
        $f.Registry[$KeyDev].Certificate | Should -Be $Good.Thumbprint.ToLowerInvariant()
    }
    It 'automatic restore during binding restores each changed instance on its own' {
        Add-ToStore $f $Good2
        $f.SetFails[$KeyDev] = $true
        $err = $null
        try { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good2.Thumbprint } catch { $err = $_.Exception.Message }
        $err | Should -Match 'Binding failed'
        $err | Should -Match 'restore FAILED for:\s+- DEV'
        $f.Registry[$KeyDefault].Certificate | Should -Be $Good.Thumbprint.ToLowerInvariant()
        $f.Log | Should -Contain "Restored MSSQLSERVER to $($Good.Thumbprint.ToLowerInvariant()) (verified)"
    }
    It 'automatic restore after a write that does not stick reports success only when verified' {
        Add-ToStore $f $Good2
        $f.SetIgnored[$KeyDev] = $true
        $err = $null
        try { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good2.Thumbprint } catch { $err = $_.Exception.Message }
        $err | Should -Match 'DEV reads'
        $err | Should -Match 'Every instance changed in this run was restored and verified'
        $f.Registry[$KeyDefault].Certificate | Should -Be $Good.Thumbprint.ToLowerInvariant()
    }
}

Describe 'Second review: recovery paths' {
    BeforeEach {
        $f = New-FakeHost (Join-Path $TestDrive ([guid]::NewGuid()))
        Add-ToStore $f $Good
        $f.Registry[$KeyDefault].Certificate = 'aaaa'; $f.Registry[$KeyDev].Certificate = 'bbbb'
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint | Out-Null
        $f.Calls.Clear()
    }

    It 'a rollback whose restart failed is retried, not skipped and not stepped past' {
        $f.RestartFails['MSSQL$DEV'] = $true
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -RestartInstances } | Should -Throw '*Rollback incomplete*MSSQL$DEV*'
        $f.Registry[$KeyDev].Certificate | Should -Be 'bbbb'
        $f.RestartFails.Clear()
        $f.Calls.Clear()
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -RestartInstances
        $r.Snapshot | Should -Not -BeNullOrEmpty
        $r.Restarted | Should -Be @('DEV')
        $f.Calls | Should -Contain 'Restart MSSQL$DEV'
        $f.Calls | Should -Not -Contain 'Restart MSSQLSERVER'
        $f.Registry[$KeyDev].Certificate | Should -Be 'bbbb'
        # Now complete: nothing left to do.
        (Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -RestartInstances).Snapshot | Should -BeNullOrEmpty
    }
    It 'a declined restart under -Confirm also stays open' {
        $f.Provider.ShouldProcess = { param($t, $a) $a -notlike 'restart service*' -or $t -ne 'MSSQL$DEV' }
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -RestartInstances | Out-Null
        $f.Provider.ShouldProcess = $null
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -RestartInstances
        $r.Restarted | Should -Be @('DEV')
    }
    It 'SQL Server Agent is started again after a failed restart is retried' {
        $f.RestartFails['MSSQL$DEV'] = $true
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -RestartInstances } | Should -Throw
        $f.Running.Contains('SQLAgent$DEV') | Should -BeFalse
        $depFile = Join-Path $f.Provider.WorkDir 'dependents-MSSQL_DEV.json'
        (Get-Content $depFile -Raw | ConvertFrom-Json).services | Should -Be @('SQLAgent$DEV')
        $f.RestartFails.Clear()
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -RestartInstances | Out-Null
        $f.Calls | Should -Contain 'Start SQLAgent$DEV'
        $f.Running.Contains('SQLAgent$DEV') | Should -BeTrue
        Test-Path $depFile | Should -BeFalse
    }
    It 'a successful restart starts the agent that ran and leaves no dependents file' {
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint -Instances MSSQLSERVER -RestartInstances | Out-Null
        $f.Calls | Should -Contain 'Start SQLSERVERAGENT'
        $f.Running.Contains('SQLSERVERAGENT') | Should -BeTrue
        @(Get-ChildItem $f.Provider.WorkDir -Filter 'dependents-*.json') | Should -BeNullOrEmpty
    }
    It 'a registry read failure stops a deployment before any snapshot or change' {
        Add-ToStore $f $Good2
        $before = @(Get-Snapshots $f).Count
        $f.ReadFails[$KeyDev] = $true
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good2.Thumbprint } | Should -Throw '*not allowed*'
        @($f.Calls | Where-Object { $_ -match '^(SetReg|RemoveReg)' }) | Should -BeNullOrEmpty
        @(Get-Snapshots $f).Count | Should -Be $before
    }
    It 'a registry read failure during rollback is a failure, never verified as absent' {
        $f.ReadFails[$KeyDev] = $true
        { Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback } | Should -Throw '*Rollback incomplete*DEV*not allowed*'
        $f.Log | Should -Not -Contain 'Restored DEV to bbbb (verified)'
    }
}

Describe 'Real registry operations (HKCU test key)' {
    BeforeAll {
        $script:TestRoot = "HKCU:\Software\PS2-VSQL-CERT-TEST-$([guid]::NewGuid())"
        New-Item -Path "$TestRoot\Instance Names\SQL" -Force | Out-Null
        New-ItemProperty -Path "$TestRoot\Instance Names\SQL" -Name 'PSREPORTING' -Value 'MSSQL16.PSREPORTING' | Out-Null
        New-ItemProperty -Path "$TestRoot\Instance Names\SQL" -Name 'DEV' -Value 'MSSQL16.DEV' | Out-Null
        New-Item -Path "$TestRoot\Empty" -Force | Out-Null
        New-ItemProperty -Path "$TestRoot\Empty" -Name 'Certificate' -Value '' | Out-Null
        New-Item -Path "$TestRoot\Absent" -Force | Out-Null
        $script:Real = Get-VsqlDefaultProvider
    }
    AfterAll { Remove-Item -LiteralPath $TestRoot -Recurse -Force }

    It 'lists every instance, including one whose name starts with PS' {
        $map = & $Real.GetInstanceMap $TestRoot
        @($map.Keys) | Should -Be @('PSREPORTING', 'DEV')
        $map['PSREPORTING'] | Should -Be 'MSSQL16.PSREPORTING'
    }
    It 'returns an empty map when no instance is registered' {
        (& $Real.GetInstanceMap "$TestRoot\Absent").Count | Should -Be 0
    }
    It 'tells an empty value from an absent one' {
        & $Real.GetRegValue "$TestRoot\Empty" 'Certificate' | Should -BeExactly ''
        $null -eq (& $Real.GetRegValue "$TestRoot\Absent" 'Certificate') | Should -BeTrue
    }
    It 'throws, rather than reporting absent, when the key cannot be read' {
        { & $Real.GetRegValue "$TestRoot\Missing" 'Certificate' } | Should -Throw
    }
    It 'writes, reads back and removes through the real operations' {
        & $Real.SetRegValue "$TestRoot\Absent" 'Certificate' 'abcd'
        & $Real.GetRegValue "$TestRoot\Absent" 'Certificate' | Should -Be 'abcd'
        & $Real.RemoveRegValue "$TestRoot\Absent" 'Certificate'
        $null -eq (& $Real.GetRegValue "$TestRoot\Absent" 'Certificate') | Should -BeTrue
    }
}

Describe '-WhatIf' {
    It 'changes nothing on the real ShouldProcess path' {
        $f = New-FakeHost (Join-Path $TestDrive 'whatif-real')
        $r = Invoke-VsqlCertificateDeployment -Provider $f.Provider -RestartInstances -WhatIf 6>$null
        Get-MutatingCalls $f | Should -BeNullOrEmpty
        @(Get-ChildItem $f.Provider.WorkDir -File | Where-Object Name -ne 'machinekey.bin') | Should -BeNullOrEmpty
        $r.Bound | Should -BeNullOrEmpty
    }
    It 'previews every step of a request' {
        $f = New-FakeHost (Join-Path $TestDrive 'whatif-steps')
        $seen = New-Object System.Collections.ArrayList
        $f.Provider.ShouldProcess = { param($t, $a) [void]$seen.Add("$a | $t"); $false }.GetNewClosure()
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -RestartInstances -WhatIf | Out-Null
        Get-MutatingCalls $f | Should -BeNullOrEmpty
        $expect = 'certreq -new', 'certreq -submit', 'certreq -accept', 'grant read to NT Service\MSSQLSERVER', 'grant read to PESCO\svc-sqldev',
        'set Certificate=<new thumbprint>* | instance MSSQLSERVER', 'set Certificate=<new thumbprint>* | instance DEV', 'restart service* | MSSQLSERVER', 'restart service* | MSSQL$DEV'
        foreach ($e in $expect) { @($seen | Where-Object { $_ -like "*$e*" }).Count | Should -Be 1 -Because "the preview should include '$e'" }
        $f.Log -join "`n" | Should -Match 'ProviderType = 12'
    }
    It 'previews a rollback without changing it' {
        $f = New-FakeHost (Join-Path $TestDrive 'whatif-rollback')
        Add-ToStore $f $Good
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -Thumbprint $Good.Thumbprint | Out-Null
        $f.Calls.Clear()
        Invoke-VsqlCertificateDeployment -Provider $f.Provider -Rollback -RestartInstances -WhatIf 6>$null | Out-Null
        Get-MutatingCalls $f | Should -BeNullOrEmpty
        $f.Registry[$KeyDev].Certificate | Should -Be $Good.Thumbprint.ToLowerInvariant()
    }
}

Describe 'Account to SID' {
    It 'maps the built-in service accounts that icacls cannot name' {
        Resolve-AccountSid 'LocalSystem' | Should -Be 'S-1-5-18'
        Resolve-AccountSid 'NT AUTHORITY\NetworkService' | Should -Be 'S-1-5-20'
        Resolve-AccountSid 'NT AUTHORITY\LocalService' | Should -Be 'S-1-5-19'
    }
    It 'translates a real account' {
        Resolve-AccountSid "$env:USERDOMAIN\$env:USERNAME" | Should -Match '^S-1-5-21-'
    }
}

Describe 'Native commands' {
    It 'captures stderr and the exit code without throwing under Stop' {
        $ErrorActionPreference = 'Stop'
        $r = Invoke-NativeCommand 'cmd.exe' @('/c', 'echo out & echo err 1>&2 & exit 3')
        $r.ExitCode | Should -Be 3
        $r.Output -join ' ' | Should -Match 'err'
    }
}