#Requires -Version 5.1
param(
    [Parameter(Mandatory=$true)]
    [string]$Path
)

$ErrorActionPreference = "Stop"
Add-Type -AssemblyName System.Windows.Forms
Add-Type -AssemblyName System.Drawing

function Get-Config {
    $configPaths = @(
        "$env:APPDATA\FreigabeKontextmenue\config.json",
        "$env:ProgramData\FreigabeKontextmenue\config.json"
    )
    
    foreach ($configPath in $configPaths) {
        if (Test-Path $configPath) {
            return Get-Content $configPath -Raw | ConvertFrom-Json
        }
    }
    
    throw "Konfiguration nicht gefunden. Bitte zuerst installieren!"
}

function Get-FreigabeInfo {
    param([string]$TargetPath)
    
    $metaDirs = @(
        "$env:ProgramData\FreigabeKontextmenue\meta",
        "$env:APPDATA\FreigabeKontextmenue\meta"
    )
    
    $pathHash = [System.BitConverter]::ToString([System.Security.Cryptography.MD5]::Create().ComputeHash([System.Text.Encoding]::UTF8.GetBytes($TargetPath))).Replace("-","")
    
    foreach ($metaDir in $metaDirs) {
        $metaFile = Join-Path $metaDir "$pathHash.json"
        if (Test-Path $metaFile) {
            return Get-Content $metaFile -Raw | ConvertFrom-Json
        }
    }
    
    return $null
}

function Save-FreigabeInfo {
    param(
        [string]$TargetPath,
        [array]$Users
    )
    
    $metaDir = if (Test-Path "$env:ProgramData\FreigabeKontextmenue") {
        "$env:ProgramData\FreigabeKontextmenue\meta"
    } else {
        "$env:APPDATA\FreigabeKontextmenue\meta"
    }
    
    $pathHash = [System.BitConverter]::ToString([System.Security.Cryptography.MD5]::Create().ComputeHash([System.Text.Encoding]::UTF8.GetBytes($TargetPath))).Replace("-","")
    $metaFile = Join-Path $metaDir "$pathHash.json"
    
    if ($Users.Count -eq 0) {
        if (Test-Path $metaFile) {
            Remove-Item $metaFile -Force
        }
    } else {
        $meta = @{
            TargetPath = $TargetPath
            Users = $Users
        }
        $meta | ConvertTo-Json | Set-Content -Path $metaFile -Encoding UTF8
    }
}

function Show-UserRemoveDialog {
    param([array]$Users)
    
    $form = New-Object System.Windows.Forms.Form
    $form.Text = "Freigabe entfernen - Benutzer auswählen"
    $form.Size = New-Object System.Drawing.Size(400, 400)
    $form.StartPosition = "CenterScreen"
    $form.FormBorderStyle = "FixedDialog"
    $form.MaximizeBox = $false
    
    $label = New-Object System.Windows.Forms.Label
    $label.Text = "Freigabe entfernen für folgende Benutzer:"
    $label.Location = New-Object System.Drawing.Point(10, 15)
    $label.Size = New-Object System.Drawing.Size(360, 20)
    $form.Controls.Add($label)
    
    $checkedListBox = New-Object System.Windows.Forms.CheckedListBox
    $checkedListBox.Location = New-Object System.Drawing.Point(10, 40)
    $checkedListBox.Size = New-Object System.Drawing.Size(360, 260)
    $checkedListBox.Font = New-Object System.Drawing.Font("Segoe UI", 10)
    $checkedListBox.CheckOnClick = $true
    $form.Controls.Add($checkedListBox)
    
    foreach ($user in $Users) {
        $checkedListBox.Items.Add($user) | Out-Null
    }
    
    $selectAllBtn = New-Object System.Windows.Forms.Button
    $selectAllBtn.Text = "Alle auswählen"
    $selectAllBtn.Location = New-Object System.Drawing.Point(10, 310)
    $selectAllBtn.Size = New-Object System.Drawing.Size(100, 25)
    $selectAllBtn.Add_Click({
        for ($i = 0; $i -lt $checkedListBox.Items.Count; $i++) {
            $checkedListBox.SetItemChecked($i, $true)
        }
    })
    $form.Controls.Add($selectAllBtn)
    
    $okBtn = New-Object System.Windows.Forms.Button
    $okBtn.Text = "Entfernen"
    $okBtn.Location = New-Object System.Drawing.Point(190, 310)
    $okBtn.Size = New-Object System.Drawing.Size(85, 30)
    $okBtn.DialogResult = [System.Windows.Forms.DialogResult]::OK
    $form.AcceptButton = $okBtn
    $form.Controls.Add($okBtn)
    
    $cancelBtn = New-Object System.Windows.Forms.Button
    $cancelBtn.Text = "Abbrechen"
    $cancelBtn.Location = New-Object System.Drawing.Point(285, 310)
    $cancelBtn.Size = New-Object System.Drawing.Size(85, 30)
    $cancelBtn.DialogResult = [System.Windows.Forms.DialogResult]::Cancel
    $form.CancelButton = $cancelBtn
    $form.Controls.Add($cancelBtn)
    
    $script:selectedUsers = @()
    
    if ($form.ShowDialog() -eq [System.Windows.Forms.DialogResult]::OK) {
        $script:selectedUsers = @($checkedListBox.CheckedItems)
    }
    
    return $script:selectedUsers
}

function Remove-FreigabePermission {
    param(
        [string]$TargetPath,
        [string]$QualifiedUserName
    )

    try {
        $acl = Get-Acl -Path $TargetPath

        $rulesToRemove = $acl.Access | Where-Object {
            $_.IdentityReference.Value -eq $QualifiedUserName
        }

        foreach ($rule in $rulesToRemove) {
            $acl.RemoveAccessRule($rule) | Out-Null
        }

        Set-Acl -Path $TargetPath -AclObject $acl
        return $true
    } catch {
        Write-Warning "Fehler beim Entfernen der Berechtigung für $QualifiedUserName : $_"
        return $false
    }
}

function Remove-UserShortcut {
    param(
        [string]$TargetPath,
        [string]$QualifiedUserName,
        [string]$BasePath
    )

    # SamAccountName aus QualifiedName extrahieren (für Ordnerpfad)
    $samAccountName = if ($QualifiedUserName -match '\\') {
        $QualifiedUserName.Split('\')[1]
    } else {
        $QualifiedUserName
    }

    $userFolder = Join-Path $BasePath $samAccountName

    if (-not (Test-Path $userFolder)) {
        return
    }

    $shortcuts = Get-ChildItem -Path $userFolder -Filter "*.lnk" -ErrorAction SilentlyContinue
    $shell = New-Object -ComObject WScript.Shell

    foreach ($shortcut in $shortcuts) {
        try {
            $lnk = $shell.CreateShortcut($shortcut.FullName)
            $shortcutTarget = $lnk.TargetPath

            $targetNormalized = $TargetPath.TrimEnd('\').ToLower()
            $shortcutTargetNormalized = $shortcutTarget.TrimEnd('\').ToLower()

            $targetName = Split-Path $TargetPath -Leaf
            $shortcutTargetName = Split-Path $shortcutTarget -Leaf

            if ($shortcutTargetNormalized -eq $targetNormalized -or
                ($targetName.ToLower() -eq $shortcutTargetName.ToLower() -and
                 $shortcutTarget -match [regex]::Escape($targetName))) {
                Remove-Item -Path $shortcut.FullName -Force
            }
        } catch {
            Write-Warning "Fehler beim Prüfen der Verknüpfung: $($shortcut.Name)"
        }
    }

    [System.Runtime.Interopservices.Marshal]::ReleaseComObject($shell) | Out-Null

    $remainingItems = Get-ChildItem -Path $userFolder -ErrorAction SilentlyContinue
    if ($remainingItems.Count -eq 0) {
        Remove-Item -Path $userFolder -Force -ErrorAction SilentlyContinue
    }
}

try {
    $config = Get-Config
    $basePath = $config.LinkBasePath
    
    if (-not (Test-Path $Path)) {
        throw "Der Pfad existiert nicht: $Path"
    }
    
    $freigabeInfo = Get-FreigabeInfo -TargetPath $Path
    
    if (-not $freigabeInfo -or $freigabeInfo.Users.Count -eq 0) {
        [System.Windows.Forms.MessageBox]::Show(
            "Für dieses Element wurden keine Freigaben über das Kontextmenü erstellt.",
            "Keine Freigaben",
            [System.Windows.Forms.MessageBoxButtons]::OK,
            [System.Windows.Forms.MessageBoxIcon]::Information
        )
        exit 0
    }
    
    $usersToRemove = Show-UserRemoveDialog -Users $freigabeInfo.Users
    
    if ($usersToRemove.Count -eq 0) {
        exit 0
    }
    
    $removedUsers = @()
    $errors = @()
    
    foreach ($qualifiedUserName in $usersToRemove) {
        try {
            Remove-FreigabePermission -TargetPath $Path -QualifiedUserName $qualifiedUserName
            Remove-UserShortcut -TargetPath $Path -QualifiedUserName $qualifiedUserName -BasePath $basePath
            $removedUsers += $qualifiedUserName
        } catch {
            $errors += "Fehler bei $qualifiedUserName : $_"
        }
    }
    
    $remainingUsers = @($freigabeInfo.Users | Where-Object { $_ -notin $removedUsers })
    Save-FreigabeInfo -TargetPath $Path -Users $remainingUsers
    
    $message = "Freigaben entfernt für:`n" + ($removedUsers -join "`n")
    
    if ($errors.Count -gt 0) {
        $message += "`n`nFehler:`n" + ($errors -join "`n")
    }
    
    [System.Windows.Forms.MessageBox]::Show(
        $message,
        "Freigaben entfernt",
        [System.Windows.Forms.MessageBoxButtons]::OK,
        $(if ($errors.Count -gt 0) { [System.Windows.Forms.MessageBoxIcon]::Warning } else { [System.Windows.Forms.MessageBoxIcon]::Information })
    )
    
} catch {
    [System.Windows.Forms.MessageBox]::Show(
        "Fehler: $($_.Exception.Message)",
        "Fehler",
        [System.Windows.Forms.MessageBoxButtons]::OK,
        [System.Windows.Forms.MessageBoxIcon]::Error
    )
    exit 1
}