#!powershell

# Copyright: (c) 2015, Adam Keech <akeech@chathamfinancial.com>
# Copyright: (c) 2015, Josh Ludwig <jludwig@chathamfinancial.com>
# Copyright: (c) 2017, Jordan Borean <jborean93@gmail.com>
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

#Requires -Module Ansible.ModuleUtils.Legacy
#Requires -Module Ansible.ModuleUtils.PrivilegeUtil

$params = Parse-Args -arguments $args -supports_check_mode $true
$check_mode = Get-AnsibleParam -obj $params -name "_ansible_check_mode" -type "bool" -default $false
$diff_mode = Get-AnsibleParam -obj $params -name "_ansible_diff" -type "bool" -default $false
$_remote_tmp = Get-AnsibleParam $params "_ansible_remote_tmp" -type "path" -default $env:TMP

$path = Get-AnsibleParam -obj $params -name "path" -type "str" -failifempty $true -aliases "key"
$name = Get-AnsibleParam -obj $params -name "name" -type "str" -aliases "entry","value"
$data = Get-AnsibleParam -obj $params -name "data"
$type = Get-AnsibleParam -obj $params -name "type" -type "str" -default "string" -validateset "none","binary","dword","expandstring","multistring","string","qword" -aliases "datatype"
$state = Get-AnsibleParam -obj $params -name "state" -type "str" -default "present" -validateset "present","absent"
$delete_key = Get-AnsibleParam -obj $params -name "delete_key" -type "bool" -default $true
$hive = Get-AnsibleParam -obj $params -name "hive" -type "path"

$result = @{
    changed = $false
    data_changed = $false
    data_type_changed = $false
}

if ($diff_mode) {
    $result.diff = @{
        before = ""
        after = ""
    }
}

$registry_util = @'
using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;

namespace Ansible.WinRegedit
{
    internal class NativeMethods
    {
        [DllImport("advapi32.dll", CharSet = CharSet.Unicode)]
        public static extern int RegLoadKeyW(
            UInt32 hKey,
            string lpSubKey,
            string lpFile);

        [DllImport("advapi32.dll", CharSet = CharSet.Unicode)]
        public static extern int RegUnLoadKeyW(
            UInt32 hKey,
            string lpSubKey);
    }

    public class Win32Exception : System.ComponentModel.Win32Exception
    {
        private string _msg;
        public Win32Exception(string message) : this(Marshal.GetLastWin32Error(), message) { }
        public Win32Exception(int errorCode, string message) : base(errorCode)
        {
            _msg = String.Format("{0} ({1}, Win32ErrorCode {2})", message, base.Message, errorCode);
        }
        public override string Message { get { return _msg; } }
        public static explicit operator Win32Exception(string message) { return new Win32Exception(message); }
    }

    public class Hive : IDisposable
    {
        private const UInt32 SCOPE = 0x80000002;  // HKLM
        private string hiveKey;
        private bool loaded = false;

        public Hive(string hiveKey, string hivePath)
        {
            this.hiveKey = hiveKey;
            int ret = NativeMethods.RegLoadKeyW(SCOPE, hiveKey, hivePath);
            if (ret != 0)
                throw new Win32Exception(ret, String.Format("Failed to load registry hive at {0}", hivePath));
            loaded = true;
        }

        public static void UnloadHive(string hiveKey)
        {
            int ret = NativeMethods.RegUnLoadKeyW(SCOPE, hiveKey);
            if (ret != 0)
                throw new Win32Exception(ret, String.Format("Failed to unload registry hive at {0}", hiveKey));
        }

        public void Dispose()
        {
            if (loaded)
            {
                // Make sure the garbage collector disposes all unused handles and waits until it is complete
                GC.Collect();
                GC.WaitForPendingFinalizers();

                UnloadHive(hiveKey);
                loaded = false;
            }
            GC.SuppressFinalize(this);
        }
        ~Hive() { this.Dispose(); }
    }
}
'@

# fire a warning if the property name isn't specified, the (Default) key ($null) can only be a string
if ($null -eq $name -and $type -ne "string") {
    Add-Warning -obj $result -message "the data type when name is not specified can only be 'string', the type has automatically been converted"
    $type = "string"
}

# Check that the registry path is in PSDrive format: HKCC, HKCR, HKCU, HKLM, HKU
if ($path -notmatch "^HK(CC|CR|CU|LM|U):\\") {
    Fail-Json $result "path: $path is not a valid powershell path, see module documentation for examples."
}

# Add a warning if the path does not contains a \ and is not the leaf path
$registry_path = (Split-Path -Path $path -NoQualifier).Substring(1)  # removes the hive: and leading \
$registry_leaf = Split-Path -Path $path -Leaf
if ($registry_path -ne $registry_leaf -and -not $registry_path.Contains('\')) {
    $msg = "path is not using '\' as a separator, support for '/' as a separator will be removed in a future Ansible version"
    Add-DeprecationWarning -obj $result -message $msg -version 2.12
    $registry_path = $registry_path.Replace('/', '\')
}

# Simplified version of Convert-HexStringToByteArray from
# https://cyber-defense.sans.org/blog/2010/02/11/powershell-byte-array-hex-convert
# Expects a hex in the format you get when you run reg.exe export,
# and converts to a byte array so powershell can modify binary registry entries
# import format is like 'hex:be,ef,be,ef,be,ef,be,ef,be,ef'
Function Convert-RegExportHexStringToByteArray($string) {
    # Remove 'hex:' from the front of the string if present
    $string = $string.ToLower() -replace '^hex\:',''

    # Remove whitespace and any other non-hex crud.
    $string = $string -replace '[^a-f0-9\\,x\-\:]',''

    # Turn commas into colons
    $string = $string -replace ',',':'

    # Maybe there's nothing left over to convert...
    if ($string.Length -eq 0) {
        return ,@()
    }

    # Split string with or without colon delimiters.
    if ($string.Length -eq 1) {
        return ,@([System.Convert]::ToByte($string,16))
    } elseif (($string.Length % 2 -eq 0) -and ($string.IndexOf(":") -eq -1)) {
        return ,@($string -split '([a-f0-9]{2})' | foreach-object { if ($_) {[System.Convert]::ToByte($_,16)}})
    } elseif ($string.IndexOf(":") -ne -1) {
        return ,@($string -split ':+' | foreach-object {[System.Convert]::ToByte($_,16)})
    } else {
        return ,@()
    }
}

Function Compare-RegistryProperties($existing, $new) {
    # Outputs $true if the property values don't match
    if ($existing -is [Array]) {
        (Compare-Object -ReferenceObject $existing -DifferenceObject $new -SyncWindow 0).Length -ne 0
    } else {
        $existing -cne $new
    }
}

Function Get-DiffValue {
    param(
        [Parameter(Mandatory=$true)][Microsoft.Win32.RegistryValueKind]$Type,
        [Parameter(Mandatory=$true)][Object]$Value
    )

    $diff = @{ type = $Type.ToString(); value = $Value }

    $enum = [Microsoft.Win32.RegistryValueKind]
    if ($Type -in @($enum::Binary, $enum::None)) {
        $diff.value = [System.Collections.Generic.List`1[String]]@()
        foreach ($dec_value in $Value) {
            $diff.value.Add("0x{0:x2}" -f $dec_value)
        }
    } elseif ($Type -eq $enum::DWord) {
        $diff.value = "0x{0:x8}" -f $Value
    } elseif ($Type -eq $enum::QWord) {
        $diff.value = "0x{0:x16}" -f $Value
    }

    return $diff
}

Function Set-StateAbsent {
    param(
        # Used for diffs and exception messages to match up against Ansible input
        [Parameter(Mandatory=$true)][String]$PrintPath,
        [Parameter(Mandatory=$true)][Microsoft.Win32.RegistryKey]$Hive,
        [Parameter(Mandatory=$true)][String]$Path,
        [String]$Name,
        [Switch]$DeleteKey
    )

    $key = $Hive.OpenSubKey($Path, $true)
    if ($null -eq $key) {
        # Key does not exist, no need to delete anything
        return
    }

    try {
        if ($DeleteKey -and -not $Name) {
            # delete_key=yes is set and name is null/empty, so delete the entire key
            $key.Dispose()
            $key = $null
            if (-not $check_mode) {
                try {
                    $Hive.DeleteSubKeyTree($Path, $false)
                } catch {
                    Fail-Json -obj $result -message "failed to delete registry key at $($PrintPath): $($_.Exception.Message)"
                }
            }
            $result.changed = $true

            if ($diff_mode) {
                $result.diff.before = @{$PrintPath = @{}}
                $result.diff.after = @{}
            }
        } else {
            # delete_key=no or name is not null/empty, delete the property not the full key
            $property = $key.GetValue($Name)
            if ($null -eq $property) {
                # property does not exist
                return
            }
            $property_type = $key.GetValueKind($Name)  # used for the diff

            if (-not $check_mode) {
                try {
                    $key.DeleteValue($Name)
                } catch {
                    Fail-Json -obj $result -message "failed to delete registry property '$Name' at $($PrintPath): $($_.Exception.Message)"
                }
            }

            $result.changed = $true
            if ($diff_mode) {
                $diff_value = Get-DiffValue -Type $property_type -Value $property
                $result.diff.before = @{ $PrintPath = @{ $Name = $diff_value } }
                $result.diff.after = @{ $PrintPath = @{} }
            }
        }
    } finally {
        if ($key) {
            $key.Dispose()
        }
    }
}

Function Set-StatePresent {
    param(
        [Parameter(Mandatory=$true)][String]$PrintPath,
        [Parameter(Mandatory=$true)][Microsoft.Win32.RegistryKey]$Hive,
        [Parameter(Mandatory=$true)][String]$Path,
        [String]$Name,
        [Object]$Data,
        [Microsoft.Win32.RegistryValueKind]$Type
    )

    $key = $Hive.OpenSubKey($Path, $true)
    try {
        if ($null -eq $key) {
            # the key does not exist, create it so the next steps work
            if (-not $check_mode) {
                try {
                    $key = $Hive.CreateSubKey($Path)
                } catch {
                    Fail-Json -obj $result -message "failed to create registry key at $($PrintPath): $($_.Exception.Message)"
                }
            }
            $result.changed = $true

            if ($diff_mode) {
                $result.diff.before = @{}
                $result.diff.after = @{$PrintPath = @{}}
            }
        } elseif ($diff_mode) {
            # Make sure the diff is in an expected state for the key
            $result.diff.before = @{$PrintPath = @{}}
            $result.diff.after = @{$PrintPath = @{}}
        }

        if ($null -eq $key -or $null -eq $Data) {
            # Check mode and key was created above, we cannot do any more work, or $Data is $null which happens when
            # we create a new key but haven't explicitly set the data
            return
        }

        $property = $key.GetValue($Name, $null, [Microsoft.Win32.RegistryValueOptions]::DoNotExpandEnvironmentNames)
        if ($null -ne $property) {
            # property exists, need to compare the values and type
            $existing_type = $key.GetValueKind($name)
            $change_value = $false

            if ($Type -ne $existing_type) {
                $change_value = $true
                $result.data_type_changed = $true
                $data_mismatch = Compare-RegistryProperties -existing $property -new $Data
                if ($data_mismatch) {
                    $result.data_changed = $true
                }
            } else {
                $data_mismatch = Compare-RegistryProperties -existing $property -new $Data
                if ($data_mismatch) {
                    $change_value = $true
                    $result.data_changed = $true
                }
            }

            if ($change_value) {
                if (-not $check_mode) {
                    try {
                        $key.SetValue($Name, $Data, $Type)
                    } catch {
                        Fail-Json -obj $result -message "failed to change registry property '$Name' at $($PrintPath): $($_.Exception.Message)"
                    }
                }
                $result.changed = $true

                if ($diff_mode) {
                    $result.diff.before.$PrintPath.$Name = Get-DiffValue -Type $existing_type -Value $property
                    $result.diff.after.$PrintPath.$Name = Get-DiffValue -Type $Type -Value $Data
                }
            } elseif ($diff_mode) {
                $diff_value = Get-DiffValue -Type $existing_type -Value $property
                $result.diff.before.$PrintPath.$Name = $diff_value
                $result.diff.after.$PrintPath.$Name = $diff_value
            }
        } else {
            # property doesn't exist just create a new one
            if (-not $check_mode) {
                try {
                    $key.SetValue($Name, $Data, $Type)
                } catch {
                    Fail-Json -obj $result -message "failed to create registry property '$Name' at $($PrintPath): $($_.Exception.Message)"
                }
            }
            $result.changed = $true

            if ($diff_mode) {
                $result.diff.after.$PrintPath.$Name = Get-DiffValue -Type $Type -Value $Data
            }
        }
    } finally {
        if ($key) {
            $key.Dispose()
        }
    }
}

# convert property names "" to $null as "" refers to (Default)
if ($name -eq "") {
    $name = $null
}

# convert the data to the required format
if ($type -in @("binary", "none")) {
    if ($null -eq $data) {
        $data = ""
    }

    # convert the data from string to byte array if in hex: format
    if ($data -is [String]) {
        $data = [byte[]](Convert-RegExportHexStringToByteArray -string $data)
    } elseif ($data -is [Int]) {
        if ($data -gt 255) {
            Fail-Json $result "cannot convert binary data '$data' to byte array, please specify this value as a yaml byte array or a comma separated hex value string"
        }
        $data = [byte[]]@([byte]$data)
    } elseif ($data -is [Array]) {
        $data = [byte[]]$data
    }
} elseif ($type -in @("dword", "qword")) {
    # dword's and dword's don't allow null values, set to 0
    if ($null -eq $data) {
        $data = 0
    }

    if ($data -is [String]) {
        # if the data is a string we need to convert it to an unsigned int64
        # it needs to be unsigned as Ansible passes in an unsigned value while
        # powershell uses a signed data type. The value will then be converted
        # below
        $data = [UInt64]$data
    }

    if ($type -eq "dword") {
        if ($data -gt [UInt32]::MaxValue) {
            Fail-Json $result "data cannot be larger than 0xffffffff when type is dword"
        } elseif ($data -gt [Int32]::MaxValue) {
            # when dealing with larger int32 (> 2147483647 or 0x7FFFFFFF) powershell
            # automatically converts it to a signed int64. We need to convert this to
            # signed int32 by parsing the hex string value.
            $data = "0x$("{0:x}" -f $data)"
        }
        $data = [Int32]$data
    } else {
        if ($data -gt [UInt64]::MaxValue) {
            Fail-Json $result "data cannot be larger than 0xffffffffffffffff when type is qword"
        } elseif ($data -gt [Int64]::MaxValue) {
            $data = "0x$("{0:x}" -f $data)"
        }
        $data = [Int64]$data
    }
} elseif ($type -in @("string", "expandstring") -and $name) {
    # a null string or expandstring must be empty quotes
    # Only do this if $name has been defined (not the default key)
    if ($null -eq $data) {
        $data = ""
    }
} elseif ($type -eq "multistring") {
    # convert the data for a multistring to a String[] array
    if ($null -eq $data) {
        $data = [String[]]@()
    } elseif ($data -isnot [Array]) {
        $new_data = New-Object -TypeName String[] -ArgumentList 1
        $new_data[0] = $data.ToString([CultureInfo]::InvariantCulture)
        $data = $new_data
    } else {
        $new_data = New-Object -TypeName String[] -ArgumentList $data.Count
        foreach ($entry in $data) {
            $new_data[$data.IndexOf($entry)] = $entry.ToString([CultureInfo]::InvariantCulture)
        }
        $data = $new_data
    }
}

# convert the type string to the .NET class
$type = [System.Enum]::Parse([Microsoft.Win32.RegistryValueKind], $type, $true)

$registry_hive = switch(Split-Path -Path $path -Qualifier) {
    "HKCR:" { [Microsoft.Win32.Registry]::ClassesRoot }
    "HKCC:" { [Microsoft.Win32.Registry]::CurrentConfig }
    "HKCU:" { [Microsoft.Win32.Registry]::CurrentUser }
    "HKLM:" { [Microsoft.Win32.Registry]::LocalMachine }
    "HKU:" { [Microsoft.Win32.Registry]::Users }
}
$loaded_hive = $null
try {
    if ($hive) {
        if (-not (Test-Path -LiteralPath $hive)) {
            Fail-Json -obj $result -message "hive at path '$hive' is not valid or accessible, cannot load hive"
        }

        $original_tmp = $env:TMP
        $env:TMP = $_remote_tmp
        Add-Type -TypeDefinition $registry_util
        $env:TMP = $original_tmp

        try {
            Set-AnsiblePrivilege -Name SeBackupPrivilege -Value $true
            Set-AnsiblePrivilege -Name SeRestorePrivilege -Value $true
        } catch [System.ComponentModel.Win32Exception] {
            Fail-Json -obj $result -message "failed to enable SeBackupPrivilege and SeRestorePrivilege for the current process: $($_.Exception.Message)"
        }

        if (Test-Path -Path HKLM:\ANSIBLE) {
            Add-Warning -obj $result -message "hive already loaded at HKLM:\ANSIBLE, had to unload hive for win_regedit to continue"
            try {
                [Ansible.WinRegedit.Hive]::UnloadHive("ANSIBLE")
            } catch [System.ComponentModel.Win32Exception] {
                Fail-Json -obj $result -message "failed to unload registry hive HKLM:\ANSIBLE from $($hive): $($_.Exception.Message)"
            }
        }

        try {
            $loaded_hive = New-Object -TypeName Ansible.WinRegedit.Hive -ArgumentList "ANSIBLE", $hive
        } catch [System.ComponentModel.Win32Exception] {
            Fail-Json -obj $result -message "failed to load registry hive from '$hive' to HKLM:\ANSIBLE: $($_.Exception.Message)"
        }
    }

    if ($state -eq "present") {
        Set-StatePresent -PrintPath $path -Hive $registry_hive -Path $registry_path -Name $name -Data $data -Type $type
    } else {
        Set-StateAbsent -PrintPath $path -Hive $registry_hive -Path $registry_path -Name $name -DeleteKey:$delete_key
    }
} finally {
    $registry_hive.Dispose()
    if ($loaded_hive) {
        $loaded_hive.Dispose()
    }
}

Exit-Json $result