param([string]$CSVFileName,[string]$EmailAddress,[string]$Username,[string]$Password,[string]$Domain,[bool]$Impersonate,[string]$EwsUrl,[string]$EWSManagedApiPath);

#
# Import-CalendarCSV.ps1
#
# By David Barrett, Microsoft Ltd. Use at your own risk.
#

Function ShowParams()
{
    Write-Host "Import-CalendarCSV -CSVFileName <string> -EmailAddress <string>";
    Write-Host "                   [-Username <string> -Password <string> [-Domain <string>]]";
    Write-Host "                   [-Impersonate <bool>]";
    Write-Host "                   [-EwsUrl <string>]";
    Write-Host "                   [-EWSManagedApiPath <string>]";
    Write-Host "";
    Write-Host "Required:";
    Write-Host " -CSVFileName : Filename of the CSV file to import appointments for this user from.";
    Write-Host " -EmailAddress : Mailbox SMTP email address";
    Write-Host "";
    Write-Host "Optional:";
    Write-Host " -Username : Username for the account being used to connect to EWS (if not specified, current user is assumed)";
    Write-Host " -Password : Password for the specified user (required if username specified)";
    Write-Host " -Domain : If specified, used for authentication (not required even if username specified)";
    Write-Host " -Impersonate : Set to $true to use impersonation.";
    Write-Host " -EwsUrl : Forces a particular EWS URl (otherwise autodiscover is used, which is recommended)";
    Write-Host " -EWSManagedApiDLLFilePath : Full and path to the DLL for EWS Managed API (if not specified, default path for v1.1 is used)";
    Write-Host "";
}

$RequiredFields=@{
    "Subject" = "Subject";
    "StartDate" = "Start Date";
    "StartTime" = "Start Time";
    "EndDate" = "End Date";
    "EndTime" = "End Time"
}

# Check email address
 if (!$EmailAddress)
 {
    ShowParams;
    throw "Required parameter EmailAddress missing";
 }

# CSV File Checks
if (!$CSVFileName)
{
    ShowParams;
    throw "Required parameter CSVFileName missing";
}
if (!(Get-Item -Path $CSVFileName -ErrorAction SilentlyContinue))
{
    throw "Unable to open file: $CSVFileName";
}

# Import CSV File
try
{
    $CSVFile = Import-Csv -Path $CSVFileName;
}
catch { }
if (!$CSVFile)
{
    Write-Host "CSV header line not found, using predefined header: Subject;StartDate;StartTime;EndDate;EndTime";
    $CSVFile = Import-Csv -Path $CSVFileName -header Subject,StartDate,StartTime,EndDate,EndTime;
}

# Check file has required fields
foreach ($Key in $RequiredFields.Keys)
{
    if (!$CSVFile[0].$Key)
    {
        # Missing required field
        throw "Import file is missing required field: $Key";
    }
}

# Check EWS Managed API available
 if (!$EWSManagedApiPath)
 {
     $EWSManagedApiPath = "C:\Program Files\Microsoft\Exchange\Web Services\2.0\Microsoft.Exchange.WebServices.dll"
     $dllpath = "C:\Program Files\Microsoft\Exchange\Web Services\2.0\Microsoft.Exchange.WebServices.dll"
 }
 if (!(Get-Item -Path $EWSManagedApiPath -ErrorAction SilentlyContinue))
 {
     throw "EWS Managed API could not be found at $($EWSManagedApiPath).";
 }

# Load EWS Managed API
 [void][Reflection.Assembly]::LoadFile($EWSManagedApiPath);

# Create Service Object.  We only need Exchange 2007 schema for creating calendar items (this will work with Exchange>=12)
$ExchangeVersion = [Microsoft.Exchange.WebServices.Data.ExchangeVersion]::Exchange2016
$service = New-Object Microsoft.Exchange.WebServices.Data.ExchangeService($ExchangeVersion)

# Set credentials if specified, or use logged on user.
$psCred = Get-Credential

$creds = New-Object System.Net.NetworkCredential($psCred.UserName.ToString(),$psCred.GetNetworkCredential().password.ToString())
$AccountWithImpersonationRights = $psCred.UserName
 if ($Username -and $Password)
 {
     if ($Domain)
     {
         $service.Credentials = New-Object  Microsoft.Exchange.WebServices.Data.WebCredentials($Username,$Password,$Domain);
     } else {
         $service.Credentials = New-Object  Microsoft.Exchange.WebServices.Data.WebCredentials($Username,$Password);
     }

} else {
     $service.UseDefaultCredentials = $true;
 }
$service.Credentials = $creds

# Set EWS URL if specified, or use autodiscover if no URL specified.
if ($EwsUrl)
{
    $service.URL = New-Object Uri($EwsUrl);
}
else
{
    try
    {
        Write-Host "Performing autodiscover for $EmailAddress";
        #$service.AutodiscoverUrl($EmailAddress);
        $service.AutodiscoverUrl($AccountWithImpersonationRights ,{$true})
    }
    catch
    {
        throw;
    }
}

# Bind to the calendar folder

if ($Impersonate)
{
    $service.ImpersonatedUserId = New-Object Microsoft.Exchange.WebServices.Data.ImpersonatedUserId([Microsoft.Exchange.WebServices.Data.ConnectingIdType]::SmtpAddress,$EmailAddress );
}
try {
    $CalendarFolder = [Microsoft.Exchange.WebServices.Data.CalendarFolder]::Bind($service, [Microsoft.Exchange.WebServices.Data.WellKnownFolderName]::Calendar);
} catch {
    throw;
}

# Parse the CSV file and add the appointments
foreach ($CalendarItem in $CSVFile)
{
    # Create the appointment and set the fields
    $NoError=$true;
    try
    {
        $Appointment = New-Object Microsoft.Exchange.WebServices.Data.Appointment($service);
        $Appointment.Subject=$CalendarItem."Subject";
        $StartDate=[DateTime]($CalendarItem."StartDate" + " " + $CalendarItem."StartTime");
        $Appointment.Start=$StartDate;
        $EndDate=[DateTime]($CalendarItem."EndDate" + " " + $CalendarItem."EndTime");
        $Appointment.End=$EndDate;
    }
    catch
    {
        # If we fail to set any of the required fields, we will not write the appointment
        $NoError=$false;
    }

    # Check for any other fields
    foreach ($Field in ($CalendarItem | Get-Member -MemberType Properties))
    {
        if (!($RequiredFields.Keys -contains $Field.Name))
        {
            # This is a custom (optional) field, so try to map it
            try
            {
                $Appointment.$($Field.Name)=$CalendarItem.$($Field.Name);
            }
            catch
            {
                # Failed to write this field
                Write-Host "Failed to set custom field $($Field.Name)" -ForegroundColor yellow;
            }
        }
    }

    if ($NoError)
    {
        # Save the appointment
        $Appointment.Save([Microsoft.Exchange.WebServices.Data.WellKnownFolderName]::Calendar);
        Write-Host "Created $($CalendarItem."Subject")" -ForegroundColor green;
    }
    else
    {
        # Failed to set a required field
        Write-Host "Failed to create appointment: $($CalendarItem."Subject")" -ForegroundColor red;
    }
}