param (
    [string] $UserName = $null,
    [string] $Password = $null,
    [Switch] $Enabled,
    [Switch] $Scheduled,
    [Switch] $DisabledMailboxes,
    [Switch] $Today,
    [String] $ActiveOOFAfterDays
    
)

#Checks ExchangeOnline module availability and connects the module
Function ConnectToExchange {
    $Exchange = (get-module ExchangeOnlineManagement -ListAvailable).Name
    if ($Exchange -eq $null) {
        Write-host "Important: ExchangeOnline PowerShell module is unavailable. It is mandatory to have this module installed in the system to run the script successfully." 
        $confirm = Read-Host Are you sure you want to install module? [Y] Yes [N] No  
        if ($confirm -match "[yY]") { 
            Write-host "Installing ExchangeOnlineManagement"
            Install-Module ExchangeOnlineManagement -Repository PSGallery -AllowClobber -Force
            Write-host "ExchangeOnline PowerShell module is installed in the machine successfully."
        }
        elseif ($confirm -cnotmatch "[yY]" ) { 
            Write-host "Exiting. `nNote: ExchangeOnline PowerShell module must be available in your system to run the script." 
            Exit 
        }
    }
    #Storing credential in script for scheduling purpose/Passing credential as parameter
    if (($UserName -ne "") -and ($Password -ne "")) {   
        $SecuredPassword = ConvertTo-SecureString -AsPlainText $Password -Force   
        $Credential = New-Object System.Management.Automation.PSCredential $UserName, $SecuredPassword 
        Connect-ExchangeOnline -Credential $Credential -ShowProgress $false | Out-Null
    }
    else {
        Connect-ExchangeOnline | Out-Null
    }
    Write-Host "ExchangeOnline PowerShell module is connected successfully"
    #End of Connecting Exchange Online
}

#This function checks the user choice and retrieves the OOF status
Function RetrieveOOFReport {
    #Checks the users with scheduled OOF setup
    if ($Scheduled.IsPresent) {
        $global:ExportCSVFileName = "OOFScheduledUsersReport-" + ((Get-Date -format "MMM-dd hh-mm-ss tt").ToString()) + ".csv" 
        Get-mailbox -ResultSize Unlimited | foreach-object {
            $CurrUser = $_
            $CurrOOFConfigData = Get-MailboxAutoReplyConfiguration -Identity ($CurrUser.PrimarySmtpAddress) | Where-object { $_.AutoReplyState -eq "Scheduled" }
            if ($null -ne $CurrOOFConfigData ) {
                PrepareOOFReport
                ExportScheduledOOF
            }
        }
    }
    #Checks the OOF status on and after user mentioned days 
    elseif ($ActiveOOFAfterDays -gt 0) {
        $global:ExportCSVFileName = "UpcomingOOFStatusReport-" + ((Get-Date -format "MMM-dd hh-mm-ss tt").ToString()) + ".csv" 
        $OOFStartDate = (Get-date).AddDays($ActiveOOFAfterDays).Date.ToString().split(" ") | Select -Index 0
        Get-mailbox -ResultSize Unlimited | foreach-object {
            $CurrUser = $_
            $CurrOOFConfigData = Get-MailboxAutoReplyConfiguration -Identity ($CurrUser.PrimarySmtpAddress) | Where-object { $_.AutoReplyState -ne "Disabled" }
            if ($null -ne $CurrOOFConfigData ) {
                $CurrOOFStartDate = $CurrOOFConfigData.StartTime.ToString().split(" ") | select -Index 0
                $CurrOOFEndDate = $CurrOOFConfigData.EndTime.ToString().split(" ") | Select -Index 0
                $ActiveOOFAfterFlag = "true"
                if($CurrOOFConfigData.AutoReplyState -eq "Enabled" -or ($OOFStartDate -ge $CurrOOFStartDate -and $OOFStartDate -le $CurrOOFEndDate)){
                    PrepareOOFReport
                    ExportAllActiveOOFSetup
                }
            }
        }
    }
    #Checks the OOF with enabled status
    elseif ($Enabled.IsPresent) {
        $global:ExportCSVFileName = "OOFEnabledUsersReport-" + ((Get-Date -format "MMM-dd hh-mm-ss tt").ToString()) + ".csv" 
        Get-mailbox -ResultSize Unlimited | foreach-object {
            $CurrUser = $_
            $CurrOOFConfigData = Get-MailboxAutoReplyConfiguration -Identity ($CurrUser.PrimarySmtpAddress) | Where-object { $_.AutoReplyState -eq "Enabled" } 
            if ($null -ne $CurrOOFConfigData ) {
                $EnabledFlag = 'true'
                PrepareOOFReport
                ExportEnabledOOF
            }
        }
    }
    #Checks whether OOF starting day is current day and process
    elseif ($Today.Ispresent) {
        $global:ExportCSVFileName = "OOFUsersTodayReport-" + ((Get-Date -format "MMM-dd hh-mm-ss tt").ToString()) + ".csv" 
        $CurrDate = (Get-Date).Date.ToString().split(" ") | Select -Index 0
        Get-mailbox -ResultSize Unlimited | foreach-object {
            $CurrUser = $_
            $CurrOOFConfigData = Get-MailboxAutoReplyConfiguration -Identity ($CurrUser.PrimarySmtpAddress) | Where-object { $_.AutoReplyState -ne "Disabled" }
            if ($null -ne $CurrOOFConfigData ) {
                $CurrOOFStartDate = $CurrOOFConfigData.StartTime.ToString().split(" ") | select -Index 0
                $CurrOOFEndDate = $CurrOOFConfigData.EndTime.ToString().split(" ") | Select -Index 0
                if ($CurrDate -ge $CurrOOFStartDate -and $CurrDate -le $CurrOOFEndDate) {
                    PrepareOOFReport
                    ExportAllActiveOOFSetup
                }
            }
        }
    }
    
    #Checks the disabled mailoxes OOF configuration
    elseif ($DisabledMailboxes.Ispresent) {
        $global:ExportCSVFileName = "DisabledAccountsOOFConfigurationReport-" + ((Get-Date -format "MMM-dd hh-mm-ss tt").ToString()) + ".csv" 
        Get-mailbox -ResultSize Unlimited | Where-Object { $_.AccountDisabled -eq $TRUE } | foreach-object {
            $CurrUser = $_
            $CurrOOFConfigData = Get-MailboxAutoReplyConfiguration -Identity ($CurrUser.PrimarySmtpAddress) | Where-object { $_.AutoReplyState -ne "Disabled" }
            if ($null -ne $CurrOOFConfigData ) {
                PrepareOOFReport
                ExportDisabledMailboxOOFSetup
            }
        }
    }   
    #Checks the all active OOF configuration
    else {
        $global:ExportCSVFileName = "OutofOfficeConfigurationReport-" + ((Get-Date -format "MMM-dd hh-mm-ss tt").ToString()) + ".csv" 
        Get-mailbox -ResultSize Unlimited | foreach-object {
            $CurrUser = $_
            $CurrOOFConfigData = Get-MailboxAutoReplyConfiguration -Identity ($CurrUser.PrimarySmtpAddress) | Where-object { $_.AutoReplyState -ne "Disabled" }
            if ($null -ne $CurrOOFConfigData ) {   
                PrepareOOFReport
                ExportAllActiveOOFSetup
            }
        }
    }
}

#Checks the Boolean values
Function GetPrintableValue($RawData) {
    if ($null -eq $RawData -or $RawData.Equals($false)) {
        return "No"
    }
    else {
        return "Yes"
    }
}

#Saves the users with OOF configuration
Function PrepareOOFReport {
    $global:ReportSize = $global:ReportSize + 1
    
    $EmailAddress = $CurrUser.PrimarySmtpAddress
    $AccountStatus = $CurrUser.AccountDisabled
    $MailboxOwner = $CurrOOFConfigData.MailboxOwnerId
    $OOFStatus = $CurrOOFConfigData.AutoReplyState
    $AutoCancelRequests = GetPrintableValue $CurrOOFConfigData.AutoDeclineFutureRequestsWhenOOF
    $CancelAllEvents = GetPrintableValue $CurrOOFConfigData.DeclineAllEventsForScheduledOOF
    $CancelScheduledEvents = GetPrintableValue $CurrOOFConfigData.DeclineEventsForScheduledOOF
    $CreateOOFEvent = GetPrintableValue $CurrOOFConfigData.CreateOOFEvent
    $ExternalAudience = $CurrOOFConfigData.ExternalAudience
    $StartTime = $CurrOOFConfigData.StartTime
    $EndTime = $CurrOOFConfigData.EndTime
    $Duration = $EndTime - $StartTime
    $TimeSpan = "$($Duration.Days.ToString('00'))d : $($Duration.Hours.ToString('00'))h : $($Duration.Minutes.ToString('00'))m";
    
    if ($CurrOOFConfigData.InternalMessage -ne "") {
        $InternalMessage = (($CurrOOFConfigData.InternalMessage) -replace '<.*?>', '').Trim()
    } 
    else { $InternalMessage = "-" }
    if ($CurrOOFConfigData.ExternalMessage -ne "") {
        $ExternalMessage = (($CurrOOFConfigData.ExternalMessage) -replace '<[^>]+>', '').Trim()
    }
    else { $ExternalMessage = "-" }
    
    if ($EnabledFlag -eq 'true') {
        $global:OOFDuration = 'OOF Duration'
    }
    else {
        $global:OOFDuration = 'OOF Duration (Days:Hours:Mins)'
    }
    if ($OOFStatus -eq 'Enabled') {
        $StartTime = "-"
        $EndTime = "-"
        $TimeSpan = 'Until auto-reply is disabled'
    }
                
    Write-Progress "Retrieving the OOF Status of the User: $MailboxOwner" "Processed Users Count: $global:ReportSize"

    #Save values with output column names 
    $ExportResult = @{ 

        'Email Address'            = $EmailAddress;
        'Disabled Account'         = $AccountStatus;
        'Mailbox Owner'            = $MailboxOwner;
        'Auto Reply State'         = $OOFStatus;
        'Start Time'               = $StartTime;
        'End Time'                 = $EndTime;
        'Decline Future Requests'  = $AutoCancelRequests;
        'Decline All Events'       = $CancelAllEvents;
        'Decline Scheduled Events' = $CancelScheduledEvents;
        'Create OOF Event'         = $CreateOOFEvent;
        'External Audience'        = $ExternalAudience;
        'Internal Message'         = $InternalMessage;
        'External Message'         = $ExternalMessage;
        $global:OOFDuration        = $TimeSpan 
    }

    $global:ExportResults = New-Object PSObject -Property $ExportResult
}

#Exports the users with OOF schedued configuration 
Function ExportScheduledOOF {
    $global:ExportResults | Select-object 'Mailbox Owner', 'Email Address', 'Start Time', 'End Time', $global:OOFDuration, 'Decline Future Requests', 'Decline All Events', 'Decline Scheduled Events', 'Create OOF Event', 'External Audience', 'Internal Message', 'External Message', 'Disabled Account' | Export-csv -path $global:ExportCSVFileName -NoType -Append -Force
}

#Exports the users with OOF Enabled configuration
Function ExportEnabledOOF {
    $global:ExportResults | Select-object 'Mailbox Owner', 'Email Address', $global:OOFDuration, 'External Audience', 'Internal Message', 'External Message', 'Disabled Account' | Export-csv -path $global:ExportCSVFileName -NoType -Append -Force
}

#Exports all the users with OOF configuration
Function ExportAllActiveOOFSetup {
    if($ActiveOOFAfterFlag = "true"){
        $global:ExportResults | Select-object 'Mailbox Owner', 'Email Address', 'Auto Reply State', 'Start Time', 'End Time', $global:OOFDuration, 'External Audience', 'Internal Message', 'External Message','Disabled Account' | Export-csv -path $global:ExportCSVFileName -NoType -Append -Force
    }
    else{
        $global:ExportResults | Select-object 'Mailbox Owner', 'Email Address', 'Auto Reply State', 'Start Time', 'End Time', $global:OOFDuration, 'External Audience', 'Internal Message', 'External Message', 'Decline Future Requests', 'Decline All Events', 'Decline Scheduled Events', 'Create OOF Event', 'Disabled Account' | Export-csv -path $global:ExportCSVFileName -NoType -Append -Force
    }
} 

Function ExportDisabledMailboxOOFSetup {
    $global:ExportResults | Select-object 'Mailbox Owner', 'Email Address', 'Auto Reply State', 'Start Time', 'End Time', $global:OOFDuration, 'Decline Future Requests', 'Decline All Events', 'Decline Scheduled Events', 'Create OOF Event', 'External Audience', 'Internal Message', 'External Message' | Export-csv -path $global:ExportCSVFileName -NoType -Append -Force 
}

#Execution starts here
ConnectToExchange
$global:ReportSize = 0
RetrieveOOFReport

#Validates the output file
if ((Test-Path -Path $global:ExportCSVFileName) -eq "True") {     
    #Open file after code execution finishes
    Write-Host "The output file available in $global:ExportCSVFileName" -ForegroundColor Green 
    write-host "Exported $global:ReportSize records to CSV." 
    Write-Host "For more Office 365 related PowerShell scripts, check https://o365reports.com" -ForegroundColor Cyan
    $prompt = New-Object -ComObject wscript.shell    
    $userInput = $prompt.popup("Do you want to open output file?", 0, "Open Output File", 4)    
    If ($userInput -eq 6) {    
        Invoke-Item "$global:ExportCSVFileName"
    }  
} 
else {
    Write-Host "No data found with the specified criteria"
}

Disconnect-ExchangeOnline -Confirm:$false -InformationAction Ignore -ErrorAction SilentlyContinue
Write-Host "Disconnected active ExchangeOnline session"

<#
=============================================================================================
For detailed Script execution: https://o365reports.com/2021/08/18/get-mailbox-automatic-reply-configuration-using-powershell
============================================================================================
#>