#requires -pssnapin Microsoft.SharePoint.Powershell

Function Invoke-AlertFixup{
<# 
    .Synopsis 
        Fixes alert links for the provided Site Collection
    .Description 
        Fixes alert links for the provided Site Collection
		
		THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
		
    .Parameter Site 
        The url of the site collection to fix.  Should be the actual URL of the site which has already had a URL change. Required Parameter.
	.Parameter OldUrl
		The original URL of the site collection prior to the change. Required Parameter.
	.Example
		Commit changes to update all alerts (in all subwebs) in the given SPSite.  This operation can not be undone!
	
        PS >  Start-AlertFixup -site "http://teams/sites/newteam"  -Oldurl "http://teams/sites/oldteam"
	.Example         
        Preview all alerts that would be updated with the given command.
		
		PS >  Start-AlertFixup -site "http://teams/sites/newteam"  -Oldurl "http://teams/sites/oldteam" -whatif
				
    .ReturnValue 
        Microsoft.SharePoint.SPSiteSubscription
    .Link 
        
    .Notes 
    	NAME:      Invoke-AlertFixup
    	AUTHOR:    Zach Rosenfield
    	LASTEDIT:  5/26/2010
    #> 
[CmdletBinding(SupportsShouldProcess=$true, ConfirmImpact='Medium')]
Param(
	[Parameter(Mandatory=$true, Position=0, ValueFromPipeline=$true)][ValidateNotNullOrEmpty()][Microsoft.SharePoint.PowerShell.SPSitePipeBind] $Site,
	[Parameter(Mandatory=$true, ValueFromPipeline=$False)][ValidateNotNullOrEmpty()][string] $OldUrl
	)

	try{
	    Write-Host -ForegroundColor Yellow "Scanning Alerts for $($Site.SiteURL)"
		Get-SPWeb -site ([string]$Site.SiteUrl) |Foreach{  #for each spweb
			try{ 
			    Write-Host ("  = "+($_.Alerts.Count.ToString())+" alerts for subweb "+($_.Title)+","+($_.URL))		
			   
			    #counters
			    $FixCount = 0;
				$SkipCount = 0;
				
				#Fix URL for usage (remove trailing /)
				$NewUrl = $Site.SiteUrl
				if($NewUrl[($NewUrl.Length-1)] -eq '/'){ $NewUrl = $NewUrl.Substring(0, $NewUrl.Length-1) }
				if($OldUrl[($OldUrl.Length-1)] -eq '/'){ $OldUrl = $OldUrl.Substring(0, $OldUrl.Length-1) }
				
				$_.Alerts |Foreach{  #for each alert
					try{
						#Make sure we only fix for this zone
						if($_.Properties["siteUrl"]-eq $null){ $_.Properties["siteUrl"] = $OldUrl }
						if($_.Properties["siteUrl"].ToLower() -eq $OldUrl.tolower()){
							
							#Fix URL
							$_.Properties["siteUrl"] = $NewUrl
							
							#if in use, fix the Mobile URL
							if( $_.Properties["MobileUrl"] -ne "" -and $_.Properties["MobileUrl"] -ne $null){
							  if( (([string]$_.Properties["MobileUrl"]).ToLower()).Contains($OldUrl.ToLower()) ){
                        		   $_.Properties["MobileUrl"] = (([string]$_.Properties["MobileUrl"]).ToLower()).Replace($OldUrl.ToLower(),$NewUrl)
								}
                    		}
						
							#preserve the frequency:
							$Frequency = $_.AlertFrequency;
							$Status = $_.Status
							if($Frequency -eq [Microsoft.SharePoint.SPAlertFrequency]::Immediate){
							$_.AlertFrequency = [Microsoft.SharePoint.SPAlertFrequency]::Weekly
							}
							else{
							$_.AlertFrequency = [Microsoft.SharePoint.SPAlertFrequency]::Immediate
							}
						
							try{
							if($pscmdlet.ShouldProcess($_.ID, "Fix Alert (List=$($_.ListUrl))")){
								$_.Status = [Microsoft.SharePoint.SPAlertStatus]::Off
								$_.Update();
								
								#Reset Values
								$_.AlertFrequency = $Frequency
								$_.Status = $Status
								$_.Update();				
								
								$FixCount++
							}
							}catch{
								Write-Error "Failure changing alert ($_) in SPWeb {$_.URL}"
							}
						}#End "Zone Check"
						else{ $SkipCount++ }
					
					}catch{
						Write-Error "Failure accessing the alert object ($_) in SPWeb {$_.URL}"
					}
				}
				
				Write-Host -ForegroundColor Green "      Alerts Fixed: $FixCount"
				if($SkipCount -gt 0){ Write-Host -ForegroundColor Yellow "      Alerts Skipped (Zone): $SkipCount" }
			}catch{
			  Write-Error "Failure reading alerts from SPWeb {$_.URL}"
			  throw
			}
		}
	}catch{
		Write-Error $_       
		throw
	}

}