#set($expression = "")
#set($expressionNames = {})
#set($expressionValues = {})

#foreach($key in $ctx.args.input.keySet())
    #if ($expression.length().equals(0))
    	#set($expression = "SET #$key = :$key")
    #else
    	#set($expression = "${expression}, #$key = :$key")
    #end
    $util.qr($expressionNames.put("#$key", $key))
    $util.qr($expressionValues.put(":$key", $ctx.args.input.get($key)))
#end

{
    "version" : "2018-05-29",
    "operation" : "UpdateItem",
    "key" : {
        "key": $util.dynamodb.toDynamoDBJson($ctx.args.key)
    },
    "update" : {
        "expression": "$expression",
        "expressionNames": $util.toJson($expressionNames),
        "expressionValues": $util.dynamodb.toMapValuesJson($expressionValues)
    }
}

## [Start] Determine request authentication mode **
#if( $util.isNullOrEmpty($authMode) && !$util.isNull($ctx.identity) && !$util.isNull($ctx.identity.sub) && !$util.isNull($ctx.identity.issuer) && !$util.isNull($ctx.identity.username) && !$util.isNull($ctx.identity.claims) && !$util.isNull($ctx.identity.sourceIp) && !$util.isNull($ctx.identity.defaultAuthStrategy) )
  #set( $authMode = "userPools" )
#end
## [End] Determine request authentication mode **
## [Start] Check authMode and execute owner/group checks **
#if( $authMode == "userPools" )
  ## [Start] Owner Authorization Checks **
  #set( $isOwnerAuthorized = false )
  ## Authorization rule: { allow: owner, ownerField: "owner", identityClaim: "cognito:username" } **
  #set( $allowedOwners0 = $util.defaultIfNull($ctx.args.input.owner, null) )
  #set( $identityValue = $util.defaultIfNull($ctx.identity.claims.get("username"), $util.defaultIfNull($ctx.identity.claims.get("cognito:username"), "___xamznone____")) )
  #if( $util.isList($allowedOwners0) )
    #foreach( $allowedOwner in $allowedOwners0 )
      #if( $allowedOwner == $identityValue )
        #set( $isOwnerAuthorized = true )
      #end
    #end
  #end
  #if( $util.isString($allowedOwners0) )
    #if( $allowedOwners0 == $identityValue )
      #set( $isOwnerAuthorized = true )
    #end
  #end
  #if( $util.isNull($allowedOwners0) && (! $ctx.args.input.containsKey("owner")) )
    $util.qr($ctx.args.input.put("owner", $identityValue))
    #set( $isOwnerAuthorized = true )
  #end
  ## [End] Owner Authorization Checks **

  ## [Start] Throw if unauthorized **
  #if( !($isStaticGroupAuthorized == true || $isDynamicGroupAuthorized == true || $isOwnerAuthorized == true) )
    $util.unauthorized()
  #end
  ## [End] Throw if unauthorized **
#end
## [End] Check authMode and execute owner/group checks **