SET NOCOUNT ON;

DECLARE @DbName SYSNAME;
DECLARE @DbFileName SYSNAME;
DECLARE @RowsOrLog VARCHAR(4);
DECLARE @SpaceToLeavePercentage VARCHAR(2);
DECLARE @Sql VARCHAR(MAX);
DECLARE @ShrinkSql VARCHAR(MAX);
DECLARE @NumberOfShrinks INT;
DECLARE @FreeMbRounded INT;
DECLARE @TargetFreeMbRounded INT;
DECLARE @ShrinkIncrementInMb INT;
DECLARE @ShrinkToInMb INT;
DECLARE @TruncateOnly BIT;

/*SET USER INPUT VARIABLES*/
SET @DbName = '_DatabaseName_';
SET @RowsOrLog = 'Rows';
SET @SpaceToLeavePercentage = '10';
SET @NumberOfShrinks = 1;

--SET @TruncateOnly = 1;
IF OBJECT_ID('tempdb..##DbStats') IS NOT NULL
BEGIN
	DROP TABLE ##DbStats
END;

IF OBJECT_ID('tempdb..#Check') IS NOT NULL
BEGIN
	DROP TABLE #Check
END;

CREATE TABLE ##DbStats (
	Id_DbStats INT NOT NULL IDENTITY(1, 1) PRIMARY KEY
	,LogicalName SYSNAME
	,FreeMbRounded INT
	,TargetFreeMbRounded INT
	,DiffMb INT
	,ShrinkIncrementInMb INT
	,NumberOfShrinksLeft INT
	);

CREATE TABLE #Check (
	Id_DbStats INT NOT NULL IDENTITY(1, 1) PRIMARY KEY
	,LogicalName SYSNAME
	,FreeMbRounded INT
	,TargetFreeMbRounded INT
	,DiffMb INT
	,ShrinkIncrementInMb INT
	,NumberOfShrinksLeft INT
	);

IF @SpaceToLeavePercentage IS NULL
BEGIN
	SET @SpaceToLeavePercentage = '10'
END

SET @Sql = '
USE ' + QUOTENAME(@DbName) + ';
SELECT LogicalName
,FreeMbRounded
,TargetFreeMbRounded
,FLOOR(FreeMbRounded) - FLOOR(TargetFreeMbRounded) AS DiffMb
FROM (
SELECT NAME AS LogicalName
	,CAST(ROUND(CONVERT(DECIMAL(12, 1), (size - FILEPROPERTY(NAME, ''SpaceUsed'')) / 128.0), 0) AS INT) AS FreeMbRounded
	,CAST(ROUND(CONVERT(DECIMAL(12, 1),((((size - FILEPROPERTY(NAME, ''SpaceUsed'')) / 128.0) / 100.0) * ' + @SpaceToLeavePercentage + ')), 0) AS INT) AS TargetFreeMbRounded
FROM ' + QUOTENAME(@DbName) + '.sys.database_files 
WHERE type_desc = ''' + @RowsOrLog + '''
) AS a
';

INSERT INTO ##DbStats (
	LogicalName
	,FreeMbRounded
	,TargetFreeMbRounded
	,DiffMb
	)
EXEC (@Sql);

SET @TargetFreeMbRounded = (
		SELECT TargetFreeMbRounded
		FROM ##DbStats
		)
SET @DbFileName = (
		SELECT LogicalName
		FROM ##DbStats
		);

IF @TruncateOnly = 1
BEGIN
	SET @ShrinkSql = '
USE ' + QUOTENAME(@DbName) + ';

DBCC SHRINKFILE (
		N' + '''' + @DbFileName + '''' + '
		, 0
		, TRUNCATEONLY
		) WITH NO_INFOMSGS;
';

	EXEC (@ShrinkSql);
END
ELSE
BEGIN
	SET @ShrinkIncrementInMb = (
			(
				SELECT (FLOOR(MAX(FreeMbRounded)) - @TargetFreeMbRounded)
				FROM ##DbStats
				) / @NumberOfShrinks
			);

	UPDATE ##DbStats
	SET ShrinkIncrementInMb = @ShrinkIncrementInMb
		,NumberOfShrinksLeft = @NumberOfShrinks
	WHERE NumberOfShrinksLeft IS NULL;

	SELECT TOP 1 *
	FROM ##DbStats
	ORDER BY Id_DbStats DESC;

	IF @ShrinkIncrementInMb > 0
	BEGIN
		WHILE @NumberOfShrinks > 0
		BEGIN
			SET @FreeMbRounded = (
					SELECT FreeMbRounded
					FROM ##DbStats
					WHERE Id_DbStats = (
							SELECT MAX(Id_DbStats)
							FROM ##DbStats
							)
					);

			IF @TargetFreeMbRounded > (@FreeMbRounded - @ShrinkIncrementInMb)
			BEGIN
				SET @ShrinkToInMb = @TargetFreeMbRounded;
			END
			ELSE
			BEGIN
				SET @ShrinkToInMb = (@FreeMbRounded - @ShrinkIncrementInMb);
			END

			SET @ShrinkSql = '
USE ' + QUOTENAME(@DbName) + ';

DBCC SHRINKFILE (
		N' + '''' + @DbFileName + '''' + '
		,' + CONVERT(VARCHAR(12), @ShrinkToInMb) + '
		) WITH NO_INFOMSGS;
';

			EXEC (@ShrinkSql);

			SET @NumberOfShrinks = @NumberOfShrinks - 1;
			SET @Sql = '
USE ' + QUOTENAME(@DbName) + ';
SELECT LogicalName
,FreeMbRounded
,' + CONVERT(VARCHAR(255), @TargetFreeMbRounded) + '
,FLOOR(FreeMbRounded) - ' + CONVERT(VARCHAR(255), @TargetFreeMbRounded) + ' AS DiffMb
,' + CONVERT(VARCHAR(255), @ShrinkIncrementInMb) + '
,' + CONVERT(VARCHAR(255), @NumberOfShrinks) + '
FROM (
SELECT NAME AS LogicalName
	,CAST(ROUND(CONVERT(DECIMAL(12, 1), (size - FILEPROPERTY(NAME, ''SpaceUsed'')) / 128.0), 0) AS INT) AS FreeMbRounded
	,CAST(ROUND(CONVERT(DECIMAL(12, 1),((((size - FILEPROPERTY(NAME, ''SpaceUsed'')) / 128.0) / 100.0) * ' + @SpaceToLeavePercentage + ')), 0) AS INT) AS TargetFreeMbRounded
FROM ' + QUOTENAME(@DbName) + '.sys.database_files 
WHERE type_desc = ''' + @RowsOrLog + '''
) AS a
';

			INSERT INTO ##DbStats (
				LogicalName
				,FreeMbRounded
				,TargetFreeMbRounded
				,DiffMb
				,ShrinkIncrementInMb
				,NumberOfShrinksLeft
				)
			EXEC (@Sql);

			SELECT TOP 1 *
			FROM ##DbStats
			ORDER BY Id_DbStats DESC;
		END
	END
	ELSE
	BEGIN
		SELECT *
		FROM ##DbStats;
	END

	DROP TABLE ##DbStats
END;
		--DROP TABLE ##DbStats
		/*CHECK TO RUN IN ANOTHER SSMS WINDOW*/
		/*
SELECT TOP 1 Id_DbStats
	,LogicalName
	,FreeMbRounded
	,TargetFreeMbRounded
	,DiffMb
	,ShrinkIncrementInMb
	,NumberOfShrinksLeft
FROM ##DbStats WITH (NOLOCK)
ORDER BY Id_DbStats DESC;
/*
/*CHECK PROGRESS*/
/*
SELECT percent_complete AS PercentageComplete
	,start_time AS StartTime
	,STATUS AS CurrentStatus
	,command AS Command
	,estimated_completion_time AS EstimatedCompletionTime
	,cpu_time AS CpuTime
	,total_elapsed_time AS TotalElapsedTime
FROM sys.dm_exec_requests
WHERE Command = 'DbccFilesCompact'
*/
*/
/*
DROP TABLE ##DbStats
*/
*/