-- =============================================
-- Author:		Dr. Stefan Ott
-- Create date: 2026-09-17
-- Description:	App-facing counterpart to the manual [dbo].[_BackupAndClearInvoiceFile] maintenance
--              tool (see that proc's header comment and Docs/Decisions/0025's "Alternatives
--              considered"). That proc is explicitly manual-only and leaves no application log
--              entry, so it is never called from here — this is a separate proc for the hidden
--              admin/backupclearinvoicefile action (fds_sys > 4 gate, IntranetController.Admin.cs),
--              which logs through the normal ILogger/DB-log-sink pipeline (ADR 0024) instead.
--
--              Copies the invoice's current [file] bytes into [dbo].[fds__invoice_file_backups],
--              then clears [file] so the document regenerates on next read (ADR 0025). Both steps
--              run in one transaction. Only a finalised, non-external invoice qualifies — the same
--              precondition ADR 0025 puts on regeneration: clearing a draft's file would let the
--              next read persist a draft render (fds__setInvoiceFile writes WHERE [file] IS NULL)
--              that then blocks the real final PDF forever; an external (MFR) document cannot be
--              regenerated at all. The calling service checks this too; this is defense in depth.
--              An empty OUTPUT rowset means nothing was backed up/cleared (invoice missing, not
--              finalised, external, or [file] already NULL) — rows-affected can't be used for this
--              because of SET NOCOUNT ON (same reasoning as fds__setInvoiceFile, ADR 0025).
-- =============================================
CREATE PROCEDURE [dbo].[fds__admin_backupAndClearInvoiceFile]
	@authuser varchar(25),
	@Id       varchar(10)
AS
BEGIN
	SET NOCOUNT ON;
	-- The clear must never commit without its backup row: XACT_ABORT turns any statement-level
	-- error inside the transaction into a doomed transaction, and the CATCH rolls back and re-raises
	-- so the caller sees an error instead of an OUTPUT row (same pattern as the mfr__updt__* procs).
	SET XACT_ABORT ON;

	INSERT INTO [dbo].[fds__admin_activity] ([activity], [authuser], [info])
		VALUES ('fds__admin_backupAndClearInvoiceFile', @authuser,
			(SELECT * FROM (VALUES(@Id)) AS z([id]) FOR JSON PATH, INCLUDE_NULL_VALUES, WITHOUT_ARRAY_WRAPPER));

	BEGIN TRY
	BEGIN TRANSACTION;

	INSERT INTO [dbo].[fds__invoice_file_backups] ([InvoiceId], [DocumentName], [file], [BackedUpBy])
		SELECT [Id], [DocumentName], [file], @authuser
		FROM [dbo].[fds__invoices]
		WHERE [Id] = @Id AND [file] IS NOT NULL
		  AND [DateFinalized] IS NOT NULL AND ISNULL([IsExternal], 0) = 0;

	UPDATE [dbo].[fds__invoices]
		SET [file] = NULL
		OUTPUT inserted.[Id]
		WHERE [Id] = @Id AND [file] IS NOT NULL
		  AND [DateFinalized] IS NOT NULL AND ISNULL([IsExternal], 0) = 0;

	COMMIT TRANSACTION;
	END TRY
	BEGIN CATCH
		IF @@TRANCOUNT > 0 ROLLBACK TRANSACTION;

		INSERT INTO dbo.[fds__admin_dberrors] ([UserName], [ErrorNumber], [ErrorState], [ErrorSeverity], [ErrorLine], [ErrorProcedure], [ErrorMessage], [ErrorDateTime])
		VALUES (SUSER_SNAME(), ERROR_NUMBER(), ERROR_STATE(), ERROR_SEVERITY(), ERROR_LINE(), ERROR_PROCEDURE(), ERROR_MESSAGE(), GETDATE());

		THROW;
	END CATCH;
END