!	crs_reserve_prr.scp			reb, 19-Jan-1990 07:12

!PURPOSE:  to select previous reservation in file for current ROOM

.label begin
	decimal i
	get #prevkey=#lastkey=#firstkey=#nextkey=#old_dt=""
	get #cpref=$crs_last_used:8		
	get #sroom=crs_reserve.room[$crs_last_used]

	get #display_msg=-
"Searching for previous reservation for '" #sroom "' . . . "
	get oa$display=#display_msg\force	


.label id_first_key
	get #firstkey=""
	for first crs_reserve with .crs_key:8 beginning #cpref and -
		.crs_key:30:30 beginning #sroom do -
			get #firstkey=.crs_key
	.if #firstkey:8 nes #cpref:8 or #firstkey eqs "" then -
		.goto decrement
	
.label id_last_key
	get #lastkey=$crs_last_used
	.if #firstkey eqs #lastkey then .goto decrement

.label loop_one
	get #prevkey=""
	for crs_reserve with -
		.crs_key:8 beginning #cpref and -
		.crs_key lts #lastkey and -
		     .crs_key:30:30 beginning #sroom do -
			get #prevkey=.crs_key
	.if #prevkey:8 gts #cpref then .goto decrement
	.if #prevkey nes "" then .goto found
	.goto decrement

.label found
	get $crs_last_used=#prevkey
	get #display_msg=-
"The previous reservation for '" #sroom "' has been selected."
	get oa$display=#display_msg
	.goto exit_procedure

.label decrement

	display Checking previous day's date...\force
	get #nextkey=crs_reserve:crs_key.%next[""]
	.if #cpref:8 lts #nextkey:8 or -
		#nextkey eqs $crs_last_used then -
			.goto top_of_file

	get #date=oa$date_nbs:8

	get #cyr = #date:4
	get #cmon = #date:2:4
	get #cday = #date:2:6

	compute #cday=#cday-8
	.if #cday gts "1" then .goto build_date

.label check_day
	compute #cmon=#cmon-1
	.if #cmon gts "1" then .goto add_more_days
	get #cmon="12"
	compute #cyr=#cyr-1

.label add_more_days
	.if #cmon eq 1 or #cmon eq 3 or #cmon eq 5 or #cmon eq 7 -
		or #cmon eq 8 or #cmon eq 10 or #cmon eq 12 then -
			compute #cday=#cday+31 -
	else .if #cmon eq 4 or #cmon eq 6 or #cmon eq 9 or #cmon eq 11 then -
			compute #cday=#cday+30 else -
	compute #cday=#cday+29

.label build_date
	.if #cday:1:1 eqs "" then get #cday="0" #cday
	.if #cmon:1:1 eqs "" then get #cmon="0" #cmon
	get #firstdate=#cyr:4 #cmon:2 #cday:2

	.if #cpref lts #firstdate then .goto top_of_file

	get #bday=#nextkey:8

.label calc_prev_date
	get #pyr=#cpref:4
	get #pmon=#cpref:2:4
	get #pday=#cpref:2:6

	compute #pday=#pday-1
	.if #pday gts "1" then .goto build_prev_date

.label check_prev_day
	compute #pmon=#pmon-1
	.if #pmon gts "1" then .goto add_more_prev_days
	get #pmon="12"
	compute #pyr=#pyr-1

.label add_more_prev_days
	.if #pmon eq 1 or #pmon eq 3 or #pmon eq 5 or #pmon eq 7 -
		or #pmon eq 8 or #pmon eq 10 or #pmon eq 12 then -
			compute #pday=#pday+31 -
	else .if #pmon eq 4 or #pmon eq 6 or #pmon eq 9 or #pmon eq 11 then -
			compute #pday=#pday+30 else -
	compute #pday=#pday+29

.label build_prev_date
	.if #pday:1:1 eqs "" then get #pday="0" #pday
	.if #pmon:1:1 eqs "" then get #pmon="0" #pmon
	get #cpref=#pyr:4 #pmon:2 #pday:2

	.if #cpref lts #firstdate then .goto top_of_file

	get #bday=#nextkey:8

	date_convert #old_dt,#cpref,9
	get oa$display="Checking " #old_dt " . . . "\force

.label loop_two
	get #prevkey=""
	for crs_reserve with -
		.crs_key:8 beginning #cpref and -
		     .crs_key:30:30 beginning #sroom do -
			get #prevkey=.crs_key
	.if #prevkey nes "" then .goto found
	.goto id_first_key
	
.label top_of_file
	oa$msg_purge
	get oa$display=-
"You have reached the first reservation for room '" #sroom "'."
	.goto exit_procedure

.label exit_procedure
	.exit