call_remote_process.R

existing_data <- inputs %>% select(start_date, end_date, name) %>% filter(site_id==Y)

if (existing_data>1){
   if (!is.null(process_data)){
   
   	# construct file names, will be used for querying the db
	process_file = process_file.nc
	raw_file = raw_file.nc
	
	# check if processed file exists with overlapping date
	if (nrow(process_res <- inputs %>% select(id, start_date, end_date, name) %>% filter(name==process_file && (end_date >= as.Date(req_start) && start_date <= as.Date(req_end))) == 1)){
	actual_date_stage <- set_date_stage(process_res, req_start, req_end, process_data)
	get_data <- FALSE
	
	}
	# if not check the raw file if it already exists for processing and overlaps
	else if(nrow(raw_res <- inputs %>% select(id, start_date, end_date, name) %>% filter(name==raw_file && (end_date >= as.Date(req_start) && start_date <= as.Date(req_end))) == 1)){
	actual_date_stage = set_date_stage(raw_res, req_start, req_end, get_data)
	# if raw file exists extract its path
	if (actual_date_stage$get_data == False){
		existing_file <- dbfile.file(pass id and other info)
	}
	process_data <- TRUE
	}
   }
   # if raw data/bands is requested check if there is any overlap
   else if(nrow(raw_res <- inputs %>% select(id, start_date, end_date, name) %>% filter(name==raw_file && (end_date >= as.Date(req_start) && start_date <= as.Date(req_end))) == 1)){
	actual_date_stage = set_date_stage(raw_res, req_start, req_end, get_data)
	}
}
else{
if(!is.null(get_data){
get_data <- TRUE
}
if(!is.null(process_data){
process_data <- TRUE
}
}


output = remote_process(pass all arguments)

if(get_data){
	dbfile.input.insert(output$raw_file)
}
	
if(process_data){
	dbfile.input.insert(output$process_file)
}
	
   

# result - query df 
# req_start, req_end - start, end requetsed by user
# stage - get_data or process_data	

set_date_stage <- function(result, req_start, req_end, stage){
db_start = result$start_date # dates from existing db record
db_end = result$end_date

stage <- TRUE

if(db_start <= req_start && <= req_end <=db_end){
            print("data already exits")
            req_start <- NULL
            req_end <- NULL
            stage <- FALSE
            
# lower overlap case
}else if(req_start < db_start) && (db_start <= req_end && req_end <= db_end){
            req_end <- db_start - 1

# upper overlap case        
}else if (req_end > db_end) && (db_start <= req_start && req_start <= db_end){
            req_start <- db_end + 1

}
return list(req_start, req_end, stage)
}