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/**
 * @file datatop_opt.c
 * @brief Adds getopt functionality for CLI commands.
 *
 * Contains method for getopt functionality used for parsing
 * the CLI arguments into executable commands. Handles
 * errors which arise when parsing.
 */

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <ctype.h>
#include <getopt.h>
#include "datatop_opt.h"
#include "datatop_interface.h"
#include "datatop_linked_list.h"
#include "datatop_fileops.h"

/**
 * @brief Populate the comand line options with sane defaults
 *
 * @param clopts Struct used to hold data regarding CLI arguments.
 */
void dtop_load_default_options(struct cli_opts *clopts)
{
	memset(clopts, 0, sizeof(struct cli_opts));

	clopts->priority = DEFAULT_NICE;
}

/**
 * @brief Parses all CLI commands for main() to execute.
 *
 * @param clopts Struct used to hold data regarding CLI arguments.
 * @param argc Parameter used to read CLI commands from.
 * @param argv Parameter used to read CLI arguments from.
 * @return PARSE_SUCCESS - CLI arguments read successfully,
 * @return PARSE_FAILURE - CLI arguments and/or input not valid.
 * @return PARSE_FORCE_EXIT - Exit immediately, print help options.
 */
int dtop_parse_cli_opts(struct cli_opts *clopts, int argc, char **argv)
{
	int option;

	if (!clopts || !*argv) {
		printf("Internal Error: Null Pointer\n");
		goto error;
	}

	while ((option = getopt(argc, argv, "phi:t:w:s:n:")) != -1) {
		switch (option) {
		case 'p':
			clopts->print_cl = OPT_CHOSE;
		break;

		case 'h':
			dtop_print_help_opts();
			return PARSE_FORCE_EXIT;
		break;

		case 'n':
			clopts->priority = strtol(optarg, 0, 10);
			if (clopts->priority > 19 || clopts->priority < -20) {
				printf("Argument for -n is not valid. ");
				printf("Must be between -20 and 19.\n");
				goto error;
			}
		break;

		case 'i':
			clopts->poll_per = strtol(optarg, 0, 10);
			if (clopts->poll_per <= 0) {
				printf("Argument for -i is not valid. ");
				printf("Must be positive integer.\n");
				goto error;
			}
		break;

		case 't':
			clopts->poll_time = strtol(optarg, 0, 10);
			clopts->poll_time_selected = POLL_TIME_SELECTED;
			if (clopts->poll_time <= 0) {
				printf("Argument for -t is not valid. ");
				printf("Must be positive integer.\n");
				goto error;
			}
		break;

		case 'w':
			if (dtop_check_writefile_access(optarg) == VALID) {
				clopts->file_name = optarg;
				clopts->print_csv = OPT_CHOSE;
			} else {
				goto error;
			}
		break;

		case 's':
			if (dtop_check_writefile_access(optarg) == VALID)
				clopts->snapshot_file = optarg;
			else
				goto error;
		break;

		case '?':
		default:
			goto error;
		}
	}

	if (clopts->poll_time == 0) {
		if (clopts->print_csv == 1)
			clopts->poll_time = POLL_NOT_SPECIFIED;
		else
			clopts->poll_time = POLL_TIME_DEFAULT;
	}
	if (clopts->poll_per == 0)
		clopts->poll_per = DEFAULT_POLL_INTERVAL;

	return PARSE_SUCCESS;

error:
	printf("See datatop -h for help\n");
	return PARSE_FAILURE;
}

/**
 * @brief Prints the options the user has for the program to terminal.
 */
void dtop_print_help_opts(void)
{
	printf("The following datatop commands are:\n");
	printf("\t-p\t\t\tPrint output to terminal\n");
	printf("\t-i , seconds\t\tSpecify polling period\n");
	printf("\t-t , seconds\t\tSpecify polling duration\n");
	printf("\t-w , file name (.csv)\tWrite output to a file\n");
	printf("\t-s , file name\t\tPrint system snapshot to a file\n");
	printf("\t-n , nice value\t\tSet niceness (default 19)\n");
	printf("\t-h\t\t\tGet help\n");
}


/**
* @brief Prints the interactive options the user can enter during runtime.
*/
void dtop_print_interactive_opts(void)
{
	printf("The following interactive commands are:\n");
	printf("\tq | quit\tTerminate program at any time\n");
	printf("\ti\t\tPrint dp differences, reset initial dp values\n");
	printf("\tl\t\tPrint dp differences since last reset\n");
	printf("\n");
}