/*
 * A simple address book program to keep track
 * of information for people you know, with user-defined
 * functions for dealing with file formatting, and support
 * for command-line parameters.
 */
#include <stdio.h>
#include <string.h>
#include <getopt.h>

#define TAB '\t'
#define MAX_BLOCK 20
#define MAXLINE 80
#define TRUE 1
#define FALSE 0

struct _PersonalInfo
{
	char name[20];
	char lastname[20];
	char phone_number[20];
	char workplace[30];
};

typedef struct _PersonalInfo PersonalInfo;

void get_block(char *line, char *cs, const char delimiter);
void print_record(PersonalInfo *pInfo);
void get_record(char *line, PersonalInfo *pInfo);
void app(PersonalInfo *pInfo, FILE *fp);
void fetch(char buffer[]);
int search(PersonalInfo *pInfo, char search_criteria[]);
void print_usage(const char *prog_name);

/*
 * main driver program, with basic error checking for the
 * command line parameters first, set file editing modes,
 * and finally, if all went well enter a loop to fetch
 * records from the file.
 */
int main(int argc, char *argv[])
{
	FILE *fp;
	PersonalInfo info, *pInfo = &info;
	char buf[MAXLINE];
	char *mode = "r";
	int ret_val, srch = 0, found_records = 0;
	char srch_term[MAX_BLOCK];
	unsigned short int j = 0;
	/*
	 * store program name for use by the
	 * print_usage() function and create arrays
	 * of short & long options for getopt_long.
	 */
	const char *program_name = argv[0];
	const char *const shrt_optns = "ahs";
	const struct option lng_optns[] = {
		{"help", 0, NULL, 'h'},
		{"append", 0, NULL, 'a'},
		{"search", 0, NULL, 's'},
		{NULL, 0, NULL, 0}	/* required */
	};
	int next_option;

	/*
	 * if insufficient command line options, print
	 * a message and exit with error code.
	 */
	if(argc < 2)
	{
		print_usage(program_name);
	}
	/* examine command line parameters */
	do
	{
		next_option = getopt_long(argc, argv, shrt_optns, lng_optns, NULL);
		switch(next_option)
		{
			case 'a':
				mode = "a";
				break;
			case 'h':
				print_usage(program_name);
				break;
			case 's':
				srch = 1;
				printf("Search For: ");
				fetch(srch_term);
				printf("\n");
				break;
			case '?':
				exit(-1);
				break;
			case -1:
				/* done with options */
				break;
		}
	} while(next_option != -1);
	/* open file */
	if((fp = fopen(argv[optind], mode)) == NULL)
	{
		fprintf(stderr, "%s: Error: Cannot open file.\n", argv[0]);
		exit(-1);
	}
	if(*mode == 'a')
		app(pInfo, fp);
	/* read in lines until EOF */
	while(fgets(buf, 80, fp))
	{
		get_record(buf, pInfo);
		if(srch == TRUE)
		{
			ret_val = search(pInfo, srch_term);
			if(ret_val)
				found_records++;
		}
		else
		{
			print_record(pInfo);
			j++;
		}
	}
	if(found_records == 0 && srch == TRUE)
		fprintf(stderr, "Cannot find search criteria!\n");
	else
		printf("Success! %d record(s) returned.\n",
			(srch == FALSE) ? j : found_records);
	fclose(fp);
	return 0;
}

/* get_str: Fetch one block of information separated by tabs */
void get_block(char *line, char *cs, const char delimiter)
{
	char buf[MAX_BLOCK];
	static int i = 0;
 
	while(line[i] != '\0')
	{
		if(line[i] == delimiter)
		{
			i++;
			break;
		}
		else if(line[i] == '\n')
		{
			i = 0;
			break;
		}
		*cs++ = line[i++];
	}
	*cs = '\0';
}

/* print_record: Print each text segment out as a record on separate lines */
void print_record(PersonalInfo *pInfo)
{
	static int j = 1;

	printf("Record No.: %d\n", j++);
	printf("Firstname: %s\n", pInfo->name);
	printf("Lastname: %s\n", pInfo->lastname);
	printf("Phone No.: %s\n", pInfo->phone_number);
	printf("Workplace: %s\n\n", pInfo->workplace);
}

/* get_record: Set each text piece into structure counterparts */
void get_record(char *line, PersonalInfo *pInfo)
{
	get_block(line, pInfo->name, TAB);
	get_block(line, pInfo->lastname, TAB);
	get_block(line, pInfo->phone_number, TAB);
	get_block(line, pInfo->workplace, TAB);
}

/* fetch: Store input from user */
void fetch(char buffer[])
{
	int c, i;
	int max = MAX_BLOCK;

	i = 0;
	while((c = getchar()) != '\n')
	{
		if(i >= max)
			break;
		buffer[i++] = c;
	}
	buffer[i] = '\0';
}

/* append: Write new record to end of file */
void app(PersonalInfo *pInfo, FILE *fp)
{
	char line[MAXLINE];

	printf("Firstname: ");
	fetch(pInfo->name);
	printf("Lastname: ");
	fetch(pInfo->lastname);
	printf("Phone Number: ");
	fetch(pInfo->phone_number);
	printf("Work: ");
	fetch(pInfo->workplace);

	/* construct line from input */
	strcpy(line, pInfo->name);
	strcat(line, "\t");
	strcat(line, pInfo->lastname);
	strcat(line, "\t");
	strcat(line, pInfo->phone_number);
	strcat(line, "\t");
	strcat(line, pInfo->workplace);
	strcat(line, "\n\0");

	/* write it to file */
	fputs(line, fp);
}

int search(PersonalInfo *pInfo, char search_criteria[])
{
	if(strcmp(pInfo->name, search_criteria) == 0)
	{
		print_record(pInfo);
		return TRUE;
	}
	else if(strcmp(pInfo->lastname, search_criteria) == 0)
	{
		print_record(pInfo);
		return TRUE;
	}
	else if(strcmp(pInfo->phone_number, search_criteria) == 0)
	{
		print_record(pInfo);
		return TRUE;
	}
	else if(strcmp(pInfo->workplace, search_criteria) == 0)
	{
		print_record(pInfo);
		return TRUE;
	}

	return 0;
}

void print_usage(const char *prog_name)
{
	fprintf(stderr,
		"Usage: %s [optional-flags] file_name\n"
		"--help -h		print this information\n"
		"--append -a		add records or create new file if not present\n"
		"--search -s		find records in specified file\n",
		prog_name);
	exit(-1);
}