#include <stdio.h>
#include <string.h>
#define INSERT_LAB 1
#define SAVE 2
#define DONE 3
#define MAX_NAME_LENGTH 80
#define MAX_LABS 15

typedef struct{
	char name[MAX_NAME_LENGTH];
	int id;
	double labs[MAX_LABS];
	int num_labs;
} student_t;

int get_choice();
int get_students(student_t students[], int *num_students);
void print_students(const student_t students[], int num_students);
int insert_lab(student_t students[], int num_students);
int save_students(const student_t students[], int num_students);

int main(void) {
	
	student_t students[40];
	int num_students;
	int choice;
	int result = 0;
	
	result = get_students(students, &num_students);
	if(!result) {
		printf("There was a problem retrieving data...cannot continue.\n");
		return (1); //exit with 
	}
	print_students(students, num_students);
	choice = get_choice();
	while(choice != DONE) {
		
		if(choice == INSERT_LAB) {
			result = insert_lab(students, num_students);	
		} else if(choice == SAVE) {
			result = save_students(students, num_students);
		} else {
			result = 0;	
		}
		
		if(!result) {
			printf("Your choice could not be correctly performed.\n");
		}
		print_students(students, num_students);
		choice = get_choice();
	}
	return (0);
}


int get_choice() {
	int choice;	
	printf("You can perform the following operations:\n");
	printf("\t1. Insert a lab score\n");
	printf("\t2. Save current data\n");
	printf("\t3. Quit the program\n");
	printf("Enter your choice:");
	scanf("%d", &choice);
	return choice;
	
}

int get_students(student_t students[], int *num_students) {
	char filename[50];
	char trash[10];
	FILE *infile;
	int result, i, j;
	char *status;

	printf("Enter the name of the data file: ");
	gets(filename);
	infile = fopen(filename, "r");
	if(infile != NULL) {
		result = fscanf(infile, "%d", num_students);		
		fgets(trash, 10, infile);
		if(result == EOF) {
			printf("Your file is corrupt.\n");
			return (0);
		}	
		for(i = 0; i < *num_students; i++) {
			status = fgets(students[i].name, 80, infile);
			if(status == NULL) {
				printf("Your file is corrupt.\n");
				return (0);
			}
			if(students[i].name[strlen(students[i].name)-1] == '\n') {
				students[i].name[strlen(students[i].name)-1] = '\0';
			}
			result = fscanf(infile, "%d", &students[i].id);
			fgets(trash, 10, infile);
			if(result == EOF) {
				printf("Your file is corrupt.\n");
				return (0);
			}

			result = fscanf(infile, "%d", &students[i].num_labs);
			fgets(trash, 10, infile);
			if(result == EOF) {
				printf("Your file is corrupt.\n");
				return (0);
			}
			for(j = 0; j < students[i].num_labs; j++) {
				result = fscanf(infile, "%lf", &students[i].labs[j]);
				if(result == EOF) {
					printf("Your file is corrupt.\n");
					return (0);
				}
			}
			fgets(trash, 10, infile);
		}
		fclose(infile);
		return (1);
	} else {
		printf("The file %s could not be opened correctly.\n", filename);
		return (0);
	}
}

void print_students(const student_t students[], int num_students) {
	int i, j;
	printf("\n*****************************************************\n\n");
	for(i = 0; i < num_students; i++) {
		printf("Student %d:\n", (i+1));
		printf("\tName: %s\n", students[i].name);
		printf("\tID: %d\n", students[i].id);
		for(j = 0; j < students[i].num_labs; j++) {
			printf("\tLab %d: %lf\n", (j+1), students[i].labs[j]);
		}
	}
	printf("\n*****************************************************\n\n");
}

int insert_lab(student_t students[], int num_students) {
	double new_lab_score = 1;
	int i;

	fflush(stdin);
	for(i = 0; i < num_students; i++) {
		if(students[i].num_labs < MAX_LABS) {
			do {
				if(new_lab_score < 0) {
					printf("Score must be greater than 0.\n");
				}
				printf("Enter lab score for %s: ", students[i].name);
				scanf("%lf", &new_lab_score);
			} while(new_lab_score < 0);
			students[i].labs[students[i].num_labs++] = new_lab_score;
		} else {
			printf("Student %s has finished all labs.\n", students[i].name);
		}
	}
	return 1;
}

int save_students(const student_t students[], int num_students) {
	char filename[50];
	//char trash[10];
	FILE *outfile;
	int i, j;
	//char *status;

	fflush(stdin);
	printf("Enter the name of the data file: ");
	gets(filename);
	outfile = fopen(filename, "w");
	if(outfile != NULL) {
		fprintf(outfile, "%d\n", num_students);
		for(i = 0; i < num_students; i++) {
			fprintf(outfile, "%s\n", students[i].name);
			fprintf(outfile, "%d\n", students[i].id);
			fprintf(outfile, "%d\n", students[i].num_labs);
			for(j = 0; j < students[i].num_labs; j++) {
				fprintf(outfile, "%lf\n", students[i].labs[j]);
			}
		}
		fclose(outfile);		
	} else {
		printf("Cannot write to file %s.\n", filename);
		return 0;
	}

	printf("Data saved...\n");
	return 1;
}