/*В структурах хранится информация о студентах. Одним из элементов
структуры является объединение, в котором, в зависимости от места жительства
(иногородний студент или нет), информация задается в виде :
область …, район …, город …, ул.…, д.…, кв.…;
По запросу из командной строки, в зависимости от вида информации, вывести
данные о тех или иных студентах, используя указатели на функции.*/
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
struct students{

	char* name;
	char* surname;
	char* patronymic;
	int unit;

	union {

		char* region;
		char* borough;
		char* city;
		char* street;
		int house;
		int flat;

	}placeOfLiving;
};

char* charStringInput(){

	char *string = (char*)malloc(sizeof(char)* 50);
	if (!string){
		printf("Memory error\n");
		return 0;
	}
	fflush(stdin);
	gets(string);
	fflush(stdin);
	int i = 0;
	while (string[i] != '\0'){
		if (!('a' <= string[i]) && (string[i] <= 'z') || (('A' <= string[i] ) && (string[i] <= 'Z'))){
			printf("This string cannot contain any numbers or symbols besides letters!\n Please,input write string : ");
			charStringInput();
		}
		i++;
	}
	string = (char*)realloc(string, sizeof(char)*i);
	if (!string){
		printf("Memory error\n");
		return 0;
	}
	string[i] = '\0';
	return string;
}

int integerInput(){
	int number;
	if (!scanf("%d", &number) || (number < 1)){
		printf("Please,enter number once more\n");
		fflush(stdin);
	}
	fflush(stdin);
	return number;
}

struct students* initStruct(){
	struct students *oneStudent = (struct students*)malloc(sizeof(struct students));
	if (!oneStudent){
		printf("Memory error\n");
		return 0;
	}
	printf("Enter the name of student: ");
	oneStudent->name = charStringInput();

	printf("Enter the surname of student: ");
	oneStudent->surname = charStringInput();

	printf("Enter the patronymic of student: ");
	oneStudent->patronymic = charStringInput();

	printf("What information about a student do you want to record?\n");
	printf("1 - region\n2 - borough\n3 - city\n4- street\n5-number of a house\n6-number of a flat\n Choice: ");
	while (!(scanf_s("%d", &oneStudent->unit))){
		rewind(stdin);
		printf("Error: cannot use symbols and numbers greater than 3 and less than 1!\nOption: ");
	}
	switch (oneStudent->unit) {
	case 1:
		printf("Enter the region of this student : ");
		oneStudent->placeOfLiving.region = charStringInput();
		break;
	case 2:
		printf("Enter the borough where the student lives: ");
		oneStudent->placeOfLiving.borough = charStringInput();
		break;
	case 3:
		printf("Enter city where the student lives: ");
		oneStudent->placeOfLiving.city = charStringInput();
		break;

	case 4:
		printf("Enter street where the student lives: ");
		oneStudent->placeOfLiving.street = charStringInput();
		break;
	case 5:
		printf("Enter the number of house where the student lives: ");
		oneStudent->placeOfLiving.house = integerInput();
		break;
	case 6:
		printf("Enter the number of flat where the student lives: ");
		oneStudent->placeOfLiving.flat = integerInput();
		break;
	}
	return oneStudent;
}

void printStudent(struct students** table, int i){

		printf("Name of %d student is %s\n", i + 1, table[i]->name);
		printf("Surname of %d student is %s\n", i + 1, table[i]->surname);
		printf("Patrinymic of %d student is %s\n", i + 1, table[i]->patronymic);

		switch (table[i]->unit) {
		case 1:
			printf("The region of this student is %s\n", table[i]->placeOfLiving.region);
			break;
		case 2:
			printf("The borough of this student is %s\n", table[i]->placeOfLiving.borough);
			break;
		case 3:
			printf("The city of this student is %s\n", table[i]->placeOfLiving.city);
			break;

		case 4:
			printf("The street of this student is %s\n", table[i]->placeOfLiving.street);
			break;
		case 5:
			printf("The hosue of this student is %d\n", table[i]->placeOfLiving.house);
			break;
		case 6:
			printf("The flat of this student is %d\n", table[i]->placeOfLiving.flat);
			break;
		}

}

struct students** createTable(struct students** table, int* numberOfStudents){
	table = (struct students**)malloc(sizeof(struct students*));
	int  size = 0;
	char answer;
	bool statement = true;
	do {

		printf("\nDo you want add students?(enter 'y' or 'n'):");
		answer = getchar();
		fflush(stdin);
		switch (answer) {

		case 'y': {
					  table = (struct students**)realloc(table, sizeof(struct students*)*(*numberOfStudents + 1));
					  if (!table){
						  printf("Memory error\n");
						  return 0;
					  }
					  table[*numberOfStudents] = (struct students*)malloc(sizeof(struct students*));
					  if (!table[*numberOfStudents]){
						  printf("Memory error\n");
						  return 0;
					  }
					  table[*numberOfStudents] = initStruct();
					  (*numberOfStudents)++;
					  break;
		}

		case 'n':{
					 statement = false;
					 break;
		}

		default:{
					printf("\nError,please enter 'y' or 'n'");
					break;
		}

		}
	} while (statement);
	return table;
}

int searchRightStringInCommandLine(struct students** table, char* str){
	int i = 0;
	if ((str[i] <= 'Z') && (str[i] >= 'A')){
		str[i] = char(((int)str[i] + 32));
	}
		if (strcmp(str, "region") == 0 ) {
			return 1;
		}
		if (strcmp(str, "borough") == 0 ) {
			return 2;
		}
		if (strcmp(str, "city") == 0) {
			return 3;
		}
		if (strcmp(str, "street")) {
			return 4;
		}
		if (strcmp(str, "house")) {
			return 5;
		}
		if (strcmp(str, "flat")) {
			return 6;
		}
	return 0;
}

int main(int argc, char **argv) {
	if (!argv[1]){
		printf("Command line is empty!\n");
		return 0;
	}
	int numberOfStudents = 0;

	struct students **	table = (students**)malloc(sizeof(students*));
	students**(*pointerToCreating)(students** table, int* numberOfStudents);
	pointerToCreating = createTable;
	table = pointerToCreating(table, &numberOfStudents);

	int choice;
	bool exitVariable = true;
	do{
		printf("1-to print table\n2-to search students for a given item\n3-to exit\n Choice: ");
		scanf("%d", &choice);
		fflush(stdin);
		switch (choice){
		case 1:{
				   for (int i = 0; i < numberOfStudents; i++){
					   printStudent(table, i);
				   }
				   break;
		}
		case 2:{
				   bool flag = false;
				   int j = 1;
				   char* str;
				   for (int i = 0; i < numberOfStudents; i++){
					   while (argv[j]){
						   int number = searchRightStringInCommandLine(table, argv[j]);
						   if (number == table[i]->unit){
							   flag = true;
							   printStudent(table, i);
						   }
						   j++;
					   }
					   j = 1;
				   }
				   if (flag == false){
					   printf("There no students suitable to arguments of command line\n");
				   }
				   break;
		}
		case 3:{
				   exitVariable = false;
				   break;
		}
		default:{
					printf("Please,enter your choice!\n");
		}
		}
	} while (exitVariable);

	return 0;
}