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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <stdbool.h>

#define MAXLENGTH 11
#define MAXCOUNT 5  // Maximum number of names

typedef struct {
    char *name;       // Change name to a char pointer
    long int birthday;
    int count;
} NameEntry;
void flushInputBuffer();
bool isValidDate(long int date);
int getBirthdayInput();
int main() {
    int count = 0;
    NameEntry *names[MAXCOUNT];
    char nameInput[MAXLENGTH];
    char intro[] = "Names Entry and Sorting Program\nPlease input name (max: 5 entries, enter '0' to finish).\n";
    char nameInputPrompt[] = "  Name (First Last): ";
    char birthdayInputPrompt[] = "  Birthday (YYYYMMDD): ";
    char errorMessage[] = "Incorrect name or birthday format.\n";
    char sortedNamesTitle[] = "\nSorted Names:\n";
    int error = 0;
    int exitInput = 0;  // Variable to track '0' input
    long int birthdayInput;

    printf(intro);

    while (count < MAXCOUNT) {
        printf(nameInputPrompt);
        if (fgets(nameInput, sizeof(nameInput), stdin) != NULL) {
            // Manually remove the newline character if present
            size_t length = strlen(nameInput);	
			if (length > MAXLENGTH) {
            continue;
		}
			if (strcmp(nameInput, "0\n") == 0) {
                exitInput = 1;  // User entered '0', set the exit flag
                break; // Exit the loop
			} 
			if (length == 1 && nameInput[0] == '\n') {
            	printf("Empty string");
                return 0; 
			} 
			
			
			else if (strlen(nameInput) > 0 && strlen(nameInput) < MAXLENGTH ) {
                // Allocate memory for a new NameEntry struct
                names[count] = (NameEntry *)malloc(sizeof(NameEntry));
                if (names[count] == NULL) {
                    printf("Memory allocation failed\n");
                    exit(EXIT_FAILURE);
                }

                // Allocate memory for the name member (character array) and copy the input
                names[count]->name = (char *)malloc(MAXLENGTH);
                if (names[count]->name == NULL) {
                    printf("Memory allocation failed\n");
                    free(names[count]); // Free the previously allocated struct
                    exit(EXIT_FAILURE);
                }

                names[count]->count = count + 1;
                names[count]->birthday = 0; // Initialize birthday to zero

                strncpy(names[count]->name, nameInput, MAXLENGTH);
    		    long int birthdayInput = getBirthdayInput();
        		names[count]->birthday = birthdayInput;
                // Display the information in the specified order and format
                printf("[%-10s]  [%-10ld] Entry count: [%d] malloc-address: [%p] name-address: [%p]\n",
				names[count]->name, names[count]->birthday, names[count]->count, (void *)names[count], (void *)(names[count]->name));
                    
                count++;
            } else {
                printf("Name is too long or empty\n");
            }
        } else {
            printf("Input error\n");
            exit(EXIT_FAILURE);
        }
    }

    if (!error || exitInput) {
        // Bubble sort the names
        int i, j;
        for (i = 0; i < count - 1; i++) {
            for (j = i + 1; j < count; j++) {
                if (strcmp(names[i]->name, names[j]->name) > 0) {
                    // Swap the pointers to NameEntry structs
                    NameEntry *temp = names[i];
                    names[i] = names[j];
                    names[j] = temp;
                }
            }
        }

        printf(sortedNamesTitle);

        for (i = 0; i < count; i++) {
            // Display the information in the specified order and format
            printf("[Name: %-10s]  [Birthday: %ld]  [Entry count: %d]\n  [Name Address: %p]  [NameEntry Address: %p]\n",
			    names[i]->name, names[i]->birthday, i + 1, (void *)names[i], (void *)(names[i]->name));
            // Free the dynamically allocated name member
            free(names[i]->name);
            // Free the dynamically allocated NameEntry struct
            free(names[i]);
        }
    }

    return 0;
}

int getBirthdayInput() {
    long int birthday;
    char buffer[100]; // Buffer to read user input
    while (1) {
        printf("  Birthday (YYYYMMDD): ");
        if (fgets(buffer, sizeof(buffer), stdin) != NULL) {
            // Remove trailing newline character, if present
            if (buffer[strlen(buffer) - 1] == '\n') {
                buffer[strlen(buffer) - 1] = '\0';
            }

            // Check if the input is empty (only Enter key)
            if (strlen(buffer) == 0) {
                printf("Invalid birthday format\n");
                continue; // Prompt again
            }

            // Attempt to convert the input to a long integer
            if (sscanf(buffer, "%ld", &birthday) != 1) {
                printf("Invalid birthday format\n");
                continue;
            }

            if (birthday < 9) {
                printf("Invalid birthday format\n");
                continue;
            } else if (!isValidDate(birthday)) {
                printf("Invalid date\n");
                continue;
            } else {
                return birthday;
            }
        } else {
            printf("Input error\n");
            return 0; // Exit with an error code
        }

        // Clear the input buffer
        flushInputBuffer();
    }
}

void flushInputBuffer() {
    int c;
    while ((c = getchar()) != '\n' && c != EOF);
}
bool isValidDate(long int date) {
    int year = date / 10000;
    int month = (date / 100) % 100;
    int day = date % 100;
    if (year < 0000 || year > 9999) {
        return false; // Invalid year
    }
    if (month < 1 || month > 12) {
        return false; // Invalid month
    }
    int maxDays[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

    if (day < 1 || day > maxDays[month]) {
        return false; 
    }
    return true; 
}