// C program for array implementation of stack
// adapted from https://www.geeksforgeeks.org/stack-data-structure-introduction-program/

#include <cs50.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_VALUES 10
#define MAX_LENGTH 25

// A structure to represent a stack
typedef struct
{
    int top;
    int capacity;
    char *array[MAX_VALUES];
} stack;

// Function prototypes
stack *create_stack(int capacity);
bool is_full(stack *stack);
int is_empty(stack *stack);
char *pop(stack *stack);
void push(stack *stack, char *item);

// Jack creates a stack
int main(void)
{
    stack *stack = create_stack(MAX_VALUES);
    if (stack == NULL)
    {
        printf("Could not create stack.\n");
    }

    push(stack, "Blue Shirt");
    push(stack, "Green Shirt");
    push(stack, "Red Shirt");
    push(stack, "White Shirt");

    // Add your own elements to the stack
    while (true)
    {
        char *item = get_string("Enter an item of clothing to add to the stack: ");

        // Exit loop if nothing entered
        if (strlen(item) == 0)
        {
            break;
        }

        push(stack, item);
    }

    char *popped = pop(stack);
    if (!popped)
    {
        printf("The stack is empty\n");
    }
    else
    {
        printf("%s popped from stack\n", popped);
    }

    return 0;
}

// Function to create a stack of MAX_VALUES capacity.
stack *create_stack(int capacity)
{
    // Check capacity
    if (capacity < 1 || capacity > MAX_VALUES)
    {
        return NULL;
    }

    stack *stack = malloc(sizeof(stack));
    if (stack == NULL)
    {
        return NULL;
    }

    stack->capacity = capacity;
    stack->top = -1;

    return stack;
}

// Stack is full when top is equal to the last index
bool is_full(stack *stack)
{
    return stack->top == stack->capacity - 1;
}

// Stack is empty when top is equal to -1
int is_empty(stack *stack)
{
    return stack->top == -1;
}

// Function to remove an item from stack.  It decreases top by 1
char *pop(stack *stack)
{
    // TODO
    return NULL;
}

// Function to add an item to stack.  It increases top by 1
void push(stack *stack, char *item)
{
    // TODO
}