#include "tinyprintf.h"

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

int tinyprintf(const char *format, ...)
{
    if (format == NULL || *format == '\0')
    {
        return 0;
    }

    va_list ap;
    va_start(ap, format);
    int res = 0;

    size_t i = 0;
    while (format[i])
    {
        if (format[i] != '%')
        {
            putchar(format[i]);
            res++;
        }
        else
        {
            dispatch(format[i + 1], ap, &res);
            format++;
        }
        format++;
    }
    va_end(ap);
    return res;
}

void dispatch(char c, va_list ap, int *res)
{
    switch (c)
    {
    case '%':
        putchar('%');
        (*res)++;
        break;
    case 'd':
        handle_d(va_arg(ap, int), res);
        break;
    case 'u':
        handle_u(va_arg(ap, unsigned int), res);
        break;
    case 'x':
        handle_x(va_arg(ap, unsigned int), res);
        break;
    case 'o':
        handle_o(va_arg(ap, unsigned int), res);
        break;
    case 'c':
        putchar(va_arg(ap, int));
        (*res)++;
        break;
    case 's':
        handle_s(va_arg(ap, char *), res);
        break;
    default:
        putchar('%');
        putchar(c);
        *res += 2;
        break;
    }
}

void handle_d(int val, int *res)
{
    if (val < 0)
    {
        putchar('-');
        (*res)++;
        val = -val;
    }

    if (val == 0)
    {
        putchar('0');
        (*res)++;
    }

    int t = val;
    int n = 0;
    while (t > 0)
    {
        t /= 10;
        n++;
    }

    char *s = malloc(n * sizeof(char));
    int m = n;
    if (s == NULL)
    {
        return;
    }
    n--;
    for (; n >= 0; n--)
    {
        s[n] = val % 10 + '0';
        val /= 10;
    }

    // actual printing
    for (int i = 0; i < m; i++)
    {
        putchar(s[i]);
        (*res)++;
    }
    free(s);
}

void handle_s(char *s, int *res)
{
    if (s == NULL)
    {
        char *text = "(null)";
        for (; *text; text++)
        {
            putchar(*text);
            (*res)++;
        }
        return;
    }
    for (; *s; s++)
    {
        putchar(*s);
        (*res)++;
    }
}

void handle_u(unsigned int val, int *res)
{
    if (val == 0)
    {
        putchar('0');
        (*res)++;
    }

    unsigned int t = val;
    int n = 0;
    while (t > 0)
    {
        t /= 10;
        n++;
    }

    char *s = malloc(n * sizeof(char));
    int m = n;
    if (s == NULL)
    {
        return;
    }
    n--;
    for (; n >= 0; n--)
    {
        s[n] = val % 10 + '0';
        val /= 10;
    }

    // actual printing
    for (int i = 0; i < m; i++)
    {
        putchar(s[i]);
        (*res)++;
    }
    free(s);
}

void handle_x(unsigned int val, int *res)
{
    if (val == 0)
    {
        putchar('0');
        (*res)++;
    }

    unsigned int t = val;
    int n = 0;
    while (t > 0)
    {
        t /= 16;
        n++;
    }

    char *s = malloc(n * sizeof(char));
    int m = n;
    if (s == NULL)
    {
        return;
    }
    n--;
    for (; n >= 0; n--)
    {
        s[n] = val % 16 + '0';
        if (s[n] > '9')
        {
            s[n] = (s[n] - '0') % 10 + 'a';
        }
        val /= 16;
    }

    // actual printing
    for (int i = 0; i < m; i++)
    {
        putchar(s[i]);
        (*res)++;
    }
    free(s);
}

void handle_o(unsigned int val, int *res)
{
    if (val == 0)
    {
        putchar('0');
        (*res)++;
    }

    unsigned int t = val;
    int n = 0;
    while (t > 0)
    {
        t /= 8;
        n++;
    }

    char *s = malloc(n * sizeof(char));
    int m = n;
    if (s == NULL)
    {
        return;
    }
    n--;
    for (; n >= 0; n--)
    {
        s[n] = val % 8 + '0';
        val /= 8;
    }

    // actual printing
    for (int i = 0; i < m; i++)
    {
        putchar(s[i]);
        (*res)++;
    }
    free(s);
}