#include "kio.h"
#include "string.h"

#include <limits.h>
#include <stdarg.h>                 /* va_*() */

static void fmt_d2a(char * buf, int val);
static void fmt_u2a(char * buf, unsigned int val);
static void fmt_ll2a(char * buf, long long val);
static void fmt_ull2a(char * buf, unsigned long long val);
static void fmt_x2a(char * buf, unsigned int val);
static void fmt_o2a(char * buf, unsigned int val);

extern "C" {

void kprintf(char * fmt, ...)
{
    va_list args;
    va_start(args, fmt);

    kvprintf(fmt, args);

    va_end(args);
}

void kvprintf(char * fmt, va_list args)
{
    char tmpbuf[25];
    for ( ; *fmt; fmt++)
    {
        if (*fmt == '%')
        {
            fmt++;
            if (*fmt)
            {
                switch (*fmt)
                {
                    case 'c':
                        kputc(va_arg(args, int));
                        break;
                    case 'd':
                        fmt_d2a(tmpbuf, va_arg(args, int));
                        kputs(tmpbuf);
                        break;
                    case 'l':
                        fmt_ll2a(tmpbuf, va_arg(args, long long));
                        kputs(tmpbuf);
                        break;
                    case 'L':
                        fmt_ull2a(tmpbuf, va_arg(args, unsigned long long));
                        kputs(tmpbuf);
                        break;
                    case 'o':
                        fmt_o2a(tmpbuf, va_arg(args, unsigned int));
                        kputs(tmpbuf);
                        break;
                    case 's':
                        kputs(va_arg(args, char *));
                        break;
                    case 'u':
                        fmt_u2a(tmpbuf, va_arg(args, unsigned int));
                        kputs(tmpbuf);
                        break;
                    case 'x':
                        fmt_x2a(tmpbuf, va_arg(args, unsigned int));
                        kputs(tmpbuf);
                        break;
                    case '%':
                        kputc('%');
                        break;
                }
            }
        }
        else
        {
            kputc(*fmt);
        }
    }
}

void kputc(char c)
{
}

void kputs(char * s)
{
    while (*s)
    {
        kputc(*s);
        s++;
    }
}

} /* extern "C" */

static void fmt_d2a(char * buf, int val)
{
    if (val == INT_MIN)
    {
        strcpy(buf, "-2147483648");
    }
    else
    {
        if (val < 0)
        {
            *buf++ = '-';
            val = -val;
        }
        fmt_u2a(buf, (unsigned int) val);
    }
}

static void fmt_u2a(char * buf, unsigned int val)
{
    bool printing = false;
    for (unsigned int div = 1000000000; div >= 1; div /= 10)
    {
        unsigned int n = val / div;
        if (n)
        {
            printing = true;
        }
        if (printing)
        {
            *buf++ = '0' + (val % div);
        }
        val -= n * div;
    }
}

static void fmt_ll2a(char * buf, long long val)
{
    if (val == LONG_LONG_MIN)
    {
        strcpy(buf, "-9223372036854775808");
    }
    else
    {
        if (val < 0)
        {
            *buf++ = '-';
            val = -val;
        }
        fmt_ull2a(buf, (unsigned long long) val);
    }
}

static void fmt_ull2a(char * buf, unsigned long long val)
{
    bool printing = false;
    for (unsigned long long div = 10000000000000000000ull; div >= 1; div /= 10)
    {
        unsigned long long n = val / div;
        if (n)
        {
            printing = true;
        }
        if (printing)
        {
            *buf++ = '0' + (val % div);
        }
        val -= n * div;
    }
}

static void fmt_x2a(char * buf, unsigned int val)
{
    bool printing = false;
    for (int s = 28; s >= 0; s -= 4)
    {
        unsigned int n = (val >> s) & 0xF;
        if (n)
        {
            printing = true;
        }
        if (printing)
        {
            *buf++ = "0123456789ABCDEF"[n];
        }
    }
}

static void fmt_o2a(char * buf, unsigned int val)
{
    bool printing = false;
    for (int s = 30; s >= 0; s -= 3)
    {
        unsigned int n = (val >> s) & 0x7;
        if (n)
        {
            printing = true;
        }
        if (printing)
        {
            *buf++ = "01234567"[n];
        }
    }
}