#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>
#include <stdarg.h>
#include "klog.h"
#include "kfont.h"
#include "fb.h"
#include "fb_text.h"
#include "stream.h"
#include "hos_printf.h"
#include "mem.h"

static struct {
    size_t console_width;
    size_t console_height;
    size_t x;
    size_t y;
    bool need_shift;
} klog;

static void shift_line(void)
{
    uint32_t * fb = fb_addr();
    uint32_t w = fb_width();
    size_t console_fb_line_words = w * kfont.line_height;
    for (size_t row = 0u; row < klog.console_height; row++)
    {
        memcpy32(fb, fb + console_fb_line_words, console_fb_line_words);
        fb += console_fb_line_words;
    }
    fb_fill(0, kfont.line_height * (klog.console_height - 1u), w, kfont.line_height, 0u, 0x2Cu, 0x55u);
}

static void klog_fb_write1(char c)
{
    if (klog.need_shift)
    {
        shift_line();
        klog.need_shift = false;
    }
    if (c == '\n')
    {
        if (klog.y == (klog.console_height - 1u))
        {
            klog.need_shift = true;
        }
        else
        {
            klog.y++;
        }
        klog.x = 0u;
    }
    else
    {
        int px = klog.x * kfont.advance;
        int py = klog.y * kfont.line_height;
        fb_text_render_char(c, px, py, 0xFFu, 0x80u, 0u);
        klog.x++;
        if (klog.x == klog.console_width)
        {
            if (klog.y == (klog.console_height - 1u))
            {
                klog.need_shift = true;
            }
            else
            {
                klog.y++;
            }
            klog.x = 0u;
        }
    }
}

static void klog_fb_write(const char * src, size_t length)
{
    for (size_t i = 0u; i < length; i++)
    {
        klog_fb_write1(src[i]);
    }
}

static const stream_t klog_fb_stream = {
    klog_fb_write,
    klog_fb_write1,
};

void klog_init(void)
{
    klog.console_width = fb_width() / kfont.advance;
    klog.console_height = fb_height() / kfont.line_height;
    klog.x = 0u;
    klog.y = 0u;
    klog.need_shift = false;
    fb_fill(0, 0, fb_width(), fb_height(), 0u, 0x2Cu, 0x55u);
}

void klog_printf(const char * fmt, ...)
{
    va_list va;
    va_start(va, fmt);
    hos_vprintf(&klog_fb_stream, fmt, va);
    va_end(va);
}