// ============================================================================
// lib/framebuffer.cpp - Early kernel framebuffer console
//
// Renders text directly to the linear framebuffer using a minimal
// built-in 8x16 bitmap font (PC VGA style, ASCII 32-126).
// ============================================================================

#include <kernel/kprint.h>
#include <stdarg.h>

namespace kcon {

// ── Character cell dimensions ──────────────────────────────────────────────

static constexpr uint32_t CHAR_W    = 8;   // Font glyph width in pixels
static constexpr uint32_t CHAR_H    = 16;  // Font glyph height in pixels
static constexpr uint32_t TAB_WIDTH = 4;   // Tab stop width in character cells

// ── Colors (0x00RRGGBB) ────────────────────────────────────────────────────

static constexpr uint32_t FG_COLOR = CONFIG_FBCON_FG_COLOR;  // Light grey
static constexpr uint32_t BG_COLOR = CONFIG_FBCON_BG_COLOR;  // Dark blue

// ── Console state ──────────────────────────────────────────────────────────
//
// All mutable state lives in one struct so callers can reason about it as
// a unit and we avoid scattered bare globals.
#pragma message("when i add drivers abstract, move it to another console interface and use framebuffer as driver")

struct Console {
public:
    uint32_t* fb     = nullptr; // Framebuffer base (as 32-bit pixels)
    uint32_t  width  = 0;       // Pixels per row
    uint32_t  height = 0;       // Rows in pixels
    uint32_t  pitch  = 0;       // Bytes per scanline (>= width * 4)
    uint32_t  col    = 0;       // Cursor column in character cells
    uint32_t  row    = 0;       // Cursor row in character cells
    bool      is_bgr = false;

    // C++23 multi-dimensional subscript: direct reference to pixel (x, y).
    // pitch is in bytes; each pixel is 4 bytes.  No bounds checking — callers
    // must validate coordinates before calling (put_pixel does this).
    [[nodiscard]] uint32_t& operator[](uint32_t x, uint32_t y) noexcept {
        auto* row_ptr = reinterpret_cast<uint32_t*>(
            reinterpret_cast<uintptr_t>(fb) + static_cast<uintptr_t>(y) * pitch);
        return row_ptr[x];
    }
};

static Console g_con{};

// ── Minimal 8x16 bitmap font (ASCII 32–126) ───────────────────────────────
// Each character is 16 bytes (one byte per row, 8 pixels wide).
// We store a blank (space) for anything outside the range.

// clang-format off
static const uint8_t g_font[][16] = {
    // 32: space
    {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
    // 33: !
    {0x00,0x00,0x18,0x3C,0x3C,0x3C,0x18,0x18,0x18,0x00,0x18,0x18,0x00,0x00,0x00,0x00},
    // 34: "
    {0x00,0x66,0x66,0x66,0x24,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
    // 35: #
    {0x00,0x00,0x00,0x6C,0x6C,0xFE,0x6C,0x6C,0xFE,0x6C,0x6C,0x00,0x00,0x00,0x00,0x00},
    // 36: $
    {0x00,0x10,0x10,0x7C,0xD6,0xD0,0x7C,0x16,0xD6,0x7C,0x10,0x10,0x00,0x00,0x00,0x00},
    // 37: %
    {0x00,0x00,0x00,0x00,0xC2,0xC6,0x0C,0x18,0x30,0x60,0xC6,0x86,0x00,0x00,0x00,0x00},
    // 38: &
    {0x00,0x00,0x38,0x6C,0x6C,0x38,0x76,0xDC,0xCC,0xCC,0xCC,0x76,0x00,0x00,0x00,0x00},
    // 39: '
    {0x00,0x30,0x30,0x30,0x60,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
    // 40: (
    {0x00,0x00,0x0C,0x18,0x30,0x30,0x30,0x30,0x30,0x30,0x18,0x0C,0x00,0x00,0x00,0x00},
    // 41: )
    {0x00,0x00,0x30,0x18,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x18,0x30,0x00,0x00,0x00,0x00},
    // 42: *
    {0x00,0x00,0x00,0x00,0x00,0x66,0x3C,0xFF,0x3C,0x66,0x00,0x00,0x00,0x00,0x00,0x00},
    // 43: +
    {0x00,0x00,0x00,0x00,0x00,0x18,0x18,0x7E,0x18,0x18,0x00,0x00,0x00,0x00,0x00,0x00},
    // 44: ,
    {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x18,0x18,0x18,0x30,0x00,0x00,0x00},
    // 45: -
    {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xFE,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
    // 46: .
    {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x18,0x18,0x00,0x00,0x00,0x00},
    // 47: /
    {0x00,0x00,0x00,0x00,0x02,0x06,0x0C,0x18,0x30,0x60,0xC0,0x80,0x00,0x00,0x00,0x00},
    // 48-57: 0-9
    {0x00,0x00,0x7C,0xC6,0xC6,0xCE,0xDE,0xF6,0xE6,0xC6,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x18,0x38,0x78,0x18,0x18,0x18,0x18,0x18,0x18,0x7E,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x7C,0xC6,0x06,0x0C,0x18,0x30,0x60,0xC0,0xC6,0xFE,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x7C,0xC6,0x06,0x06,0x3C,0x06,0x06,0x06,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x0C,0x1C,0x3C,0x6C,0xCC,0xFE,0x0C,0x0C,0x0C,0x1E,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xFE,0xC0,0xC0,0xC0,0xFC,0x06,0x06,0x06,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x38,0x60,0xC0,0xC0,0xFC,0xC6,0xC6,0xC6,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xFE,0xC6,0x06,0x06,0x0C,0x18,0x30,0x30,0x30,0x30,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x7C,0xC6,0xC6,0xC6,0x7C,0xC6,0xC6,0xC6,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x7C,0xC6,0xC6,0xC6,0x7E,0x06,0x06,0x06,0x0C,0x78,0x00,0x00,0x00,0x00},
    // 58: :
    {0x00,0x00,0x00,0x00,0x18,0x18,0x00,0x00,0x00,0x18,0x18,0x00,0x00,0x00,0x00,0x00},
    // 59: ;
    {0x00,0x00,0x00,0x00,0x18,0x18,0x00,0x00,0x00,0x18,0x18,0x30,0x00,0x00,0x00,0x00},
    // 60: <
    {0x00,0x00,0x00,0x06,0x0C,0x18,0x30,0x60,0x30,0x18,0x0C,0x06,0x00,0x00,0x00,0x00},
    // 61: =
    {0x00,0x00,0x00,0x00,0x00,0x7E,0x00,0x00,0x7E,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
    // 62: >
    {0x00,0x00,0x00,0x60,0x30,0x18,0x0C,0x06,0x0C,0x18,0x30,0x60,0x00,0x00,0x00,0x00},
    // 63: ?
    {0x00,0x00,0x7C,0xC6,0xC6,0x0C,0x18,0x18,0x18,0x00,0x18,0x18,0x00,0x00,0x00,0x00},
    // 64: @
    {0x00,0x00,0x7C,0xC6,0xC6,0xDE,0xDE,0xDE,0xDC,0xC0,0xC0,0x7C,0x00,0x00,0x00,0x00},
    // 65-90: A-Z
    {0x00,0x00,0x10,0x38,0x6C,0xC6,0xC6,0xFE,0xC6,0xC6,0xC6,0xC6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xFC,0x66,0x66,0x66,0x7C,0x66,0x66,0x66,0x66,0xFC,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x3C,0x66,0xC2,0xC0,0xC0,0xC0,0xC0,0xC2,0x66,0x3C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xF8,0x6C,0x66,0x66,0x66,0x66,0x66,0x66,0x6C,0xF8,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xFE,0x66,0x62,0x68,0x78,0x68,0x60,0x62,0x66,0xFE,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xFE,0x66,0x62,0x68,0x78,0x68,0x60,0x60,0x60,0xF0,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x3C,0x66,0xC2,0xC0,0xC0,0xDE,0xC6,0xC6,0x66,0x3A,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xC6,0xC6,0xC6,0xC6,0xFE,0xC6,0xC6,0xC6,0xC6,0xC6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x3C,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x3C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x1E,0x0C,0x0C,0x0C,0x0C,0x0C,0xCC,0xCC,0xCC,0x78,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xE6,0x66,0x66,0x6C,0x78,0x78,0x6C,0x66,0x66,0xE6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xF0,0x60,0x60,0x60,0x60,0x60,0x60,0x62,0x66,0xFE,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xC6,0xEE,0xFE,0xFE,0xD6,0xC6,0xC6,0xC6,0xC6,0xC6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xC6,0xE6,0xF6,0xFE,0xDE,0xCE,0xC6,0xC6,0xC6,0xC6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x7C,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xFC,0x66,0x66,0x66,0x7C,0x60,0x60,0x60,0x60,0xF0,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x7C,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0xD6,0xDE,0x7C,0x0C,0x0E,0x00,0x00},
    {0x00,0x00,0xFC,0x66,0x66,0x66,0x7C,0x6C,0x66,0x66,0x66,0xE6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x7C,0xC6,0xC6,0x60,0x38,0x0C,0x06,0xC6,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xFF,0xDB,0x99,0x18,0x18,0x18,0x18,0x18,0x18,0x3C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0x6C,0x38,0x10,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xC6,0xC6,0xC6,0xC6,0xD6,0xD6,0xD6,0xFE,0xEE,0x6C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xC6,0xC6,0x6C,0x7C,0x38,0x38,0x7C,0x6C,0xC6,0xC6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xCC,0xCC,0xCC,0xCC,0x78,0x30,0x30,0x30,0x30,0x78,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xFE,0xC6,0x86,0x0C,0x18,0x30,0x60,0xC2,0xC6,0xFE,0x00,0x00,0x00,0x00},
    // 91: [
    {0x00,0x00,0x3C,0x30,0x30,0x30,0x30,0x30,0x30,0x30,0x30,0x3C,0x00,0x00,0x00,0x00},
    // 92: backslash
    {0x00,0x00,0x00,0x80,0xC0,0x60,0x30,0x18,0x0C,0x06,0x02,0x00,0x00,0x00,0x00,0x00},
    // 93: ]
    {0x00,0x00,0x3C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x0C,0x3C,0x00,0x00,0x00,0x00},
    // 94: ^
    {0x10,0x38,0x6C,0xC6,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
    // 95: _
    {0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xFF,0x00,0x00,0x00},
    // 96: `
    {0x00,0x30,0x18,0x0C,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
    // 97-122: a-z
    {0x00,0x00,0x00,0x00,0x00,0x78,0x0C,0x7C,0xCC,0xCC,0xCC,0x76,0x00,0x00,0x00,0x00},
    {0x00,0x00,0xE0,0x60,0x60,0x78,0x6C,0x66,0x66,0x66,0x66,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0x7C,0xC6,0xC0,0xC0,0xC0,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x1C,0x0C,0x0C,0x3C,0x6C,0xCC,0xCC,0xCC,0xCC,0x76,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0x7C,0xC6,0xFE,0xC0,0xC0,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x38,0x6C,0x64,0x60,0xF0,0x60,0x60,0x60,0x60,0xF0,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0x76,0xCC,0xCC,0xCC,0xCC,0xCC,0x7C,0x0C,0xCC,0x78,0x00},
    {0x00,0x00,0xE0,0x60,0x60,0x6C,0x76,0x66,0x66,0x66,0x66,0xE6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x18,0x18,0x00,0x38,0x18,0x18,0x18,0x18,0x18,0x3C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x06,0x06,0x00,0x0E,0x06,0x06,0x06,0x06,0x06,0x06,0x66,0x66,0x3C,0x00},
    {0x00,0x00,0xE0,0x60,0x60,0x66,0x6C,0x78,0x78,0x6C,0x66,0xE6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x38,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x18,0x3C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0xEC,0xFE,0xD6,0xD6,0xD6,0xD6,0xC6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0xDC,0x66,0x66,0x66,0x66,0x66,0x66,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0x7C,0xC6,0xC6,0xC6,0xC6,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0xDC,0x66,0x66,0x66,0x66,0x66,0x7C,0x60,0x60,0xF0,0x00},
    {0x00,0x00,0x00,0x00,0x00,0x76,0xCC,0xCC,0xCC,0xCC,0xCC,0x7C,0x0C,0x0C,0x1E,0x00},
    {0x00,0x00,0x00,0x00,0x00,0xDC,0x76,0x66,0x60,0x60,0x60,0xF0,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0x7C,0xC6,0x60,0x38,0x0C,0xC6,0x7C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x10,0x30,0x30,0xFC,0x30,0x30,0x30,0x30,0x36,0x1C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0xCC,0xCC,0xCC,0xCC,0xCC,0xCC,0x76,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0xC6,0xC6,0xC6,0xC6,0xC6,0x6C,0x38,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0xC6,0xC6,0xD6,0xD6,0xD6,0xFE,0x6C,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0xC6,0x6C,0x38,0x38,0x38,0x6C,0xC6,0x00,0x00,0x00,0x00},
    {0x00,0x00,0x00,0x00,0x00,0xC6,0xC6,0xC6,0xC6,0xC6,0xC6,0x7E,0x06,0x0C,0xF8,0x00},
    {0x00,0x00,0x00,0x00,0x00,0xFE,0xCC,0x18,0x30,0x60,0xC6,0xFE,0x00,0x00,0x00,0x00},
    // 123: {
    {0x00,0x00,0x0E,0x18,0x18,0x18,0x70,0x18,0x18,0x18,0x18,0x0E,0x00,0x00,0x00,0x00},
    // 124: |
    {0x00,0x00,0x18,0x18,0x18,0x18,0x00,0x18,0x18,0x18,0x18,0x18,0x00,0x00,0x00,0x00},
    // 125: }
    {0x00,0x00,0x70,0x18,0x18,0x18,0x0E,0x18,0x18,0x18,0x18,0x70,0x00,0x00,0x00,0x00},
    // 126: ~
    {0x00,0x00,0x76,0xDC,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},
};
// clang-format on

static constexpr int FONT_FIRST = 32;
static constexpr int FONT_LAST  = 126;

// ── Pixel helpers ──────────────────────────────────────────────────────────

static void put_pixel(uint32_t x, uint32_t y, uint32_t rgb) noexcept {
    if (x >= g_con.width || y >= g_con.height) return;

    // Swap R and B channels if the framebuffer uses BGR layout.
    const uint32_t color = g_con.is_bgr
        ? ((rgb & 0xFFu) << 16) | (rgb & 0xFF00u) | ((rgb >> 16) & 0xFFu)
        : rgb;

    g_con[x, y] = color;  // C++23 multi-dimensional subscript
}

// ── Scroll the screen up by one character row ──────────────────────────────

static void scroll() noexcept {
    const uint32_t shift     = CHAR_H * g_con.pitch;
    const uint32_t total     = g_con.height * g_con.pitch;
    auto* const fb_bytes     = reinterpret_cast<uint8_t*>(g_con.fb);

    // Shift everything up by CHAR_H rows (raw byte memmove equivalent).
    for (uint32_t i = 0; i < total - shift; ++i)
        fb_bytes[i] = fb_bytes[i + shift];

    // Fill the newly exposed bottom rows with the background color.
    for (uint32_t row = g_con.height - CHAR_H; row < g_con.height; ++row)
        for (uint32_t col = 0; col < g_con.width; ++col)
            put_pixel(col, row, BG_COLOR);
}

// ── Render a glyph at character-cell position (col, row) ──────────────────

static void render_char(uint32_t col, uint32_t row, char c) noexcept {
    // Treat char as unsigned to avoid negative indices for high-ASCII.
    int idx = static_cast<int>(static_cast<unsigned char>(c)) - FONT_FIRST;
    if (idx < 0 || idx > (FONT_LAST - FONT_FIRST)) idx = 0; // fall back to space

    const uint32_t px = col * CHAR_W;
    const uint32_t py = row * CHAR_H;

    for (uint32_t y = 0; y < CHAR_H; ++y) {
        const uint8_t bits = g_font[idx][y];
        for (uint32_t x = 0; x < CHAR_W; ++x) {
            const uint32_t color = (bits & (0x80u >> x)) ? FG_COLOR : BG_COLOR;
            put_pixel(px + x, py + y, color);
        }
    }
}

// ── Public API ─────────────────────────────────────────────────────────────

void init(const FramebufferInfo& fb) {
    g_con.fb     = reinterpret_cast<uint32_t*>(fb.base);
    g_con.width  = fb.width;
    g_con.height = fb.height;
    g_con.pitch  = fb.pitch;
    g_con.is_bgr = (fb.format == PixelFormat::BGR);
    g_con.col    = 0;
    g_con.row    = 0;
    clear();
}

void clear() {
    for (uint32_t y = 0; y < g_con.height; ++y)
        for (uint32_t x = 0; x < g_con.width; ++x)
            put_pixel(x, y, BG_COLOR);
    g_con.col = 0;
    g_con.row = 0;
}

void putchar(char c) {
    const uint32_t max_cols = g_con.width  / CHAR_W;
    const uint32_t max_rows = g_con.height / CHAR_H;

    if (c == '\n') {
        g_con.col = 0;
        ++g_con.row;
    } else if (c == '\r') {
        g_con.col = 0;
    } else if (c == '\t') {
        // Advance to the next TAB_WIDTH-aligned column.
        g_con.col = (g_con.col + TAB_WIDTH) & ~(TAB_WIDTH - 1u);
    } else {
        render_char(g_con.col, g_con.row, c);
        ++g_con.col;
    }

    if (g_con.col >= max_cols) {
        g_con.col = 0;
        ++g_con.row;
    }

    if (g_con.row >= max_rows) {
        scroll();
        g_con.row = max_rows - 1;
    }
}

void puts(const char* s) {
    if (!s) return;
    while (*s) putchar(*s++);
}

void println(const char* s) {
    puts(s);
    putchar('\n');
}

void put_hex(uint64_t val) {
    puts("0x");
    bool leading = true;
    for (int i = 60; i >= 0; i -= 4) {
        const uint8_t nibble = static_cast<uint8_t>((val >> i) & 0xFu);
        if (nibble == 0 && leading && i > 0) continue;
        leading = false;
        putchar(nibble < 10 ? '0' + nibble : 'A' + nibble - 10);
    }
    if (leading) putchar('0');
}

void put_dec(uint64_t val) {
    if (val == 0) { putchar('0'); return; }
    char buf[20];
    int len = 0;
    while (val > 0) {
        buf[len++] = static_cast<char>('0' + val % 10);
        val /= 10;
    }
    for (int j = len - 1; j >= 0; --j) putchar(buf[j]);
}

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

    while (*fmt) {
        if (*fmt != '%') {
            putchar(*fmt++);
            continue;
        }
        ++fmt; // skip '%'

        switch (*fmt) {
            case 's': {
                const char* s = va_arg(args, const char*);
                puts(s ? s : "(null)");
                break;
            }
            case 'd': {
                int64_t v = va_arg(args, int64_t);
                if (v < 0) { putchar('-'); v = -v; }
                put_dec(static_cast<uint64_t>(v));
                break;
            }
            case 'u': {
                put_dec(va_arg(args, uint64_t));
                break;
            }
            case 'x':
            case 'p': {
                put_hex(va_arg(args, uint64_t));
                break;
            }
            case '%':
                putchar('%');
                break;
            case '\0':
                goto done;
            default:
                putchar('%');
                putchar(*fmt);
                break;
        }
        ++fmt;
    }
done:
    va_end(args);
}

} // namespace kcon