/*
  StarForth — Steady-State Virtual Machine Runtime

  Copyright (c) 2023–2025 Robert A. James
  All rights reserved.

  Licensed under the StarForth License, Version 1.0
*/

/* keyboard_words.c — raw scancode-ring diagnostic word (FABRIC.md item
 * 4.3.5). Kernel-only, amd64-only; no-op elsewhere. */

#include "include/keyboard_words.h"
#include "../../include/word_registry.h"

#if defined(__STARKERNEL__) && defined(ARCH_AMD64)
#include "starkernel/i8042.h"
#endif

#if defined(__STARKERNEL__) && defined(ARCH_RISCV64)
#include "starkernel/virtio_input.h"
#endif

/* KBD-SCAN ( -- c -1 | 0 ) */
static void kbw_scan(VM *vm)
{
#if defined(__STARKERNEL__) && defined(ARCH_AMD64)
    uint8_t sc;
    if (i8042_pop_scancode(&sc)) {
        vm_push(vm, (cell_t)sc);
        vm_push(vm, -1);
    } else {
        vm_push(vm, 0);
    }
#else
    vm_push(vm, 0);
#endif
}

/* KBD-DEBUG ( -- isr_count spurious_count ): cheap standing diagnostic,
 * not scaffolding -- confirms the interrupt path is alive (isr_count) and
 * flags the failure mode item 4.3.5 found (a real IRQ misreported as
 * spurious) without needing a live debugger. */
extern volatile uint32_t g_i8042_isr_count;
extern volatile uint32_t g_spurious_count;
static void kbw_debug(VM *vm)
{
#if defined(__STARKERNEL__) && defined(ARCH_AMD64)
    vm_push(vm, (cell_t)g_i8042_isr_count);
    vm_push(vm, (cell_t)g_spurious_count);
#else
    vm_push(vm, 0);
    vm_push(vm, 0);
#endif
}

/* VKBD-EVENT ( -- code value -1 | 0 ): item 4.3.5c, riscv64 virtio-input.
 * Pop one decoded EV_KEY event off the interrupt-fed ring buffer. Pushes
 * code and value and -1 (true) if one was available, or just 0 (false) if
 * the buffer was empty. Distinct word from KBD-SCAN rather than a shared
 * one: different device, different event shape (Linux-style code/value
 * pair vs. a raw XT scancode byte) -- convergence onto one interface is
 * item 4.3.5f's explicit job, not this one's. */
static void kbw_vevent(VM *vm)
{
#if defined(__STARKERNEL__) && defined(ARCH_RISCV64)
    uint16_t code;
    uint32_t value;
    if (virtio_input_pop_event(&code, &value)) {
        vm_push(vm, (cell_t)code);
        vm_push(vm, (cell_t)value);
        vm_push(vm, -1);
    } else {
        vm_push(vm, 0);
    }
#else
    vm_push(vm, 0);
#endif
}

/* VKBD-DEBUG ( -- isr_count ): standing diagnostic, same shape as
 * KBD-DEBUG -- confirms the virtio-input interrupt path is alive. */
extern volatile uint32_t g_virtio_input_isr_count;
static void kbw_vdebug(VM *vm)
{
#if defined(__STARKERNEL__) && defined(ARCH_RISCV64)
    vm_push(vm, (cell_t)g_virtio_input_isr_count);
#else
    vm_push(vm, 0);
#endif
}

void register_keyboard_words(VM *vm)
{
    register_word(vm, "KBD-SCAN", kbw_scan);
    register_word(vm, "KBD-DEBUG", kbw_debug);
    register_word(vm, "VKBD-EVENT", kbw_vevent);
    register_word(vm, "VKBD-DEBUG", kbw_vdebug);
}