#define MODULE "power"

#include "power/reboot.h"
#include "acpi/FADT.h"
#include "acpi/RSDT.h"
#include "assert.h"
#include "interrupts/IDT.h"
#include "interrupts/Interrupts.h"
#include "io/IO.h"
#include "log/Log.h"
#include "panic/hang.h"
#include "std/string.h"

static void try_acpi_reboot()
{
    kinfoln("Fetching pointer to RSDT/XSDT");
    ACPI::SDTHeader* rootSDT = ACPI::GetRSDTOrXSDT();
    if (!rootSDT)
    {
        kinfoln("The pointer to the RSDT/XSDT is null");
        return;
    }
    if (!ACPI::ValidateSDTHeader(rootSDT))
    {
        kinfoln("The RSDT/XSDT has an invalid header");
        return;
    }
    if (strncmp(rootSDT->Signature, "RSDT", 4) != 0 && strncmp(rootSDT->Signature, "XSDT", 4) != 0)
    {
        kinfoln("The RSDT/XSDT's signature is not RSDT or XSDT");
        return;
    }
    kinfoln("Searching for the FADT");
    ACPI::FADT* fadt = (ACPI::FADT*)ACPI::FindTable(rootSDT, "FACP");
    if (!fadt)
    {
        kinfoln("Unable to find the FADT");
        return;
    }
    if (fadt->header.Revision < 2)
    {
        kinfoln("ACPI revision is too low (%d), ACPI Reset is only implemented in ACPI 2.0+", fadt->header.Revision);
        return;
    }
    if (!(fadt->Flags & 1 << 10))
    {
        kinfoln("This system does not support ACPI Reset");
        return;
    }
    switch (fadt->ResetReg.AddressSpace)
    {
    case ACPI::SystemIO:
        kinfoln("Attempting ACPI Reset via SystemIO: sending byte %d to port %lx", fadt->ResetValue,
                fadt->ResetReg.Address);
        IO::outb(fadt->ResetReg.Address, fadt->ResetValue);
        break;
    case ACPI::GeneralPurposeIO:
        kinfoln("Attempting ACPI Reset via GeneralPurposeIO: sending byte %d to port %lx", fadt->ResetValue,
                fadt->ResetReg.Address);
        IO::outb(fadt->ResetReg.Address, fadt->ResetValue);
        break;
    default: kinfoln("This method of rebooting via ACPI is not yet implemented"); return;
    }
    kinfoln("Tried to reboot, but apparently did nothing");
}

static void try_kbd_reboot()
{
    Interrupts::disable();

    uint8_t temp;
    do {
        temp = IO::inb(0x64);
        if (temp & 0b1) IO::inb(0x60);
    } while (temp & 0b10);

    IO::outb(0x64, 0xFE);
}

static void try_idt_triple_fault()
{
    IDTR idtr;
    idtr.limit = 0x0000;
    idtr.offset = 0x0000;
    asm volatile("lidt %0" : : "m"(idtr));
    Interrupts::enable();
    asm volatile("int $0x80");
}

[[noreturn]] void reboot()
{
    kinfoln("Attempting reboot using ACPI");
    try_acpi_reboot();
    kinfoln("Attempting reboot using keyboard RESET pulsing");
    try_kbd_reboot();
    kinfoln("Attempting reboot by triple faulting");
    try_idt_triple_fault();
    kerrorln("Failed to reboot, halting machine");
    hang();
}