/*
 * Copyright (c) 2020, Liav A. <liavalb@hotmail.co.il>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <AK/Assertions.h>
#include <AK/String.h>
#include <Kernel/Arch/i386/CPU.h>
#include <Kernel/CommandLine.h>
#include <Kernel/Devices/VMWareBackdoor.h>
#include <Kernel/MousePacket.h>
#include <Kernel/IO.h>

namespace Kernel {

#define VMWARE_CMD_GETVERSION 0x0a

#define VMMOUSE_READ_ID 0x45414552
#define VMMOUSE_DISABLE 0x000000f5
#define VMMOUSE_REQUEST_RELATIVE 0x4c455252
#define VMMOUSE_REQUEST_ABSOLUTE 0x53424152

#define VMMOUSE_QEMU_VERSION 0x3442554a
#define VMMOUSE_LEFT_CLICK 0x20
#define VMMOUSE_RIGHT_CLICK 0x10
#define VMMOUSE_MIDDLE_CLICK 0x08

#define VMWARE_MAGIC 0x564D5868
#define VMWARE_PORT 0x5658
#define VMWARE_PORT_HIGHBANDWIDTH 0x5659

//#define VMWAREBACKDOOR_DEBUG

inline void vmware_out(VMWareCommand& command)
{
    command.magic = VMWARE_MAGIC;
    command.port = VMWARE_PORT;
    command.si = 0;
    command.di = 0;
    asm volatile("in %%dx, %0"
                 : "+a"(command.ax), "+b"(command.bx), "+c"(command.cx), "+d"(command.dx), "+S"(command.si), "+D"(command.di));
}

inline void vmware_high_bandwidth_send(VMWareCommand& command)
{

    command.magic = VMWARE_MAGIC;
    command.port = VMWARE_PORT_HIGHBANDWIDTH;

    asm volatile("cld; rep; outsb"
                 : "+a"(command.ax), "+b"(command.bx), "+c"(command.cx), "+d"(command.dx), "+S"(command.si), "+D"(command.di));
}

inline void vmware_high_bandwidth_get(VMWareCommand& command)
{
    command.magic = VMWARE_MAGIC;
    command.port = VMWARE_PORT_HIGHBANDWIDTH;
    asm volatile("cld; rep; insb"
                 : "+a"(command.ax), "+b"(command.bx), "+c"(command.cx), "+d"(command.dx), "+S"(command.si), "+D"(command.di));
}

static VMWareBackdoor* s_vmware_backdoor;

static bool detect_presence()
{
    VMWareCommand command;
    command.bx = ~VMWARE_MAGIC;
    command.command = VMWARE_CMD_GETVERSION;
    vmware_out(command);
    if (command.bx != VMWARE_MAGIC || command.ax == 0xFFFFFFFF)
        return false;
    return true;
}

VMWareBackdoor* VMWareBackdoor::initialize()
{
    ASSERT(s_vmware_backdoor == nullptr);
    if (!detect_presence())
        return nullptr;

    s_vmware_backdoor = new VMWareBackdoor;
    klog() << "VMWare backdoor opened.";
    return s_vmware_backdoor;
}

VMWareBackdoor* VMWareBackdoor::the()
{
    return s_vmware_backdoor;
}

VMWareBackdoor::VMWareBackdoor()
{
    if (kernel_command_line().lookup("vmmouse").value_or("on") == "on")
        enable_absolute_vmmouse();
}

bool VMWareBackdoor::detect_vmmouse()
{
    VMWareCommand command;
    command.bx = VMMOUSE_READ_ID;
    command.command = VMMOUSE_COMMAND;
    send(command);
    command.bx = 1;
    command.command = VMMOUSE_DATA;
    send(command);
    if (command.ax != VMMOUSE_QEMU_VERSION)
        return false;
    return true;
}
bool VMWareBackdoor::vmmouse_is_absolute() const
{
    return m_vmmouse_absolute;
}

void VMWareBackdoor::enable_absolute_vmmouse()
{
    InterruptDisabler disabler;
    if (!detect_vmmouse())
        return;
    klog() << "VMWareBackdoor: Enabling absolute mouse mode";

    VMWareCommand command;

    command.bx = 0;
    command.command = VMMOUSE_STATUS;
    send(command);
    if (command.ax == 0xFFFF0000) {
        klog() << "VMWareBackdoor: VMMOUSE_STATUS got bad status";
        return;
    }

    // Enable absolute vmmouse
    command.bx = VMMOUSE_REQUEST_ABSOLUTE;
    command.command = VMMOUSE_COMMAND;
    send(command);
    m_vmmouse_absolute = true;
}
void VMWareBackdoor::disable_absolute_vmmouse()
{
    InterruptDisabler disabler;
    VMWareCommand command;
    command.bx = VMMOUSE_REQUEST_RELATIVE;
    command.command = VMMOUSE_COMMAND;
    send(command);
    m_vmmouse_absolute = false;
}

void VMWareBackdoor::send_high_bandwidth(VMWareCommand& command)
{
    vmware_high_bandwidth_send(command);
#ifdef VMWAREBACKDOOR_DEBUG
    dbg() << "VMWareBackdoor Command High bandwidth Send Results: EAX " << String::format("%x", command.ax) << " EBX " << String::format("%x", command.bx) << " ECX " << String::format("%x", command.cx) << " EDX " << String::format("%x", command.dx);
#endif
}

void VMWareBackdoor::get_high_bandwidth(VMWareCommand& command)
{
    vmware_high_bandwidth_get(command);
#ifdef VMWAREBACKDOOR_DEBUG
    dbg() << "VMWareBackdoor Command High bandwidth Get Results: EAX " << String::format("%x", command.ax) << " EBX " << String::format("%x", command.bx) << " ECX " << String::format("%x", command.cx) << " EDX " << String::format("%x", command.dx);
#endif
}

void VMWareBackdoor::send(VMWareCommand& command)
{
    vmware_out(command);
#ifdef VMWAREBACKDOOR_DEBUG
    dbg() << "VMWareBackdoor Command Send Results: EAX " << String::format("%x", command.ax) << " EBX " << String::format("%x", command.bx) << " ECX " << String::format("%x", command.cx) << " EDX " << String::format("%x", command.dx);
#endif
}

Optional<MousePacket> VMWareBackdoor::receive_mouse_packet()
{
    VMWareCommand command;
    command.bx = 0;
    command.command = VMMOUSE_STATUS;
    send(command);
    if (command.ax == 0xFFFF0000) {
#ifdef PS2MOUSE_DEBUG
        klog() << "PS2MouseDevice: Resetting VMWare mouse";
#endif
        disable_absolute_vmmouse();
        enable_absolute_vmmouse();
        return {};
    }
    int words = command.ax & 0xFFFF;

    if (!words || words % 4)
        return {};
    command.size = 4;
    command.command = VMMOUSE_DATA;
    send(command);

    int buttons = (command.ax & 0xFFFF);
    int x = (command.bx);
    int y = (command.cx);
    int z = (command.dx);

#ifdef PS2MOUSE_DEBUG
    dbg() << "Absolute Mouse: Buttons " << String::format("%x", buttons);
    dbg() << "Mouse: X " << x << ", Y " << y << ", Z " << z;
#endif
    MousePacket packet;
    packet.x = x;
    packet.y = y;
    packet.z = z;
    if (buttons & VMMOUSE_LEFT_CLICK)
        packet.buttons |= MousePacket::LeftButton;
    if (buttons & VMMOUSE_RIGHT_CLICK)
        packet.buttons |= MousePacket::RightButton;
    if (buttons & VMMOUSE_MIDDLE_CLICK)
        packet.buttons |= MousePacket::MiddleButton;

    packet.is_relative = false;
    return packet;
}

}