// Copyright 2015 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#include "core/hle/service/service.h"
#include "core/hle/service/hid/hid.h"
#include "core/hle/service/hid/hid_spvr.h"
#include "core/hle/service/hid/hid_user.h"

#include "core/arm/arm_interface.h"
#include "core/hle/kernel/event.h"
#include "core/hle/kernel/shared_memory.h"
#include "core/hle/hle.h"

#include "video_core/video_core.h"

namespace Service {
namespace HID {

static const int MAX_CIRCLEPAD_POS = 0x9C; ///< Max value for a circle pad position

Kernel::SharedPtr<Kernel::SharedMemory> g_shared_mem = nullptr;

Kernel::SharedPtr<Kernel::Event> g_event_pad_or_touch_1;
Kernel::SharedPtr<Kernel::Event> g_event_pad_or_touch_2;
Kernel::SharedPtr<Kernel::Event> g_event_accelerometer;
Kernel::SharedPtr<Kernel::Event> g_event_gyroscope;
Kernel::SharedPtr<Kernel::Event> g_event_debug_pad;

static u32 next_pad_index = 0;
static u32 next_touch_index = 0;

/**
 * Gets a pointer to the PadData structure inside HID shared memory
 */
static inline SharedMem* GetSharedMem() {
    if (g_shared_mem == nullptr)
        return nullptr;
    return reinterpret_cast<SharedMem*>(g_shared_mem->GetPointer().ValueOr(nullptr));
}

// TODO(peachum):
// Add a method for setting analog input from joystick device for the circle Pad.
//
// This method should:
//     * Be called after both PadButton<Press, Release>().
//     * Be called before PadUpdateComplete()
//     * Set current PadEntry.circle_pad_<axis> using analog data
//     * Set PadData.raw_circle_pad_data
//     * Set PadData.current_state.circle_right = 1 if current PadEntry.circle_pad_x >= 41
//     * Set PadData.current_state.circle_up = 1 if current PadEntry.circle_pad_y >= 41
//     * Set PadData.current_state.circle_left = 1 if current PadEntry.circle_pad_x <= -41
//     * Set PadData.current_state.circle_right = 1 if current PadEntry.circle_pad_y <= -41

void HIDUpdate() {
    SharedMem* shared_mem = GetSharedMem();

    if (shared_mem == nullptr)
        return;

    const PadState& state = VideoCore::g_emu_window->GetPadState();

    shared_mem->pad.current_state.hex = state.hex;
    shared_mem->pad.index = next_pad_index;
    ++next_touch_index %= shared_mem->pad.entries.size();

    // Get the previous Pad state
    u32 last_entry_index = (shared_mem->pad.index - 1) % shared_mem->pad.entries.size();
    PadState old_state = shared_mem->pad.entries[last_entry_index].current_state;

    // Compute bitmask with 1s for bits different from the old state
    PadState changed = { { (state.hex ^ old_state.hex) } };

    // Get the current Pad entry
    PadDataEntry* pad_entry = &shared_mem->pad.entries[shared_mem->pad.index];

    // Update entry properties
    pad_entry->current_state.hex = state.hex;
    pad_entry->delta_additions.hex = changed.hex & state.hex;
    pad_entry->delta_removals.hex = changed.hex & old_state.hex;;

    // Set circle Pad
    pad_entry->circle_pad_x = state.circle_left  ? -MAX_CIRCLEPAD_POS :
                              state.circle_right ?  MAX_CIRCLEPAD_POS : 0x0;
    pad_entry->circle_pad_y = state.circle_down  ? -MAX_CIRCLEPAD_POS :
                              state.circle_up    ?  MAX_CIRCLEPAD_POS : 0x0;

    // If we just updated index 0, provide a new timestamp
    if (shared_mem->pad.index == 0) {
        shared_mem->pad.index_reset_ticks_previous = shared_mem->pad.index_reset_ticks;
        shared_mem->pad.index_reset_ticks = (s64)Core::g_app_core->GetTicks();
    }

    shared_mem->touch.index = next_touch_index;
    ++next_touch_index %= shared_mem->touch.entries.size();

    // Get the current touch entry
    TouchDataEntry* touch_entry = &shared_mem->touch.entries[shared_mem->touch.index];
    bool pressed = false;

    std::tie(touch_entry->x, touch_entry->y, pressed) = VideoCore::g_emu_window->GetTouchState();
    touch_entry->valid = pressed ? 1 : 0;

    // TODO(bunnei): We're not doing anything with offset 0xA8 + 0x18 of HID SharedMemory, which
    // supposedly is "Touch-screen entry, which contains the raw coordinate data prior to being
    // converted to pixel coordinates." (http://3dbrew.org/wiki/HID_Shared_Memory#Offset_0xA8).

    // If we just updated index 0, provide a new timestamp
    if (shared_mem->touch.index == 0) {
        shared_mem->touch.index_reset_ticks_previous = shared_mem->touch.index_reset_ticks;
        shared_mem->touch.index_reset_ticks = (s64)Core::g_app_core->GetTicks();
    }
    
    // Signal both handles when there's an update to Pad or touch
    g_event_pad_or_touch_1->Signal();
    g_event_pad_or_touch_2->Signal();
}

void GetIPCHandles(Service::Interface* self) {
    u32* cmd_buff = Kernel::GetCommandBuffer();

    cmd_buff[1] = 0; // No error
    // TODO(yuriks): Return error from SendSyncRequest is this fails (part of IPC marshalling)
    cmd_buff[3] = Kernel::g_handle_table.Create(Service::HID::g_shared_mem).MoveFrom();
    cmd_buff[4] = Kernel::g_handle_table.Create(Service::HID::g_event_pad_or_touch_1).MoveFrom();
    cmd_buff[5] = Kernel::g_handle_table.Create(Service::HID::g_event_pad_or_touch_2).MoveFrom();
    cmd_buff[6] = Kernel::g_handle_table.Create(Service::HID::g_event_accelerometer).MoveFrom();
    cmd_buff[7] = Kernel::g_handle_table.Create(Service::HID::g_event_gyroscope).MoveFrom();
    cmd_buff[8] = Kernel::g_handle_table.Create(Service::HID::g_event_debug_pad).MoveFrom();
}

void HIDInit() {
    using namespace Kernel;

    AddService(new HID_U_Interface);
    AddService(new HID_SPVR_Interface);

    g_shared_mem = SharedMemory::Create("HID:SharedMem");

    next_pad_index = 0;
    next_touch_index = 0;

    // Create event handles
    g_event_pad_or_touch_1 = Event::Create(RESETTYPE_ONESHOT, "HID:EventPadOrTouch1");
    g_event_pad_or_touch_2 = Event::Create(RESETTYPE_ONESHOT, "HID:EventPadOrTouch2");
    g_event_accelerometer  = Event::Create(RESETTYPE_ONESHOT, "HID:EventAccelerometer");
    g_event_gyroscope      = Event::Create(RESETTYPE_ONESHOT, "HID:EventGyroscope");
    g_event_debug_pad      = Event::Create(RESETTYPE_ONESHOT, "HID:EventDebugPad");
}

void HIDShutdown() {
}

} // namespace HID

} // namespace Service