// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/events/ozone/evdev/touch_event_converter_evdev.h"

#include <errno.h>
#include <fcntl.h>
#include <linux/input.h>
#include <poll.h>
#include <stdio.h>
#include <unistd.h>

#include <cmath>
#include <limits>

#include "base/bind.h"
#include "base/callback.h"
#include "base/command_line.h"
#include "base/logging.h"
#include "base/memory/scoped_vector.h"
#include "base/message_loop/message_loop.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/trace_event/trace_event.h"
#include "ui/events/devices/device_data_manager.h"
#include "ui/events/devices/device_util_linux.h"
#include "ui/events/event.h"
#include "ui/events/event_constants.h"
#include "ui/events/event_switches.h"
#include "ui/events/event_utils.h"
#include "ui/events/ozone/evdev/device_event_dispatcher_evdev.h"
#include "ui/events/ozone/evdev/touch_evdev_types.h"
#include "ui/events/ozone/evdev/touch_noise/touch_noise_finder.h"

namespace {

const int kMaxTrackingId = 0xffff;  // TRKID_MAX in kernel.

struct TouchCalibration {
  int bezel_left;
  int bezel_right;
  int bezel_top;
  int bezel_bottom;
};

void GetTouchCalibration(TouchCalibration* cal) {
  std::vector<std::string> parts;
  if (Tokenize(base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
                   switches::kTouchCalibration),
               ",", &parts) >= 4) {
    if (!base::StringToInt(parts[0], &cal->bezel_left))
      LOG(ERROR) << "Incorrect left border calibration value passed.";
    if (!base::StringToInt(parts[1], &cal->bezel_right))
      LOG(ERROR) << "Incorrect right border calibration value passed.";
    if (!base::StringToInt(parts[2], &cal->bezel_top))
      LOG(ERROR) << "Incorrect top border calibration value passed.";
    if (!base::StringToInt(parts[3], &cal->bezel_bottom))
      LOG(ERROR) << "Incorrect bottom border calibration value passed.";
  }
}

int32_t AbsCodeToMtCode(int32_t code) {
  switch (code) {
    case ABS_X:
      return ABS_MT_POSITION_X;
    case ABS_Y:
      return ABS_MT_POSITION_Y;
    case ABS_PRESSURE:
      return ABS_MT_PRESSURE;
    case ABS_DISTANCE:
      return ABS_MT_DISTANCE;
    default:
      return -1;
  }
}

const int kTrackingIdForUnusedSlot = -1;

}  // namespace

namespace ui {

TouchEventConverterEvdev::TouchEventConverterEvdev(
    int fd,
    base::FilePath path,
    int id,
    InputDeviceType type,
    const EventDeviceInfo& devinfo,
    DeviceEventDispatcherEvdev* dispatcher)
    : EventConverterEvdev(fd,
                          path,
                          id,
                          type,
                          devinfo.name(),
                          devinfo.vendor_id(),
                          devinfo.product_id()),
      dispatcher_(dispatcher) {
  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
          switches::kExtraTouchNoiseFiltering)) {
    touch_noise_finder_.reset(new TouchNoiseFinder);
  }
}

TouchEventConverterEvdev::~TouchEventConverterEvdev() {
}

void TouchEventConverterEvdev::Initialize(const EventDeviceInfo& info) {
  has_mt_ = info.HasMultitouch();

  if (has_mt_) {
    pressure_min_ = info.GetAbsMinimum(ABS_MT_PRESSURE);
    pressure_max_ = info.GetAbsMaximum(ABS_MT_PRESSURE);
    x_min_tuxels_ = info.GetAbsMinimum(ABS_MT_POSITION_X);
    x_num_tuxels_ = info.GetAbsMaximum(ABS_MT_POSITION_X) - x_min_tuxels_ + 1;
    y_min_tuxels_ = info.GetAbsMinimum(ABS_MT_POSITION_Y);
    y_num_tuxels_ = info.GetAbsMaximum(ABS_MT_POSITION_Y) - y_min_tuxels_ + 1;
    touch_points_ =
        std::min<int>(info.GetAbsMaximum(ABS_MT_SLOT) + 1, kNumTouchEvdevSlots);
    current_slot_ = info.GetAbsValue(ABS_MT_SLOT);
  } else {
    pressure_min_ = info.GetAbsMinimum(ABS_PRESSURE);
    pressure_max_ = info.GetAbsMaximum(ABS_PRESSURE);
    x_min_tuxels_ = info.GetAbsMinimum(ABS_X);
    x_num_tuxels_ = info.GetAbsMaximum(ABS_X) - x_min_tuxels_ + 1;
    y_min_tuxels_ = info.GetAbsMinimum(ABS_Y);
    y_num_tuxels_ = info.GetAbsMaximum(ABS_Y) - y_min_tuxels_ + 1;
    touch_points_ = 1;
    current_slot_ = 0;
  }

  quirk_left_mouse_button_ =
      !has_mt_ && !info.HasKeyEvent(BTN_TOUCH) && info.HasKeyEvent(BTN_LEFT);

  // Apply --touch-calibration.
  if (type() == INPUT_DEVICE_INTERNAL) {
    TouchCalibration cal = {};
    GetTouchCalibration(&cal);
    x_min_tuxels_ += cal.bezel_left;
    x_num_tuxels_ -= cal.bezel_left + cal.bezel_right;
    y_min_tuxels_ += cal.bezel_top;
    y_num_tuxels_ -= cal.bezel_top + cal.bezel_bottom;

    VLOG(1) << "applying touch calibration: "
            << base::StringPrintf("[%d, %d, %d, %d]", cal.bezel_left,
                                  cal.bezel_right, cal.bezel_top,
                                  cal.bezel_bottom);
  }

  events_.resize(touch_points_);

  if (has_mt_) {
    for (size_t i = 0; i < events_.size(); ++i) {
      events_[i].x = info.GetAbsMtSlotValueWithDefault(ABS_MT_POSITION_X, i, 0);
      events_[i].y = info.GetAbsMtSlotValueWithDefault(ABS_MT_POSITION_Y, i, 0);
      events_[i].tracking_id = info.GetAbsMtSlotValueWithDefault(
          ABS_MT_TRACKING_ID, i, kTrackingIdForUnusedSlot);
      events_[i].touching = (events_[i].tracking_id >= 0);
      events_[i].slot = i;

      // Dirty the slot so we'll update the consumer at the first opportunity.
      // We can't dispatch here as this is currently called on the worker pool.
      // TODO(spang): Move initialization off worker pool.
      events_[i].altered = true;

      // Optional bits.
      events_[i].radius_x =
          info.GetAbsMtSlotValueWithDefault(ABS_MT_TOUCH_MAJOR, i, 0) / 2.0f;
      events_[i].radius_y =
          info.GetAbsMtSlotValueWithDefault(ABS_MT_TOUCH_MINOR, i, 0) / 2.0f;
      events_[i].pressure = ScalePressure(
          info.GetAbsMtSlotValueWithDefault(ABS_MT_PRESSURE, i, 0));
    }
  } else {
    // TODO(spang): Add key state to EventDeviceInfo to allow initial contact.
    // (and make sure to take into account quirk_left_mouse_button_)
    events_[0].x = 0;
    events_[0].y = 0;
    events_[0].tracking_id = kTrackingIdForUnusedSlot;
    events_[0].touching = false;
    events_[0].slot = 0;
    events_[0].radius_x = 0;
    events_[0].radius_y = 0;
    events_[0].pressure = 0;
  }
}

void TouchEventConverterEvdev::Reinitialize() {
  EventDeviceInfo info;
  if (!info.Initialize(fd_)) {
    LOG(ERROR) << "Failed to synchronize state for touch device: "
               << path_.value();
    Stop();
    return;
  }

  Initialize(info);
}

bool TouchEventConverterEvdev::HasTouchscreen() const {
  return true;
}

gfx::Size TouchEventConverterEvdev::GetTouchscreenSize() const {
  return gfx::Size(x_num_tuxels_, y_num_tuxels_);
}

int TouchEventConverterEvdev::GetTouchPoints() const {
  return touch_points_;
}

void TouchEventConverterEvdev::OnEnabled() {
  ReportEvents(EventTimeForNow());
}

void TouchEventConverterEvdev::OnDisabled() {
  ReleaseTouches();
}

void TouchEventConverterEvdev::OnFileCanReadWithoutBlocking(int fd) {
  TRACE_EVENT1("evdev",
               "TouchEventConverterEvdev::OnFileCanReadWithoutBlocking", "fd",
               fd);

  input_event inputs[kNumTouchEvdevSlots * 6 + 1];
  ssize_t read_size = read(fd, inputs, sizeof(inputs));
  if (read_size < 0) {
    if (errno == EINTR || errno == EAGAIN)
      return;
    if (errno != ENODEV)
      PLOG(ERROR) << "error reading device " << path_.value();
    Stop();
    return;
  }

  if (!enabled_) {
    dropped_events_ = true;
    return;
  }

  for (unsigned i = 0; i < read_size / sizeof(*inputs); i++) {
    if (!has_mt_) {
      // Emulate the device as an MT device with only 1 slot by inserting extra
      // MT protocol events in the stream.
      EmulateMultitouchEvent(inputs[i]);
    }

    ProcessMultitouchEvent(inputs[i]);
  }
}

void TouchEventConverterEvdev::ProcessMultitouchEvent(
    const input_event& input) {
  if (input.type == EV_SYN) {
    ProcessSyn(input);
  } else if (dropped_events_) {
    // Do nothing. This branch indicates we have lost sync with the driver.
  } else if (input.type == EV_ABS) {
    if (events_.size() <= current_slot_) {
      LOG(ERROR) << "current_slot_ (" << current_slot_
                 << ") >= events_.size() (" << events_.size() << ")";
    } else {
      ProcessAbs(input);
    }
  } else if (input.type == EV_KEY) {
    ProcessKey(input);
  } else if (input.type == EV_MSC) {
    // Ignored.
  } else {
    NOTIMPLEMENTED() << "invalid type: " << input.type;
  }
}

void TouchEventConverterEvdev::EmulateMultitouchEvent(
    const input_event& event) {
  input_event emulated_event = event;

  if (event.type == EV_ABS) {
    emulated_event.code = AbsCodeToMtCode(event.code);
    if (emulated_event.code >= 0)
      ProcessMultitouchEvent(emulated_event);
  } else if (event.type == EV_KEY) {
    if (event.code == BTN_TOUCH ||
        (quirk_left_mouse_button_ && event.code == BTN_LEFT)) {
      emulated_event.type = EV_ABS;
      emulated_event.code = ABS_MT_TRACKING_ID;
      emulated_event.value =
          event.value ? NextTrackingId() : kTrackingIdForUnusedSlot;
      ProcessMultitouchEvent(emulated_event);
    }
  }
}

void TouchEventConverterEvdev::ProcessKey(const input_event& input) {
  switch (input.code) {
    case BTN_TOUCH:
    case BTN_LEFT:
      break;
    default:
      NOTIMPLEMENTED() << "invalid code for EV_KEY: " << input.code;
  }
}

void TouchEventConverterEvdev::ProcessAbs(const input_event& input) {
  switch (input.code) {
    case ABS_MT_TOUCH_MAJOR:
      // TODO(spang): If we have all of major, minor, and orientation,
      // we can scale the ellipse correctly. However on the Pixel we get
      // neither minor nor orientation, so this is all we can do.
      events_[current_slot_].radius_x = input.value / 2.0f;
      break;
    case ABS_MT_TOUCH_MINOR:
      events_[current_slot_].radius_y = input.value / 2.0f;
      break;
    case ABS_MT_POSITION_X:
      events_[current_slot_].x = input.value;
      break;
    case ABS_MT_POSITION_Y:
      events_[current_slot_].y = input.value;
      break;
    case ABS_MT_TRACKING_ID:
      UpdateTrackingId(current_slot_, input.value);
      break;
    case ABS_MT_PRESSURE:
      events_[current_slot_].pressure = ScalePressure(input.value);
      break;
    case ABS_MT_SLOT:
      if (input.value >= 0 &&
          static_cast<size_t>(input.value) < events_.size()) {
        current_slot_ = input.value;
      } else {
        LOG(ERROR) << "invalid touch event index: " << input.value;
        return;
      }
      break;
    default:
      DVLOG(5) << "unhandled code for EV_ABS: " << input.code;
      return;
  }
  events_[current_slot_].altered = true;
}

void TouchEventConverterEvdev::ProcessSyn(const input_event& input) {
  switch (input.code) {
    case SYN_REPORT:
      ReportEvents(EventConverterEvdev::TimeDeltaFromInputEvent(input));
      break;
    case SYN_DROPPED:
      // Some buffer has overrun. We ignore all events up to and
      // including the next SYN_REPORT.
      dropped_events_ = true;
      break;
    default:
      NOTIMPLEMENTED() << "invalid code for EV_SYN: " << input.code;
  }
}

EventType TouchEventConverterEvdev::GetEventTypeForTouch(
    const InProgressTouchEvdev& touch) {
  if (touch.cancelled)
    return ET_UNKNOWN;

  if (touch_noise_finder_ && touch_noise_finder_->SlotHasNoise(touch.slot)) {
    if (touch.touching && !touch.was_touching)
      return ET_UNKNOWN;
    return ET_TOUCH_CANCELLED;
  }

  if (touch.touching)
    return touch.was_touching ? ET_TOUCH_MOVED : ET_TOUCH_PRESSED;
  return touch.was_touching ? ET_TOUCH_RELEASED : ET_UNKNOWN;
}

void TouchEventConverterEvdev::ReportEvent(const InProgressTouchEvdev& event,
                                           EventType event_type,
                                           const base::TimeDelta& timestamp) {
  dispatcher_->DispatchTouchEvent(TouchEventParams(
      input_device_.id, event.slot, event_type, gfx::PointF(event.x, event.y),
      gfx::Vector2dF(event.radius_x, event.radius_y), event.pressure,
      timestamp));
}

void TouchEventConverterEvdev::ReportEvents(base::TimeDelta delta) {
  if (dropped_events_) {
    Reinitialize();
    dropped_events_ = false;
  }

  if (touch_noise_finder_)
    touch_noise_finder_->HandleTouches(events_, delta);

  for (size_t i = 0; i < events_.size(); i++) {
    InProgressTouchEvdev* event = &events_[i];
    if (!event->altered)
      continue;

    EventType event_type = GetEventTypeForTouch(*event);
    if (event_type == ET_UNKNOWN || event_type == ET_TOUCH_CANCELLED)
      event->cancelled = true;

    if (event_type != ET_UNKNOWN)
      ReportEvent(*event, event_type, delta);

    event->was_touching = event->touching;
    event->altered = false;
  }
}

void TouchEventConverterEvdev::UpdateTrackingId(int slot, int tracking_id) {
  InProgressTouchEvdev* event = &events_[slot];

  if (event->tracking_id == tracking_id)
    return;

  event->tracking_id = tracking_id;
  event->touching = (tracking_id >= 0);
  event->altered = true;

  if (tracking_id >= 0)
    event->cancelled = false;
}

void TouchEventConverterEvdev::ReleaseTouches() {
  for (size_t slot = 0; slot < events_.size(); slot++)
    UpdateTrackingId(slot, kTrackingIdForUnusedSlot);

  ReportEvents(EventTimeForNow());
}

float TouchEventConverterEvdev::ScalePressure(int32_t value) {
  float pressure = value - pressure_min_;
  if (pressure_max_ - pressure_min_)
    pressure /= pressure_max_ - pressure_min_;
  return pressure;
}

int TouchEventConverterEvdev::NextTrackingId() {
  return next_tracking_id_++ & kMaxTrackingId;
}

}  // namespace ui