//
// Android screen interface for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2018 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file.  If this
// file is missing or damaged, see the license at:
//
//     https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
//     https://www.fltk.org/bugs.php
//


/**
 @cond AndroidDev
 \defgroup AndroidDeveloper Android Developer Documentation
 \{
 */


#include "../../config_lib.h"
#include "Fl_Android_Screen_Driver.H"
#include "Fl_Android_Application.H"
#include "Fl_Android_Graphics_Font.H"
#include <FL/Fl.H>
#include <FL/platform.H>
#include <FL/Fl_Graphics_Driver.H>
#include <FL/Fl_RGB_Image.H>
#include <FL/fl_ask.H>
#include <stdio.h>
#include <errno.h>
#include <math.h>


/**
 \class Fl_Android_Screen_Driver

 Handle Android screen devices.

 \todo This class is in an early development stage
 */


static void nothing() {}
void (*fl_unlock_function)() = nothing;
void (*fl_lock_function)() = nothing;

static void timer_do_callback(int timerIndex);


/**
 Creates a driver that manages all Android screen and display related calls.
 */
Fl_Screen_Driver *Fl_Screen_Driver::newScreenDriver()
{
  return new Fl_Android_Screen_Driver();
}


extern int fl_send_system_handlers(void *e);


/**
 Create the screen driver.
 */
Fl_Android_Screen_Driver::Fl_Android_Screen_Driver() :
  super(),
  pContentChanged(false),
  pClearDesktop(false)
{
}


/**
 Call the FLTK System handler with Android specific events.

 \return always 1, assuming the event was handled

 \see Fl_Android_Platform_Event
 */
int Fl_Android_Screen_Driver::handle_app_command()
{
  // get the command
  int8_t cmd = Fl_Android_Application::read_cmd();

  // setup the Android glue and prepare all settings for calling into FLTK
  Fl_Android_Application::pre_exec_cmd(cmd);

  // call all registered FLTK system handlers
  Fl::e_number = ((uint32_t)(cmd-Fl_Android_Application::APP_CMD_INPUT_CHANGED)) + FL_ANDROID_EVENT_INPUT_CHANGED;
  fl_send_system_handlers(nullptr);

  // fixup and finalize application wide command handling
  Fl_Android_Application::post_exec_cmd(cmd);
  return 1;
}


int Fl_Android_Screen_Driver::handle_input_event()
{
  AInputQueue *queue = Fl_Android_Application::input_event_queue();
  AInputEvent *event = nullptr;

  if (AInputQueue_getEvent(queue, &event) >= 0) {
    if (AInputQueue_preDispatchEvent(queue, event)==0) {
      int consumed = 0;
      switch (AInputEvent_getType(event)) {
        case  AINPUT_EVENT_TYPE_KEY:
          consumed = handle_keyboard_event(queue, event);
          break;
        case AINPUT_EVENT_TYPE_MOTION:
          consumed = handle_mouse_event(queue, event);
          break;
        default:
          // don't do anything. There may be additional event types in the future
          AInputQueue_finishEvent(queue, event, consumed);
          break;
      }
      // TODO: handle all events here
//      AInputQueue_finishEvent(queue, event, consumed);
    }
  }
  return 0;
}


int Fl_Android_Screen_Driver::handle_mouse_event(AInputQueue *queue, AInputEvent *event)
{
  int ex = Fl::e_x_root = (int)(AMotionEvent_getX(event, 0) * 600 /
                                 ANativeWindow_getWidth(Fl_Android_Application::native_window()));
  int ey = Fl::e_y_root = (int)(AMotionEvent_getY(event, 0) * 800 /
                                 ANativeWindow_getHeight(Fl_Android_Application::native_window()));

  // FIXME: find the window in which the event happened
  Fl_Window *win = Fl::grab();
  if (!win) {
    win = Fl::first_window();
    if (win && !win->modal()) {
      while (win) {
        if (ex >= win->x() && ex < win->x() + win->w() && ey >= win->y() &&
            ey < win->y() + win->h())
          break;
        win = Fl::next_window(win);
      }
    }
  }
  if (!win) {
    AInputQueue_finishEvent(queue, event, 0);
    return 0;
  }

  if (win) {
    Fl::e_x = ex-win->x();
    Fl::e_y = ey-win->y();
  } else {
    Fl::e_x = ex;
    Fl::e_y = ey;
  }

  Fl::e_state = FL_BUTTON1;
  Fl::e_keysym = FL_Button + 1;
  if (AMotionEvent_getAction(event) == AMOTION_EVENT_ACTION_DOWN) {
    AInputQueue_finishEvent(queue, event, 1);
    Fl::e_is_click = 1;
//    Fl_Android_Application::log_i("Mouse push %x %d at %d, %d", win, Fl::event_button(), Fl::event_x(), Fl::event_y());
    if (win) Fl::handle(FL_PUSH, win); // do NOT send a push event into the "Desktop"
  } else if (AMotionEvent_getAction(event) == AMOTION_EVENT_ACTION_MOVE) {
    AInputQueue_finishEvent(queue, event, 1);
//    Fl_Android_Application::log_i("Mouse drag %x %d at %d, %d", win, Fl::event_button(), Fl::event_x(), Fl::event_y());
    if (win) Fl::handle(FL_DRAG, win);
  } else if (AMotionEvent_getAction(event) == AMOTION_EVENT_ACTION_UP) {
    AInputQueue_finishEvent(queue, event, 1);
    Fl::e_state = 0;
//    Fl_Android_Application::log_i("Mouse release %x %d at %d, %d", win, Fl::event_button(), Fl::event_x(), Fl::event_y());
    if (win) Fl::handle(FL_RELEASE, win);
  } else {
    AInputQueue_finishEvent(queue, event, 0);
  }
  return 1;
}


/**
 Handle all events in the even queue.

 \todo what should this function return?

 \param time_to_wait
 \return we do not know
 */
int Fl_Android_Screen_Driver::handle_queued_events(double time_to_wait)
{
  int ret = 0;
  // Read all pending events.
  int ident;
  int events;
  int delay_millis = time_to_wait*1000;
  bool done = false;

  int delay = Fl::damage() ? 0 : delay_millis;
  while (!done) {
    ident = ALooper_pollOnce(delay, nullptr, &events, nullptr);
    switch (ident) {
      case Fl_Android_Application::LOOPER_ID_MAIN:
        ret = handle_app_command();
        break;
      case Fl_Android_Application::LOOPER_ID_INPUT:
        ret = handle_input_event();
        break;
      case Fl_Android_Application::LOOPER_ID_TIMER:
        timer_do_callback(Fl_Android_Application::receive_timer_index());
        break;
      case ALOOPER_POLL_WAKE:
        Fl_Android_Application::log_e("Someone woke up ALooper_pollOnce.");
        done = true;
        break;
      case ALOOPER_POLL_CALLBACK:
        Fl_Android_Application::log_e(
                "Someone added a callback to ALooper_pollOnce.");
        done = true;
        break;
      case ALOOPER_POLL_TIMEOUT:
        done = true; // timer expired, return to FLTK
        break;
      case ALOOPER_POLL_ERROR:
        Fl_Android_Application::log_e(
                "Something caused an ERROR in ALooper_pollOnce.");
        done = true; // return to the app to find the error
        break;
      default:
        Fl_Android_Application::log_e(
                "Unknown return value from ALooper_pollOnce.");
        done = true; // return to the app, just in case
        break;
    }
    // we need to repeat this as long as there are messages in the queue, or any
    // change in the graphical interface will trigger a redraw immediately. To
    // save time and energy, we want to collect graphics changes and execute
    // them as soon as no more events are pending.
    // Setting delay to zero on the second round makes sure that all events
    // are handled first, and the call returns only when no more
    // events are pending.
    delay = 0;
  }
  return ret;
}


/**
 Wait for a maximum of `time_to_wait` until something happens.

 \param time_to_wait in seconds
 \return We really do not know; check other platforms to see what is
        consistent here.

 \todo return the remaining time to reach 'time_to_wait'
 */
double Fl_Android_Screen_Driver::wait(double time_to_wait)
{
  Fl::run_checks();
  static int in_idle = 0;
  if (Fl::idle) {
    if (!in_idle) {
      in_idle = 1;
      Fl::idle();
      in_idle = 0;
    }
    // the idle function may turn off idle, we can then wait:
    if (Fl::idle) time_to_wait = 0.0;
  }

  if (time_to_wait==0.0) {
    // if there is no wait time, handle the event and show the results right away
    fl_unlock_function();
    handle_queued_events(time_to_wait);
    fl_lock_function();
    // FIXME: kludge to erase a window after it was hidden
    if (pClearDesktop && fl_graphics_driver) {
      ((Fl_Android_Graphics_Driver*)fl_graphics_driver)->make_current(nullptr);
      fl_rectf(0, 0, 600, 800, FL_BLACK);
      pClearDesktop = false;
      pContentChanged = true;
    }
    Fl::flush();
  } else {
    // if there is wait time, show the pending changes and then handle the events
    // FIXME: kludge to erase a window after it was hidden
    if (pClearDesktop && fl_graphics_driver) {
      ((Fl_Android_Graphics_Driver*)fl_graphics_driver)->make_current(nullptr);
      fl_rectf(0, 0, 600, 800, FL_BLACK);
      pClearDesktop = false;
      pContentChanged = true;
    }
    Fl::flush();
    if (Fl::idle && !in_idle) // 'idle' may have been set within flush()
      time_to_wait = 0.0;
    fl_unlock_function();
    handle_queued_events(time_to_wait);
    fl_lock_function();
  }

  return 0.0;
}


/**
 On Android, we currently write into a memory buffer and copy
 the content to the screen.

 \see fl_flush()
 */
void Fl_Android_Screen_Driver::flush()
{
  Fl_Screen_Driver::flush();
  // FIXME: do this only if anything actually changed on screen (need to optimize)!
  if (pContentChanged) {
    if (Fl_Android_Application::copy_screen())
      pContentChanged = false;
  }
}


// ---- timers -----------------------------------------------------------------


struct TimerData
{
  timer_t handle;
  struct sigevent sigevent;
  Fl_Timeout_Handler callback;
  void *data;
  bool used;
  bool triggered;
  struct itimerspec timeout;
};
static TimerData* timerData = nullptr;
static int NTimerData = 0;
static int nTimerData = 0;


static int allocate_more_timers()
{
  if (NTimerData == 0) {
    NTimerData = 8;
  }
  if (NTimerData>256) { // out of timers
    return -1;
  }
  NTimerData *= 2;
  timerData = (TimerData*)realloc(timerData, sizeof(TimerData) * NTimerData);
  return nTimerData;
}


static void timer_signal_handler(union sigval data)
{
  int timerIndex = data.sival_int;
  Fl_Android_Application::send_timer_index(timerIndex);
}


static void timer_do_callback(int timerIndex)
{
  TimerData& t = timerData[timerIndex];
  t.triggered = false;
  if (t.callback) {
    t.callback(t.data);
    // TODO: should we release the timer at this point?
  }
}


void Fl_Android_Screen_Driver::add_timeout(double time, Fl_Timeout_Handler cb, void *data)
{
  repeat_timeout(time, cb, data);
}


void Fl_Android_Screen_Driver::repeat_timeout(double time, Fl_Timeout_Handler cb, void *data)
{
  int ret = -1;
  int timerIndex = -1;

  // first, find the timer associated with this handler
  for (int i = 0; i < nTimerData; ++i) {
    TimerData& t = timerData[i];
    if ( (t.used) && (t.callback==cb) && (t.data==data) ) {
      timerIndex = i;
      break;
    }
  }

  // if we did not have a timer yet, find a free slot
  if (timerIndex==-1) {
    for (int i = 0; i < nTimerData; ++i) {
      if (!timerData[i].used)
        timerIndex = i;
      break;
    }
  }

  // if that didn't work, allocate more timers
  if (timerIndex==-1) {
    if (nTimerData==NTimerData)
      allocate_more_timers();
    timerIndex = nTimerData++;
  }

  // if that didn't work either, we ran out of timers
  if (timerIndex==-1) {
    Fl::error("FLTK ran out of timer slots.");
    return;
  }

  TimerData& t = timerData[timerIndex];
  if (!t.used) {
    t.data = data;
    t.callback = cb;
    memset(&t.sigevent, 0, sizeof(struct sigevent));
    t.sigevent.sigev_notify = SIGEV_THREAD;
    t.sigevent.sigev_notify_function = timer_signal_handler;
    t.sigevent.sigev_value.sival_int = timerIndex;
    ret = timer_create(CLOCK_MONOTONIC, &t.sigevent, &t.handle);
    if (ret==-1) {
      Fl_Android_Application::log_e("Can't create timer: %s", strerror(errno));
      return;
    }
    t.used = true;
  }

  double ff;
  t.timeout = {
          { 0, 0 },
          { (time_t)floor(time), (long)(modf(time, &ff)*1000000000) }
  };
  ret = timer_settime(t.handle, 0, &t.timeout, nullptr);
  if (ret==-1) {
    Fl_Android_Application::log_e("Can't launch timer: %s", strerror(errno));
    return;
  }
  t.triggered = true;
}


int Fl_Android_Screen_Driver::has_timeout(Fl_Timeout_Handler cb, void *data)
{
  for (int i = 0; i < nTimerData; ++i) {
    TimerData& t = timerData[i];
    if ( (t.used) && (t.callback==cb) && (t.data==data) ) {
      return 1;
    }
  }
  return 0;
}


void Fl_Android_Screen_Driver::remove_timeout(Fl_Timeout_Handler cb, void *data)
{
  for (int i = 0; i < nTimerData; ++i) {
    TimerData& t = timerData[i];
    if ( t.used && (t.callback==cb) && ( (t.data==data) || (data==nullptr) ) ) {
      if (t.used)
        timer_delete(t.handle);
      t.triggered = t.used = false;
    }
  }
}


/**
 Play some system sound.

 This function plays some rather arbitrary system sounds.

 \param type

 \see Fl_Screen_Driver::beep(int)
 \see fl_beep(int)
 */
void Fl_Android_Screen_Driver::beep(int type)
{
  int androidSoundID = 93;  // default to TONE_CDMA_ALERT_CALL_GUARD
  switch (type) {
    case FL_BEEP_DEFAULT:       androidSoundID = 92; break;
    case FL_BEEP_MESSAGE:       androidSoundID = 86; break;
    case FL_BEEP_ERROR:         androidSoundID = 87; break;
    case FL_BEEP_QUESTION:      androidSoundID = 91; break;
    case FL_BEEP_PASSWORD:      androidSoundID = 95; break;
    case FL_BEEP_NOTIFICATION:  androidSoundID = 93; break;
  }
  Fl_Android_Java java;
  if (java.is_attached()) {

    jclass class_tone_generator = java.env()->FindClass("android/media/ToneGenerator");

    jmethodID toneGeneratorConstructor = java.env()->GetMethodID(
            class_tone_generator, "<init>",
            "(II)V");

    jobject toneGeneratorObj = java.env()->NewObject(
            class_tone_generator, toneGeneratorConstructor,
            4,  // STREAM_ALARM
            100); // volume

    jmethodID method_start_tone = java.env()->GetMethodID(
            class_tone_generator,
            "startTone",
            "(II)Z");

    java.env()->CallBooleanMethod(
            toneGeneratorObj, method_start_tone,
            androidSoundID,
            1000);

    java.env()->DeleteLocalRef(class_tone_generator);
    java.env()->DeleteLocalRef(toneGeneratorObj);
  }

}


/**
 Get the current mouse coordinates.

 This is used, among other things, to position the FLTK standard dialogs in
 a way that makes it easy to click the most common button. For an Android
 touch screen, this makes no sense at all, which is why we return the center
 of the screen for now.

 \todo rethink the dialog positioning scheme for touch devices.

 \todo this method assumes a fixed screen resolution

 \param [out] x
 \param [out] y
 \return
 */
int Fl_Android_Screen_Driver::get_mouse(int &x, int &y)
{
  x = 600/2;
  y = 800/2;
  return 1;
}


void Fl_Android_Screen_Driver::grab(Fl_Window* win)
{
  if (win) {
    if (!Fl::grab_) {
      // TODO: will we need to fix any focus and/or direct the input stream to a window
    }
    Fl::grab_ = win;
  } else {
    if (Fl::grab_) {
      Fl::grab_ = 0;
    }
  }
}


/**
 \}
 \endcond
 */