//
// Implementation of default Pen/Tablet event driver.
//
// Copyright 2025 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
//

#include "src/drivers/Base/Fl_Base_Pen_Events.H"
#include <stdlib.h>


class Fl_Widget;


Fl_Pen_EventData fl_pen_event_data;
Fl_Pen_SubscriberList fl_pen_subscriber_list;
Fl_Pen_Subscriber *fl_pen_pushed = 0;
Fl_Pen_Subscriber *fl_pen_below = 0;


void fl_pen_event_data_init(Fl_Pen_EventData *d) {
  d->x = 0.0;
  d->y = 0.0;
  d->rx = 0.0;
  d->ry = 0.0;
  d->tilt_x = 0.0;
  d->tilt_y = 0.0;
  d->pressure = 1.0;
  d->proximity = 0.0;
  d->barrel_pressure = 0.0;
  d->twist = 0.0;
  d->pen_id = 0;
  d->state = (Fl_Pen_State)0;
  d->trigger = (Fl_Pen_State)0;
}


// ---- Fl_Pen_SubscriberList implementation ------------------------------------

Fl_Pen_SubscriberList::Fl_Pen_SubscriberList() {
  items_ = 0;
  widgets_ = 0;
  count_ = 0;
  alloc_ = 0;
}

Fl_Pen_SubscriberList::~Fl_Pen_SubscriberList() {
  int i;
  for (i = 0; i < count_; i++) {
    delete items_[i];
  }
  if (items_) free(items_);
  if (widgets_) free(widgets_);
}

/* Remove subscribers that have a 0 as a widget */
void Fl_Pen_SubscriberList::cleanup() {
  int i, j;
  for (i = 0, j = 0; i < count_; i++) {
    if (items_[i]->widget()) {
      if (i != j) {
        items_[j] = items_[i];
        widgets_[j] = widgets_[i];
      }
      j++;
    } else {
      delete items_[i];
    }
  }
  count_ = j;
}

Fl_Pen_Subscriber *Fl_Pen_SubscriberList::find(Fl_Widget *w) {
  int i;
  for (i = 0; i < count_; i++) {
    if (widgets_[i] == w) return items_[i];
  }
  return 0;
}

/* Add a new subscriber, or return an existing one. */
Fl_Pen_Subscriber *Fl_Pen_SubscriberList::add(Fl_Widget *w) {
  Fl_Pen_Subscriber *existing;
  cleanup();
  existing = find(w);
  if (existing) return existing;

  if (count_ >= alloc_) {
    int new_alloc = alloc_ ? alloc_ * 2 : 8;
    items_ = (Fl_Pen_Subscriber **)realloc(items_, new_alloc * sizeof(Fl_Pen_Subscriber *));
    widgets_ = (Fl_Widget **)realloc(widgets_, new_alloc * sizeof(Fl_Widget *));
    alloc_ = new_alloc;
  }
  Fl_Pen_Subscriber *sub = new Fl_Pen_Subscriber(w);
  items_[count_] = sub;
  widgets_[count_] = w;
  count_++;
  return sub;
}

/* Remove a subscriber from the list. */
void Fl_Pen_SubscriberList::remove(Fl_Widget *w) {
  int i;
  for (i = 0; i < count_; i++) {
    if (widgets_[i] == w) {
      items_[i]->clear();
      delete items_[i];
      count_--;
      if (i < count_) {
        items_[i] = items_[count_];
        widgets_[i] = widgets_[count_];
      }
      return;
    }
  }
}

// ---- Fl_Pen_Driver implementation --------------------------------------------
// Override the methods below to handle subscriptions and queries by user apps.

void Fl_Pen_Driver::subscribe(Fl_Widget* widget) {
  if (widget == 0) return;
  fl_pen_subscriber_list.add(widget);
}

void Fl_Pen_Driver::unsubscribe(Fl_Widget* widget) {
  if (widget == 0) return;
  fl_pen_subscriber_list.remove(widget);
}

void Fl_Pen_Driver::release() {
  fl_pen_pushed = 0;
  fl_pen_below = 0;
}

Fl_Pen_Trait Fl_Pen_Driver::traits() {
  return FL_PEN_TRAIT_NONE;
}

Fl_Pen_Trait Fl_Pen_Driver::pen_traits(int pen_id) {
  (void)pen_id;
  return FL_PEN_TRAIT_NONE;
}

// ---- Fl_Pen API --------------------------------------------------------------

void Fl_Pen_subscribe(Fl_Widget* widget) {
  fl_pen_driver->subscribe(widget);
}

void Fl_Pen_unsubscribe(Fl_Widget* widget) {
  fl_pen_driver->unsubscribe(widget);
}

void Fl_Pen_release(void) {
  fl_pen_driver->release();
}

Fl_Pen_Trait Fl_Pen_driver_traits(void) {
  return fl_pen_driver->traits();
}

Fl_Pen_Trait Fl_Pen_pen_traits(int pen_id) {
  return fl_pen_driver->pen_traits(pen_id);
}

double Fl_Pen_event_x(void) { return fl_pen_event_data.x; }

double Fl_Pen_event_y(void) { return fl_pen_event_data.y; }

double Fl_Pen_event_x_root(void) { return fl_pen_event_data.rx; }

double Fl_Pen_event_y_root(void) { return fl_pen_event_data.ry; }

int Fl_Pen_event_pen_id(void) { return fl_pen_event_data.pen_id; }

double Fl_Pen_event_pressure(void) { return fl_pen_event_data.pressure; }

double Fl_Pen_event_barrel_pressure(void) { return fl_pen_event_data.barrel_pressure; }

double Fl_Pen_event_tilt_x(void) { return fl_pen_event_data.tilt_x; }

double Fl_Pen_event_tilt_y(void) { return fl_pen_event_data.tilt_y; }

double Fl_Pen_event_twist(void) { return fl_pen_event_data.twist; }

double Fl_Pen_event_proximity(void) { return fl_pen_event_data.proximity; }

Fl_Pen_State Fl_Pen_event_state(void) { return fl_pen_event_data.state; }

Fl_Pen_State Fl_Pen_event_trigger(void) { return fl_pen_event_data.trigger; }