// Copyright 2025 International Digital Economy Academy
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

///|
pub struct EventHandler {
  collision_events : Array[@collision.CollisionEvent]
  mut collision_callback : ((
    @dynamics.RigidBodySet,
    @collision.ColliderSet,
    @collision.CollisionEvent,
  ) -> Unit)?
  intersection_events : Array[@collision.IntersectionEvent]
  mut intersection_callback : ((
    @dynamics.RigidBodySet,
    @collision.ColliderSet,
    @collision.IntersectionEvent,
  ) -> Unit)?
  contact_force_events : Array[@collision.ContactForceEvent]
  mut contact_force_callback : ((
    @core.Real,
    @dynamics.RigidBodySet,
    @collision.ColliderSet,
    @collision.ContactForceEvent,
  ) -> Unit)?
}

///|
pub fn EventHandler::EventHandler() -> EventHandler {
  {
    collision_events: [],
    collision_callback: None,
    intersection_events: [],
    intersection_callback: None,
    contact_force_events: [],
    contact_force_callback: None,
  }
}

///|
pub fn EventHandler::on_collision_event(
  self : EventHandler,
  callback : (
    @dynamics.RigidBodySet,
    @collision.ColliderSet,
    @collision.CollisionEvent,
  ) -> Unit,
) -> EventHandler {
  self.collision_callback = Some(callback)
  self
}

///|
pub fn EventHandler::handle_collision_event(
  self : EventHandler,
  bodies : @dynamics.RigidBodySet,
  colliders : @collision.ColliderSet,
  event : @collision.CollisionEvent,
) -> Unit {
  if self.collision_callback is Some(callback) {
    callback(bodies, colliders, event)
  }
  self.collision_events.push(event)
}

///|
pub fn EventHandler::on_intersection_event(
  self : EventHandler,
  callback : (
    @dynamics.RigidBodySet,
    @collision.ColliderSet,
    @collision.IntersectionEvent,
  ) -> Unit,
) -> EventHandler {
  self.intersection_callback = Some(callback)
  self
}

///|
pub fn EventHandler::handle_intersection_event(
  self : EventHandler,
  bodies : @dynamics.RigidBodySet,
  colliders : @collision.ColliderSet,
  event : @collision.IntersectionEvent,
) -> Unit {
  if self.intersection_callback is Some(callback) {
    callback(bodies, colliders, event)
  }
  self.intersection_events.push(event)
}

///|
pub fn EventHandler::on_contact_force_event(
  self : EventHandler,
  callback : (
    @core.Real,
    @dynamics.RigidBodySet,
    @collision.ColliderSet,
    @collision.ContactForceEvent,
  ) -> Unit,
) -> EventHandler {
  self.contact_force_callback = Some(callback)
  self
}

///|
pub fn EventHandler::handle_contact_force_event(
  self : EventHandler,
  dt : @core.Real,
  bodies : @dynamics.RigidBodySet,
  colliders : @collision.ColliderSet,
  event : @collision.ContactForceEvent,
) -> Unit {
  if self.contact_force_callback is Some(callback) {
    callback(dt, bodies, colliders, event)
  }
  self.contact_force_events.push(event)
}

///|
pub fn EventHandler::push_collision_event(
  self : EventHandler,
  event : @collision.CollisionEvent,
) -> Unit {
  self.collision_events.push(event)
}

///|
pub fn EventHandler::push_intersection_event(
  self : EventHandler,
  event : @collision.IntersectionEvent,
) -> Unit {
  self.intersection_events.push(event)
}

///|
pub fn EventHandler::push_contact_force_event(
  self : EventHandler,
  event : @collision.ContactForceEvent,
) -> Unit {
  self.contact_force_events.push(event)
}

///|
pub fn EventHandler::take_collision_events(
  self : EventHandler,
) -> Array[@collision.CollisionEvent] {
  let result : Array[@collision.CollisionEvent] = []
  for i in 0.. Array[@collision.IntersectionEvent] {
  let result : Array[@collision.IntersectionEvent] = []
  for i in 0.. Array[@collision.ContactForceEvent] {
  let result : Array[@collision.ContactForceEvent] = []
  for i in 0.. ChannelEventCollector {
  { handler: EventHandler() }
}

///|
pub fn ChannelEventCollector::handle_collision_event(
  self : ChannelEventCollector,
  bodies : @dynamics.RigidBodySet,
  colliders : @collision.ColliderSet,
  event : @collision.CollisionEvent,
) -> Unit {
  self.handler.handle_collision_event(bodies, colliders, event)
}

///|
pub fn ChannelEventCollector::handle_intersection_event(
  self : ChannelEventCollector,
  bodies : @dynamics.RigidBodySet,
  colliders : @collision.ColliderSet,
  event : @collision.IntersectionEvent,
) -> Unit {
  self.handler.handle_intersection_event(bodies, colliders, event)
}

///|
pub fn ChannelEventCollector::handle_contact_force_event(
  self : ChannelEventCollector,
  dt : @core.Real,
  bodies : @dynamics.RigidBodySet,
  colliders : @collision.ColliderSet,
  event : @collision.ContactForceEvent,
) -> Unit {
  self.handler.handle_contact_force_event(dt, bodies, colliders, event)
}

///|
pub fn ChannelEventCollector::take_collision_events(
  self : ChannelEventCollector,
) -> Array[@collision.CollisionEvent] {
  self.handler.take_collision_events()
}

///|
pub fn ChannelEventCollector::take_intersection_events(
  self : ChannelEventCollector,
) -> Array[@collision.IntersectionEvent] {
  self.handler.take_intersection_events()
}

///|
pub fn ChannelEventCollector::take_contact_force_events(
  self : ChannelEventCollector,
) -> Array[@collision.ContactForceEvent] {
  self.handler.take_contact_force_events()
}