#include "simulation.h"

#include "consts.h"
#include "level.h"

void Simulation::tick(
  double dt,
  const Uint8* keystate)
{
  for (id_type id : active_)
  {
    Entity& entity = entities_.at(id);

    // Control
    if (entity.player &&
        !entity.moving)
    {
      if (keystate[SDL_SCANCODE_LEFT] &&
          entity.gridPos.x() > 0 &&
          level_.getTileset().canPlayerMoveTo(
            level_.at(entity.gridPos - vec2s { 1, 0 })))
      {
        entity.moving = true;
        entity.destPos = entity.gridPos - vec2s { 1, 0 };
      }
      else if (keystate[SDL_SCANCODE_UP] &&
          entity.gridPos.y() > 0 &&
          level_.getTileset().canPlayerMoveTo(
            level_.at(entity.gridPos - vec2s { 0, 1 })))
      {
        entity.moving = true;
        entity.destPos = entity.gridPos - vec2s { 0, 1 };
      } else if (keystate[SDL_SCANCODE_RIGHT] &&
          entity.gridPos.x() < (level_.getSize().w() - 1) &&
          level_.getTileset().canPlayerMoveTo(
            level_.at(entity.gridPos + vec2s { 1, 0 })))
      {
        entity.moving = true;
        entity.destPos = entity.gridPos + vec2s { 1, 0 };
      }
      else if (keystate[SDL_SCANCODE_DOWN] &&
          entity.gridPos.y() < (level_.getSize().h() - 1) &&
          level_.getTileset().canPlayerMoveTo(
            level_.at(entity.gridPos + vec2s { 0, 1 })))
      {
        entity.moving = true;
        entity.destPos = entity.gridPos + vec2s { 0, 1 };
      }

      if (entity.moving)
      {
        entity.movementTween = 0.0;
      }
    }




    // Collision




    // Movement
    if (entity.moving)
    {
      entity.movementTween += entity.speed * dt;

      if (entity.movementTween >= 1.0)
      {
        entity.moving = false;
        entity.gridPos = entity.destPos;
      }
    }

    if (entity.moving)
    {
      entity.pos.x() =
        TILE_SIZE.x() * entity.destPos.x() * entity.movementTween +
        TILE_SIZE.x() * entity.gridPos.x() * (1.0 - entity.movementTween);

      entity.pos.y() =
        TILE_SIZE.y() * entity.destPos.y() * entity.movementTween +
        TILE_SIZE.y() * entity.gridPos.y() * (1.0 - entity.movementTween);
    } else {
      entity.pos = TILE_SIZE * entity.gridPos;
    }
  }
}

Simulation::id_type Simulation::emplaceEntity()
{
  id_type nextId;

  if (!available_.empty())
  {
    nextId = available_.front();
    available_.pop_front();

    entities_.at(nextId) = Entity();
  } else {
    nextId = entities_.size();
    entities_.emplace_back();
  }

  active_.insert(nextId);

  return nextId;
}

void Simulation::deleteEntity(id_type id)
{
  available_.push_back(id);
  active_.erase(id);
}