#include <cassert>
#include "componentarray.hpp"

template <typename T>
void ComponentArray<T>::InsertData(Entity entity, T component) {
  assert(mEntityToIndexMap.find(entity) == mEntityToIndexMap.end() &&
         "Component added to same entity more than once.");

  // Put new entry at end and update the maps
  size_t newIndex = mSize;
  mEntityToIndexMap[entity] = newIndex;
  mIndexToEntityMap[newIndex] = entity;
  mComponentArray[newIndex] = component;
  ++mSize;
};
template <typename T> void ComponentArray<T>::RemoveData(Entity entity) {
  assert(mEntityToIndexMap.find(entity) != mEntityToIndexMap.end() &&
         "Removing non-existent component.");

  // Copy element at end into deleted element's place to maintain density
  size_t indexOfRemovedEntity = mEntityToIndexMap[entity];
  size_t indexOfLastElement = mSize - 1;
  mComponentArray[indexOfRemovedEntity] = mComponentArray[indexOfLastElement];

  // Update map to point to moved spot
  Entity entityOfLastElement = mIndexToEntityMap[indexOfLastElement];
  mEntityToIndexMap[entityOfLastElement] = indexOfRemovedEntity;
  mIndexToEntityMap[indexOfRemovedEntity] = entityOfLastElement;

  mEntityToIndexMap.erase(entity);
  mIndexToEntityMap.erase(indexOfLastElement);

  --mSize;
};
template <typename T> T &ComponentArray<T>::GetData(Entity entity) {
  assert(mEntityToIndexMap.find(entity) != mEntityToIndexMap.end() &&
         "Retrieving non-existent component.");

  // Return a reference to the entity's component
  return mComponentArray[mEntityToIndexMap[entity]];
};
template <typename T> void ComponentArray<T>::EntityDestroyed(Entity entity) {
  if (mEntityToIndexMap.find(entity) != mEntityToIndexMap.end()) {
    // Remove the entity's component if it existed
    RemoveData(entity);
  }
};