/**
 * Copyright (c) 2024 Dominic Masters
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#include "entitydirection.h"
#include "assert/assert.h"

void entityDirectionOffsetGet(
  const entitydirection_t dir,
  uint16_t *x,
  uint16_t *y
) {
  switch(dir) {
    case ENTITY_DIRECTION_SOUTH:
      *x = 0;
      *y = 1;
      break;
    case ENTITY_DIRECTION_NORTH:
      *x = 0;
      *y = -1;
      break;
    case ENTITY_DIRECTION_WEST:
      *x = -1;
      *y = 0;
      break;
    case ENTITY_DIRECTION_EAST:
      *x = 1;
      *y = 0;
      break;
    default:
      assertUnreachable("Invalid entity direction.");
  }
}

void entityDirectionOffsetAdd(
  const entitydirection_t dir,
  uint16_t *x,
  uint16_t *y
) {
  switch(dir) {
    case ENTITY_DIRECTION_SOUTH:
      *y += 1;
      break;
    case ENTITY_DIRECTION_NORTH:
      *y -= 1;
      break;
    case ENTITY_DIRECTION_WEST:
      *x -= 1;
      break;
    case ENTITY_DIRECTION_EAST:
      *x += 1;
      break;
    default:
      assertUnreachable("Invalid entity direction.");
  }
}

entitydirection_t entityDirectionLookAt(
  const uint16_t srcX, const uint16_t srcY,
  const uint16_t trgX, const uint16_t trgY
) {
  if(srcX < trgX) return ENTITY_DIRECTION_EAST;
  if(srcX > trgX) return ENTITY_DIRECTION_WEST;
  if(srcY < trgY) return ENTITY_DIRECTION_SOUTH;
  if(srcY > trgY) return ENTITY_DIRECTION_NORTH;
  return ENTITY_DIRECTION_SOUTH;
}