/**
 * Copyright (c) 2026 Dominic Masters
 * 
 * This software is released under the MIT License.
 * https://opensource.org/licenses/MIT
 */

#include "entity/entitymanager.h"
#include "entity/entity.h"
#include "entity/component/display/entityposition.h"
#include "display/framebuffer/framebuffer.h"
#include "display/screen/screen.h"

void entityCameraInit(const entityid_t ent, const componentid_t comp) {
  entitycamera_t *cam = (entitycamera_t *)componentGetData(
    ent, comp, COMPONENT_TYPE_CAMERA
  );
  cam->nearClip = 0.1f;
  cam->farClip = 100.0f;
  cam->projType = ENTITY_CAMERA_PROJECTION_TYPE_PERSPECTIVE;
  cam->perspective.fov = glm_rad(45.0f);
}

void entityCameraGetProjection(
  const entityid_t ent,
  const componentid_t comp,
  mat4 out
) {
  entitycamera_t *cam = (entitycamera_t *)componentGetData(
    ent, comp, COMPONENT_TYPE_CAMERA
  );

  if(
    cam->projType == ENTITY_CAMERA_PROJECTION_TYPE_PERSPECTIVE ||
    cam->projType == ENTITY_CAMERA_PROJECTION_TYPE_PERSPECTIVE_FLIPPED
  ) {
    glm_mat4_identity(out);
    glm_perspective(
      cam->perspective.fov,
      SCREEN.aspect,
      cam->nearClip,
      cam->farClip,
      out
    );

    if(cam->projType == ENTITY_CAMERA_PROJECTION_TYPE_PERSPECTIVE_FLIPPED) {
      out[1][1] *= -1.0f;
    }
  } else if(cam->projType == ENTITY_CAMERA_PROJECTION_TYPE_ORTHOGRAPHIC) {
    glm_mat4_identity(out);
    glm_ortho(
      cam->orthographic.left,
      cam->orthographic.right,
      cam->orthographic.top,
      cam->orthographic.bottom,
      cam->nearClip,
      cam->farClip,
      out
    );
  }
}

entityid_t entityCameraGetCurrent(void) {
  entityid_t camEnts[ENTITY_COUNT_MAX];
  componentid_t camComps[ENTITY_COUNT_MAX];
  entityid_t count = componentGetEntitiesWithComponent(
    COMPONENT_TYPE_CAMERA, camEnts, camComps
  );
  if(count == 0) return ENTITY_COUNT_MAX;
  return camEnts[0];
}

void entityCameraGetForward(const entityid_t entityId, vec2 out) {
  componentid_t posComp = entityGetComponent(entityId, COMPONENT_TYPE_POSITION);
  entityposition_t *pos = entityPositionGet(entityId, posComp);
  // View matrix column layout: M[col][row],
  // forward = {-M[0][2], -M[1][2], -M[2][2]}
  float_t fx = -pos->worldTransform[0][2];
  float_t fz = -pos->worldTransform[2][2];
  float_t len = sqrtf(fx * fx + fz * fz);
  if(len > 1e-6f) { fx /= len; fz /= len; }
  out[0] = fx;
  out[1] = fz;
}

void entityCameraGetRight(const entityid_t entityId, vec2 out) {
  componentid_t posComp = entityGetComponent(entityId, COMPONENT_TYPE_POSITION);
  entityposition_t *pos = entityPositionGet(entityId, posComp);
  // View matrix column layout: right = {M[0][0], M[1][0], M[2][0]}
  float_t rx = pos->worldTransform[0][0];
  float_t rz = pos->worldTransform[2][0];
  float_t len = sqrtf(rx * rx + rz * rz);
  if(len > 1e-6f) { rx /= len; rz /= len; }
  out[0] = rx;
  out[1] = rz;
}