// Camera module for lance3d
var model_c = use('model')

// Private camera state
var _view_matrix = null
var _proj_matrix = null
var _eye = {x: 0, y: 0, z: 5}
var _target = {x: 0, y: 0, z: 0}
var _up = {x: 0, y: 1, z: 0}
var _fov = 60
var _near = 0.1
var _far = 1000
var _aspect = 4/3
var _projection_type = "perspective"

function set_aspect(aspect) {
  _aspect = aspect
}

function look_at(ex, ey, ez, tx, ty, tz, upx, upy, upz) {
  upx = upx != null ? upx : 0
  upy = upy != null ? upy : 1
  upz = upz != null ? upz : 0
  
  _eye = {x: ex, y: ey, z: ez}
  _target = {x: tx, y: ty, z: tz}
  _up = {x: upx, y: upy, z: upz}
  
  _view_matrix = model_c.compute_view_matrix(ex, ey, ez, tx, ty, tz, upx, upy, upz)
}

function perspective(fov_deg, near, far) {
  _fov = fov_deg || 60
  _near = near || 0.1
  _far = far || 1000
  _projection_type = "perspective"
  
  _proj_matrix = model_c.compute_perspective(_fov, _aspect, _near, _far)
}

function ortho(left, right, bottom, top, near, far) {
  near = near != null ? near : -1
  far = far != null ? far : 1
  _projection_type = "ortho"
  
  _proj_matrix = model_c.compute_ortho(left, right, bottom, top, near, far)
}

function get_view_matrix() {
  return _view_matrix || model_c.mat4_identity()
}

function get_proj_matrix() {
  return _proj_matrix || model_c.mat4_identity()
}

function get_eye() {
  return {x: _eye.x, y: _eye.y, z: _eye.z}
}

function get_target() {
  return {x: _target.x, y: _target.y, z: _target.z}
}

function get_state() {
  return {
    view_matrix: _view_matrix,
    proj_matrix: _proj_matrix,
    eye: _eye,
    target: _target,
    up: _up,
    fov: _fov,
    near: _near,
    far: _far,
    aspect: _aspect,
    projection_type: _projection_type
  }
}

return {
  set_aspect: set_aspect,
  look_at: look_at,
  perspective: perspective,
  ortho: ortho,
  get_view_matrix: get_view_matrix,
  get_proj_matrix: get_proj_matrix,
  get_eye: get_eye,
  get_target: get_target,
  get_state: get_state
}