/**
@module ember
*/
import { peekMeta } from '@ember/-internals/meta';
import { isPath } from './path_cache';
import { unwatchKey, watchKey } from './watch_key';
import { unwatchPath, watchPath } from './watch_path';
/**
  Starts watching a property on an object. Whenever the property changes,
  invokes `Ember.notifyPropertyChange`. This is the primitive used by observers
  and dependent keys; usually you will never call this method directly but instead
  use higher level methods like `addObserver()`.

  @private
  @method watch
  @for Ember
  @param obj
  @param {String} keyPath
  @param {Object} meta
*/
export function watch(obj, keyPath, meta) {
    if (isPath(keyPath)) {
        watchPath(obj, keyPath, meta);
    }
    else {
        watchKey(obj, keyPath, meta);
    }
}
export function isWatching(obj, key) {
    return watcherCount(obj, key) > 0;
}
export function watcherCount(obj, key) {
    let meta = peekMeta(obj);
    return (meta !== undefined && meta.peekWatching(key)) || 0;
}
/**
  Stops watching a property on an object. Usually you will never call this method directly but instead
  use higher level methods like `removeObserver()`.

  @private
  @method unwatch
  @for Ember
  @param obj
  @param {String} keyPath
  @param {Object} meta
*/
export function unwatch(obj, keyPath, meta) {
    if (isPath(keyPath)) {
        unwatchPath(obj, keyPath, meta);
    }
    else {
        unwatchKey(obj, keyPath, meta);
    }
}