/**
 * OKQuery!
 * Takes configuration and gives you something that can run a DB query
 * based on the configurations.
 */
function OKQuery(db, options) {
  if (!(this instanceof OKQuery)) return new OKQuery(db, options);
  options = options || {};
  if (!db)
    throw new Error('No DB provided to query.');
  if (!options.type)
    throw new Error('No resource type provided to query');
  var type = options.type;
  var id = options.id || '*';
  Object.defineProperty(this, 'type', {
    value: type,
    writable: false
  });
  this.get = createQuery(db, type, id);
}

function createQuery(db, type, id) {
  if (isDynamic(id)) {
    return queryDynamic(db, type);
  } else if (isSet(id)) {
    return queryAll(db, type);
  } else {
    return querySingle(db, type, id);
  }
}

function queryDynamic(db, type) {
  return function(options) {
    options = options || {};
    return db.get(type, options.id);
  }
}

function queryAll(db, type) {
  return function() {
    return db.getAll(type);
  }
}

function querySingle(db, type, id) {
  return function() {
    return db.get(type, id);
  }
}

function isDynamic(id) {
  return id && id.charAt(0) === ':';
}

function isSet(id) {
  return id && id === '*';
}

module.exports = OKQuery;