// Borrowed from here:
// https://github.com/colonyamerican/eslint-plugin-cah/issues/3

'use strict'

module.exports = function (context) {
  var MESSAGE = '"{{name}}" is not defined.'

  /**
   * Checks for and reports reassigned constants
   *
   * @param {Scope} scope - an escope Scope object
   * @returns {void}
   * @private
   */
  function isDeclared (scope, ref) {
    return scope.variables.some(function (variable) {
      if (variable.name !== ref.identifier.name) {
        return false
      }

      if (!variable.defs || !variable.defs.length) {
        return false
      }

      return true
    })
  }

  return {
    'Program:exit': function () {
      var scope = context.getScope()

      scope.implicit.left.forEach(function (ref) {
        if (ref.identifier.name !== 'Promise') {
          return
        }

        if (!isDeclared(scope, ref)) {
          context.report(ref.identifier, MESSAGE, { name: ref.identifier.name })
        }
      })
    }
  }
}