'use strict'
  
  function isFunction (funktion) {
    return funktion && {}.toString.call(funktion) === '[object Function]'
  }
  
  // Default to complaining loudly when things don't go according to plan.
  var logger = console.error.bind(console)
  
  // Keep initialization idempotent.
  function shimmer (options) {
    if (options && options.logger) {
      if (!isFunction(options.logger)) logger("new logger isn't a function, not replacing")
      else logger = options.logger
    }
  }
  
  function wrap (nodule, name, wrapper) {
    if (!nodule || !nodule[name]) {
      logger('no original function ' + name + ' to wrap')
      return
    }
  
    if (!wrapper) {
      logger('no wrapper function')
      logger((new Error()).stack)
      return
    }
  
    if (!isFunction(nodule[name]) || !isFunction(wrapper)) {
      logger('original object and wrapper must be functions')
      return
    }
  
    var original = nodule[name]
    var wrapped = wrapper(original, name)
  
    wrapped.__original = original
    wrapped.__unwrap = function () {
      if (nodule[name] === wrapped) nodule[name] = original
    }
    wrapped.__wrapped = true
  
    nodule[name] = wrapped
  
    return wrapped
  }
  
  function massWrap (nodules, names, wrapper) {
    if (!nodules) {
      logger('must provide one or more modules to patch')
      logger((new Error()).stack)
      return
    } else if (!Array.isArray(nodules)) {
      nodules = [nodules]
    }
  
    if (!(names && Array.isArray(names))) {
      logger('must provide one or more functions to wrap on modules')
      return
    }
  
    nodules.forEach(function (nodule) {
      names.forEach(function (name) {
        wrap(nodule, name, wrapper)
      })
    })
  }
  
  function unwrap (nodule, name) {
    if (!nodule || !nodule[name]) {
      logger('no function to unwrap.')
      logger((new Error()).stack)
      return
    }
  
    if (!nodule[name].__unwrap) {
      logger('no original to unwrap to -- has ' + name + ' already been unwrapped?')
    } else {
      return nodule[name].__unwrap()
    }
  }
  
  shimmer.wrap = wrap
  shimmer.massWrap = massWrap
  shimmer.unwrap = unwrap
  
  module.exports = shimmer