var Vue // late bind
var version
var map = window.__VUE_HOT_MAP__ = Object.create(null)
var installed = false
var isBrowserify = false
var initHookName = 'beforeCreate'

exports.install = function (vue, browserify) {
  if (installed) return
  installed = true

  Vue = vue.__esModule ? vue.default : vue
  version = Vue.version.split('.').map(Number)
  isBrowserify = browserify

  // compat with < 2.0.0-alpha.7
  if (Vue.config._lifecycleHooks.indexOf('init') > -1) {
    initHookName = 'init'
  }

  exports.compatible = version[0] >= 2
  if (!exports.compatible) {
    console.warn(
      '[HMR] You are using a version of vue-hot-reload-api that is ' +
      'only compatible with Vue.js core ^2.0.0.'
    )
    return
  }
}

/**
 * Create a record for a hot module, which keeps track of its constructor
 * and instances
 *
 * @param {String} id
 * @param {Object} options
 */

exports.createRecord = function (id, options) {
  var Ctor = null
  if (typeof options === 'function') {
    Ctor = options
    options = Ctor.options
  }
  makeOptionsHot(id, options)
  map[id] = {
    Ctor: Vue.extend(options),
    instances: []
  }
}

/**
 * Make a Component options object hot.
 *
 * @param {String} id
 * @param {Object} options
 */

function makeOptionsHot (id, options) {
  injectHook(options, initHookName, function () {
    map[id].instances.push(this)
  })
  injectHook(options, 'beforeDestroy', function () {
    var instances = map[id].instances
    instances.splice(instances.indexOf(this), 1)
  })
}

/**
 * Inject a hook to a hot reloadable component so that
 * we can keep track of it.
 *
 * @param {Object} options
 * @param {String} name
 * @param {Function} hook
 */

function injectHook (options, name, hook) {
  var existing = options[name]
  options[name] = existing
    ? Array.isArray(existing)
      ? existing.concat(hook)
      : [existing, hook]
    : [hook]
}

function tryWrap (fn) {
  return function (id, arg) {
    try { fn(id, arg) } catch (e) {
      console.error(e)
      console.warn('Something went wrong during Vue component hot-reload. Full reload required.')
    }
  }
}

exports.rerender = tryWrap(function (id, options) {
  var record = map[id]
  if (!options) {
    record.instances.slice().forEach(function (instance) {
      instance.$forceUpdate()
    })
    return
  }
  if (typeof options === 'function') {
    options = options.options
  }
  record.Ctor.options.render = options.render
  record.Ctor.options.staticRenderFns = options.staticRenderFns
  record.instances.slice().forEach(function (instance) {
    instance.$options.render = options.render
    instance.$options.staticRenderFns = options.staticRenderFns
    instance._staticTrees = [] // reset static trees
    instance.$forceUpdate()
  })
})

exports.reload = tryWrap(function (id, options) {
  var record = map[id]
  if (options) {
    if (typeof options === 'function') {
      options = options.options
    }
    makeOptionsHot(id, options)
    if (version[1] < 2) {
      // preserve pre 2.2 behavior for global mixin handling
      record.Ctor.extendOptions = options
    }
    var newCtor = record.Ctor.super.extend(options)
    record.Ctor.options = newCtor.options
    record.Ctor.cid = newCtor.cid
    record.Ctor.prototype = newCtor.prototype
    if (newCtor.release) {
      // temporary global mixin strategy used in < 2.0.0-alpha.6
      newCtor.release()
    }
  }
  record.instances.slice().forEach(function (instance) {
    if (instance.$vnode && instance.$vnode.context) {
      instance.$vnode.context.$forceUpdate()
    } else {
      console.warn('Root or manually mounted instance modified. Full reload required.')
    }
  })
})
