export default function (CodeMirror, {
  cb,
  keyboardUp,
  keyboardDown,
  keyboardEnter
}) {
  const HINT_ELEMENT_CLASS = 'CodeMirror-hint'
  const ACTIVE_HINT_ELEMENT_CLASS = 'CodeMirror-hint-active'

  // This is the old interface, kept around for now to stay
  // backwards-compatible.
  CodeMirror.showHint = function (cm, getHints, options) {
    if (!getHints) return cm.showHint(options)
    if (options && options.async) getHints.async = true
    const newOpts = { hint: getHints }
    if (options) for (const prop in options) newOpts[prop] = options[prop]
    return cm.showHint(newOpts)
  }

  CodeMirror.defineExtension('showHint', function (options) {
    options = parseOptions(this, this.getCursor('start'), options)
    const selections = this.listSelections()
    if (selections.length > 1) return
    // By default, don't allow completion when something is selected.
    // A hint function can have a `supportsSelection` property to
    // indicate that it can handle selections.
    if (this.somethingSelected()) {
      if (!options.hint.supportsSelection) return
      // Don't try with cross-line selections
      for (let i = 0; i < selections.length; i++) {
        if (selections[i].head.line != selections[i].anchor.line) return
      }
    }
    if (this.state.completionActive) this.state.completionActive.close()
    const completion = this.state.completionActive = new Completion(this, options)
    if (!completion.options.hint) return

    CodeMirror.signal(this, 'startCompletion', this)
    completion.update(true)

    cb && cb({ completion })
  })

  CodeMirror.defineExtension('closeHint', function () {
    if (this.state.completionActive) this.state.completionActive.close()
  })

  function Completion (cm, options) {
    this.cm = cm
    this.options = options
    this.widget = null
    this.debounce = 0
    this.tick = 0
    this.startPos = this.cm.getCursor('start')
    this.startLen = this.cm.getLine(this.startPos.line).length - this.cm.getSelection().length

    if (this.options.updateOnCursorActivity) {
      const self = this
      cm.on('cursorActivity', this.activityFunc = function () {
        self.cursorActivity()
      })
    }
  }

  const requestAnimationFrame = window.requestAnimationFrame || function (fn) {
    return setTimeout(fn, 1000 / 60)
  }
  const cancelAnimationFrame = window.cancelAnimationFrame || clearTimeout

  Completion.prototype = {
    close: function () {
      if (!this.active()) return
      this.cm.state.completionActive = null
      this.tick = null
      if (this.options.updateOnCursorActivity) {
        this.cm.off('cursorActivity', this.activityFunc)
      }

      if (this.widget && this.data) CodeMirror.signal(this.data, 'close')
      if (this.widget) this.widget.close()
      CodeMirror.signal(this.cm, 'endCompletion', this.cm)
    },

    active: function () {
      return this.cm.state.completionActive == this
    },

    pick: function (data, i) {
      const completion = data.list[i]; const self = this
      this.cm.operation(function () {
        if (completion.hint) {
          completion.hint(self.cm, data, completion)
        } else if (completion.field) {
          if (completion.text === 'in' || completion.text === 'like') {
            completion.text = ' ' + completion.text
          }
          let myString = self.cm.getValue().substring(data.from.ch, data.to.ch) + getText(completion)
          if (completion.text === 'has') {
            myString = getText(completion) + '(' + self.cm.getValue().substring(data.from.ch, data.to.ch) + ', ) '
          }
          self.cm.replaceRange(myString, data.from, data.to, 'complete')
        } else {
          self.cm.replaceRange(getText(completion), completion.from || data.from, completion.to || data.to, 'complete')
        }
        CodeMirror.signal(data, 'pick', completion)
        self.cm.scrollIntoView()
      })
      if (this.options.closeOnPick) {
        this.close()
      }
    },

    cursorActivity: function () {
      if (this.debounce) {
        cancelAnimationFrame(this.debounce)
        this.debounce = 0
      }

      let identStart = this.startPos
      if (this.data) {
        identStart = this.data.from
      }

      const pos = this.cm.getCursor(); const line = this.cm.getLine(pos.line)
      if (pos.line != this.startPos.line || line.length - pos.ch != this.startLen - this.startPos.ch ||
        pos.ch < identStart.ch || this.cm.somethingSelected() ||
        (!pos.ch || this.options.closeCharacters.test(line.charAt(pos.ch - 1)))) {
        this.close()
      } else {
        const self = this
        this.debounce = requestAnimationFrame(function () {
          self.update()
        })
        if (this.widget) this.widget.disable()
      }
    },

    update: function (first) {
      if (this.tick == null) return
      const self = this; const myTick = ++this.tick
      fetchHints(this.options.hint, this.cm, this.options, function (data) {
        if (self.tick == myTick) self.finishUpdate(data, first)
      })
    },

    finishUpdate: function (data, first) {
      if (this.data) CodeMirror.signal(this.data, 'update')

      const picked = (this.widget && this.widget.picked) || (first && this.options.completeSingle)
      if (this.widget) this.widget.close()

      this.data = data

      if (data && data.list.length) {
        if (picked && data.list.length == 1) {
          this.pick(data, 0)
        } else {
          this.widget = new Widget(this, data)
          CodeMirror.signal(data, 'shown')
        }
      }
    }
  }

  function parseOptions (cm, pos, options) {
    const editor = cm.options.hintOptions
    const out = {}
    for (var prop in defaultOptions) out[prop] = defaultOptions[prop]
    if (editor) {
      for (var prop in editor) {
        if (editor[prop] !== undefined) out[prop] = editor[prop]
      }
    }
    if (options) {
      for (var prop in options) {
        if (options[prop] !== undefined) out[prop] = options[prop]
      }
    }
    if (out.hint.resolve) out.hint = out.hint.resolve(cm, pos)
    return out
  }

  function getText (completion) {
    if (typeof completion == 'string') {
      return completion
    } else {
      return completion.text
    }
  }

  function buildKeyMap (completion, handle) {
    const baseMap = {
      Up: function () {
        handle.moveFocus(-1)
      },
      Down: function () {
        handle.moveFocus(1)
      },
      PageUp: function () {
        handle.moveFocus(-handle.menuSize() + 1, true)
      },
      PageDown: function () {
        handle.moveFocus(handle.menuSize() - 1, true)
      },
      Home: function () {
        handle.setFocus(0)
      },
      End: function () {
        handle.setFocus(handle.length - 1)
      },
      // Enter: handle.pick,
      // Tab: handle.pick,
      Tab: keyboardEnter,
      Enter: keyboardEnter,
      Esc: handle.close
    }

    const mac = /Mac/.test(navigator.platform)

    if (mac) {
      baseMap['Ctrl-P'] = function () {
        handle.moveFocus(-1)
      }
      baseMap['Ctrl-N'] = function () {
        handle.moveFocus(1)
      }
    }

    const custom = completion.options.customKeys
    const ourMap = custom ? {} : baseMap

    function addBinding (key, val) {
      let bound
      if (typeof val != 'string') {
        bound = function (cm) {
          return val(cm, handle)
        }
      }// This mechanism is deprecated
      else if (baseMap.hasOwnProperty(val)) {
        bound = baseMap[val]
      } else {
        bound = val
      }
      ourMap[key] = bound
    }

    if (custom) {
      for (var key in custom) {
        if (custom.hasOwnProperty(key)) {
          addBinding(key, custom[key])
        }
      }
    }
    const extra = completion.options.extraKeys
    if (extra) {
      for (var key in extra) {
        if (extra.hasOwnProperty(key)) {
          addBinding(key, extra[key])
        }
      }
    }
    return ourMap
  }

  function getHintElement (hintsElement, el) {
    while (el && el != hintsElement) {
      if (el.nodeName.toUpperCase() === 'LI' && el.parentNode == hintsElement) return el
      el = el.parentNode
    }
  }

  function Widget (completion, data) {
    this.id = 'cm-complete-' + Math.floor(Math.random(1e6))
    this.completion = completion
    this.data = data
    this.picked = false
    const widget = this; const cm = completion.cm
    const ownerDocument = cm.getInputField().ownerDocument
    const parentWindow = ownerDocument.defaultView || ownerDocument.parentWindow

    const hints = this.hints = ownerDocument.createElement('ul')
    // $(hints).append(`
    //   <h1>lalallalla</h1>
    // `)
    hints.setAttribute('role', 'listbox')
    hints.setAttribute('aria-expanded', 'true')
    hints.id = this.id
    const theme = completion.cm.options.theme
    hints.className = 'CodeMirror-hints ' + theme
    this.selectedHint = data.selectedHint || 0

    const completions = data.list
    for (let i = 0; i < completions.length; ++i) {
      const elt = hints.appendChild(ownerDocument.createElement('li')); const cur = completions[i]
      let className = HINT_ELEMENT_CLASS + (i != this.selectedHint ? '' : ' ' + ACTIVE_HINT_ELEMENT_CLASS)
      if (cur.className != null) className = cur.className + ' ' + className
      elt.className = className
      if (i == this.selectedHint) elt.setAttribute('aria-selected', 'true')
      elt.id = this.id + '-' + i
      elt.setAttribute('role', 'option')
      if (cur.render) {
        cur.render(elt, data, cur)
      } else {
        elt.appendChild(ownerDocument.createTextNode(cur.displayText || getText(cur)))
      }
      elt.hintId = i
    }

    const container = completion.options.container || ownerDocument.body
    let pos = cm.cursorCoords(completion.options.alignWithWord ? data.from : null)
    let left = pos.left; let top = pos.bottom; let below = true
    let offsetLeft = 0; let offsetTop = 0
    if (container !== ownerDocument.body) {
      // We offset the cursor position because left and top are relative to the offsetParent's top left corner.
      const isContainerPositioned = ['absolute', 'relative', 'fixed'].indexOf(parentWindow.getComputedStyle(container).position) !== -1
      const offsetParent = isContainerPositioned ? container : container.offsetParent
      const offsetParentPosition = offsetParent.getBoundingClientRect()
      const bodyPosition = ownerDocument.body.getBoundingClientRect()
      offsetLeft = (offsetParentPosition.left - bodyPosition.left - offsetParent.scrollLeft)
      offsetTop = (offsetParentPosition.top - bodyPosition.top - offsetParent.scrollTop)
    }
    hints.style.left = (left - offsetLeft) + 'px'
    hints.style.top = (top - offsetTop) + 'px'
    // todo 隐藏codemirror自带的提示
    hints.style.display = 'none'

    // If we're at the edge of the screen, then we want the menu to appear on the left of the cursor.
    const winW = parentWindow.innerWidth || Math.max(ownerDocument.body.offsetWidth, ownerDocument.documentElement.offsetWidth)
    const winH = parentWindow.innerHeight || Math.max(ownerDocument.body.offsetHeight, ownerDocument.documentElement.offsetHeight)

    // 不用默认的DOM 下拉提示
    // container.appendChild(hints);
    hints.remove()

    cm.getInputField().setAttribute('aria-autocomplete', 'list')
    cm.getInputField().setAttribute('aria-owns', this.id)
    cm.getInputField().setAttribute('aria-activedescendant', this.id + '-' + this.selectedHint)

    let box = completion.options.moveOnOverlap ? hints.getBoundingClientRect() : new DOMRect()
    const scrolls = completion.options.paddingForScrollbar ? hints.scrollHeight > hints.clientHeight + 1 : false

    // Compute in the timeout to avoid reflow on init
    let startScroll
    setTimeout(function () {
      startScroll = cm.getScrollInfo()
    })

    const overlapY = box.bottom - winH
    if (overlapY > 0) {
      const height = box.bottom - box.top; const curTop = pos.top - (pos.bottom - box.top)
      if (curTop - height > 0) { // Fits above cursor
        hints.style.top = (top = pos.top - height - offsetTop) + 'px'
        below = false
      } else if (height > winH) {
        hints.style.height = (winH - 5) + 'px'
        hints.style.top = (top = pos.bottom - box.top - offsetTop) + 'px'
        const cursor = cm.getCursor()
        if (data.from.ch != cursor.ch) {
          pos = cm.cursorCoords(cursor)
          hints.style.left = (left = pos.left - offsetLeft) + 'px'
          box = hints.getBoundingClientRect()
        }
      }
    }
    let overlapX = box.right - winW
    if (scrolls) overlapX += cm.display.nativeBarWidth
    if (overlapX > 0) {
      if (box.right - box.left > winW) {
        hints.style.width = (winW - 5) + 'px'
        overlapX -= (box.right - box.left) - winW
      }
      hints.style.left = (left = Math.max(pos.left - overlapX - offsetLeft, 0)) + 'px'
    }
    if (scrolls) {
      for (let node = hints.firstChild; node; node = node.nextSibling) {
        node.style.paddingRight = cm.display.nativeBarWidth + 'px'
      }
    }

    // debugger
    cm.addKeyMap(this.keyMap = buildKeyMap(completion, {
      moveFocus: function (n, avoidWrap) {
        n === -1 ? keyboardUp && keyboardUp() : keyboardDown && keyboardDown()
        widget.changeActive(widget.selectedHint + n, avoidWrap)
      },
      setFocus: function (n) {
        widget.changeActive(n)
      },
      menuSize: function () {
        return widget.screenAmount()
      },
      length: completions.length,
      close: function () {
        completion.close()
      },
      pick: function () {
        widget.pick()
      },
      data: data
    }))

    if (completion.options.closeOnUnfocus) {
      let closingOnBlur
      cm.on('blur', this.onBlur = function () {
        closingOnBlur = setTimeout(function () {
          completion.close()
        }, 100)
      })
      cm.on('focus', this.onFocus = function () {
        clearTimeout(closingOnBlur)
      })
    }

    cm.on('scroll', this.onScroll = function () {
      const curScroll = cm.getScrollInfo(); const editor = cm.getWrapperElement().getBoundingClientRect()
      if (!startScroll) startScroll = cm.getScrollInfo()
      const newTop = top + startScroll.top - curScroll.top
      let point = newTop - (parentWindow.pageYOffset || (ownerDocument.documentElement || ownerDocument.body).scrollTop)
      if (!below) point += hints.offsetHeight
      if (point <= editor.top || point >= editor.bottom) return completion.close()
      hints.style.top = newTop + 'px'
      hints.style.left = (left + startScroll.left - curScroll.left) + 'px'
    })

    CodeMirror.on(hints, 'dblclick', function (e) {
      const t = getHintElement(hints, e.target || e.srcElement)
      if (t && t.hintId != null) {
        widget.changeActive(t.hintId)
        widget.pick()
      }
    })

    CodeMirror.on(hints, 'click', function (e) {
      const t = getHintElement(hints, e.target || e.srcElement)
      if (t && t.hintId != null) {
        widget.changeActive(t.hintId)
        if (completion.options.completeOnSingleClick) widget.pick()
      }
    })

    CodeMirror.on(hints, 'mousedown', function () {
      setTimeout(function () {
        cm.focus()
      }, 20)
    })

    // The first hint doesn't need to be scrolled to on init
    const selectedHintRange = this.getSelectedHintRange()
    if (selectedHintRange.from !== 0 || selectedHintRange.to !== 0) {
      this.scrollToActive()
    }

    CodeMirror.signal(data, 'select', completions[this.selectedHint], hints.childNodes[this.selectedHint])
    return true
  }

  Widget.prototype = {
    close: function () {
      if (this.completion.widget != this) return
      this.completion.widget = null
      if (this.hints.parentNode) this.hints.parentNode.removeChild(this.hints)
      this.completion.cm.removeKeyMap(this.keyMap)
      const input = this.completion.cm.getInputField()
      input.removeAttribute('aria-activedescendant')
      input.removeAttribute('aria-owns')

      const cm = this.completion.cm
      if (this.completion.options.closeOnUnfocus) {
        cm.off('blur', this.onBlur)
        cm.off('focus', this.onFocus)
      }
      cm.off('scroll', this.onScroll)
    },

    disable: function () {
      this.completion.cm.removeKeyMap(this.keyMap)
      const widget = this
      this.keyMap = {
        Enter: function () {
          widget.picked = true
        }
      }
      this.completion.cm.addKeyMap(this.keyMap)
    },

    pick: function () {
      this.completion.pick(this.data, this.selectedHint)
    },

    changeActive: function (i, avoidWrap) {
      if (i >= this.data.list.length) {
        i = avoidWrap ? this.data.list.length - 1 : 0
      } else if (i < 0) {
        i = avoidWrap ? 0 : this.data.list.length - 1
      }
      if (this.selectedHint == i) return
      let node = this.hints.childNodes[this.selectedHint]
      if (node) {
        node.className = node.className.replace(' ' + ACTIVE_HINT_ELEMENT_CLASS, '')
        node.removeAttribute('aria-selected')
      }
      node = this.hints.childNodes[this.selectedHint = i]
      node.className += ' ' + ACTIVE_HINT_ELEMENT_CLASS
      node.setAttribute('aria-selected', 'true')
      this.completion.cm.getInputField().setAttribute('aria-activedescendant', node.id)
      this.scrollToActive()
      CodeMirror.signal(this.data, 'select', this.data.list[this.selectedHint], node)
    },

    scrollToActive: function () {
      const selectedHintRange = this.getSelectedHintRange()
      const node1 = this.hints.childNodes[selectedHintRange.from]
      const node2 = this.hints.childNodes[selectedHintRange.to]
      const firstNode = this.hints.firstChild
      if (node1.offsetTop < this.hints.scrollTop) {
        this.hints.scrollTop = node1.offsetTop - firstNode.offsetTop
      } else if (node2.offsetTop + node2.offsetHeight > this.hints.scrollTop + this.hints.clientHeight) {
        this.hints.scrollTop = node2.offsetTop + node2.offsetHeight - this.hints.clientHeight + firstNode.offsetTop
      }
    },

    screenAmount: function () {
      return Math.floor(this.hints.clientHeight / this.hints.firstChild.offsetHeight) || 1
    },

    getSelectedHintRange: function () {
      const margin = this.completion.options.scrollMargin || 0
      return {
        from: Math.max(0, this.selectedHint - margin),
        to: Math.min(this.data.list.length - 1, this.selectedHint + margin)
      }
    }
  }

  function applicableHelpers (cm, helpers) {
    if (!cm.somethingSelected()) return helpers
    const result = []
    for (let i = 0; i < helpers.length; i++) {
      if (helpers[i].supportsSelection) result.push(helpers[i])
    }
    return result
  }

  function fetchHints (hint, cm, options, callback) {
    if (hint.async) {
      hint(cm, callback, options)
    } else {
      const result = hint(cm, options)
      if (result && result.then) {
        result.then(callback)
      } else {
        callback(result)
      }
    }
  }

  function resolveAutoHints (cm, pos) {
    const helpers = cm.getHelpers(pos, 'hint'); let words
    if (helpers.length) {
      const resolved = function (cm, callback, options) {
        const app = applicableHelpers(cm, helpers)

        function run (i) {
          if (i == app.length) return callback(null)
          fetchHints(app[i], cm, options, function (result) {
            if (result && result.list.length > 0) {
              callback(result)
            } else {
              run(i + 1)
            }
          })
        }

        run(0)
      }
      resolved.async = true
      resolved.supportsSelection = true
      return resolved
    } else if (words = cm.getHelper(cm.getCursor(), 'hintWords')) {
      return function (cm) {
        return CodeMirror.hint.fromList(cm, { words: words })
      }
    } else if (CodeMirror.hint.anyword) {
      return function (cm, options) {
        return CodeMirror.hint.anyword(cm, options)
      }
    } else {
      return function () {
      }
    }
  }

  CodeMirror.registerHelper('hint', 'auto', {
    resolve: resolveAutoHints
  })

  CodeMirror.registerHelper('hint', 'fromList', function (cm, options) {
    const cur = cm.getCursor(); const token = cm.getTokenAt(cur)
    let term; let from = CodeMirror.Pos(cur.line, token.start); const to = cur
    if (token.start < cur.ch && /\w/.test(token.string.charAt(cur.ch - token.start - 1))) {
      term = token.string.substr(0, cur.ch - token.start)
    } else {
      term = ''
      from = cur
    }
    const found = []
    for (let i = 0; i < options.words.length; i++) {
      const word = options.words[i]
      if (word.slice(0, term.length) == term) {
        found.push(word)
      }
    }

    if (found.length) {
      return {
        list: found,
        from: from,
        to: to
      }
    }
  })

  CodeMirror.commands.autocomplete = CodeMirror.showHint

  var defaultOptions = {
    hint: CodeMirror.hint.auto,
    completeSingle: true,
    alignWithWord: true,
    closeCharacters: /[\s()\[\]{};:>,]/,

    closeOnPick: false,
    closeOnUnfocus: false, // 阻止提示信息 失焦关闭
    // closeOnUnfocus: false,

    updateOnCursorActivity: true,
    completeOnSingleClick: true,
    container: null,
    customKeys: null,
    extraKeys: null,
    paddingForScrollbar: true,
    moveOnOverlap: true
  }
  CodeMirror.defineOption('hintOptions', null)
}