import { Display } from "../display/Display.js"
import { onFocus, onBlur } from "../display/focus.js"
import { maybeUpdateLineNumberWidth } from "../display/line_numbers.js"
import { endOperation, operation, startOperation } from "../display/operations.js"
import { initScrollbars } from "../display/scrollbars.js"
import { onScrollWheel } from "../display/scroll_events.js"
import { setScrollLeft, updateScrollTop } from "../display/scrolling.js"
import { clipPos, Pos } from "../line/pos.js"
import { posFromMouse } from "../measurement/position_measurement.js"
import { eventInWidget } from "../measurement/widgets.js"
import Doc from "../model/Doc.js"
import { attachDoc } from "../model/document_data.js"
import { Range } from "../model/selection.js"
import { extendSelection } from "../model/selection_updates.js"
import { ie, ie_version, mobile, webkit } from "../util/browser.js"
import { e_preventDefault, e_stop, on, signal, signalDOMEvent } from "../util/event.js"
import { bind, copyObj, Delayed } from "../util/misc.js"

import { clearDragCursor, onDragOver, onDragStart, onDrop } from "./drop_events.js"
import { ensureGlobalHandlers } from "./global_events.js"
import { onKeyDown, onKeyPress, onKeyUp } from "./key_events.js"
import { clickInGutter, onContextMenu, onMouseDown } from "./mouse_events.js"
import { themeChanged } from "./utils.js"
import { defaults, optionHandlers, Init } from "./options.js"

// A CodeMirror instance represents an editor. This is the object
// that user code is usually dealing with.

export function CodeMirror(place, options) {
  if (!(this instanceof CodeMirror)) return new CodeMirror(place, options)

  this.options = options = options ? copyObj(options) : {}
  // Determine effective options based on given values and defaults.
  copyObj(defaults, options, false)

  let doc = options.value
  if (typeof doc == "string") doc = new Doc(doc, options.mode, null, options.lineSeparator, options.direction)
  else if (options.mode) doc.modeOption = options.mode
  this.doc = doc

  let input = new CodeMirror.inputStyles[options.inputStyle](this)
  let display = this.display = new Display(place, doc, input, options)
  display.wrapper.CodeMirror = this
  themeChanged(this)
  if (options.lineWrapping)
    this.display.wrapper.className += " CodeMirror-wrap"
  initScrollbars(this)

  this.state = {
    keyMaps: [],  // stores maps added by addKeyMap
    overlays: [], // highlighting overlays, as added by addOverlay
    modeGen: 0,   // bumped when mode/overlay changes, used to invalidate highlighting info
    overwrite: false,
    delayingBlurEvent: false,
    focused: false,
    suppressEdits: false, // used to disable editing during key handlers when in readOnly mode
    pasteIncoming: -1, cutIncoming: -1, // help recognize paste/cut edits in input.poll
    selectingText: false,
    draggingText: false,
    highlight: new Delayed(), // stores highlight worker timeout
    keySeq: null,  // Unfinished key sequence
    specialChars: null
  }

  if (options.autofocus && !mobile) display.input.focus()

  // Override magic textarea content restore that IE sometimes does
  // on our hidden textarea on reload
  if (ie && ie_version < 11) setTimeout(() => this.display.input.reset(true), 20)

  registerEventHandlers(this)
  ensureGlobalHandlers()

  startOperation(this)
  this.curOp.forceUpdate = true
  attachDoc(this, doc)

  if ((options.autofocus && !mobile) || this.hasFocus())
    setTimeout(bind(onFocus, this), 20)
  else
    onBlur(this)

  for (let opt in optionHandlers) if (optionHandlers.hasOwnProperty(opt))
    optionHandlers[opt](this, options[opt], Init)
  maybeUpdateLineNumberWidth(this)
  if (options.finishInit) options.finishInit(this)
  for (let i = 0; i < initHooks.length; ++i) initHooks[i](this)
  endOperation(this)
  // Suppress optimizelegibility in Webkit, since it breaks text
  // measuring on line wrapping boundaries.
  if (webkit && options.lineWrapping &&
      getComputedStyle(display.lineDiv).textRendering == "optimizelegibility")
    display.lineDiv.style.textRendering = "auto"
}

// The default configuration options.
CodeMirror.defaults = defaults
// Functions to run when options are changed.
CodeMirror.optionHandlers = optionHandlers

export default CodeMirror

// Attach the necessary event handlers when initializing the editor
function registerEventHandlers(cm) {
  let d = cm.display
  on(d.scroller, "mousedown", operation(cm, onMouseDown))
  // Older IE's will not fire a second mousedown for a double click
  if (ie && ie_version < 11)
    on(d.scroller, "dblclick", operation(cm, e => {
      if (signalDOMEvent(cm, e)) return
      let pos = posFromMouse(cm, e)
      if (!pos || clickInGutter(cm, e) || eventInWidget(cm.display, e)) return
      e_preventDefault(e)
      let word = cm.findWordAt(pos)
      extendSelection(cm.doc, word.anchor, word.head)
    }))
  else
    on(d.scroller, "dblclick", e => signalDOMEvent(cm, e) || e_preventDefault(e))
  // Some browsers fire contextmenu *after* opening the menu, at
  // which point we can't mess with it anymore. Context menu is
  // handled in onMouseDown for these browsers.
  on(d.scroller, "contextmenu", e => onContextMenu(cm, e))

  // Used to suppress mouse event handling when a touch happens
  let touchFinished, prevTouch = {end: 0}
  function finishTouch() {
    if (d.activeTouch) {
      touchFinished = setTimeout(() => d.activeTouch = null, 1000)
      prevTouch = d.activeTouch
      prevTouch.end = +new Date
    }
  }
  function isMouseLikeTouchEvent(e) {
    if (e.touches.length != 1) return false
    let touch = e.touches[0]
    return touch.radiusX <= 1 && touch.radiusY <= 1
  }
  function farAway(touch, other) {
    if (other.left == null) return true
    let dx = other.left - touch.left, dy = other.top - touch.top
    return dx * dx + dy * dy > 20 * 20
  }
  on(d.scroller, "touchstart", e => {
    if (!signalDOMEvent(cm, e) && !isMouseLikeTouchEvent(e) && !clickInGutter(cm, e)) {
      d.input.ensurePolled()
      clearTimeout(touchFinished)
      let now = +new Date
      d.activeTouch = {start: now, moved: false,
                       prev: now - prevTouch.end <= 300 ? prevTouch : null}
      if (e.touches.length == 1) {
        d.activeTouch.left = e.touches[0].pageX
        d.activeTouch.top = e.touches[0].pageY
      }
    }
  })
  on(d.scroller, "touchmove", () => {
    if (d.activeTouch) d.activeTouch.moved = true
  })
  on(d.scroller, "touchend", e => {
    let touch = d.activeTouch
    if (touch && !eventInWidget(d, e) && touch.left != null &&
        !touch.moved && new Date - touch.start < 300) {
      let pos = cm.coordsChar(d.activeTouch, "page"), range
      if (!touch.prev || farAway(touch, touch.prev)) // Single tap
        range = new Range(pos, pos)
      else if (!touch.prev.prev || farAway(touch, touch.prev.prev)) // Double tap
        range = cm.findWordAt(pos)
      else // Triple tap
        range = new Range(Pos(pos.line, 0), clipPos(cm.doc, Pos(pos.line + 1, 0)))
      cm.setSelection(range.anchor, range.head)
      cm.focus()
      e_preventDefault(e)
    }
    finishTouch()
  })
  on(d.scroller, "touchcancel", finishTouch)

  // Sync scrolling between fake scrollbars and real scrollable
  // area, ensure viewport is updated when scrolling.
  on(d.scroller, "scroll", () => {
    if (d.scroller.clientHeight) {
      updateScrollTop(cm, d.scroller.scrollTop)
      setScrollLeft(cm, d.scroller.scrollLeft, true)
      signal(cm, "scroll", cm)
    }
  })

  // Listen to wheel events in order to try and update the viewport on time.
  on(d.scroller, "mousewheel", e => onScrollWheel(cm, e))
  on(d.scroller, "DOMMouseScroll", e => onScrollWheel(cm, e))

  // Prevent wrapper from ever scrolling
  on(d.wrapper, "scroll", () => d.wrapper.scrollTop = d.wrapper.scrollLeft = 0)

  d.dragFunctions = {
    enter: e => {if (!signalDOMEvent(cm, e)) e_stop(e)},
    over: e => {if (!signalDOMEvent(cm, e)) { onDragOver(cm, e); e_stop(e) }},
    start: e => onDragStart(cm, e),
    drop: operation(cm, onDrop),
    leave: e => {if (!signalDOMEvent(cm, e)) { clearDragCursor(cm) }}
  }

  let inp = d.input.getField()
  on(inp, "keyup", e => onKeyUp.call(cm, e))
  on(inp, "keydown", operation(cm, onKeyDown))
  on(inp, "keypress", operation(cm, onKeyPress))
  on(inp, "focus", e => onFocus(cm, e))
  on(inp, "blur", e => onBlur(cm, e))
}

let initHooks = []
CodeMirror.defineInitHook = f => initHooks.push(f)
