import { gecko, ie, ie_version, mobile, webkit } from "../util/browser.js"
import { elt, eltP } from "../util/dom.js"
import { scrollerGap } from "../util/misc.js"
import { getGutters, renderGutters } from "./gutters.js"

// The display handles the DOM integration, both for input reading
// and content drawing. It holds references to DOM nodes and
// display-related state.

export function Display(place, doc, input, options) {
  let d = this
  this.input = input

  // Covers bottom-right square when both scrollbars are present.
  d.scrollbarFiller = elt("div", null, "CodeMirror-scrollbar-filler")
  d.scrollbarFiller.setAttribute("cm-not-content", "true")
  // Covers bottom of gutter when coverGutterNextToScrollbar is on
  // and h scrollbar is present.
  d.gutterFiller = elt("div", null, "CodeMirror-gutter-filler")
  d.gutterFiller.setAttribute("cm-not-content", "true")
  // Will contain the actual code, positioned to cover the viewport.
  d.lineDiv = eltP("div", null, "CodeMirror-code")
  // Elements are added to these to represent selection and cursors.
  d.selectionDiv = elt("div", null, null, "position: relative; z-index: 1")
  d.cursorDiv = elt("div", null, "CodeMirror-cursors")
  // A visibility: hidden element used to find the size of things.
  d.measure = elt("div", null, "CodeMirror-measure")
  // When lines outside of the viewport are measured, they are drawn in this.
  d.lineMeasure = elt("div", null, "CodeMirror-measure")
  // Wraps everything that needs to exist inside the vertically-padded coordinate system
  d.lineSpace = eltP("div", [d.measure, d.lineMeasure, d.selectionDiv, d.cursorDiv, d.lineDiv],
                    null, "position: relative; outline: none")
  let lines = eltP("div", [d.lineSpace], "CodeMirror-lines")
  // Moved around its parent to cover visible view.
  d.mover = elt("div", [lines], null, "position: relative")
  // Set to the height of the document, allowing scrolling.
  d.sizer = elt("div", [d.mover], "CodeMirror-sizer")
  d.sizerWidth = null
  // Behavior of elts with overflow: auto and padding is
  // inconsistent across browsers. This is used to ensure the
  // scrollable area is big enough.
  d.heightForcer = elt("div", null, null, "position: absolute; height: " + scrollerGap + "px; width: 1px;")
  // Will contain the gutters, if any.
  d.gutters = elt("div", null, "CodeMirror-gutters")
  d.lineGutter = null
  // Actual scrollable element.
  d.scroller = elt("div", [d.sizer, d.heightForcer, d.gutters], "CodeMirror-scroll")
  d.scroller.setAttribute("tabIndex", "-1")
  // The element in which the editor lives.
  d.wrapper = elt("div", [d.scrollbarFiller, d.gutterFiller, d.scroller], "CodeMirror")

  // This attribute is respected by automatic translation systems such as Google Translate,
  // and may also be respected by tools used by human translators.
  d.wrapper.setAttribute('translate', 'no')

  // Work around IE7 z-index bug (not perfect, hence IE7 not really being supported)
  if (ie && ie_version < 8) { d.gutters.style.zIndex = -1; d.scroller.style.paddingRight = 0 }
  if (!webkit && !(gecko && mobile)) d.scroller.draggable = true

  if (place) {
    if (place.appendChild) place.appendChild(d.wrapper)
    else place(d.wrapper)
  }

  // Current rendered range (may be bigger than the view window).
  d.viewFrom = d.viewTo = doc.first
  d.reportedViewFrom = d.reportedViewTo = doc.first
  // Information about the rendered lines.
  d.view = []
  d.renderedView = null
  // Holds info about a single rendered line when it was rendered
  // for measurement, while not in view.
  d.externalMeasured = null
  // Empty space (in pixels) above the view
  d.viewOffset = 0
  d.lastWrapHeight = d.lastWrapWidth = 0
  d.updateLineNumbers = null

  d.nativeBarWidth = d.barHeight = d.barWidth = 0
  d.scrollbarsClipped = false

  // Used to only resize the line number gutter when necessary (when
  // the amount of lines crosses a boundary that makes its width change)
  d.lineNumWidth = d.lineNumInnerWidth = d.lineNumChars = null
  // Set to true when a non-horizontal-scrolling line widget is
  // added. As an optimization, line widget aligning is skipped when
  // this is false.
  d.alignWidgets = false

  d.cachedCharWidth = d.cachedTextHeight = d.cachedPaddingH = null

  // Tracks the maximum line length so that the horizontal scrollbar
  // can be kept static when scrolling.
  d.maxLine = null
  d.maxLineLength = 0
  d.maxLineChanged = false

  // Used for measuring wheel scrolling granularity
  d.wheelDX = d.wheelDY = d.wheelStartX = d.wheelStartY = null

  // True when shift is held down.
  d.shift = false

  // Used to track whether anything happened since the context menu
  // was opened.
  d.selForContextMenu = null

  d.activeTouch = null

  d.gutterSpecs = getGutters(options.gutters, options.lineNumbers)
  renderGutters(d)

  input.init(d)
}