import { delayBlurEvent, ensureFocus } from "../display/focus.js"
import { operation } from "../display/operations.js"
import { visibleLines } from "../display/update_lines.js"
import { clipPos, cmp, maxPos, minPos, Pos } from "../line/pos.js"
import { getLine, lineAtHeight } from "../line/utils_line.js"
import { posFromMouse } from "../measurement/position_measurement.js"
import { eventInWidget } from "../measurement/widgets.js"
import { normalizeSelection, Range, Selection } from "../model/selection.js"
import { extendRange, extendSelection, replaceOneSelection, setSelection } from "../model/selection_updates.js"
import { captureRightClick, chromeOS, ie, ie_version, mac, webkit } from "../util/browser.js"
import { getOrder, getBidiPartAt } from "../util/bidi.js"
import { activeElt } from "../util/dom.js"
import { e_button, e_defaultPrevented, e_preventDefault, e_target, hasHandler, off, on, signal, signalDOMEvent } from "../util/event.js"
import { dragAndDrop } from "../util/feature_detection.js"
import { bind, countColumn, findColumn, sel_mouse } from "../util/misc.js"
import { addModifierNames } from "../input/keymap.js"
import { Pass } from "../util/misc.js"

import { dispatchKey } from "./key_events.js"
import { commands } from "./commands.js"

const DOUBLECLICK_DELAY = 400

class PastClick {
  constructor(time, pos, button) {
    this.time = time
    this.pos = pos
    this.button = button
  }

  compare(time, pos, button) {
    return this.time + DOUBLECLICK_DELAY > time &&
      cmp(pos, this.pos) == 0 && button == this.button
  }
}

let lastClick, lastDoubleClick
function clickRepeat(pos, button) {
  let now = +new Date
  if (lastDoubleClick && lastDoubleClick.compare(now, pos, button)) {
    lastClick = lastDoubleClick = null
    return "triple"
  } else if (lastClick && lastClick.compare(now, pos, button)) {
    lastDoubleClick = new PastClick(now, pos, button)
    lastClick = null
    return "double"
  } else {
    lastClick = new PastClick(now, pos, button)
    lastDoubleClick = null
    return "single"
  }
}

// A mouse down can be a single click, double click, triple click,
// start of selection drag, start of text drag, new cursor
// (ctrl-click), rectangle drag (alt-drag), or xwin
// middle-click-paste. Or it might be a click on something we should
// not interfere with, such as a scrollbar or widget.
export function onMouseDown(e) {
  let cm = this, display = cm.display
  if (signalDOMEvent(cm, e) || display.activeTouch && display.input.supportsTouch()) return
  display.input.ensurePolled()
  display.shift = e.shiftKey

  if (eventInWidget(display, e)) {
    if (!webkit) {
      // Briefly turn off draggability, to allow widgets to do
      // normal dragging things.
      display.scroller.draggable = false
      setTimeout(() => display.scroller.draggable = true, 100)
    }
    return
  }
  if (clickInGutter(cm, e)) return
  let pos = posFromMouse(cm, e), button = e_button(e), repeat = pos ? clickRepeat(pos, button) : "single"
  window.focus()

  // #3261: make sure, that we're not starting a second selection
  if (button == 1 && cm.state.selectingText)
    cm.state.selectingText(e)

  if (pos && handleMappedButton(cm, button, pos, repeat, e)) return

  if (button == 1) {
    if (pos) leftButtonDown(cm, pos, repeat, e)
    else if (e_target(e) == display.scroller) e_preventDefault(e)
  } else if (button == 2) {
    if (pos) extendSelection(cm.doc, pos)
    setTimeout(() => display.input.focus(), 20)
  } else if (button == 3) {
    if (captureRightClick) cm.display.input.onContextMenu(e)
    else delayBlurEvent(cm)
  }
}

function handleMappedButton(cm, button, pos, repeat, event) {
  let name = "Click"
  if (repeat == "double") name = "Double" + name
  else if (repeat == "triple") name = "Triple" + name
  name = (button == 1 ? "Left" : button == 2 ? "Middle" : "Right") + name

  return dispatchKey(cm,  addModifierNames(name, event), event, bound => {
    if (typeof bound == "string") bound = commands[bound]
    if (!bound) return false
    let done = false
    try {
      if (cm.isReadOnly()) cm.state.suppressEdits = true
      done = bound(cm, pos) != Pass
    } finally {
      cm.state.suppressEdits = false
    }
    return done
  })
}

function configureMouse(cm, repeat, event) {
  let option = cm.getOption("configureMouse")
  let value = option ? option(cm, repeat, event) : {}
  if (value.unit == null) {
    let rect = chromeOS ? event.shiftKey && event.metaKey : event.altKey
    value.unit = rect ? "rectangle" : repeat == "single" ? "char" : repeat == "double" ? "word" : "line"
  }
  if (value.extend == null || cm.doc.extend) value.extend = cm.doc.extend || event.shiftKey
  if (value.addNew == null) value.addNew = mac ? event.metaKey : event.ctrlKey
  if (value.moveOnDrag == null) value.moveOnDrag = !(mac ? event.altKey : event.ctrlKey)
  return value
}

function leftButtonDown(cm, pos, repeat, event) {
  if (ie) setTimeout(bind(ensureFocus, cm), 0)
  else cm.curOp.focus = activeElt()

  let behavior = configureMouse(cm, repeat, event)

  let sel = cm.doc.sel, contained
  if (cm.options.dragDrop && dragAndDrop && !cm.isReadOnly() &&
      repeat == "single" && (contained = sel.contains(pos)) > -1 &&
      (cmp((contained = sel.ranges[contained]).from(), pos) < 0 || pos.xRel > 0) &&
      (cmp(contained.to(), pos) > 0 || pos.xRel < 0))
    leftButtonStartDrag(cm, event, pos, behavior)
  else
    leftButtonSelect(cm, event, pos, behavior)
}

// Start a text drag. When it ends, see if any dragging actually
// happen, and treat as a click if it didn't.
function leftButtonStartDrag(cm, event, pos, behavior) {
  let display = cm.display, moved = false
  let dragEnd = operation(cm, e => {
    if (webkit) display.scroller.draggable = false
    cm.state.draggingText = false
    off(display.wrapper.ownerDocument, "mouseup", dragEnd)
    off(display.wrapper.ownerDocument, "mousemove", mouseMove)
    off(display.scroller, "dragstart", dragStart)
    off(display.scroller, "drop", dragEnd)
    if (!moved) {
      e_preventDefault(e)
      if (!behavior.addNew)
        extendSelection(cm.doc, pos, null, null, behavior.extend)
      // Work around unexplainable focus problem in IE9 (#2127) and Chrome (#3081)
      if (webkit || ie && ie_version == 9)
        setTimeout(() => {display.wrapper.ownerDocument.body.focus(); display.input.focus()}, 20)
      else
        display.input.focus()
    }
  })
  let mouseMove = function(e2) {
    moved = moved || Math.abs(event.clientX - e2.clientX) + Math.abs(event.clientY - e2.clientY) >= 10
  }
  let dragStart = () => moved = true
  // Let the drag handler handle this.
  if (webkit) display.scroller.draggable = true
  cm.state.draggingText = dragEnd
  dragEnd.copy = !behavior.moveOnDrag
  // IE's approach to draggable
  if (display.scroller.dragDrop) display.scroller.dragDrop()
  on(display.wrapper.ownerDocument, "mouseup", dragEnd)
  on(display.wrapper.ownerDocument, "mousemove", mouseMove)
  on(display.scroller, "dragstart", dragStart)
  on(display.scroller, "drop", dragEnd)

  delayBlurEvent(cm)
  setTimeout(() => display.input.focus(), 20)
}

function rangeForUnit(cm, pos, unit) {
  if (unit == "char") return new Range(pos, pos)
  if (unit == "word") return cm.findWordAt(pos)
  if (unit == "line") return new Range(Pos(pos.line, 0), clipPos(cm.doc, Pos(pos.line + 1, 0)))
  let result = unit(cm, pos)
  return new Range(result.from, result.to)
}

// Normal selection, as opposed to text dragging.
function leftButtonSelect(cm, event, start, behavior) {
  let display = cm.display, doc = cm.doc
  e_preventDefault(event)

  let ourRange, ourIndex, startSel = doc.sel, ranges = startSel.ranges
  if (behavior.addNew && !behavior.extend) {
    ourIndex = doc.sel.contains(start)
    if (ourIndex > -1)
      ourRange = ranges[ourIndex]
    else
      ourRange = new Range(start, start)
  } else {
    ourRange = doc.sel.primary()
    ourIndex = doc.sel.primIndex
  }

  if (behavior.unit == "rectangle") {
    if (!behavior.addNew) ourRange = new Range(start, start)
    start = posFromMouse(cm, event, true, true)
    ourIndex = -1
  } else {
    let range = rangeForUnit(cm, start, behavior.unit)
    if (behavior.extend)
      ourRange = extendRange(ourRange, range.anchor, range.head, behavior.extend)
    else
      ourRange = range
  }

  if (!behavior.addNew) {
    ourIndex = 0
    setSelection(doc, new Selection([ourRange], 0), sel_mouse)
    startSel = doc.sel
  } else if (ourIndex == -1) {
    ourIndex = ranges.length
    setSelection(doc, normalizeSelection(cm, ranges.concat([ourRange]), ourIndex),
                 {scroll: false, origin: "*mouse"})
  } else if (ranges.length > 1 && ranges[ourIndex].empty() && behavior.unit == "char" && !behavior.extend) {
    setSelection(doc, normalizeSelection(cm, ranges.slice(0, ourIndex).concat(ranges.slice(ourIndex + 1)), 0),
                 {scroll: false, origin: "*mouse"})
    startSel = doc.sel
  } else {
    replaceOneSelection(doc, ourIndex, ourRange, sel_mouse)
  }

  let lastPos = start
  function extendTo(pos) {
    if (cmp(lastPos, pos) == 0) return
    lastPos = pos

    if (behavior.unit == "rectangle") {
      let ranges = [], tabSize = cm.options.tabSize
      let startCol = countColumn(getLine(doc, start.line).text, start.ch, tabSize)
      let posCol = countColumn(getLine(doc, pos.line).text, pos.ch, tabSize)
      let left = Math.min(startCol, posCol), right = Math.max(startCol, posCol)
      for (let line = Math.min(start.line, pos.line), end = Math.min(cm.lastLine(), Math.max(start.line, pos.line));
           line <= end; line++) {
        let text = getLine(doc, line).text, leftPos = findColumn(text, left, tabSize)
        if (left == right)
          ranges.push(new Range(Pos(line, leftPos), Pos(line, leftPos)))
        else if (text.length > leftPos)
          ranges.push(new Range(Pos(line, leftPos), Pos(line, findColumn(text, right, tabSize))))
      }
      if (!ranges.length) ranges.push(new Range(start, start))
      setSelection(doc, normalizeSelection(cm, startSel.ranges.slice(0, ourIndex).concat(ranges), ourIndex),
                   {origin: "*mouse", scroll: false})
      cm.scrollIntoView(pos)
    } else {
      let oldRange = ourRange
      let range = rangeForUnit(cm, pos, behavior.unit)
      let anchor = oldRange.anchor, head
      if (cmp(range.anchor, anchor) > 0) {
        head = range.head
        anchor = minPos(oldRange.from(), range.anchor)
      } else {
        head = range.anchor
        anchor = maxPos(oldRange.to(), range.head)
      }
      let ranges = startSel.ranges.slice(0)
      ranges[ourIndex] = bidiSimplify(cm, new Range(clipPos(doc, anchor), head))
      setSelection(doc, normalizeSelection(cm, ranges, ourIndex), sel_mouse)
    }
  }

  let editorSize = display.wrapper.getBoundingClientRect()
  // Used to ensure timeout re-tries don't fire when another extend
  // happened in the meantime (clearTimeout isn't reliable -- at
  // least on Chrome, the timeouts still happen even when cleared,
  // if the clear happens after their scheduled firing time).
  let counter = 0

  function extend(e) {
    let curCount = ++counter
    let cur = posFromMouse(cm, e, true, behavior.unit == "rectangle")
    if (!cur) return
    if (cmp(cur, lastPos) != 0) {
      cm.curOp.focus = activeElt()
      extendTo(cur)
      let visible = visibleLines(display, doc)
      if (cur.line >= visible.to || cur.line < visible.from)
        setTimeout(operation(cm, () => {if (counter == curCount) extend(e)}), 150)
    } else {
      let outside = e.clientY < editorSize.top ? -20 : e.clientY > editorSize.bottom ? 20 : 0
      if (outside) setTimeout(operation(cm, () => {
        if (counter != curCount) return
        display.scroller.scrollTop += outside
        extend(e)
      }), 50)
    }
  }

  function done(e) {
    cm.state.selectingText = false
    counter = Infinity
    // If e is null or undefined we interpret this as someone trying
    // to explicitly cancel the selection rather than the user
    // letting go of the mouse button.
    if (e) {
      e_preventDefault(e)
      display.input.focus()
    }
    off(display.wrapper.ownerDocument, "mousemove", move)
    off(display.wrapper.ownerDocument, "mouseup", up)
    doc.history.lastSelOrigin = null
  }

  let move = operation(cm, e => {
    if (e.buttons === 0 || !e_button(e)) done(e)
    else extend(e)
  })
  let up = operation(cm, done)
  cm.state.selectingText = up
  on(display.wrapper.ownerDocument, "mousemove", move)
  on(display.wrapper.ownerDocument, "mouseup", up)
}

// Used when mouse-selecting to adjust the anchor to the proper side
// of a bidi jump depending on the visual position of the head.
function bidiSimplify(cm, range) {
  let {anchor, head} = range, anchorLine = getLine(cm.doc, anchor.line)
  if (cmp(anchor, head) == 0 && anchor.sticky == head.sticky) return range
  let order = getOrder(anchorLine)
  if (!order) return range
  let index = getBidiPartAt(order, anchor.ch, anchor.sticky), part = order[index]
  if (part.from != anchor.ch && part.to != anchor.ch) return range
  let boundary = index + ((part.from == anchor.ch) == (part.level != 1) ? 0 : 1)
  if (boundary == 0 || boundary == order.length) return range

  // Compute the relative visual position of the head compared to the
  // anchor (<0 is to the left, >0 to the right)
  let leftSide
  if (head.line != anchor.line) {
    leftSide = (head.line - anchor.line) * (cm.doc.direction == "ltr" ? 1 : -1) > 0
  } else {
    let headIndex = getBidiPartAt(order, head.ch, head.sticky)
    let dir = headIndex - index || (head.ch - anchor.ch) * (part.level == 1 ? -1 : 1)
    if (headIndex == boundary - 1 || headIndex == boundary)
      leftSide = dir < 0
    else
      leftSide = dir > 0
  }

  let usePart = order[boundary + (leftSide ? -1 : 0)]
  let from = leftSide == (usePart.level == 1)
  let ch = from ? usePart.from : usePart.to, sticky = from ? "after" : "before"
  return anchor.ch == ch && anchor.sticky == sticky ? range : new Range(new Pos(anchor.line, ch, sticky), head)
}


// Determines whether an event happened in the gutter, and fires the
// handlers for the corresponding event.
function gutterEvent(cm, e, type, prevent) {
  let mX, mY
  if (e.touches) {
    mX = e.touches[0].clientX
    mY = e.touches[0].clientY
  } else {
    try { mX = e.clientX; mY = e.clientY }
    catch(e) { return false }
  }
  if (mX >= Math.floor(cm.display.gutters.getBoundingClientRect().right)) return false
  if (prevent) e_preventDefault(e)

  let display = cm.display
  let lineBox = display.lineDiv.getBoundingClientRect()

  if (mY > lineBox.bottom || !hasHandler(cm, type)) return e_defaultPrevented(e)
  mY -= lineBox.top - display.viewOffset

  for (let i = 0; i < cm.display.gutterSpecs.length; ++i) {
    let g = display.gutters.childNodes[i]
    if (g && g.getBoundingClientRect().right >= mX) {
      let line = lineAtHeight(cm.doc, mY)
      let gutter = cm.display.gutterSpecs[i]
      signal(cm, type, cm, line, gutter.className, e)
      return e_defaultPrevented(e)
    }
  }
}

export function clickInGutter(cm, e) {
  return gutterEvent(cm, e, "gutterClick", true)
}

// CONTEXT MENU HANDLING

// To make the context menu work, we need to briefly unhide the
// textarea (making it as unobtrusive as possible) to let the
// right-click take effect on it.
export function onContextMenu(cm, e) {
  if (eventInWidget(cm.display, e) || contextMenuInGutter(cm, e)) return
  if (signalDOMEvent(cm, e, "contextmenu")) return
  if (!captureRightClick) cm.display.input.onContextMenu(e)
}

function contextMenuInGutter(cm, e) {
  if (!hasHandler(cm, "gutterContextMenu")) return false
  return gutterEvent(cm, e, "gutterContextMenu", false)
}
