text: import { eltP } from "../util/dom.js"
  import { eventMixin, hasHandler, on } from "../util/event.js"
  import { endOperation, operation, runInOp, startOperation } from "../display/operations.js"
  import { clipPos, cmp, Pos } from "../line/pos.js"
  import { lineNo, updateLineHeight } from "../line/utils_line.js"
  import { clearLineMeasurementCacheFor, findViewForLine, textHeight } from "../measurement/position_measurement.js"
  import { seeReadOnlySpans, seeCollapsedSpans, seeIsolateSpans } from "../line/saw_special_spans.js"
  import { addMarkedSpan, conflictingCollapsedRange, conflictingIsolateRange, getMarkedSpanFor, lineIsHidden, lineLength, MarkedSpan, removeMarkedSpan, visualLine } from "../line/spans.js"
  import { copyObj, indexOf, lst } from "../util/misc.js"
  import { signalLater } from "../util/operation_group.js"
  import { widgetHeight } from "../measurement/widgets.js"
  import { regChange, regLineChange } from "../display/view_tracking.js"
  
  import { linkedDocs } from "./document_data.js"
  import { addChangeToHistory } from "./history.js"
  import { reCheckSelection } from "./selection_updates.js"
  
  // TEXTMARKERS
  
  // Created with markText and setBookmark methods. A TextMarker is a
  // handle that can be used to clear or find a marked position in the
  // document. Line objects hold arrays (markedSpans) containing
  // {from, to, marker} object pointing to such marker objects, and
  // indicating that such a marker is present on that line. Multiple
  // lines may point to the same marker when it spans across lines.
  // The spans will have null for their from/to properties when the
  // marker continues beyond the start/end of the line. Markers have
  // links back to the lines they currently touch.
  
  // Collapsed markers have unique ids, in order to be able to order
  // them, which is needed for uniquely determining an outer marker
  // when they overlap (they may nest, but not partially overlap).
  let nextMarkerId = 0
  
  export class TextMarker {
    constructor(doc, type) {
      this.lines = []
      this.type = type
      this.doc = doc
      this.id = ++nextMarkerId
    }
  
    // Clear the marker.
    clear() {
      if (this.explicitlyCleared) return
      let cm = this.doc.cm, withOp = cm && !cm.curOp
      if (withOp) startOperation(cm)
      if (hasHandler(this, "clear")) {
        let found = this.find()
        if (found) signalLater(this, "clear", found.from, found.to)
      }
      let min = null, max = null
      for (let i = 0; i < this.lines.length; ++i) {
        let line = this.lines[i]
        let span = getMarkedSpanFor(line.markedSpans, this)
        if (cm && !this.collapsed) regLineChange(cm, lineNo(line), "text")
        else if (cm) {
          if (span.to != null) max = lineNo(line)
          if (span.from != null) min = lineNo(line)
        }
        if (cm) { cm.state.newIsolate = true; }
        line.markedSpans = removeMarkedSpan(line.markedSpans, span)
        if (span.from == null && this.collapsed && !lineIsHidden(this.doc, line) && cm)
          updateLineHeight(line, textHeight(cm.display))
      }
      if (cm && this.collapsed && !cm.options.lineWrapping) for (let i = 0; i < this.lines.length; ++i) {
        let visual = visualLine(this.lines[i]), len = lineLength(visual)
        if (len > cm.display.maxLineLength) {
          cm.display.maxLine = visual
          cm.display.maxLineLength = len
          cm.display.maxLineChanged = true
        }
      }
  
      if (min != null && cm && this.collapsed) regChange(cm, min, max + 1)
      this.lines.length = 0
      this.explicitlyCleared = true
      if (this.atomic && this.doc.cantEdit) {
        this.doc.cantEdit = false
        if (cm) reCheckSelection(cm.doc)
      }
      if (cm) signalLater(cm, "markerCleared", cm, this, min, max)
      if (withOp) endOperation(cm)
      if (this.parent) this.parent.clear()
    }
  
    // Find the position of the marker in the document. Returns a {from,
    // to} object by default. Side can be passed to get a specific side
    // -- 0 (both), -1 (left), or 1 (right). When lineObj is true, the
    // Pos objects returned contain a line object, rather than a line
    // number (used to prevent looking up the same line twice).
    find(side, lineObj) {
      if (side == null && this.type == "bookmark") side = 1
      let from, to
      for (let i = 0; i < this.lines.length; ++i) {
        let line = this.lines[i]
        let span = getMarkedSpanFor(line.markedSpans, this)
        if (span.from != null) {
          from = Pos(lineObj ? line : lineNo(line), span.from)
          if (side == -1) return from
        }
        if (span.to != null) {
          to = Pos(lineObj ? line : lineNo(line), span.to)
          if (side == 1) return to
        }
      }
      return from && {from: from, to: to}
    }
  
    // Signals that the marker's widget changed, and surrounding layout
    // should be recomputed.
    changed() {
      let pos = this.find(-1, true), widget = this, cm = this.doc.cm
      if (!pos || !cm) return
      runInOp(cm, () => {
        let line = pos.line, lineN = lineNo(pos.line)
        let view = findViewForLine(cm, lineN)
        if (view) {
          clearLineMeasurementCacheFor(view)
          cm.curOp.selectionChanged = cm.curOp.forceUpdate = true
        }
        cm.curOp.updateMaxLine = true
        if (!lineIsHidden(widget.doc, line) && widget.height != null) {
          let oldHeight = widget.height
          widget.height = null
          let dHeight = widgetHeight(widget) - oldHeight
          if (dHeight)
            updateLineHeight(line, line.height + dHeight)
        }
        signalLater(cm, "markerChanged", cm, this)
      })
    }
  
    attachLine(line) {
      if (!this.lines.length && this.doc.cm) {
        let op = this.doc.cm.curOp
        if (!op.maybeHiddenMarkers || indexOf(op.maybeHiddenMarkers, this) == -1)
          (op.maybeUnhiddenMarkers || (op.maybeUnhiddenMarkers = [])).push(this)
      }
      this.lines.push(line)
    }
  
    detachLine(line) {
      this.lines.splice(indexOf(this.lines, line), 1)
      if (!this.lines.length && this.doc.cm) {
        let op = this.doc.cm.curOp
        ;(op.maybeHiddenMarkers || (op.maybeHiddenMarkers = [])).push(this)
      }
    }
  }
  eventMixin(TextMarker)
  
  // Create a marker, wire it up to the right lines, and
  export function markText(doc, from, to, options, type) {
    // Shared markers (across linked documents) are handled separately
    // (markTextShared will call out to this again, once per
    // document).
    if (options && options.shared) return markTextShared(doc, from, to, options, type)
    // Ensure we are in an operation.
    if (doc.cm && !doc.cm.curOp) return operation(doc.cm, markText)(doc, from, to, options, type)
  
    let marker = new TextMarker(doc, type), diff = cmp(from, to)
    if (options) copyObj(options, marker, false)
    // Don't connect empty markers unless clearWhenEmpty is false
    if (diff > 0 || diff == 0 && marker.clearWhenEmpty !== false)
      return marker
    if (marker.replacedWith) {
      // Showing up as a widget implies collapsed (widget replaces text)
      marker.collapsed = true
      marker.widgetNode = eltP("span", [marker.replacedWith], "CodeMirror-widget")
      if (!options.handleMouseEvents) marker.widgetNode.setAttribute("cm-ignore-events", "true")
      if (options.insertLeft) marker.widgetNode.insertLeft = true
    }
    if (marker.collapsed) {
      if (conflictingCollapsedRange(doc, from.line, from, to, marker) ||
          from.line != to.line && conflictingCollapsedRange(doc, to.line, from, to, marker))
        throw new Error("Inserting collapsed marker partially overlapping an existing one")
      seeCollapsedSpans()
    }
    if (marker.isolate) {
      if (conflictingIsolateRange(doc, from.line, from, to, marker) ||
          from.line != to.line && conflictingIsolateRange(doc, to.line, from, to, marker))
          { throw new Error("Inserting isolate marker partially overlapping an existing one") }
      seeIsolateSpans()
    }
  
    if (marker.addToHistory)
      addChangeToHistory(doc, {from: from, to: to, origin: "markText"}, doc.sel, NaN)
  
    let curLine = from.line, cm = doc.cm, updateMaxLine
    doc.iter(curLine, to.line + 1, line => {
      if (cm && marker.collapsed && !cm.options.lineWrapping && visualLine(line) == cm.display.maxLine)
        updateMaxLine = true
      if (marker.collapsed && curLine != from.line) updateLineHeight(line, 0)
      addMarkedSpan(line, new MarkedSpan(marker,
                                         curLine == from.line ? from.ch : null,
                                         curLine == to.line ? to.ch : null))
      ++curLine
    })
    // lineIsHidden depends on the presence of the spans, so needs a second pass
    if (marker.collapsed) doc.iter(from.line, to.line + 1, line => {
      if (lineIsHidden(doc, line)) updateLineHeight(line, 0)
    })
  
    if (marker.clearOnEnter) on(marker, "beforeCursorEnter", () => marker.clear())
  
    if (marker.readOnly) {
      seeReadOnlySpans()
      if (doc.history.done.length || doc.history.undone.length)
        doc.clearHistory()
    }
    if (marker.collapsed) {
      marker.id = ++nextMarkerId
      marker.atomic = true
    }
    if (marker.isolate) { doc.cm.state.newIsolate = true; }
    if (cm) {
      // Sync editor state
      if (updateMaxLine) cm.curOp.updateMaxLine = true
      if (marker.collapsed)
        regChange(cm, from.line, to.line + 1)
      else if (marker.className || marker.title || marker.startStyle || marker.endStyle || marker.css)
        for (let i = from.line; i <= to.line; i++) regLineChange(cm, i, "text")
      if (marker.atomic) reCheckSelection(cm.doc)
      signalLater(cm, "markerAdded", cm, marker)
    }
    return marker
  }
  
  // SHARED TEXTMARKERS
  
  // A shared marker spans multiple linked documents. It is
  // implemented as a meta-marker-object controlling multiple normal
  // markers.
  export class SharedTextMarker {
    constructor(markers, primary) {
      this.markers = markers
      this.primary = primary
      for (let i = 0; i < markers.length; ++i)
        markers[i].parent = this
    }
  
    clear() {
      if (this.explicitlyCleared) return
      this.explicitlyCleared = true
      for (let i = 0; i < this.markers.length; ++i)
        this.markers[i].clear()
      signalLater(this, "clear")
    }
  
    find(side, lineObj) {
      return this.primary.find(side, lineObj)
    }
  }
  eventMixin(SharedTextMarker)
  
  function markTextShared(doc, from, to, options, type) {
    options = copyObj(options)
    options.shared = false
    let markers = [markText(doc, from, to, options, type)], primary = markers[0]
    let widget = options.widgetNode
    linkedDocs(doc, doc => {
      if (widget) options.widgetNode = widget.cloneNode(true)
      markers.push(markText(doc, clipPos(doc, from), clipPos(doc, to), options, type))
      for (let i = 0; i < doc.linked.length; ++i)
        if (doc.linked[i].isParent) return
      primary = lst(markers)
    })
    return new SharedTextMarker(markers, primary)
  }
  
  export function findSharedMarkers(doc) {
    return doc.findMarks(Pos(doc.first, 0), doc.clipPos(Pos(doc.lastLine())), m => m.parent)
  }
  
  export function copySharedMarkers(doc, markers) {
    for (let i = 0; i < markers.length; i++) {
      let marker = markers[i], pos = marker.find()
      let mFrom = doc.clipPos(pos.from), mTo = doc.clipPos(pos.to)
      if (cmp(mFrom, mTo)) {
        let subMark = markText(doc, mFrom, mTo, marker.primary, marker.primary.type)
        marker.markers.push(subMark)
        subMark.parent = marker
      }
    }
  }
  
  export function detachSharedMarkers(markers) {
    for (let i = 0; i < markers.length; i++) {
      let marker = markers[i], linked = [marker.primary.doc]
      linkedDocs(marker.primary.doc, d => linked.push(d))
      for (let j = 0; j < marker.markers.length; j++) {
        let subMarker = marker.markers[j]
        if (indexOf(linked, subMarker.doc) == -1) {
          subMarker.parent = null
          marker.markers.splice(j--, 1)
        }
      }
    }
  }
  