import { getOrder } from "../util/bidi"
import { ie, ie_version, webkit } from "../util/browser"
import { elt, eltP, joinClasses } from "../util/dom"
import { eventMixin, signal } from "../util/event"
import { hasBadBidiRects, zeroWidthElement } from "../util/feature_detection"
import { lst, spaceStr } from "../util/misc"

import { getLineStyles } from "./highlight"
import { attachMarkedSpans, compareCollapsedMarkers, detachMarkedSpans, lineIsHidden, visualLineContinued } from "./spans"
import { getLine, lineNo, updateLineHeight } from "./utils_line"

// LINE DATA STRUCTURE

// Line objects. These hold state related to a line, including
// highlighting info (the styles array).
export class Line {
  constructor(text, markedSpans, estimateHeight) {
    this.text = text
    attachMarkedSpans(this, markedSpans)
    this.height = estimateHeight ? estimateHeight(this) : 1
  }

  lineNo() { return lineNo(this) }
}
eventMixin(Line)

// Change the content (text, markers) of a line. Automatically
// invalidates cached information and tries to re-estimate the
// line's height.
export function updateLine(line, text, markedSpans, estimateHeight) {
  line.text = text
  if (line.stateAfter) line.stateAfter = null
  if (line.styles) line.styles = null
  if (line.order != null) line.order = null
  detachMarkedSpans(line)
  attachMarkedSpans(line, markedSpans)
  let estHeight = estimateHeight ? estimateHeight(line) : 1
  if (estHeight != line.height) updateLineHeight(line, estHeight)
}

// Detach a line from the document tree and its markers.
export function cleanUpLine(line) {
  line.parent = null
  detachMarkedSpans(line)
}

// Convert a style as returned by a mode (either null, or a string
// containing one or more styles) to a CSS style. This is cached,
// and also looks for line-wide styles.
let styleToClassCache = {}, styleToClassCacheWithMode = {}
function interpretTokenStyle(style, options) {
  if (!style || /^\s*$/.test(style)) return null
  let cache = options.addModeClass ? styleToClassCacheWithMode : styleToClassCache
  return cache[style] ||
    (cache[style] = style.replace(/\S+/g, "cm-$&"))
}

// Render the DOM representation of the text of a line. Also builds
// up a 'line map', which points at the DOM nodes that represent
// specific stretches of text, and is used by the measuring code.
// The returned object contains the DOM node, this map, and
// information about line-wide styles that were set by the mode.
export function buildLineContent(cm, lineView) {
  // The padding-right forces the element to have a 'border', which
  // is needed on Webkit to be able to get line-level bounding
  // rectangles for it (in measureChar).
  let content = eltP("span", null, null, webkit ? "padding-right: .1px" : null)
  let builder = {pre: eltP("pre", [content], "CodeMirror-line"), content: content,
                 col: 0, pos: 0, cm: cm,
                 trailingSpace: false,
                 splitSpaces: (ie || webkit) && cm.getOption("lineWrapping")}
  lineView.measure = {}

  // Iterate over the logical lines that make up this visual line.
  for (let i = 0; i <= (lineView.rest ? lineView.rest.length : 0); i++) {
    let line = i ? lineView.rest[i - 1] : lineView.line, order
    builder.pos = 0
    builder.addToken = buildToken
    // Optionally wire in some hacks into the token-rendering
    // algorithm, to deal with browser quirks.
    if (hasBadBidiRects(cm.display.measure) && (order = getOrder(line, cm.doc.direction)))
      builder.addToken = buildTokenBadBidi(builder.addToken, order)
    builder.map = []
    let allowFrontierUpdate = lineView != cm.display.externalMeasured && lineNo(line)
    insertLineContent(line, builder, getLineStyles(cm, line, allowFrontierUpdate))
    if (line.styleClasses) {
      if (line.styleClasses.bgClass)
        builder.bgClass = joinClasses(line.styleClasses.bgClass, builder.bgClass || "")
      if (line.styleClasses.textClass)
        builder.textClass = joinClasses(line.styleClasses.textClass, builder.textClass || "")
    }

    // Ensure at least a single node is present, for measuring.
    if (builder.map.length == 0)
      builder.map.push(0, 0, builder.content.appendChild(zeroWidthElement(cm.display.measure)))

    // Store the map and a cache object for the current logical line
    if (i == 0) {
      lineView.measure.map = builder.map
      lineView.measure.cache = {}
    } else {
      ;(lineView.measure.maps || (lineView.measure.maps = [])).push(builder.map)
      ;(lineView.measure.caches || (lineView.measure.caches = [])).push({})
    }
  }

  // See issue #2901
  if (webkit) {
    let last = builder.content.lastChild
    if (/\bcm-tab\b/.test(last.className) || (last.querySelector && last.querySelector(".cm-tab")))
      builder.content.className = "cm-tab-wrap-hack"
  }

  signal(cm, "renderLine", cm, lineView.line, builder.pre)
  if (builder.pre.className)
    builder.textClass = joinClasses(builder.pre.className, builder.textClass || "")

  return builder
}

export function defaultSpecialCharPlaceholder(ch) {
  let token = elt("span", "\u2022", "cm-invalidchar")
  token.title = "\\u" + ch.charCodeAt(0).toString(16)
  token.setAttribute("aria-label", token.title)
  return token
}

// Build up the DOM representation for a single token, and add it to
// the line map. Takes care to render special characters separately.
function buildToken(builder, text, style, startStyle, endStyle, title, css) {
  if (!text) return
  let displayText = builder.splitSpaces ? splitSpaces(text, builder.trailingSpace) : text
  let special = builder.cm.state.specialChars, mustWrap = false
  let content
  if (!special.test(text)) {
    builder.col += text.length
    content = document.createTextNode(displayText)
    builder.map.push(builder.pos, builder.pos + text.length, content)
    if (ie && ie_version < 9) mustWrap = true
    builder.pos += text.length
  } else {
    content = document.createDocumentFragment()
    let pos = 0
    while (true) {
      special.lastIndex = pos
      let m = special.exec(text)
      let skipped = m ? m.index - pos : text.length - pos
      if (skipped) {
        let txt = document.createTextNode(displayText.slice(pos, pos + skipped))
        if (ie && ie_version < 9) content.appendChild(elt("span", [txt]))
        else content.appendChild(txt)
        builder.map.push(builder.pos, builder.pos + skipped, txt)
        builder.col += skipped
        builder.pos += skipped
      }
      if (!m) break
      pos += skipped + 1
      let txt
      if (m[0] == "\t") {
        let tabSize = builder.cm.options.tabSize, tabWidth = tabSize - builder.col % tabSize
        txt = content.appendChild(elt("span", spaceStr(tabWidth), "cm-tab"))
        txt.setAttribute("role", "presentation")
        txt.setAttribute("cm-text", "\t")
        builder.col += tabWidth
      } else if (m[0] == "\r" || m[0] == "\n") {
        txt = content.appendChild(elt("span", m[0] == "\r" ? "\u240d" : "\u2424", "cm-invalidchar"))
        txt.setAttribute("cm-text", m[0])
        builder.col += 1
      } else {
        txt = builder.cm.options.specialCharPlaceholder(m[0])
        txt.setAttribute("cm-text", m[0])
        if (ie && ie_version < 9) content.appendChild(elt("span", [txt]))
        else content.appendChild(txt)
        builder.col += 1
      }
      builder.map.push(builder.pos, builder.pos + 1, txt)
      builder.pos++
    }
  }
  builder.trailingSpace = displayText.charCodeAt(text.length - 1) == 32
  if (style || startStyle || endStyle || mustWrap || css) {
    let fullStyle = style || ""
    if (startStyle) fullStyle += startStyle
    if (endStyle) fullStyle += endStyle
    let token = elt("span", [content], fullStyle, css)
    if (title) token.title = title
    return builder.content.appendChild(token)
  }
  builder.content.appendChild(content)
}

function splitSpaces(text, trailingBefore) {
  if (text.length > 1 && !/  /.test(text)) return text
  let spaceBefore = trailingBefore, result = ""
  for (let i = 0; i < text.length; i++) {
    let ch = text.charAt(i)
    if (ch == " " && spaceBefore && (i == text.length - 1 || text.charCodeAt(i + 1) == 32))
      ch = "\u00a0"
    result += ch
    spaceBefore = ch == " "
  }
  return result
}

// Work around nonsense dimensions being reported for stretches of
// right-to-left text.
function buildTokenBadBidi(inner, order) {
  return (builder, text, style, startStyle, endStyle, title, css) => {
    style = style ? style + " cm-force-border" : "cm-force-border"
    let start = builder.pos, end = start + text.length
    for (;;) {
      // Find the part that overlaps with the start of this text
      let part
      for (let i = 0; i < order.length; i++) {
        part = order[i]
        if (part.to > start && part.from <= start) break
      }
      if (part.to >= end) return inner(builder, text, style, startStyle, endStyle, title, css)
      inner(builder, text.slice(0, part.to - start), style, startStyle, null, title, css)
      startStyle = null
      text = text.slice(part.to - start)
      start = part.to
    }
  }
}

function buildCollapsedSpan(builder, size, marker, ignoreWidget) {
  let widget = !ignoreWidget && marker.widgetNode
  if (widget) builder.map.push(builder.pos, builder.pos + size, widget)
  if (!ignoreWidget && builder.cm.display.input.needsContentAttribute) {
    if (!widget)
      widget = builder.content.appendChild(document.createElement("span"))
    widget.setAttribute("cm-marker", marker.id)
  }
  if (widget) {
    builder.cm.display.input.setUneditable(widget)
    builder.content.appendChild(widget)
  }
  builder.pos += size
  builder.trailingSpace = false
}

// Outputs a number of spans to make up a line, taking highlighting
// and marked text into account.
function insertLineContent(line, builder, styles) {
  let spans = line.markedSpans, allText = line.text, at = 0
  if (!spans) {
    for (let i = 1; i < styles.length; i+=2)
      builder.addToken(builder, allText.slice(at, at = styles[i]), interpretTokenStyle(styles[i+1], builder.cm.options))
    return
  }

  let len = allText.length, pos = 0, i = 1, text = "", style, css
  let nextChange = 0, spanStyle, spanEndStyle, spanStartStyle, title, collapsed
  for (;;) {
    if (nextChange == pos) { // Update current marker set
      spanStyle = spanEndStyle = spanStartStyle = title = css = ""
      collapsed = null; nextChange = Infinity
      let foundBookmarks = [], endStyles
      for (let j = 0; j < spans.length; ++j) {
        let sp = spans[j], m = sp.marker
        if (m.type == "bookmark" && sp.from == pos && m.widgetNode) {
          foundBookmarks.push(m)
        } else if (sp.from <= pos && (sp.to == null || sp.to > pos || m.collapsed && sp.to == pos && sp.from == pos)) {
          if (sp.to != null && sp.to != pos && nextChange > sp.to) {
            nextChange = sp.to
            spanEndStyle = ""
          }
          if (m.className) spanStyle += " " + m.className
          if (m.css) css = (css ? css + ";" : "") + m.css
          if (m.startStyle && sp.from == pos) spanStartStyle += " " + m.startStyle
          if (m.endStyle && sp.to == nextChange) (endStyles || (endStyles = [])).push(m.endStyle, sp.to)
          if (m.title && !title) title = m.title
          if (m.collapsed && (!collapsed || compareCollapsedMarkers(collapsed.marker, m) < 0))
            collapsed = sp
        } else if (sp.from > pos && nextChange > sp.from) {
          nextChange = sp.from
        }
      }
      if (endStyles) for (let j = 0; j < endStyles.length; j += 2)
        if (endStyles[j + 1] == nextChange) spanEndStyle += " " + endStyles[j]

      if (!collapsed || collapsed.from == pos) for (let j = 0; j < foundBookmarks.length; ++j)
        buildCollapsedSpan(builder, 0, foundBookmarks[j])
      if (collapsed && (collapsed.from || 0) == pos) {
        buildCollapsedSpan(builder, (collapsed.to == null ? len + 1 : collapsed.to) - pos,
                           collapsed.marker, collapsed.from == null)
        if (collapsed.to == null) return
        if (collapsed.to == pos) collapsed = false
      }
    }
    if (pos >= len) break

    let upto = Math.min(len, nextChange)
    while (true) {
      if (text) {
        let end = pos + text.length
        if (!collapsed) {
          let tokenText = end > upto ? text.slice(0, upto - pos) : text
          builder.addToken(builder, tokenText, style ? style + spanStyle : spanStyle,
                           spanStartStyle, pos + tokenText.length == nextChange ? spanEndStyle : "", title, css)
        }
        if (end >= upto) {text = text.slice(upto - pos); pos = upto; break}
        pos = end
        spanStartStyle = ""
      }
      text = allText.slice(at, at = styles[i++])
      style = interpretTokenStyle(styles[i++], builder.cm.options)
    }
  }
}


// These objects are used to represent the visible (currently drawn)
// part of the document. A LineView may correspond to multiple
// logical lines, if those are connected by collapsed ranges.
export function LineView(doc, line, lineN) {
  // The starting line
  this.line = line
  // Continuing lines, if any
  this.rest = visualLineContinued(line)
  // Number of logical lines in this visual line
  this.size = this.rest ? lineNo(lst(this.rest)) - lineN + 1 : 1
  this.node = this.text = null
  this.hidden = lineIsHidden(doc, line)
}

// Create a range of LineView objects for the given lines.
export function buildViewArray(cm, from, to) {
  let array = [], nextPos
  for (let pos = from; pos < to; pos = nextPos) {
    let view = new LineView(cm.doc, getLine(cm.doc, pos), pos)
    nextPos = pos + view.size
    array.push(view)
  }
  return array
}
