/**
 * screen.js - screen node for blessed
 * Copyright (c) 2013-2015, Christopher Jeffrey and contributors (MIT License).
 * https://github.com/chjj/blessed
 */

/**
 * Modules
 */

const path = require('node:path'),
  fs = require('node:fs'),
  cp = require('node:child_process')

const colors = require('../colors'),
  program = require('../program'),
  unicode = require('../unicode')

const nextTick = global.setImmediate || process.nextTick.bind(process)

const Node = require('./node')

/**
 * Screen
 */

function Screen(options) {
  const self = this
  if (!(this instanceof Node)) {
    return new Screen(options)
  }

  Screen.bind(this)

  options = options || {}
  if (options.rsety && options.listen) {
    options = { program: options }
  }

  this.program = options.program

  if (!this.program) {
    this.program = program({
      input: options.input,
      output: options.output,
      log: options.log,
      debug: options.debug,
      dump: options.dump,
      terminal: options.terminal || options.term,
      resizeTimeout: options.resizeTimeout,
      forceUnicode: options.forceUnicode,
      tput: true,
      buffer: true,
      zero: true
    })
  } else {
    this.program.setupTput()
    this.program.useBuffer = true
    this.program.zero = true
    this.program.options.resizeTimeout = options.resizeTimeout
    if (options.forceUnicode != null) {
      this.program.tput.features.unicode = options.forceUnicode
      this.program.tput.unicode = options.forceUnicode
    }
  }

  this.tput = this.program.tput

  Node.call(this, options)

  this.autoPadding = options.autoPadding !== false
  this.tabc = Array((options.tabSize || 4) + 1).join(' ')
  this.dockBorders = options.dockBorders

  this.ignoreLocked = options.ignoreLocked || []

  this._unicode = this.tput.unicode || this.tput.numbers.U8 === 1
  this.fullUnicode = this.options.fullUnicode && this._unicode

  this.dattr = (0 << 18) | (0x1ff << 9) | 0x1ff

  this.renders = 0
  this.position = {
    left: (this.left = this.aleft = this.rleft = 0),
    right: (this.right = this.aright = this.rright = 0),
    top: (this.top = this.atop = this.rtop = 0),
    bottom: (this.bottom = this.abottom = this.rbottom = 0),
    get height() {
      return self.height
    },
    get width() {
      return self.width
    }
  }

  this.ileft = 0
  this.itop = 0
  this.iright = 0
  this.ibottom = 0
  this.iheight = 0
  this.iwidth = 0

  this.padding = {
    left: 0,
    top: 0,
    right: 0,
    bottom: 0
  }

  this.hover = null
  this.history = []
  this.clickable = []
  this.keyable = []
  this.grabKeys = false
  this.lockKeys = false
  this.focused
  this._buf = ''

  this._ci = -1

  if (options.title) {
    this.title = options.title
  }

  options.cursor = options.cursor || {
    artificial: options.artificialCursor,
    shape: options.cursorShape,
    blink: options.cursorBlink,
    color: options.cursorColor
  }

  this.cursor = {
    artificial: options.cursor.artificial || false,
    shape: options.cursor.shape || 'block',
    blink: options.cursor.blink || false,
    color: options.cursor.color || null,
    _set: false,
    _state: 1,
    _hidden: true
  }

  this.program.on('resize', function () {
    self.alloc()
    self.render()
    ;(function emit(el) {
      el.emit('resize')
      el.children.forEach(emit)
    })(self)
  })

  this.program.on('focus', function () {
    self.emit('focus')
  })

  this.program.on('blur', function () {
    self.emit('blur')
  })

  this.program.on('warning', function (text) {
    self.emit('warning', text)
  })

  this.on('newListener', function fn(type) {
    if (type === 'keypress' || type.indexOf('key ') === 0 || type === 'mouse') {
      if (type === 'keypress' || type.indexOf('key ') === 0) {
        self._listenKeys()
      }
      if (type === 'mouse') {
        self._listenMouse()
      }
    }
    if (
      type === 'mouse' ||
      type === 'click' ||
      type === 'mouseover' ||
      type === 'mouseout' ||
      type === 'mousedown' ||
      type === 'mouseup' ||
      type === 'mousewheel' ||
      type === 'wheeldown' ||
      type === 'wheelup' ||
      type === 'mousemove'
    ) {
      self._listenMouse()
    }
  })

  this.setMaxListeners(Infinity)

  this.enter()

  this.postEnter()
}

Screen.global = null

Screen.total = 0

Screen.instances = []

Screen.bind = function (screen) {
  if (!Screen.global) {
    Screen.global = screen
  }

  if (!~Screen.instances.indexOf(screen)) {
    Screen.instances.push(screen)
    screen.index = Screen.total
    Screen.total++
  }

  if (Screen._bound) {
    return
  }
  Screen._bound = true

  process.on(
    'uncaughtException',
    (Screen._exceptionHandler = function (err) {
      if (process.listeners('uncaughtException').length > 1) {
        return
      }
      Screen.instances.slice().forEach(function (screen) {
        screen.destroy()
      })
      err = err || new Error('Uncaught Exception.')
      console.error(err.stack ? err.stack + '' : err + '')
      nextTick(function () {
        process.exit(1)
      })
    })
  )

  ;['SIGTERM', 'SIGINT', 'SIGQUIT'].forEach(function (signal) {
    const name = '_' + signal.toLowerCase() + 'Handler'
    process.on(
      signal,
      (Screen[name] = function () {
        if (process.listeners(signal).length > 1) {
          return
        }
        nextTick(function () {
          process.exit(0)
        })
      })
    )
  })

  process.on(
    'exit',
    (Screen._exitHandler = function () {
      Screen.instances.slice().forEach(function (screen) {
        screen.destroy()
      })
    })
  )
}

Object.setPrototypeOf(Screen.prototype, Node.prototype)

Screen.prototype.type = 'screen'

Screen.prototype.__defineGetter__('title', function () {
  return this.program.title
})

Screen.prototype.__defineSetter__('title', function (title) {
  return (this.program.title = title)
})

Screen.prototype.__defineGetter__('terminal', function () {
  return this.program.terminal
})

Screen.prototype.__defineSetter__('terminal', function (terminal) {
  this.setTerminal(terminal)
  return this.program.terminal
})

Screen.prototype.setTerminal = function (terminal) {
  const entered = !!this.program.isAlt
  if (entered) {
    this._buf = ''
    this.program._buf = ''
    this.leave()
  }
  this.program.setTerminal(terminal)
  this.tput = this.program.tput
  if (entered) {
    this.enter()
  }
}

Screen.prototype.enter = function () {
  if (this.program.isAlt) {
    return
  }
  if (!this.cursor._set) {
    if (this.options.cursor.shape) {
      this.cursorShape(this.cursor.shape, this.cursor.blink)
    }
    if (this.options.cursor.color) {
      this.cursorColor(this.cursor.color)
    }
  }
  if (process.platform === 'win32') {
    try {
      cp.execSync('cls', { stdio: 'ignore', timeout: 1000 })
    } catch (e) {}
  }
  this.program.alternateBuffer()
  this.program.put.keypad_xmit()
  this.program.csr(0, this.height - 1)
  this.program.hideCursor()
  this.program.cup(0, 0)
  // We need this for tmux now:
  if (this.tput.strings.ena_acs) {
    this.program._write(this.tput.enacs())
  }
  this.alloc()
}

Screen.prototype.leave = function () {
  if (!this.program.isAlt) {
    return
  }
  this.program.put.keypad_local()
  if (
    this.program.scrollTop !== 0 ||
    this.program.scrollBottom !== this.rows - 1
  ) {
    this.program.csr(0, this.height - 1)
  }
  // XXX For some reason if alloc/clear() is before this
  // line, it doesn't work on linux console.
  this.program.showCursor()
  this.alloc()
  if (this._listenedMouse) {
    this.program.disableMouse()
  }
  this.program.normalBuffer()
  if (this.cursor._set) {
    this.cursorReset()
  }
  this.program.flush()
  if (process.platform === 'win32') {
    try {
      cp.execSync('cls', { stdio: 'ignore', timeout: 1000 })
    } catch (e) {}
  }
}

Screen.prototype.postEnter = function () {
  const self = this
  if (this.options.debug) {
    const Log = require('./log')
    this.debugLog = new Log({
      screen: this,
      parent: this,
      hidden: true,
      draggable: true,
      left: 'center',
      top: 'center',
      width: '30%',
      height: '30%',
      border: 'line',
      label: ' {bold}Debug Log{/bold} ',
      tags: true,
      keys: true,
      vi: true,
      mouse: true,
      scrollbar: {
        ch: ' ',
        track: {
          bg: 'yellow'
        },
        style: {
          inverse: true
        }
      }
    })

    this.debugLog.toggle = function () {
      if (self.debugLog.hidden) {
        self.saveFocus()
        self.debugLog.show()
        self.debugLog.setFront()
        self.debugLog.focus()
      } else {
        self.debugLog.hide()
        self.restoreFocus()
      }
      self.render()
    }

    this.debugLog.key(['q', 'escape'], self.debugLog.toggle)
    this.key('f12', self.debugLog.toggle)
  }

  if (this.options.warnings) {
    this.on('warning', function (text) {
      const Box = require('./box')
      const warning = new Box({
        screen: self,
        parent: self,
        left: 'center',
        top: 'center',
        width: 'shrink',
        padding: 1,
        height: 'shrink',
        align: 'center',
        valign: 'middle',
        border: 'line',
        label: ' {red-fg}{bold}WARNING{/} ',
        content: '{bold}' + text + '{/bold}',
        tags: true
      })
      self.render()
      const timeout = setTimeout(function () {
        warning.destroy()
        self.render()
      }, 1500)
      if (timeout.unref) {
        timeout.unref()
      }
    })
  }
}

Screen.prototype._destroy = Screen.prototype.destroy
Screen.prototype.destroy = function () {
  this.leave()

  const index = Screen.instances.indexOf(this)
  if (~index) {
    Screen.instances.splice(index, 1)
    Screen.total--

    Screen.global = Screen.instances[0]

    if (Screen.total === 0) {
      Screen.global = null

      process.removeListener('uncaughtException', Screen._exceptionHandler)
      process.removeListener('SIGTERM', Screen._sigtermHandler)
      process.removeListener('SIGINT', Screen._sigintHandler)
      process.removeListener('SIGQUIT', Screen._sigquitHandler)
      process.removeListener('exit', Screen._exitHandler)
      delete Screen._exceptionHandler
      delete Screen._sigtermHandler
      delete Screen._sigintHandler
      delete Screen._sigquitHandler
      delete Screen._exitHandler

      delete Screen._bound
    }

    this.destroyed = true
    this.emit('destroy')
    this._destroy()
  }

  this.program.destroy()
}

Screen.prototype.log = function () {
  return this.program.log.apply(this.program, arguments)
}

Screen.prototype.debug = function () {
  if (this.debugLog) {
    this.debugLog.log.apply(this.debugLog, arguments)
  }
  return this.program.debug.apply(this.program, arguments)
}

Screen.prototype._listenMouse = function (el) {
  const self = this

  if (el && !~this.clickable.indexOf(el)) {
    el.clickable = true
    this.clickable.push(el)
  }

  if (this._listenedMouse) {
    return
  }
  this._listenedMouse = true

  this.program.enableMouse()
  if (this.options.sendFocus) {
    this.program.setMouse({ sendFocus: true }, true)
  }

  this.on('render', function () {
    self._needsClickableSort = true
  })

  this.program.on('mouse', function (data) {
    if (self.lockKeys) {
      return
    }

    if (self._needsClickableSort) {
      const helpers = require('../helpers')
      self.clickable = helpers.hsort(self.clickable)
      self._needsClickableSort = false
    }

    let i = 0,
      el,
      set,
      pos

    for (; i < self.clickable.length; i++) {
      el = self.clickable[i]

      if (el.detached || !el.visible) {
        continue
      }

      // if (self.grabMouse && self.focused !== el
      //     && !el.hasAncestor(self.focused)) continue;

      pos = el.lpos
      if (!pos) {
        continue
      }

      if (
        data.x >= pos.xi &&
        data.x < pos.xl &&
        data.y >= pos.yi &&
        data.y < pos.yl
      ) {
        el.emit('mouse', data)
        if (data.action === 'mousedown') {
          self.mouseDown = el
        } else if (data.action === 'mouseup') {
          ;(self.mouseDown || el).emit('click', data)
          self.mouseDown = null
        } else if (data.action === 'mousemove') {
          if (self.hover && el.index > self.hover.index) {
            set = false
          }
          if (self.hover !== el && !set) {
            if (self.hover) {
              self.hover.emit('mouseout', data)
            }
            el.emit('mouseover', data)
            self.hover = el
          }
          set = true
        }
        el.emit(data.action, data)
        break
      }
    }

    // Just mouseover?
    if (
      (data.action === 'mousemove' ||
        data.action === 'mousedown' ||
        data.action === 'mouseup') &&
      self.hover &&
      !set
    ) {
      self.hover.emit('mouseout', data)
      self.hover = null
    }

    self.emit('mouse', data)
    self.emit(data.action, data)
  })

  // Autofocus highest element.
  // this.on('element click', function(el, data) {
  //   var target;
  //   do {
  //     if (el.clickable === true && el.options.autoFocus !== false) {
  //       target = el;
  //     }
  //   } while (el = el.parent);
  //   if (target) target.focus();
  // });

  // Autofocus elements with the appropriate option.
  this.on('element click', function (el) {
    if (el.clickable === true && el.options.autoFocus !== false) {
      el.focus()
    }
  })
}

Screen.prototype.enableMouse = function (el) {
  this._listenMouse(el)
}

Screen.prototype._listenKeys = function (el) {
  const self = this

  if (el && !~this.keyable.indexOf(el)) {
    el.keyable = true
    this.keyable.push(el)
  }

  if (this._listenedKeys) {
    return
  }
  this._listenedKeys = true

  // NOTE: The event emissions used to be reversed:
  // element + screen
  // They are now:
  // screen + element
  // After the first keypress emitted, the handler
  // checks to make sure grabKeys, lockKeys, and focused
  // weren't changed, and handles those situations appropriately.
  this.program.on('keypress', function (ch, key) {
    if (self.lockKeys && !~self.ignoreLocked.indexOf(key.full)) {
      return
    }

    const focused = self.focused,
      grabKeys = self.grabKeys

    if (!grabKeys || ~self.ignoreLocked.indexOf(key.full)) {
      self.emit('keypress', ch, key)
      self.emit('key ' + key.full, ch, key)
    }

    // If something changed from the screen key handler, stop.
    if (self.grabKeys !== grabKeys || self.lockKeys) {
      return
    }

    if (focused && focused.keyable) {
      focused.emit('keypress', ch, key)
      focused.emit('key ' + key.full, ch, key)
    }
  })
}

Screen.prototype.enableKeys = function (el) {
  this._listenKeys(el)
}

Screen.prototype.enableInput = function (el) {
  this._listenMouse(el)
  this._listenKeys(el)
}

Screen.prototype._initHover = function () {
  const self = this

  if (this._hoverText) {
    return
  }
  const Box = require('./box')
  this._hoverText = new Box({
    screen: this,
    left: 0,
    top: 0,
    tags: false,
    height: 'shrink',
    width: 'shrink',
    border: 'line',
    style: {
      border: {
        fg: 'default'
      },
      bg: 'default',
      fg: 'default'
    }
  })

  this.on('mousemove', function (data) {
    if (self._hoverText.detached) {
      return
    }
    self._hoverText.rleft = data.x + 1
    self._hoverText.rtop = data.y
    self.render()
  })

  this.on('element mouseover', function (el, data) {
    if (!el._hoverOptions) {
      return
    }
    self._hoverText.parseTags = el.parseTags
    self._hoverText.setContent(el._hoverOptions.text)
    self.append(self._hoverText)
    self._hoverText.rleft = data.x + 1
    self._hoverText.rtop = data.y
    self.render()
  })

  this.on('element mouseout', function () {
    if (self._hoverText.detached) {
      return
    }
    self._hoverText.detach()
    self.render()
  })

  // XXX This can cause problems if the
  // terminal does not support allMotion.
  // Workaround: check to see if content is set.
  this.on('element mouseup', function (el) {
    if (!self._hoverText.getContent()) {
      return
    }
    if (!el._hoverOptions) {
      return
    }
    self.append(self._hoverText)
    self.render()
  })
}

Screen.prototype.__defineGetter__('cols', function () {
  return this.program.cols
})

Screen.prototype.__defineGetter__('rows', function () {
  return this.program.rows
})

Screen.prototype.__defineGetter__('width', function () {
  return this.program.cols
})

Screen.prototype.__defineGetter__('height', function () {
  return this.program.rows
})

Screen.prototype.alloc = function (dirty) {
  let x, y

  this.lines = []
  for (y = 0; y < this.rows; y++) {
    this.lines[y] = []
    for (x = 0; x < this.cols; x++) {
      this.lines[y][x] = [this.dattr, ' ']
    }
    this.lines[y].dirty = !!dirty
  }

  this.olines = []
  for (y = 0; y < this.rows; y++) {
    this.olines[y] = []
    for (x = 0; x < this.cols; x++) {
      this.olines[y][x] = [this.dattr, ' ']
    }
  }

  this.program.clear()
}

Screen.prototype.realloc = function () {
  return this.alloc(true)
}

Screen.prototype.render = function () {
  const self = this

  if (this.destroyed) {
    return
  }

  this.emit('prerender')

  this._borderStops = {}

  // TODO: Possibly get rid of .dirty altogether.
  // TODO: Could possibly drop .dirty and just clear the `lines` buffer every
  // time before a screen.render. This way clearRegion doesn't have to be
  // called in arbitrary places for the sake of clearing a spot where an
  // element used to be (e.g. when an element moves or is hidden). There could
  // be some overhead though.
  // this.screen.clearRegion(0, this.cols, 0, this.rows);
  this._ci = 0
  this.children.forEach(function (el) {
    el.index = self._ci++
    //el._rendering = true;
    el.render()
    //el._rendering = false;
  })
  this._ci = -1

  if (this.screen.dockBorders) {
    this._dockBorders()
  }

  this.draw(0, this.lines.length - 1)

  // XXX Workaround to deal with cursor pos before the screen has rendered and
  // lpos is not reliable (stale).
  if (this.focused && this.focused._updateCursor) {
    this.focused._updateCursor(true)
  }

  this.renders++

  this.emit('render')
}

Screen.prototype.blankLine = function (ch, dirty) {
  const out = []
  for (let x = 0; x < this.cols; x++) {
    out[x] = [this.dattr, ch || ' ']
  }
  out.dirty = dirty
  return out
}

Screen.prototype.insertLine = function (n, y, top, bottom) {
  // if (y === top) return this.insertLineNC(n, y, top, bottom);

  if (
    !this.tput.strings.change_scroll_region ||
    !this.tput.strings.delete_line ||
    !this.tput.strings.insert_line
  ) {
    return
  }

  this._buf += this.tput.csr(top, bottom)
  this._buf += this.tput.cup(y, 0)
  this._buf += this.tput.il(n)
  this._buf += this.tput.csr(0, this.height - 1)

  const j = bottom + 1

  while (n--) {
    this.lines.splice(y, 0, this.blankLine())
    this.lines.splice(j, 1)
    this.olines.splice(y, 0, this.blankLine())
    this.olines.splice(j, 1)
  }
}

Screen.prototype.deleteLine = function (n, y, top, bottom) {
  // if (y === top) return this.deleteLineNC(n, y, top, bottom);

  if (
    !this.tput.strings.change_scroll_region ||
    !this.tput.strings.delete_line ||
    !this.tput.strings.insert_line
  ) {
    return
  }

  this._buf += this.tput.csr(top, bottom)
  this._buf += this.tput.cup(y, 0)
  this._buf += this.tput.dl(n)
  this._buf += this.tput.csr(0, this.height - 1)

  const j = bottom + 1

  while (n--) {
    this.lines.splice(j, 0, this.blankLine())
    this.lines.splice(y, 1)
    this.olines.splice(j, 0, this.blankLine())
    this.olines.splice(y, 1)
  }
}

// This is how ncurses does it.
// Scroll down (up cursor-wise).
// This will only work for top line deletion as opposed to arbitrary lines.
Screen.prototype.insertLineNC = function (n, y, top, bottom) {
  if (
    !this.tput.strings.change_scroll_region ||
    !this.tput.strings.delete_line
  ) {
    return
  }

  this._buf += this.tput.csr(top, bottom)
  this._buf += this.tput.cup(top, 0)
  this._buf += this.tput.dl(n)
  this._buf += this.tput.csr(0, this.height - 1)

  const j = bottom + 1

  while (n--) {
    this.lines.splice(j, 0, this.blankLine())
    this.lines.splice(y, 1)
    this.olines.splice(j, 0, this.blankLine())
    this.olines.splice(y, 1)
  }
}

// This is how ncurses does it.
// Scroll up (down cursor-wise).
// This will only work for bottom line deletion as opposed to arbitrary lines.
Screen.prototype.deleteLineNC = function (n, y, top, bottom) {
  if (
    !this.tput.strings.change_scroll_region ||
    !this.tput.strings.delete_line
  ) {
    return
  }

  this._buf += this.tput.csr(top, bottom)
  this._buf += this.tput.cup(bottom, 0)
  this._buf += Array(n + 1).join('\n')
  this._buf += this.tput.csr(0, this.height - 1)

  const j = bottom + 1

  while (n--) {
    this.lines.splice(j, 0, this.blankLine())
    this.lines.splice(y, 1)
    this.olines.splice(j, 0, this.blankLine())
    this.olines.splice(y, 1)
  }
}

Screen.prototype.insertBottom = function (top, bottom) {
  return this.deleteLine(1, top, top, bottom)
}

Screen.prototype.insertTop = function (top, bottom) {
  return this.insertLine(1, top, top, bottom)
}

Screen.prototype.deleteBottom = function (top, bottom) {
  return this.clearRegion(0, this.width, bottom, bottom)
}

Screen.prototype.deleteTop = function (top, bottom) {
  // Same as: return this.insertBottom(top, bottom);
  return this.deleteLine(1, top, top, bottom)
}

// Parse the sides of an element to determine
// whether an element has uniform cells on
// both sides. If it does, we can use CSR to
// optimize scrolling on a scrollable element.
// Not exactly sure how worthwile this is.
// This will cause a performance/cpu-usage hit,
// but will it be less or greater than the
// performance hit of slow-rendering scrollable
// boxes with clean sides?
Screen.prototype.cleanSides = function (el) {
  const pos = el.lpos

  if (!pos) {
    return false
  }

  if (pos._cleanSides != null) {
    return pos._cleanSides
  }

  if (pos.xi <= 0 && pos.xl >= this.width) {
    return (pos._cleanSides = true)
  }

  if (this.options.fastCSR) {
    // Maybe just do this instead of parsing.
    if (pos.yi < 0) {
      return (pos._cleanSides = false)
    }
    if (pos.yl > this.height) {
      return (pos._cleanSides = false)
    }
    if (this.width - (pos.xl - pos.xi) < 40) {
      return (pos._cleanSides = true)
    }
    return (pos._cleanSides = false)
  }

  if (!this.options.smartCSR) {
    return false
  }

  // The scrollbar can't update properly, and there's also a
  // chance that the scrollbar may get moved around senselessly.
  // NOTE: In pratice, this doesn't seem to be the case.
  // if (this.scrollbar) {
  //   return pos._cleanSides = false;
  // }

  // Doesn't matter if we're only a height of 1.
  // if ((pos.yl - el.ibottom) - (pos.yi + el.itop) <= 1) {
  //   return pos._cleanSides = false;
  // }

  let yi = pos.yi + el.itop,
    yl = pos.yl - el.ibottom,
    first,
    ch,
    x,
    y

  if (pos.yi < 0) {
    return (pos._cleanSides = false)
  }
  if (pos.yl > this.height) {
    return (pos._cleanSides = false)
  }
  if (pos.xi - 1 < 0) {
    return (pos._cleanSides = true)
  }
  if (pos.xl > this.width) {
    return (pos._cleanSides = true)
  }

  for (x = pos.xi - 1; x >= 0; x--) {
    if (!this.olines[yi]) {
      break
    }
    first = this.olines[yi][x]
    for (y = yi; y < yl; y++) {
      if (!this.olines[y] || !this.olines[y][x]) {
        break
      }
      ch = this.olines[y][x]
      if (ch[0] !== first[0] || ch[1] !== first[1]) {
        return (pos._cleanSides = false)
      }
    }
  }

  for (x = pos.xl; x < this.width; x++) {
    if (!this.olines[yi]) {
      break
    }
    first = this.olines[yi][x]
    for (y = yi; y < yl; y++) {
      if (!this.olines[y] || !this.olines[y][x]) {
        break
      }
      ch = this.olines[y][x]
      if (ch[0] !== first[0] || ch[1] !== first[1]) {
        return (pos._cleanSides = false)
      }
    }
  }

  return (pos._cleanSides = true)
}

Screen.prototype._dockBorders = function () {
  let lines = this.lines,
    stops = this._borderStops,
    i,
    y,
    x,
    ch

  // var keys, stop;
  //
  // keys = Object.keys(this._borderStops)
  //   .map(function(k) { return +k; })
  //   .sort(function(a, b) { return a - b; });
  //
  // for (i = 0; i < keys.length; i++) {
  //   y = keys[i];
  //   if (!lines[y]) continue;
  //   stop = this._borderStops[y];
  //   for (x = stop.xi; x < stop.xl; x++) {

  stops = Object.keys(stops)
    .map(function (k) {
      return +k
    })
    .sort(function (a, b) {
      return a - b
    })

  for (i = 0; i < stops.length; i++) {
    y = stops[i]
    if (!lines[y]) {
      continue
    }
    for (x = 0; x < this.width; x++) {
      ch = lines[y][x][1]
      if (angles[ch]) {
        lines[y][x][1] = this._getAngle(lines, x, y)
        lines[y].dirty = true
      }
    }
  }
}

Screen.prototype._getAngle = function (lines, x, y) {
  let angle = 0,
    attr = lines[y][x][0],
    ch = lines[y][x][1]

  if (lines[y][x - 1] && langles[lines[y][x - 1][1]]) {
    if (!this.options.ignoreDockContrast) {
      if (lines[y][x - 1][0] !== attr) {
        return ch
      }
    }
    angle |= 1 << 3
  }

  if (lines[y - 1] && uangles[lines[y - 1][x][1]]) {
    if (!this.options.ignoreDockContrast) {
      if (lines[y - 1][x][0] !== attr) {
        return ch
      }
    }
    angle |= 1 << 2
  }

  if (lines[y][x + 1] && rangles[lines[y][x + 1][1]]) {
    if (!this.options.ignoreDockContrast) {
      if (lines[y][x + 1][0] !== attr) {
        return ch
      }
    }
    angle |= 1 << 1
  }

  if (lines[y + 1] && dangles[lines[y + 1][x][1]]) {
    if (!this.options.ignoreDockContrast) {
      if (lines[y + 1][x][0] !== attr) {
        return ch
      }
    }
    angle |= 1 << 0
  }

  // Experimental: fixes this situation:
  // +----------+
  //            | <-- empty space here, should be a T angle
  // +-------+  |
  // |       |  |
  // +-------+  |
  // |          |
  // +----------+
  // if (uangles[lines[y][x][1]]) {
  //   if (lines[y + 1] && cdangles[lines[y + 1][x][1]]) {
  //     if (!this.options.ignoreDockContrast) {
  //       if (lines[y + 1][x][0] !== attr) return ch;
  //     }
  //     angle |= 1 << 0;
  //   }
  // }

  return angleTable[angle] || ch
}

Screen.prototype.draw = function (start, end) {
  // this.emit('predraw');

  let x, y, line, out, ch, data, attr, fg, bg, flags

  let main = '',
    pre,
    post

  let clr, neq, xx

  let lx = -1,
    ly = -1,
    o

  let acs

  if (this._buf) {
    main += this._buf
    this._buf = ''
  }

  for (y = start; y <= end; y++) {
    line = this.lines[y]
    o = this.olines[y]

    if (!line.dirty && !(this.cursor.artificial && y === this.program.y)) {
      continue
    }
    line.dirty = false

    out = ''
    attr = this.dattr

    for (x = 0; x < line.length; x++) {
      data = line[x][0]
      ch = line[x][1]

      // Render the artificial cursor.
      if (
        this.cursor.artificial &&
        !this.cursor._hidden &&
        this.cursor._state &&
        x === this.program.x &&
        y === this.program.y
      ) {
        const cattr = this._cursorAttr(this.cursor, data)
        if (cattr.ch) {
          ch = cattr.ch
        }
        data = cattr.attr
      }

      // Take advantage of xterm's back_color_erase feature by using a
      // lookahead. Stop spitting out so many damn spaces. NOTE: Is checking
      // the bg for non BCE terminals worth the overhead?
      if (
        this.options.useBCE &&
        ch === ' ' &&
        (this.tput.bools.back_color_erase ||
          (data & 0x1ff) === (this.dattr & 0x1ff)) &&
        ((data >> 18) & 8) === ((this.dattr >> 18) & 8)
      ) {
        clr = true
        neq = false

        for (xx = x; xx < line.length; xx++) {
          if (line[xx][0] !== data || line[xx][1] !== ' ') {
            clr = false
            break
          }
          if (line[xx][0] !== o[xx][0] || line[xx][1] !== o[xx][1]) {
            neq = true
          }
        }

        if (clr && neq) {
          ;(lx = -1), (ly = -1)
          if (data !== attr) {
            out += this.codeAttr(data)
            attr = data
          }
          out += this.tput.cup(y, x)
          out += this.tput.el()
          for (xx = x; xx < line.length; xx++) {
            o[xx][0] = data
            o[xx][1] = ' '
          }
          break
        }

        // If there's more than 10 spaces, use EL regardless
        // and start over drawing the rest of line. Might
        // not be worth it. Try to use ECH if the terminal
        // supports it. Maybe only try to use ECH here.
        // //if (this.tput.strings.erase_chars)
        // if (!clr && neq && (xx - x) > 10) {
        //   lx = -1, ly = -1;
        //   if (data !== attr) {
        //     out += this.codeAttr(data);
        //     attr = data;
        //   }
        //   out += this.tput.cup(y, x);
        //   if (this.tput.strings.erase_chars) {
        //     // Use erase_chars to avoid erasing the whole line.
        //     out += this.tput.ech(xx - x);
        //   } else {
        //     out += this.tput.el();
        //   }
        //   if (this.tput.strings.parm_right_cursor) {
        //     out += this.tput.cuf(xx - x);
        //   } else {
        //     out += this.tput.cup(y, xx);
        //   }
        //   this.fillRegion(data, ' ',
        //     x, this.tput.strings.erase_chars ? xx : line.length,
        //     y, y + 1);
        //   x = xx - 1;
        //   continue;
        // }

        // Skip to the next line if the
        // rest of the line is already drawn.
        // if (!neq) {
        //   for (; xx < line.length; xx++) {
        //     if (line[xx][0] !== o[xx][0] || line[xx][1] !== o[xx][1]) {
        //       neq = true;
        //       break;
        //     }
        //   }
        //   if (!neq) {
        //     attr = data;
        //     break;
        //   }
        // }
      }

      // Optimize by comparing the real output
      // buffer to the pending output buffer.
      if (data === o[x][0] && ch === o[x][1]) {
        if (lx === -1) {
          lx = x
          ly = y
        }
        continue
      } else if (lx !== -1) {
        if (this.tput.strings.parm_right_cursor) {
          out += y === ly ? this.tput.cuf(x - lx) : this.tput.cup(y, x)
        } else {
          out += this.tput.cup(y, x)
        }
        ;(lx = -1), (ly = -1)
      }
      o[x][0] = data
      o[x][1] = ch

      if (data !== attr) {
        if (attr !== this.dattr) {
          out += '\x1b[m'
        }
        if (data !== this.dattr) {
          out += '\x1b['

          bg = data & 0x1ff
          fg = (data >> 9) & 0x1ff
          flags = data >> 18

          // bold
          if (flags & 1) {
            out += '1;'
          }

          // underline
          if (flags & 2) {
            out += '4;'
          }

          // blink
          if (flags & 4) {
            out += '5;'
          }

          // inverse
          if (flags & 8) {
            out += '7;'
          }

          // invisible
          if (flags & 16) {
            out += '8;'
          }

          if (bg !== 0x1ff) {
            bg = this._reduceColor(bg)
            if (bg < 16) {
              if (bg < 8) {
                bg += 40
              } else if (bg < 16) {
                bg -= 8
                bg += 100
              }
              out += bg + ';'
            } else {
              out += '48;5;' + bg + ';'
            }
          }

          if (fg !== 0x1ff) {
            fg = this._reduceColor(fg)
            if (fg < 16) {
              if (fg < 8) {
                fg += 30
              } else if (fg < 16) {
                fg -= 8
                fg += 90
              }
              out += fg + ';'
            } else {
              out += '38;5;' + fg + ';'
            }
          }

          if (out[out.length - 1] === ';') {
            out = out.slice(0, -1)
          }

          out += 'm'
        }
      }

      // If we find a double-width char, eat the next character which should be
      // a space due to parseContent's behavior.
      if (this.fullUnicode) {
        // If this is a surrogate pair double-width char, we can ignore it
        // because parseContent already counted it as length=2.
        if (unicode.charWidth(line[x][1]) === 2) {
          // NOTE: At cols=44, the bug that is avoided
          // by the angles check occurs in widget-unicode:
          // Might also need: `line[x + 1][0] !== line[x][0]`
          // for borderless boxes?
          if (x === line.length - 1 || angles[line[x + 1][1]]) {
            // If we're at the end, we don't have enough space for a
            // double-width. Overwrite it with a space and ignore.
            ch = ' '
            o[x][1] = '\0'
          } else {
            // ALWAYS refresh double-width chars because this special cursor
            // behavior is needed. There may be a more efficient way of doing
            // this. See above.
            o[x][1] = '\0'
            // Eat the next character by moving forward and marking as a
            // space (which it is).
            o[++x][1] = '\0'
          }
        }
      }

      // Attempt to use ACS for supported characters.
      // This is not ideal, but it's how ncurses works.
      // There are a lot of terminals that support ACS
      // *and UTF8, but do not declare U8. So ACS ends
      // up being used (slower than utf8). Terminals
      // that do not support ACS and do not explicitly
      // support UTF8 get their unicode characters
      // replaced with really ugly ascii characters.
      // It is possible there is a terminal out there
      // somewhere that does not support ACS, but
      // supports UTF8, but I imagine it's unlikely.
      // Maybe remove !this.tput.unicode check, however,
      // this seems to be the way ncurses does it.
      if (
        this.tput.strings.enter_alt_charset_mode &&
        !this.tput.brokenACS &&
        (this.tput.acscr[ch] || acs)
      ) {
        // Fun fact: even if this.tput.brokenACS wasn't checked here,
        // the linux console would still work fine because the acs
        // table would fail the check of: this.tput.acscr[ch]
        if (this.tput.acscr[ch]) {
          if (acs) {
            ch = this.tput.acscr[ch]
          } else {
            ch = this.tput.smacs() + this.tput.acscr[ch]
            acs = true
          }
        } else if (acs) {
          ch = this.tput.rmacs() + ch
          acs = false
        }
      } else {
        // U8 is not consistently correct. Some terminfo's
        // terminals that do not declare it may actually
        // support utf8 (e.g. urxvt), but if the terminal
        // does not declare support for ACS (and U8), chances
        // are it does not support UTF8. This is probably
        // the "safest" way to do this. Should fix things
        // like sun-color.
        // NOTE: It could be the case that the $LANG
        // is all that matters in some cases:
        // if (!this.tput.unicode && ch > '~') {
        if (!this.tput.unicode && this.tput.numbers.U8 !== 1 && ch > '~') {
          ch = this.tput.utoa[ch] || '?'
        }
      }

      out += ch
      attr = data
    }

    if (attr !== this.dattr) {
      out += '\x1b[m'
    }

    if (out) {
      main += this.tput.cup(y, 0) + out
    }
  }

  if (acs) {
    main += this.tput.rmacs()
    acs = false
  }

  if (main) {
    pre = ''
    post = ''

    pre += this.tput.sc()
    post += this.tput.rc()

    if (!this.program.cursorHidden) {
      pre += this.tput.civis()
      post += this.tput.cnorm()
    }

    // this.program.flush();
    // this.program._owrite(pre + main + post);
    this.program._write(pre + main + post)
  }

  // this.emit('draw');
}

Screen.prototype._reduceColor = function (color) {
  return colors.reduce(color, this.tput.colors)
}

// Convert an SGR string to our own attribute format.
Screen.prototype.attrCode = function (code, cur, def) {
  let flags = (cur >> 18) & 0x1ff,
    fg = (cur >> 9) & 0x1ff,
    bg = cur & 0x1ff,
    c,
    i

  code = code.slice(2, -1).split(';')
  if (!code[0]) {
    code[0] = '0'
  }

  for (i = 0; i < code.length; i++) {
    c = +code[i] || 0
    switch (c) {
      case 0: // normal
        bg = def & 0x1ff
        fg = (def >> 9) & 0x1ff
        flags = (def >> 18) & 0x1ff
        break
      case 1: // bold
        flags |= 1
        break
      case 22:
        flags = (def >> 18) & 0x1ff
        break
      case 4: // underline
        flags |= 2
        break
      case 24:
        flags = (def >> 18) & 0x1ff
        break
      case 5: // blink
        flags |= 4
        break
      case 25:
        flags = (def >> 18) & 0x1ff
        break
      case 7: // inverse
        flags |= 8
        break
      case 27:
        flags = (def >> 18) & 0x1ff
        break
      case 8: // invisible
        flags |= 16
        break
      case 28:
        flags = (def >> 18) & 0x1ff
        break
      case 39: // default fg
        fg = (def >> 9) & 0x1ff
        break
      case 49: // default bg
        bg = def & 0x1ff
        break
      case 100: // default fg/bg
        fg = (def >> 9) & 0x1ff
        bg = def & 0x1ff
        break
      default: // color
        if (c === 48 && +code[i + 1] === 5) {
          i += 2
          bg = +code[i]
          break
        } else if (c === 48 && +code[i + 1] === 2) {
          i += 2
          bg = colors.match(+code[i], +code[i + 1], +code[i + 2])
          if (bg === -1) {
            bg = def & 0x1ff
          }
          i += 2
          break
        } else if (c === 38 && +code[i + 1] === 5) {
          i += 2
          fg = +code[i]
          break
        } else if (c === 38 && +code[i + 1] === 2) {
          i += 2
          fg = colors.match(+code[i], +code[i + 1], +code[i + 2])
          if (fg === -1) {
            fg = (def >> 9) & 0x1ff
          }
          i += 2
          break
        }
        if (c >= 40 && c <= 47) {
          bg = c - 40
        } else if (c >= 100 && c <= 107) {
          bg = c - 100
          bg += 8
        } else if (c === 49) {
          bg = def & 0x1ff
        } else if (c >= 30 && c <= 37) {
          fg = c - 30
        } else if (c >= 90 && c <= 97) {
          fg = c - 90
          fg += 8
        } else if (c === 39) {
          fg = (def >> 9) & 0x1ff
        } else if (c === 100) {
          fg = (def >> 9) & 0x1ff
          bg = def & 0x1ff
        }
        break
    }
  }

  return (flags << 18) | (fg << 9) | bg
}

// Convert our own attribute format to an SGR string.
Screen.prototype.codeAttr = function (code) {
  let flags = (code >> 18) & 0x1ff,
    fg = (code >> 9) & 0x1ff,
    bg = code & 0x1ff,
    out = ''

  // bold
  if (flags & 1) {
    out += '1;'
  }

  // underline
  if (flags & 2) {
    out += '4;'
  }

  // blink
  if (flags & 4) {
    out += '5;'
  }

  // inverse
  if (flags & 8) {
    out += '7;'
  }

  // invisible
  if (flags & 16) {
    out += '8;'
  }

  if (bg !== 0x1ff) {
    bg = this._reduceColor(bg)
    if (bg < 16) {
      if (bg < 8) {
        bg += 40
      } else if (bg < 16) {
        bg -= 8
        bg += 100
      }
      out += bg + ';'
    } else {
      out += '48;5;' + bg + ';'
    }
  }

  if (fg !== 0x1ff) {
    fg = this._reduceColor(fg)
    if (fg < 16) {
      if (fg < 8) {
        fg += 30
      } else if (fg < 16) {
        fg -= 8
        fg += 90
      }
      out += fg + ';'
    } else {
      out += '38;5;' + fg + ';'
    }
  }

  if (out[out.length - 1] === ';') {
    out = out.slice(0, -1)
  }

  return '\x1b[' + out + 'm'
}

Screen.prototype.focusOffset = function (offset) {
  const shown = this.keyable.filter(function (el) {
    return !el.detached && el.visible
  }).length

  if (!shown || !offset) {
    return
  }

  let i = this.keyable.indexOf(this.focused)
  if (!~i) {
    return
  }

  if (offset > 0) {
    while (offset--) {
      if (++i > this.keyable.length - 1) {
        i = 0
      }
      if (this.keyable[i].detached || !this.keyable[i].visible) {
        offset++
      }
    }
  } else {
    offset = -offset
    while (offset--) {
      if (--i < 0) {
        i = this.keyable.length - 1
      }
      if (this.keyable[i].detached || !this.keyable[i].visible) {
        offset++
      }
    }
  }

  return this.keyable[i].focus()
}

Screen.prototype.focusPrev = Screen.prototype.focusPrevious = function () {
  return this.focusOffset(-1)
}

Screen.prototype.focusNext = function () {
  return this.focusOffset(1)
}

Screen.prototype.focusPush = function (el) {
  if (!el) {
    return
  }
  const old = this.history[this.history.length - 1]
  if (this.history.length === 10) {
    this.history.shift()
  }
  this.history.push(el)
  this._focus(el, old)
}

Screen.prototype.focusPop = function () {
  const old = this.history.pop()
  if (this.history.length) {
    this._focus(this.history[this.history.length - 1], old)
  }
  return old
}

Screen.prototype.saveFocus = function () {
  return (this._savedFocus = this.focused)
}

Screen.prototype.restoreFocus = function () {
  if (!this._savedFocus) {
    return
  }
  this._savedFocus.focus()
  delete this._savedFocus
  return this.focused
}

Screen.prototype.rewindFocus = function () {
  let old = this.history.pop(),
    el

  while (this.history.length) {
    el = this.history.pop()
    if (!el.detached && el.visible) {
      this.history.push(el)
      this._focus(el, old)
      return el
    }
  }

  if (old) {
    old.emit('blur')
  }
}

Screen.prototype._focus = function (self, old) {
  // Find a scrollable ancestor if we have one.
  let el = self
  while ((el = el.parent)) {
    if (el.scrollable) {
      break
    }
  }

  // If we're in a scrollable element,
  // automatically scroll to the focused element.
  if (el && !el.detached) {
    // NOTE: This is different from the other "visible" values - it needs the
    // visible height of the scrolling element itself, not the element within
    // it.
    const visible =
      self.screen.height - el.atop - el.itop - el.abottom - el.ibottom
    if (self.rtop < el.childBase) {
      el.scrollTo(self.rtop)
      self.screen.render()
    } else if (
      self.rtop + self.height - self.ibottom >
      el.childBase + visible
    ) {
      // Explanation for el.itop here: takes into account scrollable elements
      // with borders otherwise the element gets covered by the bottom border:
      el.scrollTo(self.rtop - (el.height - self.height) + el.itop, true)
      self.screen.render()
    }
  }

  if (old) {
    old.emit('blur', self)
  }

  self.emit('focus', old)
}

Screen.prototype.__defineGetter__('focused', function () {
  return this.history[this.history.length - 1]
})

Screen.prototype.__defineSetter__('focused', function (el) {
  return this.focusPush(el)
})

Screen.prototype.clearRegion = function (xi, xl, yi, yl, override) {
  return this.fillRegion(this.dattr, ' ', xi, xl, yi, yl, override)
}

Screen.prototype.fillRegion = function (attr, ch, xi, xl, yi, yl, override) {
  let lines = this.lines,
    cell,
    xx

  if (xi < 0) {
    xi = 0
  }
  if (yi < 0) {
    yi = 0
  }

  for (; yi < yl; yi++) {
    if (!lines[yi]) {
      break
    }
    for (xx = xi; xx < xl; xx++) {
      cell = lines[yi][xx]
      if (!cell) {
        break
      }
      if (override || attr !== cell[0] || ch !== cell[1]) {
        lines[yi][xx][0] = attr
        lines[yi][xx][1] = ch
        lines[yi].dirty = true
      }
    }
  }
}

Screen.prototype.key = function () {
  return this.program.key.apply(this, arguments)
}

Screen.prototype.onceKey = function () {
  return this.program.onceKey.apply(this, arguments)
}

Screen.prototype.unkey = Screen.prototype.removeKey = function () {
  return this.program.unkey.apply(this, arguments)
}

Screen.prototype.spawn = function (file, args, options) {
  if (!Array.isArray(args)) {
    options = args
    args = []
  }

  let screen = this,
    program = screen.program,
    spawn = require('node:child_process').spawn,
    mouse = program.mouseEnabled,
    ps

  options = options || {}

  options.stdio = options.stdio || 'inherit'

  program.lsaveCursor('spawn')
  // program.csr(0, program.rows - 1);
  program.normalBuffer()
  program.showCursor()
  if (mouse) {
    program.disableMouse()
  }

  const write = program.output.write
  program.output.write = function () {}
  program.input.pause()
  if (program.input.setRawMode) {
    program.input.setRawMode(false)
  }

  const resume = function () {
    if (resume.done) {
      return
    }
    resume.done = true

    if (program.input.setRawMode) {
      program.input.setRawMode(true)
    }
    program.input.resume()
    program.output.write = write

    program.alternateBuffer()
    // program.csr(0, program.rows - 1);
    if (mouse) {
      program.enableMouse()
      if (screen.options.sendFocus) {
        screen.program.setMouse({ sendFocus: true }, true)
      }
    }

    screen.alloc()
    screen.render()

    screen.program.lrestoreCursor('spawn', true)
  }

  ps = spawn(file, args, options)

  ps.on('error', resume)

  ps.on('exit', resume)

  return ps
}

Screen.prototype.exec = function (file, args, options, callback) {
  const ps = this.spawn(file, args, options)

  ps.on('error', function (err) {
    if (!callback) {
      return
    }
    return callback(err, false)
  })

  ps.on('exit', function (code) {
    if (!callback) {
      return
    }
    return callback(null, code === 0)
  })

  return ps
}

Screen.prototype.readEditor = function (options, callback) {
  if (typeof options === 'string') {
    options = { editor: options }
  }

  if (!callback) {
    callback = options
    options = null
  }

  if (!callback) {
    callback = function () {}
  }

  options = options || {}

  let self = this,
    editor = options.editor || process.env.EDITOR || 'vi',
    name = options.name || process.title || 'blessed',
    rnd = Math.random().toString(36).split('.').pop(),
    file = '/tmp/' + name + '.' + rnd,
    args = [file],
    opt

  opt = {
    stdio: 'inherit',
    env: process.env,
    cwd: process.env.HOME
  }

  function writeFile(callback) {
    if (!options.value) {
      return callback()
    }
    return fs.writeFile(file, options.value, callback)
  }

  return writeFile(function (err) {
    if (err) {
      return callback(err)
    }
    return self.exec(editor, args, opt, function (err, success) {
      if (err) {
        return callback(err)
      }
      return fs.readFile(file, 'utf8', function (err, data) {
        return fs.unlink(file, function () {
          if (!success) {
            return callback(new Error('Unsuccessful.'))
          }
          if (err) {
            return callback(err)
          }
          return callback(null, data)
        })
      })
    })
  })
}

Screen.prototype.displayImage = function (file, callback) {
  if (!file) {
    if (!callback) {
      return
    }
    return callback(new Error('No image.'))
  }

  file = path.resolve(process.cwd(), file)

  if (!~file.indexOf('://')) {
    file = 'file://' + file
  }

  const args = ['w3m', '-T', 'text/html']

  const input =
    '<title>press q to exit</title>' + '<img align="center" src="' + file + '">'

  const opt = {
    stdio: ['pipe', 1, 2],
    env: process.env,
    cwd: process.env.HOME
  }

  const ps = this.spawn(args[0], args.slice(1), opt)

  ps.on('error', function (err) {
    if (!callback) {
      return
    }
    return callback(err)
  })

  ps.on('exit', function (code) {
    if (!callback) {
      return
    }
    if (code !== 0) {
      return callback(new Error('Exit Code: ' + code))
    }
    return callback(null, code === 0)
  })

  ps.stdin.write(input + '\n')
  ps.stdin.end()
}

Screen.prototype.setEffects = function (el, fel, over, out, effects, temp) {
  if (!effects) {
    return
  }

  const tmp = {}
  if (temp) {
    el[temp] = tmp
  }

  if (typeof el !== 'function') {
    const _el = el
    el = function () {
      return _el
    }
  }

  fel.on(over, function () {
    const element = el()
    Object.keys(effects).forEach(function (key) {
      const val = effects[key]
      if (val !== null && typeof val === 'object') {
        tmp[key] = tmp[key] || {}
        // element.style[key] = element.style[key] || {};
        Object.keys(val).forEach(function (k) {
          const v = val[k]
          tmp[key][k] = element.style[key][k]
          element.style[key][k] = v
        })
        return
      }
      tmp[key] = element.style[key]
      element.style[key] = val
    })
    element.screen.render()
  })

  fel.on(out, function () {
    const element = el()
    Object.keys(effects).forEach(function (key) {
      const val = effects[key]
      if (val !== null && typeof val === 'object') {
        tmp[key] = tmp[key] || {}
        // element.style[key] = element.style[key] || {};
        Object.keys(val).forEach(function (k) {
          if (tmp[key].hasOwnProperty(k)) {
            element.style[key][k] = tmp[key][k]
          }
        })
        return
      }
      if (tmp.hasOwnProperty(key)) {
        element.style[key] = tmp[key]
      }
    })
    element.screen.render()
  })
}

Screen.prototype.sigtstp = function (callback) {
  const self = this
  this.program.sigtstp(function () {
    self.alloc()
    self.render()
    self.program.lrestoreCursor('pause', true)
    if (callback) {
      callback()
    }
  })
}

Screen.prototype.copyToClipboard = function (text) {
  return this.program.copyToClipboard(text)
}

Screen.prototype.cursorShape = function (shape, blink) {
  const self = this

  this.cursor.shape = shape || 'block'
  this.cursor.blink = blink || false
  this.cursor._set = true

  if (this.cursor.artificial) {
    if (!this.program.hideCursor_old) {
      const hideCursor = this.program.hideCursor
      this.program.hideCursor_old = this.program.hideCursor
      this.program.hideCursor = function () {
        hideCursor.call(self.program)
        self.cursor._hidden = true
        if (self.renders) {
          self.render()
        }
      }
    }
    if (!this.program.showCursor_old) {
      const showCursor = this.program.showCursor
      this.program.showCursor_old = this.program.showCursor
      this.program.showCursor = function () {
        self.cursor._hidden = false
        if (self.program._exiting) {
          showCursor.call(self.program)
        }
        if (self.renders) {
          self.render()
        }
      }
    }
    if (!this._cursorBlink) {
      this._cursorBlink = setInterval(function () {
        if (!self.cursor.blink) {
          return
        }
        self.cursor._state ^= 1
        if (self.renders) {
          self.render()
        }
      }, 500)
      if (this._cursorBlink.unref) {
        this._cursorBlink.unref()
      }
    }
    return true
  }

  return this.program.cursorShape(this.cursor.shape, this.cursor.blink)
}

Screen.prototype.cursorColor = function (color) {
  this.cursor.color = color != null ? colors.convert(color) : null
  this.cursor._set = true

  if (this.cursor.artificial) {
    return true
  }

  return this.program.cursorColor(colors.ncolors[this.cursor.color])
}

Screen.prototype.cursorReset = Screen.prototype.resetCursor = function () {
  this.cursor.shape = 'block'
  this.cursor.blink = false
  this.cursor.color = null
  this.cursor._set = false

  if (this.cursor.artificial) {
    this.cursor.artificial = false
    if (this.program.hideCursor_old) {
      this.program.hideCursor = this.program.hideCursor_old
      delete this.program.hideCursor_old
    }
    if (this.program.showCursor_old) {
      this.program.showCursor = this.program.showCursor_old
      delete this.program.showCursor_old
    }
    if (this._cursorBlink) {
      clearInterval(this._cursorBlink)
      delete this._cursorBlink
    }
    return true
  }

  return this.program.cursorReset()
}

Screen.prototype._cursorAttr = function (cursor, dattr) {
  let attr = dattr || this.dattr,
    cattr,
    ch

  if (cursor.shape === 'line') {
    attr &= ~(0x1ff << 9)
    attr |= 7 << 9
    ch = '\u2502'
  } else if (cursor.shape === 'underline') {
    attr &= ~(0x1ff << 9)
    attr |= 7 << 9
    attr |= 2 << 18
  } else if (cursor.shape === 'block') {
    attr &= ~(0x1ff << 9)
    attr |= 7 << 9
    attr |= 8 << 18
  } else if (typeof cursor.shape === 'object' && cursor.shape) {
    const Element = require('./element')
    cattr = Element.prototype.sattr.call(cursor, cursor.shape)

    if (
      cursor.shape.bold ||
      cursor.shape.underline ||
      cursor.shape.blink ||
      cursor.shape.inverse ||
      cursor.shape.invisible
    ) {
      attr &= ~(0x1ff << 18)
      attr |= ((cattr >> 18) & 0x1ff) << 18
    }

    if (cursor.shape.fg) {
      attr &= ~(0x1ff << 9)
      attr |= ((cattr >> 9) & 0x1ff) << 9
    }

    if (cursor.shape.bg) {
      attr &= ~(0x1ff << 0)
      attr |= cattr & 0x1ff
    }

    if (cursor.shape.ch) {
      ch = cursor.shape.ch
    }
  }

  if (cursor.color != null) {
    attr &= ~(0x1ff << 9)
    attr |= cursor.color << 9
  }

  return {
    ch: ch,
    attr: attr
  }
}

Screen.prototype.screenshot = function (xi, xl, yi, yl, term) {
  if (xi == null) {
    xi = 0
  }
  if (xl == null) {
    xl = this.cols
  }
  if (yi == null) {
    yi = 0
  }
  if (yl == null) {
    yl = this.rows
  }

  if (xi < 0) {
    xi = 0
  }
  if (yi < 0) {
    yi = 0
  }

  let x, y, line, out, ch, data, attr

  const sdattr = this.dattr

  if (term) {
    this.dattr = term.defAttr
  }

  let main = ''

  for (y = yi; y < yl; y++) {
    line = term ? term.lines[y] : this.lines[y]

    if (!line) {
      break
    }

    out = ''
    attr = this.dattr

    for (x = xi; x < xl; x++) {
      if (!line[x]) {
        break
      }

      data = line[x][0]
      ch = line[x][1]

      if (data !== attr) {
        if (attr !== this.dattr) {
          out += '\x1b[m'
        }
        if (data !== this.dattr) {
          let _data = data
          if (term) {
            if (((_data >> 9) & 0x1ff) === 257) {
              _data |= 0x1ff << 9
            }
            if ((_data & 0x1ff) === 256) {
              _data |= 0x1ff
            }
          }
          out += this.codeAttr(_data)
        }
      }

      if (this.fullUnicode) {
        if (unicode.charWidth(line[x][1]) === 2) {
          if (x === xl - 1) {
            ch = ' '
          } else {
            x++
          }
        }
      }

      out += ch
      attr = data
    }

    if (attr !== this.dattr) {
      out += '\x1b[m'
    }

    if (out) {
      main += (y > 0 ? '\n' : '') + out
    }
  }

  main = main.replace(/(?:\s*\x1b\[40m\s*\x1b\[m\s*)*$/, '') + '\n'

  if (term) {
    this.dattr = sdattr
  }

  return main
}

/**
 * Positioning
 */

Screen.prototype._getPos = function () {
  return this
}

/**
 * Angle Table
 */

const angles = {
  '\u2518': true, // '┘'
  '\u2510': true, // '┐'
  '\u250c': true, // '┌'
  '\u2514': true, // '└'
  '\u253c': true, // '┼'
  '\u251c': true, // '├'
  '\u2524': true, // '┤'
  '\u2534': true, // '┴'
  '\u252c': true, // '┬'
  '\u2502': true, // '│'
  '\u2500': true // '─'
}

const langles = {
  '\u250c': true, // '┌'
  '\u2514': true, // '└'
  '\u253c': true, // '┼'
  '\u251c': true, // '├'
  '\u2534': true, // '┴'
  '\u252c': true, // '┬'
  '\u2500': true // '─'
}

const uangles = {
  '\u2510': true, // '┐'
  '\u250c': true, // '┌'
  '\u253c': true, // '┼'
  '\u251c': true, // '├'
  '\u2524': true, // '┤'
  '\u252c': true, // '┬'
  '\u2502': true // '│'
}

const rangles = {
  '\u2518': true, // '┘'
  '\u2510': true, // '┐'
  '\u253c': true, // '┼'
  '\u2524': true, // '┤'
  '\u2534': true, // '┴'
  '\u252c': true, // '┬'
  '\u2500': true // '─'
}

const dangles = {
  '\u2518': true, // '┘'
  '\u2514': true, // '└'
  '\u253c': true, // '┼'
  '\u251c': true, // '├'
  '\u2524': true, // '┤'
  '\u2534': true, // '┴'
  '\u2502': true // '│'
}

// var cdangles = {
//   '\u250c': true  // '┌'
// };

// Every ACS angle character can be
// represented by 4 bits ordered like this:
// [langle][uangle][rangle][dangle]
const angleTable = {
  '0000': '', // ?
  '0001': '\u2502', // '│' // ?
  '0010': '\u2500', // '─' // ??
  '0011': '\u250c', // '┌'
  '0100': '\u2502', // '│' // ?
  '0101': '\u2502', // '│'
  '0110': '\u2514', // '└'
  '0111': '\u251c', // '├'
  1000: '\u2500', // '─' // ??
  1001: '\u2510', // '┐'
  1010: '\u2500', // '─' // ??
  1011: '\u252c', // '┬'
  1100: '\u2518', // '┘'
  1101: '\u2524', // '┤'
  1110: '\u2534', // '┴'
  1111: '\u253c' // '┼'
}

Object.keys(angleTable).forEach(function (key) {
  angleTable[parseInt(key, 2)] = angleTable[key]
  delete angleTable[key]
})

/**
 * Expose
 */

module.exports = Screen
