/lib/widget.js

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/**
 * widget.js - high-level interface for blessed
 * Copyright (c) 2013, Christopher Jeffrey (MIT License)
 * https://github.com/chjj/blessed
 * Still under heavy development.
 */

/**
 * Modules
 */

var EventEmitter = require('./events').EventEmitter
  , assert = require('assert')
  , path = require('path')
  , fs = require('fs');

var colors = require('./colors')
  , program = require('./program')
  , widget = exports;

/**
 * Node
 */

function Node(options) {
  if (!(this instanceof Node)) {
    return new Node(options);
  }

  EventEmitter.call(this);

  options = options || {};
  this.options = options;
  this.screen = this.screen
    || options.screen
    || Screen.global
    || (function(){throw new Error('No active screen.')})();
  this.parent = options.parent || null;
  this.children = [];
  this.$ = this._ = this.data = {};
  this.uid = Node.uid++;
  this.index = -1;

  if (this.type !== 'screen') {
    this.detached = true;
  }

  if (this.parent) {
    this.parent.append(this);
  }

  (options.children || []).forEach(this.append.bind(this));
}

Node.uid = 0;

Node.prototype.__proto__ = EventEmitter.prototype;

Node.prototype.type = 'node';

Node.prototype.insert = function(element, i) {
  var self = this;

  element.detach();
  element.parent = this;

  if (i === 0) {
    this.children.unshift(element);
  } else if (i === this.children.length) {
    this.children.push(element);
  } else {
    this.children.splice(i, 0, element);
  }

  element.emit('reparent', this);
  this.emit('adopt', element);

  (function emit(el) {
    var n = el.detached !== self.detached;
    el.detached = self.detached;
    if (n) el.emit('attach');
    el.children.forEach(emit);
  })(element);

  if (!this.screen.focused) {
    this.screen.focused = element;
  }
};

Node.prototype.prepend = function(element) {
  this.insert(element, 0);
};

Node.prototype.append = function(element) {
  this.insert(element, this.children.length);
};

Node.prototype.insertBefore = function(element, other) {
  var i = this.children.indexOf(other);
  if (~i) this.insert(element, i);
};

Node.prototype.insertAfter = function(element, other) {
  var i = this.children.indexOf(other);
  if (~i) this.insert(element, i + 1);
};

Node.prototype.remove = function(element) {
  if (element.parent !== this) return;

  var i = this.children.indexOf(element);
  if (!~i) return;

  element.clearPos();

  element.parent = null;

  this.children.splice(i, 1);

  i = this.screen.clickable.indexOf(element);
  if (~i) this.screen.clickable.splice(i, 1);
  i = this.screen.keyable.indexOf(element);
  if (~i) this.screen.keyable.splice(i, 1);

  element.emit('reparent', null);
  this.emit('remove', element);

  (function emit(el) {
    var n = el.detached !== true;
    el.detached = true;
    if (n) el.emit('detach');
    el.children.forEach(emit);
  })(element);

  if (this.screen.focused === element) {
    this.screen.rewindFocus();
  }
};

Node.prototype.detach = function() {
  if (this.parent) this.parent.remove(this);
};

Node.prototype.forDescendants = function(iter, s) {
  if (s) iter(this);
  this.children.forEach(function emit(el) {
    iter(el);
    el.children.forEach(emit);
  });
};

Node.prototype.forAncestors = function(iter, s) {
  var el = this;
  if (s) iter(this);
  while (el = el.parent) {
    iter(el);
  }
};

Node.prototype.collectDescendants = function(s) {
  var out = [];
  this.forDescendants(function(el) {
    out.push(el);
  }, s);
  return out;
};

Node.prototype.collectAncestors = function(s) {
  var out = [];
  this.forAncestors(function(el) {
    out.push(el);
  }, s);
  return out;
};

Node.prototype.emitDescendants = function() {
  var args = Array.prototype.slice(arguments)
    , iter;

  if (typeof args[args.length-1] === 'function') {
    iter = args.pop();
  }

  return this.forDescendants(function(el) {
    if (iter) iter(el);
    el.emit.apply(el, args);
  }, true);
};

Node.prototype.emitAncestors = function() {
  var args = Array.prototype.slice(arguments)
    , iter;

  if (typeof args[args.length-1] === 'function') {
    iter = args.pop();
  }

  return this.forAncestors(function(el) {
    if (iter) iter(el);
    el.emit.apply(el, args);
  }, true);
};

Node.prototype.hasDescendant = function(target) {
  return (function find(el) {
    for (var i = 0; i < el.children.length; i++) {
      if (el.children[i] === target) {
        return true;
      }
      if (find(el.children[i]) === true) {
        return true;
      }
    }
    return false;
  })(this);
};

Node.prototype.hasAncestor = function(target) {
  var el = this;
  while (el = el.parent) {
    if (el === target) return true;
  }
  return false;
};

Node.prototype.get = function(name, value) {
  if (this.data.hasOwnProperty(name)) {
    return this.data[name];
  }
  return value;
};

Node.prototype.set = function(name, value) {
  return this.data[name] = value;
};

/**
 * Screen
 */

function Screen(options) {
  var self = this;

  if (!(this instanceof Node)) {
    return new Screen(options);
  }

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

  this.program = options.program || program.global;

  if (!this.program) {
    this.program = program({
      input: options.input,
      output: options.output,
      log: options.log,
      debug: options.debug,
      dump: options.dump,
      term: options.term,
      tput: true,
      buffer: true,
      zero: true
    });
  } else {
    this.program.setupTput();
    this.program.useBuffer = true;
    this.program.zero = true;
  }

  this.tput = this.program.tput;

  if (!Screen.global) {
    Screen.global = this;
  }

  Node.call(this, options);

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

  this.ignoreLocked = options.ignoreLocked || [];

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

  this.renders = 0;
  this.position = {
    left: this.left = this.rleft = 0,
    right: this.right = this.rright = 0,
    top: this.top = this.rtop = 0,
    bottom: this.bottom = 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;

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

  this.program.on('resize', function() {
    if (!self.options.resizeTimeout) {
      return resize();
    }
    if (self._resizeTimer) {
      clearTimeout(self._resizeTimer);
      delete self._resizeTimer;
    }
    var time = typeof self.options.resizeTimeout === 'number'
      ? self.options.resizeTimeout
      : 300;
    self._resizeTimer = setTimeout(resize, time);
  });

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

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

  this.enter();

  function reset() {
    if (reset.done) return;
    reset.done = true;
    self.leave();
  }

  this._maxListeners = Infinity;

  if (this.options.handleUncaughtExceptions !== false) {
    process.on('uncaughtException', function(err) {
      reset();
      if (err) console.error(err.stack ? err.stack + '' : err + '');
      return process.exit(1);
    });
  }

  process.on('SIGTERM', function() {
    return process.exit(0);
  });

  process.on('exit', function() {
    reset();
  });

  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();
    }
  });
}

Screen.global = null;

Screen.prototype.__proto__ = Node.prototype;

Screen.prototype.type = 'screen';

Screen.prototype.enter = function() {
  if (this.program.isAlt) return;
  this.program.alternateBuffer();
  this.program.hideCursor();
  this.program.cup(0, 0);
  //this.program.csr(0, this.height - 1);
  this.alloc();
};

Screen.prototype.leave = function() {
  if (!this.program.isAlt) return;
  if (this.program.scrollTop !== 0
      || this.program.scrollBottom !== this.rows - 1) {
    this.program.csr(0, this.height - 1);
  }
  // this.program.clear();
  this.alloc();
  this.program.showCursor();
  this.program.normalBuffer();
  if (this._listenedMouse) {
    this.program.disableMouse();
  }
  this.program.flush();
};

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

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

Screen.prototype._listenMouse = function(el) {
  var 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();

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

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

    if (self._needsClickableSort) {
      self.clickable = hsort(self.clickable);
      self._needsClickableSort = false;
    }

    var 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);
  });

  // 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, data) {
    if (el.clickable === true && el.options.autoFocus !== false) {
      el.focus();
    }
  });
};

Screen.prototype._listenKeys = function(el) {
  var 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;
    }

    var focused = self.focused
      , grabKeys = self.grabKeys;

    if (!grabKeys) {
      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.__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() {
  var 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 = false;
  }

  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.render = function() {
  var self = this;

  this.emit('prerender');

  // 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;

  this.draw(0, this.rows - 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) {
  var out = [];
  for (var 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);

  var 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);

  var 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);

  var 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);

  var 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) {
  var 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 (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;
  // }

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

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

  return pos._cleanSides = true;
};

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

  var x
    , y
    , line
    , out
    , ch
    , data
    , attr
    , fg
    , bg
    , flags;

  var main = ''
    , pre
    , post;

  var clr
    , neq
    , xx;

  var lx = -1
    , ly = -1
    , o;

  var 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) continue;
    line.dirty = false;

    out = '';
    attr = this.dattr;

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

      // 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 < this.cols; 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 < this.cols; 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();
        //   }
        //   out += this.tput.cuf(xx - x);
        //   this.fillRegion(data, ' ',
        //     x, this.tput.strings.erase_chars ? xx : this.cols,
        //     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 < this.cols; 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) {
        out += y === ly
          ? this.tput.cuf(x - lx)
          : 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';
        }
      }

      // 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) {
        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.
        // if ((!this.unicode || this.tput.numbers.U8 !== 1) && ch > '~') {
        if ((!this.unicode || this.tput.numbers.U8 !== 1) && this.tput.utoa[ch]) {
          ch = this.tput.utoa[ch] || '?';
        }
      }

      // if (wideChars.test(ch)) x++;

      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.output.write(pre + main + post);
    this.program._write(pre + main + post);
  }

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

Screen.prototype._reduceColor = function(col) {
  if (col >= 16 && this.tput.colors <= 16) {
    col = colors.ccolors[col];
  } else if (col >= 8 && this.tput.colors <= 8) {
    col -= 8;
  } else if (col >= 2 && this.tput.colors <= 2) {
    col %= 2;
  }
  return col;
};

// Convert an SGR string to our own attribute format.
Screen.prototype.attrCode = function(code, cur, def) {
  var 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 = 0x1ff;
        //fg = 0x1ff;
        //flags = 0;
        bg = def & 0x1ff;
        fg = (def >> 9) & 0x1ff;
        flags = (def >> 18) & 0x1ff;
        break;
      case 1: // bold
        flags |= 1;
        break;
      case 22:
        //flags &= ~1;
        flags = (def >> 18) & 0x1ff;
        break;
      case 4: // underline
        flags |= 2;
        break;
      case 24:
        //flags &= ~2;
        flags = (def >> 18) & 0x1ff;
        break;
      case 5: // blink
        flags |= 4;
        break;
      case 25:
        //flags &= ~4;
        flags = (def >> 18) & 0x1ff;
        break;
      case 7: // inverse
        flags |= 8;
        break;
      case 27:
        //flags &= ~8;
        flags = (def >> 18) & 0x1ff;
        break;
      case 8: // invisible
        flags |= 16;
        break;
      case 28:
        //flags &= ~16;
        flags = (def >> 18) & 0x1ff;
        break;
      case 39: // default fg
        //fg = 0x1ff;
        fg = (def >> 9) & 0x1ff;
        break;
      case 49: // default bg
        //bg = 0x1ff;
        bg = def & 0x1ff;
        break;
      case 100: // default fg/bg
        //fg = 0x1ff;
        //bg = 0x1ff;
        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 = 0x1ff;
          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 = 0x1ff;
          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 = 0x1ff;
          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 = 0x1ff;
          fg = (def >> 9) & 0x1ff;
        } else if (c === 100) {
          //fg = 0x1ff;
          //bg = 0x1ff;
          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) {
  var 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) {
  var shown = this.keyable.filter(function(el) {
    return !el.detached && el.visible;
  }).length;

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

  var 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;
  var 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() {
  var 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() {
  var 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.
  var 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) {
    var ryi = self.top - el.top - el.itop
      , ryl = self.top + self.height - el.top - el.ibottom
      , visible = el.height - el.iheight;

    if (ryi < el.childBase) {
      el.scrollTo(ryi);
      self.screen.render();
    } else if (ryi >= el.childBase + visible) {
      el.scrollTo(ryi + self.height);
      self.screen.render();
    } else if (ryl >= el.childBase + visible) {
      el.scrollTo(ryi + self.height);
      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) {
  return this.fillRegion(this.dattr, ' ', xi, xl, yi, yl);
};

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

  for (; yi < yl; yi++) {
    if (!lines[yi]) break;
    for (xx = xi; xx < xl; xx++) {
      cell = lines[yi][xx];
      if (!cell) break;
      if (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 = [];
  }

  var screen = this
    , program = screen.program
    , options = options || {}
    , spawn = require('child_process').spawn
    , mouse = program.mouseEnabled
    , ps;

  options.stdio = 'inherit';

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

  var write = program.output.write;
  program.output.write = function() {};
  program.input.pause();
  program.input.setRawMode(false);

  var resume = function() {
    if (resume.done) return;
    resume.done = true;

    program.input.setRawMode(true);
    program.input.resume();
    program.output.write = write;

    program.alternateBuffer();
    //program.csr(0, program.rows - 1);
    if (mouse) program.enableMouse();

    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) {
  var callback = arguments[arguments.length-1]
    , ps = this.spawn(file, args, options);

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

  ps.on('exit', function(code) {
    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 || {};

  var self = this
    , fs = require('fs')
    , 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.setEffects = function(el, fel, over, out, effects, temp) {
  if (!effects) return;

  var tmp = {};
  if (temp) el[temp] = tmp;

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

  fel.on(over, function() {
    var element = el();
    Object.keys(effects).forEach(function(key) {
      var val = effects[key];
      if (val !== null && typeof val === 'object') {
        tmp[key] = tmp[key] || {};
        Object.keys(val).forEach(function(k) {
          var 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() {
    var element = el();
    Object.keys(effects).forEach(function(key) {
      var val = effects[key];
      if (val !== null && typeof val === 'object') {
        tmp[key] = tmp[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) {
  var self = this;
  this.program.sigtstp(function() {
    self.alloc();
    self.render();
    self.program.lrestoreCursor('pause', true);
    if (callback) callback();
  });
};

/**
 * Element
 */

function Element(options) {
  var self = this;

  if (!(this instanceof Node)) {
    return new Element(options);
  }

  options = options || {};

  // Workaround to get a `scrollable` option.
  if (options.scrollable && !this._ignore && this.type !== 'scrollable-box') {
    Object.getOwnPropertyNames(ScrollableBox.prototype).forEach(function(key) {
      if (key === 'type') return;
      Object.defineProperty(this, key,
        Object.getOwnPropertyDescriptor(ScrollableBox.prototype, key));
    }, this);
    this._ignore = true;
    ScrollableBox.call(this, options);
    delete this._ignore;
    return this;
  }

  Node.call(this, options);

  this.name = options.name;

  options.position = options.position || {
    left: options.left,
    right: options.right,
    top: options.top,
    bottom: options.bottom,
    width: options.width,
    height: options.height
  };

  // if (options.position.left == null && options.position.right == null) {
  //   options.position.left = 0;
  // }
  // if (options.position.top == null && options.position.bottom == null) {
  //   options.position.top = 0;
  // }

  if (options.position.width === 'shrink'
      || options.position.height === 'shrink') {
    if (options.position.width === 'shrink') {
      delete options.position.width;
    }
    if (options.position.height === 'shrink') {
      delete options.position.height;
    }
    options.shrink = true;
  }

  this.position = options.position;

  this.noOverflow = options.noOverflow;

  this.style = options.style;

  if (!this.style) {
    this.style = {};
    this.style.fg = options.fg;
    this.style.bg = options.bg;
    this.style.bold = options.bold;
    this.style.underline = options.underline;
    this.style.blink = options.blink;
    this.style.inverse = options.inverse;
    this.style.invisible = options.invisible;
  }

  this.hidden = options.hidden || false;
  this.fixed = options.fixed || false;
  this.align = options.align || 'left';
  this.valign = options.valign || 'top';
  this.wrap = options.wrap !== false;
  this.shrink = options.shrink;
  this.fixed = options.fixed;
  this.ch = options.ch || ' ';

  if (typeof options.padding === 'number' || !options.padding) {
    options.padding = {
      left: options.padding,
      top: options.padding,
      right: options.padding,
      bottom: options.padding
    };
  }

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

  this.border = options.border;
  if (this.border) {
    if (typeof this.border === 'string') {
      this.border = { type: this.border };
    }
    this.border.type = this.border.type || 'bg';
    if (this.border.type === 'ascii') this.border.type = 'line';
    this.border.ch = this.border.ch || ' ';
    if (!this.border.style) {
      this.border.style = this.style.border || {};
      this.border.style.fg = this.border.fg;
      this.border.style.bg = this.border.bg;
    }
    this.style.border = this.border.style;
  }

  if (options.clickable) {
    this.screen._listenMouse(this);
  }

  if (options.input || options.keyable) {
    this.screen._listenKeys(this);
  }

  this.parseTags = options.parseTags || options.tags;

  this.setContent(options.content || '', true);

  if (options.label) {
    this.setLabel(options.label);
  }

  // TODO: Possibly move this to Node for screen.on('mouse', ...).
  this.on('newListener', function fn(type) {
    //type = type.split(' ').slice(1).join(' ');
    if (type === 'mouse'
      || type === 'click'
      || type === 'mouseover'
      || type === 'mouseout'
      || type === 'mousedown'
      || type === 'mouseup'
      || type === 'mousewheel'
      || type === 'wheeldown'
      || type === 'wheelup'
      || type === 'mousemove') {
      self.screen._listenMouse(self);
    } else if (type === 'keypress' || type.indexOf('key ') === 0) {
      self.screen._listenKeys(self);
    }
  });

  this.on('resize', function() {
    self.parseContent();
  });

  this.on('attach', function() {
    self.parseContent();
  });

  this.on('detach', function() {
    delete self.lpos;
  });

  if (options.hoverBg != null) {
    options.hoverEffects = options.hoverEffects || {};
    options.hoverEffects.bg = options.hoverBg;
  }

  if (this.style.hover) {
    options.hoverEffects = this.style.hover;
    //delete this.style.hover;
  }

  if (this.style.focus) {
    options.focusEffects = this.style.focus;
    //delete this.style.focus;
  }

  // if (options.effects) {
  //   if (options.effects.hover) options.hoverEffects = options.effects.hover;
  //   if (options.effects.focus) options.focusEffects = options.effects.focus;
  // }

  [['hoverEffects', 'mouseover', 'mouseout', '_htemp'],
   ['focusEffects', 'focus', 'blur', '_ftemp']].forEach(function(props) {
    var pname = props[0], over = props[1], out = props[2], temp = props[3];
    self.screen.setEffects(self, self, over, out, self.options[pname], temp);
  });

  if (options.focused) {
    this.focus();
  }
}

Element.prototype.__proto__ = Node.prototype;

Element.prototype.type = 'element';

Element.prototype.__defineGetter__('focused', function() {
  return this.screen.focused === this;
});

Element.prototype.sattr = function(obj, fg, bg) {
  var bold = obj.bold
    , underline = obj.underline
    , blink = obj.blink
    , inverse = obj.inverse
    , invisible = obj.invisible;

  // This used to be a loop, but I decided
  // to unroll it for performance's sake.
  if (typeof bold === 'function') bold = bold(this);
  if (typeof underline === 'function') underline = underline(this);
  if (typeof blink === 'function') blink = blink(this);
  if (typeof inverse === 'function') inverse = inverse(this);
  if (typeof invisible === 'function') invisible = invisible(this);

  if (typeof fg === 'function') fg = fg(this);
  if (typeof bg === 'function') bg = bg(this);

  return ((((invisible ? 16 : 0) << 18)
    | ((inverse ? 8 : 0) << 18)
    | ((blink ? 4 : 0) << 18)
    | ((underline ? 2 : 0) << 18))
    | ((bold ? 1 : 0) << 18)
    | (colors.convert(fg) << 9))
    | colors.convert(bg);
};

Element.prototype.onScreenEvent = function(type, listener) {
  var self = this;
  if (this.parent) {
    this.screen.on(type, listener);
  }
  this.on('attach', function() {
    self.screen.on(type, listener);
  });
  this.on('detach', function() {
    self.screen.removeListener(type, listener);
  });
};

Element.prototype.hide = function() {
  if (this.hidden) return;
  this.clearPos();
  this.hidden = true;
  this.emit('hide');
  if (this.screen.focused === this) {
    this.screen.rewindFocus();
  }
};

Element.prototype.show = function() {
  if (!this.hidden) return;
  this.hidden = false;
  this.emit('show');
};

Element.prototype.toggle = function() {
  return this.hidden ? this.show() : this.hide();
};

Element.prototype.focus = function() {
  return this.screen.focused = this;
};

Element.prototype.setContent = function(content, noClear, noTags) {
  if (!noClear) this.clearPos();
  this.content = content || '';
  this.parseContent(noTags);
};

Element.prototype.getContent = function() {
  return this._clines.fake.join('\n');
};

Element.prototype.setText = function(content, noClear) {
  content = content || '';
  content = content.replace(/\x1b\[[\d;]*m/g, '');
  return this.setContent(content, noClear, true);
};

Element.prototype.getText = function() {
  return this.getContent().replace(/\x1b\[[\d;]*m/g, '');
};

Element.prototype.parseContent = function(noTags) {
  if (this.detached) return false;

  var width = this.width - this.iwidth;
  if (this._clines == null
      || this._clines.width !== width
      || this._clines.content !== this.content) {
    var content = this.content;

    content = content
      .replace(/[\x00-\x08\x0b-\x0c\x0e-\x1a\x1c-\x1f\x7f]/g, '')
      .replace(/\x1b(?!\[[\d;]*m)/g, '')
      .replace(/\r\n|\r/g, '\n')
      .replace(/\t/g, this.screen.tabc)
      .replace(wideChars, '?');

    if (!noTags) {
      content = this._parseTags(content);
    }

    this._clines = this._wrapContent(content, width);
    this._clines.width = width;
    this._clines.content = this.content;
    this._clines.attr = this._parseAttr(this._clines);
    this._clines.ci = [];
    this._clines.reduce(function(total, line) {
      this._clines.ci.push(total);
      return total + line.length + 1;
    }.bind(this), 0);

    this._pcontent = this._clines.join('\n');
    this.emit('parsed content');

    return true;
  }

  // Need to calculate this every time because the default fg/bg may change.
  this._clines.attr = this._parseAttr(this._clines) || this._clines.attr;

  return false;
};

// Convert `{red-fg}foo{/red-fg}` to `\x1b[31mfoo\x1b[39m`.
Element.prototype._parseTags = function(text) {
  if (!this.parseTags) return text;
  if (!/{\/?[\w\-,;!#]*}/.test(text)) return text;

  var program = this.screen.program
    , out = ''
    , state
    , bg = []
    , fg = []
    , flag = []
    , cap
    , slash
    , param
    , attr
    , esc;

  for (;;) {
    if (!esc && (cap = /^{escape}/.exec(text))) {
      text = text.substring(cap[0].length);
      esc = true;
      continue;
    }

    if (esc && (cap = /^([\s\S]+?){\/escape}/.exec(text))) {
      text = text.substring(cap[0].length);
      out += cap[1];
      esc = false;
      continue;
    }

    if (esc) {
      // throw new Error('Unterminated escape tag.');
      out += text;
      break;
    }

    if (cap = /^{(\/?)([\w\-,;!#]*)}/.exec(text)) {
      text = text.substring(cap[0].length);
      slash = cap[1] === '/';
      param = cap[2].replace(/-/g, ' ');

      if (param === 'open') {
        out += '{';
        continue;
      } else if (param === 'close') {
        out += '}';
        continue;
      }

      if (param.slice(-3) === ' bg') state = bg;
      else if (param.slice(-3) === ' fg') state = fg;
      else state = flag;

      if (slash) {
        if (!param) {
          out += program._attr('normal');
          bg.length = 0;
          fg.length = 0;
          flag.length = 0;
        } else {
          attr = program._attr(p…