text: // CodeMirror, copyright (c) by Marijn Haverbeke and others
  // Distributed under an MIT license: https://codemirror.net/LICENSE
  
  export default function (CodeMirror) {
    var defaults = {
      pairs: '()[]{}\'\'""',
      closeBefore: ')]}\'":;>',
      triples: '',
      explode: '[]{}',
    };
  
    var Pos = CodeMirror.Pos;
  
    CodeMirror.defineOption('autoCloseBrackets', false, function (cm, val, old) {
      if (old && old != CodeMirror.Init) {
        cm.removeKeyMap(keyMap);
        cm.state.closeBrackets = null;
      }
      if (val) {
        ensureBound(getOption(val, 'pairs'));
        cm.state.closeBrackets = val;
        cm.addKeyMap(keyMap);
      }
    });
  
    function getOption(conf, name) {
      if (name == 'pairs' && typeof conf == 'string') return conf;
      if (typeof conf == 'object' && conf[name] != null) return conf[name];
      return defaults[name];
    }
  
    var keyMap = { Backspace: handleBackspace, Enter: handleEnter };
    function ensureBound(chars) {
      for (var i = 0; i < chars.length; i++) {
        var ch = chars.charAt(i),
          key = "'" + ch + "'";
        if (!keyMap[key]) keyMap[key] = handler(ch);
      }
    }
    ensureBound(defaults.pairs + '`');
  
    function handler(ch) {
      return function (cm) {
        return handleChar(cm, ch);
      };
    }
  
    function getConfig(cm) {
      var deflt = cm.state.closeBrackets;
      if (!deflt || deflt.override) return deflt;
      var mode = cm.getModeAt(cm.getCursor());
      return mode.closeBrackets || deflt;
    }
  
    function handleBackspace(cm) {
      var conf = getConfig(cm);
      if (!conf || cm.getOption('disableInput')) return CodeMirror.Pass;
  
      var pairs = getOption(conf, 'pairs');
      var ranges = cm.listSelections();
      for (var i = 0; i < ranges.length; i++) {
        if (!ranges[i].empty()) return CodeMirror.Pass;
        var around = charsAround(cm, ranges[i].head);
        if (!around || pairs.indexOf(around) % 2 != 0) return CodeMirror.Pass;
      }
      for (var i = ranges.length - 1; i >= 0; i--) {
        var cur = ranges[i].head;
        cm.replaceRange('', Pos(cur.line, cur.ch - 1), Pos(cur.line, cur.ch + 1), '+delete');
      }
    }
  
    function handleEnter(cm) {
      var conf = getConfig(cm);
      var explode = conf && getOption(conf, 'explode');
      if (!explode || cm.getOption('disableInput')) return CodeMirror.Pass;
  
      var ranges = cm.listSelections();
      for (var i = 0; i < ranges.length; i++) {
        if (!ranges[i].empty()) return CodeMirror.Pass;
        var around = charsAround(cm, ranges[i].head);
        if (!around || explode.indexOf(around) % 2 != 0) return CodeMirror.Pass;
      }
      cm.operation(function () {
        var linesep = cm.lineSeparator() || '\n';
        cm.replaceSelection(linesep + linesep, null);
        moveSel(cm, -1);
        ranges = cm.listSelections();
        for (var i = 0; i < ranges.length; i++) {
          var line = ranges[i].head.line;
          cm.indentLine(line, null, true);
          cm.indentLine(line + 1, null, true);
        }
      });
    }
  
    function moveSel(cm, dir) {
      var newRanges = [],
        ranges = cm.listSelections(),
        primary = 0;
      for (var i = 0; i < ranges.length; i++) {
        var range = ranges[i];
        if (range.head == cm.getCursor()) primary = i;
        var pos =
          range.head.ch || dir > 0 ? { line: range.head.line, ch: range.head.ch + dir } : { line: range.head.line - 1 };
        newRanges.push({ anchor: pos, head: pos });
      }
      cm.setSelections(newRanges, primary);
    }
  
    function contractSelection(sel) {
      var inverted = CodeMirror.cmpPos(sel.anchor, sel.head) > 0;
      return {
        anchor: new Pos(sel.anchor.line, sel.anchor.ch + (inverted ? -1 : 1)),
        head: new Pos(sel.head.line, sel.head.ch + (inverted ? 1 : -1)),
      };
    }
  
    function handleChar(cm, ch) {
      var conf = getConfig(cm);
      if (!conf || cm.getOption('disableInput')) return CodeMirror.Pass;
  
      var pairs = getOption(conf, 'pairs');
      var pos = pairs.indexOf(ch);
      if (pos == -1) return CodeMirror.Pass;
  
      var closeBefore = getOption(conf, 'closeBefore');
  
      var triples = getOption(conf, 'triples');
  
      var identical = pairs.charAt(pos + 1) == ch;
      var ranges = cm.listSelections();
      var opening = pos % 2 == 0;
  
      var type;
      for (var i = 0; i < ranges.length; i++) {
        var range = ranges[i],
          cur = range.head,
          curType;
        var next = cm.getRange(cur, Pos(cur.line, cur.ch + 1));
        if (opening && !range.empty()) {
          curType = 'surround';
        } else if ((identical || !opening) && next == ch) {
          if (identical && stringStartsAfter(cm, cur)) curType = 'both';
          else if (triples.indexOf(ch) >= 0 && cm.getRange(cur, Pos(cur.line, cur.ch + 3)) == ch + ch + ch)
            curType = 'skipThree';
          else curType = 'skip';
        } else if (
          identical &&
          cur.ch > 1 &&
          triples.indexOf(ch) >= 0 &&
          cm.getRange(Pos(cur.line, cur.ch - 2), cur) == ch + ch
        ) {
          if (cur.ch > 2 && /\bstring/.test(cm.getTokenTypeAt(Pos(cur.line, cur.ch - 2)))) return CodeMirror.Pass;
          curType = 'addFour';
        } else if (identical) {
          var prev = cur.ch == 0 ? ' ' : cm.getRange(Pos(cur.line, cur.ch - 1), cur);
          if (!CodeMirror.isWordChar(next) && prev != ch && !CodeMirror.isWordChar(prev)) curType = 'both';
          else return CodeMirror.Pass;
        } else if (opening && (next.length === 0 || /\s/.test(next) || closeBefore.indexOf(next) > -1)) {
          curType = 'both';
        } else {
          return CodeMirror.Pass;
        }
        if (!type) type = curType;
        else if (type != curType) return CodeMirror.Pass;
      }
  
      var left = pos % 2 ? pairs.charAt(pos - 1) : ch;
      var right = pos % 2 ? ch : pairs.charAt(pos + 1);
      cm.operation(function () {
        if (type == 'skip') {
          moveSel(cm, 1);
        } else if (type == 'skipThree') {
          moveSel(cm, 3);
        } else if (type == 'surround') {
          var sels = cm.getSelections();
          for (var i = 0; i < sels.length; i++) sels[i] = left + sels[i] + right;
          cm.replaceSelections(sels, 'around');
          sels = cm.listSelections().slice();
          for (var i = 0; i < sels.length; i++) sels[i] = contractSelection(sels[i]);
          cm.setSelections(sels);
        } else if (type == 'both') {
          cm.replaceSelection(left + right, null);
          cm.triggerElectric(left + right);
          moveSel(cm, -1);
        } else if (type == 'addFour') {
          cm.replaceSelection(left + left + left + left, 'before');
          moveSel(cm, 1);
        }
      });
    }
  
    function charsAround(cm, pos) {
      var str = cm.getRange(Pos(pos.line, pos.ch - 1), Pos(pos.line, pos.ch + 1));
      return str.length == 2 ? str : null;
    }
  
    function stringStartsAfter(cm, pos) {
      var token = cm.getTokenAt(Pos(pos.line, pos.ch + 1));
      return (
        /\bstring/.test(token.type) && token.start == pos.ch && (pos.ch == 0 || !/\bstring/.test(cm.getTokenTypeAt(pos)))
      );
    }
  }
  