// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: http://codemirror.net/LICENSE

(function(mod) {
  if (typeof exports == "object" && typeof module == "object") // CommonJS
    mod(require("../../lib/codemirror"));
  else if (typeof define == "function" && define.amd) // AMD
    define(["../../lib/codemirror"], mod);
  else // Plain browser env
    mod(CodeMirror);
})(function(CodeMirror) {
  var defaults = {
    pairs: "()[]{}''\"\"",
    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);
      cm.execCommand("goCharLeft");
      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 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 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 &&
                 (cur.ch <= 2 || cm.getRange(Pos(cur.line, cur.ch - 3), Pos(cur.line, cur.ch - 2)) != ch)) {
        curType = "addFour";
      } else if (identical) {
        if (!CodeMirror.isWordChar(next) && enteringString(cm, cur, ch)) curType = "both";
        else return CodeMirror.Pass;
      } else if (opening && (cm.getLine(cur.line).length == cur.ch ||
                             isClosingBracket(next, pairs) ||
                             /\s/.test(next))) {
        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") {
        cm.execCommand("goCharRight");
      } else if (type == "skipThree") {
        for (var i = 0; i < 3; i++)
          cm.execCommand("goCharRight");
      } 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);
        cm.execCommand("goCharLeft");
      } else if (type == "addFour") {
        cm.replaceSelection(left + left + left + left, "before");
        cm.execCommand("goCharRight");
      }
    });
  }

  function isClosingBracket(ch, pairs) {
    var pos = pairs.lastIndexOf(ch);
    return pos > -1 && pos % 2 == 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;
  }

  // Project the token type that will exists after the given char is
  // typed, and use it to determine whether it would cause the start
  // of a string token.
  function enteringString(cm, pos, ch) {
    var line = cm.getLine(pos.line);
    var token = cm.getTokenAt(pos);
    if (/\bstring2?\b/.test(token.type) || stringStartsAfter(cm, pos)) return false;
    var stream = new CodeMirror.StringStream(line.slice(0, pos.ch) + ch + line.slice(pos.ch), 4);
    stream.pos = stream.start = token.start;
    for (;;) {
      var type1 = cm.getMode().token(stream, token.state);
      if (stream.pos >= pos.ch + 1) return /\bstring2?\b/.test(type1);
      stream.start = stream.pos;
    }
  }

  function stringStartsAfter(cm, pos) {
    var token = cm.getTokenAt(Pos(pos.line, pos.ch + 1))
    return /\bstring/.test(token.type) && token.start == pos.ch
  }
});
