/**
 * Link to the project's GitHub page:
 * https://github.com/pickhardt/coffeescript-codemirror-mode
 */
CodeMirror.defineMode("coffeescript", function(conf) {
  var ERRORCLASS = "error";

  function wordRegexp(words) {
    return new RegExp("^((" + words.join(")|(") + "))\\b");
  }

  var operators = /^(?:->|=>|\+[+=]?|-[\-=]?|\*[\*=]?|\/[\/=]?|[=!]=|<[><]?=?|>>?=?|%=?|&=?|\|=?|\^=?|\~|!|\?)/;
  var delimiters = /^(?:[()\[\]{},:`=;]|\.\.?\.?)/;
  var identifiers = /^[_A-Za-z$][_A-Za-z$0-9]*/;
  var properties = /^(@|this\.)[_A-Za-z$][_A-Za-z$0-9]*/;

  var wordOperators = wordRegexp(["and", "or", "not",
                                  "is", "isnt", "in",
                                  "instanceof", "typeof"]);
  var indentKeywords = ["for", "while", "loop", "if", "unless", "else",
                        "switch", "try", "catch", "finally", "class"];
  var commonKeywords = ["break", "by", "continue", "debugger", "delete",
                        "do", "in", "of", "new", "return", "then",
                        "this", "throw", "when", "until"];

  var keywords = wordRegexp(indentKeywords.concat(commonKeywords));

  indentKeywords = wordRegexp(indentKeywords);


  var stringPrefixes = /^('{3}|\"{3}|['\"])/;
  var regexPrefixes = /^(\/{3}|\/)/;
  var commonConstants = ["Infinity", "NaN", "undefined", "null", "true", "false", "on", "off", "yes", "no"];
  var constants = wordRegexp(commonConstants);

  // Tokenizers
  function tokenBase(stream, state) {
    // Handle scope changes
    if (stream.sol()) {
      if (state.scope.align === null) state.scope.align = false;
      var scopeOffset = state.scope.offset;
      if (stream.eatSpace()) {
        var lineOffset = stream.indentation();
        if (lineOffset > scopeOffset && state.scope.type == "coffee") {
          return "indent";
        } else if (lineOffset < scopeOffset) {
          return "dedent";
        }
        return null;
      } else {
        if (scopeOffset > 0) {
          dedent(stream, state);
        }
      }
    }
    if (stream.eatSpace()) {
      return null;
    }

    var ch = stream.peek();

    // Handle docco title comment (single line)
    if (stream.match("####")) {
      stream.skipToEnd();
      return "comment";
    }

    // Handle multi line comments
    if (stream.match("###")) {
      state.tokenize = longComment;
      return state.tokenize(stream, state);
    }

    // Single line comment
    if (ch === "#") {
      stream.skipToEnd();
      return "comment";
    }

    // Handle number literals
    if (stream.match(/^-?[0-9\.]/, false)) {
      var floatLiteral = false;
      // Floats
      if (stream.match(/^-?\d*\.\d+(e[\+\-]?\d+)?/i)) {
        floatLiteral = true;
      }
      if (stream.match(/^-?\d+\.\d*/)) {
        floatLiteral = true;
      }
      if (stream.match(/^-?\.\d+/)) {
        floatLiteral = true;
      }

      if (floatLiteral) {
        // prevent from getting extra . on 1..
        if (stream.peek() == "."){
          stream.backUp(1);
        }
        return "number";
      }
      // Integers
      var intLiteral = false;
      // Hex
      if (stream.match(/^-?0x[0-9a-f]+/i)) {
        intLiteral = true;
      }
      // Decimal
      if (stream.match(/^-?[1-9]\d*(e[\+\-]?\d+)?/)) {
        intLiteral = true;
      }
      // Zero by itself with no other piece of number.
      if (stream.match(/^-?0(?![\dx])/i)) {
        intLiteral = true;
      }
      if (intLiteral) {
        return "number";
      }
    }

    // Handle strings
    if (stream.match(stringPrefixes)) {
      state.tokenize = tokenFactory(stream.current(), false, "string");
      return state.tokenize(stream, state);
    }
    // Handle regex literals
    if (stream.match(regexPrefixes)) {
      if (stream.current() != "/" || stream.match(/^.*\//, false)) { // prevent highlight of division
        state.tokenize = tokenFactory(stream.current(), true, "string-2");
        return state.tokenize(stream, state);
      } else {
        stream.backUp(1);
      }
    }

    // Handle operators and delimiters
    if (stream.match(operators) || stream.match(wordOperators)) {
      return "operator";
    }
    if (stream.match(delimiters)) {
      return "punctuation";
    }

    if (stream.match(constants)) {
      return "atom";
    }

    if (stream.match(keywords)) {
      return "keyword";
    }

    if (stream.match(identifiers)) {
      return "variable";
    }

    if (stream.match(properties)) {
      return "property";
    }

    // Handle non-detected items
    stream.next();
    return ERRORCLASS;
  }

  function tokenFactory(delimiter, singleline, outclass) {
    return function(stream, state) {
      while (!stream.eol()) {
        stream.eatWhile(/[^'"\/\\]/);
        if (stream.eat("\\")) {
          stream.next();
          if (singleline && stream.eol()) {
            return outclass;
          }
        } else if (stream.match(delimiter)) {
          state.tokenize = tokenBase;
          return outclass;
        } else {
          stream.eat(/['"\/]/);
        }
      }
      if (singleline) {
        if (conf.mode.singleLineStringErrors) {
          outclass = ERRORCLASS;
        } else {
          state.tokenize = tokenBase;
        }
      }
      return outclass;
    };
  }

  function longComment(stream, state) {
    while (!stream.eol()) {
      stream.eatWhile(/[^#]/);
      if (stream.match("###")) {
        state.tokenize = tokenBase;
        break;
      }
      stream.eatWhile("#");
    }
    return "comment";
  }

  function indent(stream, state, type) {
    type = type || "coffee";
    var offset = 0, align = false, alignOffset = null;
    for (var scope = state.scope; scope; scope = scope.prev) {
      if (scope.type === "coffee") {
        offset = scope.offset + conf.indentUnit;
        break;
      }
    }
    if (type !== "coffee") {
      align = null;
      alignOffset = stream.column() + stream.current().length;
    } else if (state.scope.align) {
      state.scope.align = false;
    }
    state.scope = {
      offset: offset,
      type: type,
      prev: state.scope,
      align: align,
      alignOffset: alignOffset
    };
  }

  function dedent(stream, state) {
    if (!state.scope.prev) return;
    if (state.scope.type === "coffee") {
      var _indent = stream.indentation();
      var matched = false;
      for (var scope = state.scope; scope; scope = scope.prev) {
        if (_indent === scope.offset) {
          matched = true;
          break;
        }
      }
      if (!matched) {
        return true;
      }
      while (state.scope.prev && state.scope.offset !== _indent) {
        state.scope = state.scope.prev;
      }
      return false;
    } else {
      state.scope = state.scope.prev;
      return false;
    }
  }

  function tokenLexer(stream, state) {
    var style = state.tokenize(stream, state);
    var current = stream.current();

    // Handle "." connected identifiers
    if (current === ".") {
      style = state.tokenize(stream, state);
      current = stream.current();
      if (/^\.[\w$]+$/.test(current)) {
        return "variable";
      } else {
        return ERRORCLASS;
      }
    }

    // Handle scope changes.
    if (current === "return") {
      state.dedent += 1;
    }
    if (((current === "->" || current === "=>") &&
         !state.lambda &&
         !stream.peek())
        || style === "indent") {
      indent(stream, state);
    }
    var delimiter_index = "[({".indexOf(current);
    if (delimiter_index !== -1) {
      indent(stream, state, "])}".slice(delimiter_index, delimiter_index+1));
    }
    if (indentKeywords.exec(current)){
      indent(stream, state);
    }
    if (current == "then"){
      dedent(stream, state);
    }


    if (style === "dedent") {
      if (dedent(stream, state)) {
        return ERRORCLASS;
      }
    }
    delimiter_index = "])}".indexOf(current);
    if (delimiter_index !== -1) {
      while (state.scope.type == "coffee" && state.scope.prev)
        state.scope = state.scope.prev;
      if (state.scope.type == current)
        state.scope = state.scope.prev;
    }
    if (state.dedent > 0 && stream.eol() && state.scope.type == "coffee") {
      if (state.scope.prev) state.scope = state.scope.prev;
      state.dedent -= 1;
    }

    return style;
  }

  var external = {
    startState: function(basecolumn) {
      return {
        tokenize: tokenBase,
        scope: {offset:basecolumn || 0, type:"coffee", prev: null, align: false},
        lastToken: null,
        lambda: false,
        dedent: 0
      };
    },

    token: function(stream, state) {
      var fillAlign = state.scope.align === null && state.scope;
      if (fillAlign && stream.sol()) fillAlign.align = false;

      var style = tokenLexer(stream, state);
      if (fillAlign && style && style != "comment") fillAlign.align = true;

      state.lastToken = {style:style, content: stream.current()};

      if (stream.eol() && stream.lambda) {
        state.lambda = false;
      }

      return style;
    },

    indent: function(state, text) {
      if (state.tokenize != tokenBase) return 0;
      var scope = state.scope;
      var closer = text && "])}".indexOf(text.charAt(0)) > -1;
      if (closer) while (scope.type == "coffee" && scope.prev) scope = scope.prev;
      var closes = closer && scope.type === text.charAt(0);
      if (scope.align)
        return scope.alignOffset - (closes ? 1 : 0);
      else
        return (closes ? scope.prev : scope).offset;
    },

    lineComment: "#",
    fold: "indent"
  };
  return external;
});

CodeMirror.defineMIME("text/x-coffeescript", "coffeescript");
