/**
 * 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 singleOperators = new RegExp("^[\\+\\-\\*/%&|\\^~<>!\?]");
    var singleDelimiters = new RegExp('^[\\(\\)\\[\\]\\{\\}@,:`=;\\.]');
    var doubleOperators = new RegExp("^((\->)|(\=>)|(\\+\\+)|(\\+\\=)|(\\-\\-)|(\\-\\=)|(\\*\\*)|(\\*\\=)|(\\/\\/)|(\\/\\=)|(==)|(!=)|(<=)|(>=)|(<>)|(<<)|(>>)|(//))");
    var doubleDelimiters = new RegExp("^((\\.\\.)|(\\+=)|(\\-=)|(\\*=)|(%=)|(/=)|(&=)|(\\|=)|(\\^=))");
    var tripleDelimiters = new RegExp("^((\\.\\.\\.)|(//=)|(>>=)|(<<=)|(\\*\\*=))");
    var identifiers = new RegExp("^[_A-Za-z][_A-Za-z0-9]*");

    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 = new RegExp("^('{3}|\"{3}|['\"])");
    var regexPrefixes = new RegExp("^(/{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()) {
            var scopeOffset = state.scopes[0].offset;
            if (stream.eatSpace()) {
                var lineOffset = stream.indentation();
                if (lineOffset > scopeOffset) {
                    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 comments
        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) {
                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(), '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(), 'string-2');
                return state.tokenize(stream, state);
            } else {
                stream.backUp(1);
            }
        }
        
        // Handle operators and delimiters
        if (stream.match(tripleDelimiters) || stream.match(doubleDelimiters)) {
            return 'punctuation';
        }
        if (stream.match(doubleOperators)
            || stream.match(singleOperators)
            || stream.match(wordOperators)) {
            return 'operator';
        }
        if (stream.match(singleDelimiters)) {
            return 'punctuation';
        }
        
        if (stream.match(constants)) {
            return 'atom';
        }
        
        if (stream.match(keywords)) {
            return 'keyword';
        }
        
        if (stream.match(identifiers)) {
            return 'variable';
        }
        
        // Handle non-detected items
        stream.next();
        return ERRORCLASS;
    }
    
    function tokenFactory(delimiter, outclass) {
        var delim_re = new RegExp(delimiter);
        var singleline = delimiter.length == 1;
        
        return function tokenString(stream, state) {
            while (!stream.eol()) {
                stream.eatWhile(/[^'"\/\\]/);
                if (stream.eat('\\')) {
                    stream.next();
                    if (singleline && stream.eol()) {
                        return outclass;
                    }
                } else if (stream.match(delim_re)) {
                    state.tokenize = tokenBase;
                    return outclass;
                } else {
                    stream.eat(/['"\/]/);
                }
            }
            if (singleline) {
                if (conf.mode.singleLineStringErrors) {
                    outclass = ERRORCLASS
                } else {
                    state.tokenize = tokenBase;
                }
            }
            return outclass;
        };
    }
    
    function indent(stream, state, type) {
        type = type || 'coffee';
        var indentUnit = 0;
        if (type === 'coffee') {
            for (var i = 0; i < state.scopes.length; i++) {
                if (state.scopes[i].type === 'coffee') {
                    indentUnit = state.scopes[i].offset + conf.indentUnit;
                    break;
                }
            }
        } else {
            indentUnit = stream.column() + stream.current().length;
        }
        state.scopes.unshift({
            offset: indentUnit,
            type: type
        });
    }
    
    function dedent(stream, state) {
        if (state.scopes.length == 1) return;
        if (state.scopes[0].type === 'coffee') {
            var _indent = stream.indentation();
            var _indent_index = -1;
            for (var i = 0; i < state.scopes.length; ++i) {
                if (_indent === state.scopes[i].offset) {
                    _indent_index = i;
                    break;
                }
            }
            if (_indent_index === -1) {
                return true;
            }
            while (state.scopes[0].offset !== _indent) {
                state.scopes.shift();
            }
            return false
        } else {
            state.scopes.shift();
            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 (style === 'variable') {
                return 'variable';
            } else {
                return ERRORCLASS;
            }
        }
        
        // Handle properties
        if (current === '@') {
            style = state.tokenize(stream, state);
            current = stream.current();
            if (style === 'variable') {
                return 'variable-2';
            } else {
                return ERRORCLASS;
            }
        }
        
        // Handle scope changes.
        if (current === 'return') {
            state.dedent += 1;
        }
        if (((current === '->' || current === '=>') &&
                  !state.lambda &&
                  state.scopes[0].type == 'coffee' &&
                  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) {
            if (dedent(stream, state)) {
                return ERRORCLASS;
            }
        }
        if (state.dedent > 0 && stream.eol() && state.scopes[0].type == 'coffee') {
            if (state.scopes.length > 1) state.scopes.shift();
            state.dedent -= 1;
        }
        
        return style;
    }

    var external = {
        startState: function(basecolumn) {
            return {
              tokenize: tokenBase,
              scopes: [{offset:basecolumn || 0, type:'coffee'}],
              lastToken: null,
              lambda: false,
              dedent: 0
          };
        },
        
        token: function(stream, state) {
            var style = tokenLexer(stream, state);
            
            state.lastToken = {style:style, content: stream.current()};
            
            if (stream.eol() && stream.lambda) {
                state.lambda = false;
            }
            
            return style;
        },
        
        indent: function(state, textAfter) {
            if (state.tokenize != tokenBase) {
                return 0;
            }
            
            return state.scopes[0].offset;
        }
        
    };
    return external;
});

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