// Copyright (c) 2012 Henning Kiel
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of
// this software and associated documentation files (the "Software"), to deal in
// the Software without restriction, including without limitation the rights to
// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
// the Software, and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:

// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

CodeMirror.defineMode("liquid", function(config, parserConfig) {
  function chain(stream, state, f) {
    state.tokenize = f;
    return f(stream, state);
  }

  // Used as scratch variables to communicate multiple values without
  // consing up tons of objects.
  var type, content;
  function ret(tp, style, cont) {
    type = tp; content = cont;
    return style;
  }

  function liquidTokenBase(stream, state) {
    var ch = stream.next();
    if (/[\s]/.test(ch)) {
      return ret("whitespace", "liquid-whitespace");
    }
    else if (state.liquidMode == "output-markup" && ch == '}' && stream.eat('}')) {
      state.tokenize = nonLiquid;
      return ret("}}");
    }
    else if (state.liquidMode == "tag-markup" && ch == '%' && stream.eat('}')) {
      state.tokenize = nonLiquid;
      return ret("%}");
    }
    else if (ch == '"' || ch == "'")
      return chain(stream, state, liquidTokenString(ch));
    else if (/[\.,:\|\[\]]/.test(ch))
      return ret(ch);
    else if (/\d/.test(ch)) {
      stream.match(/^\d*(?:\.\d*)?/);
      return ret("number", "liquid-atom");
    }
    else {
      stream.eatWhile(/[\w_?<>=]/);
      var word = stream.current();
      return ret("word", "liquid-word", word);
    }

  }

  function liquidTokenString(quote) {
    return function(stream, state) {
      if (!nextUntilUnescaped(stream, quote))
        state.tokenize = liquidTokenBase;
      return ret("string", "liquid-string");
    };
  }

  function nextUntilUnescaped(stream, end) {
    var escaped = false, next;
    while ((next = stream.next()) != null) {
      if (next == end && !escaped)
        return false;
      // Liquid does not seem to have string quote escaping
      escaped = !escaped && next == "abc";
    }
    return escaped;
  }

  function nonLiquid(stream, state) {
    var ch = stream.next();
    state.liquidMode = null;
    if (ch == '{') {
      if (stream.eat('%')) {
        state.tokenize = liquidTokenBase;
        state.liquidMode = "tag-markup";
        return ret("{%", "liquid-markup-delimiter");
      }
      else if (stream.eat('{')) {
        state.tokenize = liquidTokenBase;
        state.liquidMode = "output-markup";
        return ret("{{", "liquid-markup-delimiter");
      }
    }
    stream.eatWhile(/[^{]/);
    return null;
  }


  function parseLiquid(state, type, content, stream) {
    var cc = state.cc;
    // Communicate our context to the combinators.
    // (Less wasteful than consing up a hundred closures on every call.)
    cx.state = state; cx.stream = stream; cx.marked = null, cx.cc = cc;

    while(true) {
      var combinator = cc.length ? cc.pop() : liquidMarkup;
      if (combinator(type, content)) {
        // Immediately work off any autocompletion objects on the stack
        while(cc.length && cc[cc.length - 1].ac)
          cc.pop()();

        if (cx.marked) return cx.marked;
        return null;
      }
    }
  }

  // Combinator utils

  var cx = {state: null, column: null, marked: null, cc: null};
  function pass() {
    for (var i = arguments.length - 1; i >= 0; i--) cx.cc.push(arguments[i]);
  }
  function cont() {
    pass.apply(null, arguments);
    return true;
  }

  // Combinators

  function expect(wanted, marker, wantedValue) {
    return function expecting(type, value) {
      if (type == wanted && (typeof(value) == "undefined" || value == wantedValue)) {
        if (typeof(marker) == 'string') cx.marked = marker;
        return cont();
      }
      else return cont(arguments.callee);
    };
  }

  function markAc(type) {
    var result = function() {
      var state = cx.state;
      state.ac = type;
      pass(unmarkAc);
    };
    result.ac = true;

    return result;
  }

  function unmarkAc() {
    cx.state.ac = null;
  }

  function liquidMarkup(type) {
    if (type == "{{") return cont(markAc('variable'), expression, maybeFilters, expect("}}", "liquid-markup-delimiter"));
    if (type == "{%") return cont(markAc('tag'), tagName, expect("%}", "liquid-markup-delimiter"));
    return cont();
  }

  var endTag = /^end[\w]+$/;
  var zeroArgTags = {"live": true, "footer": true, "comment": true};

  function tagName(type, value) {
    if (type == "word") {
      if (endTag.test(value)) {
        cx.marked = "liquid-endtag-name";
      }
      else {
        cx.marked = "liquid-tag-name";
        if (value == "include") return cont(expression, maybeIncludeArgs);
        if (value == "cycle") return cont(maybeCycleName, commasep(expression, "%}", true));
        if (value == "if" || value == "unless") return cont(markAc('variable'), expression, maybeOperator);
        if (value == "capture") return cont(expression);
        if (value == "for") return cont(expression, expect("word", "liquid-keyword", "in"), markAc('variable'), expression, maybeForArgs);
        if (value == "assign") return cont(expression, expect('word', "liquid-operator", "="), markAc('variable'), expression);
        if (zeroArgTags.hasOwnProperty(value)) return cont();
      }
    }
    return cont();
  }

  function maybeForArgs(type, value) {
    if (type == 'word' && value == 'reversed') {
      cx.marked = "liquid-keyword";
      return cont(maybeTagAttributes);
    }
    return pass(maybeTagAttributes);
  }

  function maybeTagAttributes(type) {
    if (type == "word") {
      cx.marked = "liquid-tag-attribute-name";
      return cont(expect(":"), expression, maybeTagAttributes);
    }
    return pass();
  }

  function expression(type) {
    if (type == 'word') {
      cx.marked = "liquid-variable";
      return cont(maybeMethod);
    }
    return cont();
  }

  function maybeMethod(type) {
    if (type == '.') return cont(markAc('method'), method, maybeMethod);
    if (type == '[') return cont(expression, expect(']'), maybeMethod);
    return pass();
  }

  function method(type) {
    if (type == 'word') {
      cx.marked = "liquid-method";
    }
    return cont();
  }

  var operators = {"<": true, ">": true, "<=": true, ">=": true, "==": true, "contains": true, "and": true, "or": true};

  function maybeOperator(type, value) {
    if (operators.hasOwnProperty(value)) {
      cx.marked = "liquid-operator";
      return cont(markAc('variable'), expression, maybeOperator);
    }
    return pass();
  }

  function maybeCycleName() {
    // Liquid's cycle interprets its first argument as the cycle name if it is follow by a :.
    // In order to separate between a non-name variable argument and the name argument, we
    // do a look-ahead here.
    // If we find a : after our current position, the current expression is the cycle name.
    if (cx.stream.match(/\s*:/, false)) {
      cx.stream.match(/\s*/);
      cx.marked = "liquid-tag-cycle-name";
      return cont(expect(':'));
    }
    return pass();
  }

  function maybeIncludeArgs(type, value) {
    if (type == 'word') {
      if (value == 'for' || value == 'with') {
        cx.marked = "liquid-keyword";
        return cont(expression);
      }
    }
    return pass();
  }

  function maybeFilters(type) {
    if (type == '|') return cont(markAc('filter'), filterName, maybeFilterArgs, maybeFilters);
    return pass();
  }

  function filterName() {
    cx.marked = "liquid-filter";
    return cont();
  }

  function maybeFilterArgs(type) {
    if (type == ':') return cont(commasep(expression, {"}}": true, "|": true}, true));
    return pass(maybeFilters);
  }

  function commasep(what, end, doNotEat) {
    function checkForEnd(type) {
      return (typeof(end) == "string" && type == end) || (typeof(end) == "object" && end.hasOwnProperty(type));
    }
    function proceed(type) {
      if (type == ",") return cont(what, proceed);
      if (checkForEnd(type)) return doNotEat ? pass() : cont();
      return cont(expect(end));
    }
    return function commaSeparated(type) {
      if (checkForEnd(type)) return doNotEat ? pass() : cont();
      else return pass(what, proceed);
    };
  }

  return {
    startState: function() {
      return {
        tokenize: nonLiquid,
        cc: [],
        liquidMode: null,
        ac: null
      }
    },

    resetState: function(state) {
      state.tokenize = nonLiquid;
      state.cc = [];
      state.liquidMode = null;
      state.ac = null;
      return state;
    },

    token: function(stream, state) {
      type = null;

      // Liquid markup cannot span multiple lines
      if (stream.sol()) this.resetState(state);

      var style = state.tokenize(stream, state);

      // If we have found liquid markup, we always set some common CSS classes, so we can make use
      // of the style cascade.
      if (state.liquidMode != null) {
        style = (style || "") + " liquid liquid-" + state.liquidMode;
      }

      // No parsing necessary for white space inside liquid markup or when did not detect any liquid markup.
      if (type == "whitespace" || type == null) return style;

      var parseType = parseLiquid(state, type, content, stream);

      return (style || "") + " " + (parseType || "");
    }
  };
});
CodeMirror.defineMIME("application/x-liquid-template", "liquid");

CodeMirror.defineMode("htmlmixedliquid", function(config, parserConfig) {
  return CodeMirror.overlayParser(CodeMirror.getMode(config, parserConfig.backdrop || "text/html"), CodeMirror.getMode(config, parserConfig.overlay || "application/x-liquid-template"));
});

// Compatibility with CodeMirror's formatting addon
if (CodeMirror.modeExtensions){
  CodeMirror.modeExtensions["htmlmixedliquid"] = CodeMirror.modeExtensions["htmlmixed"];

  // If the current mode is 'htmlmixed', returns the extension of a mode located at
  // the specified position (can be htmlmixed, css or javascript). Otherwise, simply
  // returns the extension of the editor's current mode.
  CodeMirror.defineExtension("getModeExtAtPos", function (pos) {
    var token = this.getTokenAt(pos);
    if (token && token.state && token.state.mode)
      return CodeMirror.modeExtensions[token.state.mode == "html" ? "htmlmixed" : token.state.mode];
    else
      if (token && token.state && token.state.base && token.state.base.mode)
        return CodeMirror.modeExtensions[token.state.base.mode == "html" ? "htmlmixed" : token.state.base.mode];
      else
        return this.getModeExt();
  });

}

CodeMirror.defineExtension("commentRangeLiquid", function (isComment, from, to) {
  var curMode = this.getModeExtAtPos(this.getCursor());
  if (isComment) { // Comment range
    var commentedText = this.getRange(from, to);
    this.replaceRange("{% comment %}" + this.getRange(from, to) + "{% endcomment %}"
      , from, to);
    if (from.line == to.line && from.ch == to.ch) { // An empty comment inserted - put cursor inside
      this.setCursor(from.line, from.ch + "{% comment %}".length);
    }
  }
  else { // Uncomment range
    var selText = this.getRange(from, to);
    var startIndex = selText.indexOf("{% comment %}");
    var endIndex = selText.lastIndexOf("{% endcomment %}");
    if (startIndex > -1 && endIndex > -1 && endIndex > startIndex) {
      // Take string till comment start
      selText = selText.substr(0, startIndex)
      // From comment start till comment end
        + selText.substring(startIndex + "{% comment %}".length, endIndex)
      // From comment end till string end
        + selText.substr(endIndex + "{% endcomment %}".length);
    }
    this.replaceRange(selText, from, to);
  }
});
