Searcher = function(data) {

this.data = data;
this.handlers = [];

}

Searcher.prototype = new function() {

// search is performed in chunks of 1000 for non-blocking user input
var CHUNK_SIZE = 1000;
// do not try to find more than 100 results
var MAX_RESULTS = 100;
var huid = 1;
var suid = 1;
var runs = 0;

this.find = function(query) {
  var queries = splitQuery(query);
  var regexps = buildRegexps(queries);
  var highlighters = buildHilighters(queries);
  var state = { from: 0, pass: 0, limit: MAX_RESULTS, n: suid++};
  var _this = this;

  this.currentSuid = state.n;

  if (!query) return;

  var run = function() {
    // stop current search thread if new search started
    if (state.n != _this.currentSuid) return;

    var results =
      performSearch(_this.data, regexps, queries, highlighters, state);
    var hasMore = (state.limit > 0 && state.pass < 4);

    triggerResults.call(_this, results, !hasMore);
    if (hasMore) {
      setTimeout(run, 2);
    }
    runs++;
  };
  runs = 0;

  // start search thread
  run();
}

    ----- Events ------    
this.ready = function(fn) {
  fn.huid = huid;
  this.handlers.push(fn);
}

    ----- Utilities ------    
function splitQuery(query) {
  return jQuery.grep(query.split(/(\s+|::?|\(\)?)/), function(string) {
    return string.match(/\S/)
  });
}

function buildRegexps(queries) {
  return jQuery.map(queries, function(query) {
    return new RegExp(query.replace(/(.)/g, '([$1])([^$1]*?)'), 'i')
  });
}

function buildHilighters(queries) {
  return jQuery.map(queries, function(query) {
    return jQuery.map(query.split(''), function(l, i) {
      return '\u0001$' + (i*2+1) + '\u0002$' + (i*2+2);
    }).join('');
  });
}

// function longMatchRegexp(index, longIndex, regexps) {
//     for (var i = regexps.length - 1; i >= 0; i--){
//         if (!index.match(regexps[i]) && !longIndex.match(regexps[i])) return false;
//     };
//     return true;
// }

/*  ----- Mathchers ------  */

/*
   This record matches if the index starts with queries[0] and the record
   matches all of the regexps
  /
function matchPassBeginning(index, longIndex, queries, regexps) {
  if (index.indexOf(queries[0]) != 0) return false;
  for (var i=1, l = regexps.length; i < l; i++) {
    if (!index.match(regexps[i]) && !longIndex.match(regexps[i]))
      return false;
  };
  return true;
}

/*
   This record matches if the longIndex starts with queries[0] and the
   longIndex matches all of the regexps
  /
function matchPassLongIndex(index, longIndex, queries, regexps) {
  if (longIndex.indexOf(queries[0]) != 0) return false;
  for (var i=1, l = regexps.length; i < l; i++) {
    if (!longIndex.match(regexps[i]))
      return false;
  };
  return true;
}

/*
   This record matches if the index contains queries[0] and the record
   matches all of the regexps
  /
function matchPassContains(index, longIndex, queries, regexps) {
  if (index.indexOf(queries[0]) == -1) return false;
  for (var i=1, l = regexps.length; i < l; i++) {
    if (!index.match(regexps[i]) && !longIndex.match(regexps[i]))
      return false;
  };
  return true;
}

/*
   This record matches if regexps[0] matches the index and the record
   matches all of the regexps
  /
function matchPassRegexp(index, longIndex, queries, regexps) {
  if (!index.match(regexps[0])) return false;
  for (var i=1, l = regexps.length; i < l; i++) {
    if (!index.match(regexps[i]) && !longIndex.match(regexps[i]))
      return false;
  };
  return true;
}

/*  ----- Highlighters ------  */
function highlightRegexp(info, queries, regexps, highlighters) {
  var result = createResult(info);
  for (var i=0, l = regexps.length; i < l; i++) {
    result.title = result.title.replace(regexps[i], highlighters[i]);
    result.namespace = result.namespace.replace(regexps[i], highlighters[i]);
  };
  return result;
}

function hltSubstring(string, pos, length) {
  return string.substring(0, pos) + '\u0001' + string.substring(pos, pos + length) + '\u0002' + string.substring(pos + length);
}

function highlightQuery(info, queries, regexps, highlighters) {
  var result = createResult(info);
  var pos = 0;
  var lcTitle = result.title.toLowerCase();

  pos = lcTitle.indexOf(queries[0]);
  if (pos != -1) {
    result.title = hltSubstring(result.title, pos, queries[0].length);
  }

  result.namespace = result.namespace.replace(regexps[0], highlighters[0]);
  for (var i=1, l = regexps.length; i < l; i++) {
    result.title = result.title.replace(regexps[i], highlighters[i]);
    result.namespace = result.namespace.replace(regexps[i], highlighters[i]);
  };
  return result;
}

function createResult(info) {
  var result = {};
  result.title = info[0];
  result.namespace = info[1];
  result.path = info[2];
  result.params = info[3];
  result.snippet = info[4];
  return result;
}

/*  ----- Searching ------  */
function performSearch(data, regexps, queries, highlighters, state) {
  var searchIndex = data.searchIndex;
  var longSearchIndex = data.longSearchIndex;
  var info = data.info;
  var result = [];
  var i = state.from;
  var l = searchIndex.length;
  var togo = CHUNK_SIZE;
  var matchFunc, hltFunc;

  while (state.pass < 4 && state.limit > 0 && togo > 0) {
    if (state.pass == 0) {
      matchFunc = matchPassBeginning;
      hltFunc = highlightQuery;
    } else if (state.pass == 1) {
      matchFunc = matchPassLongIndex;
      hltFunc = highlightQuery;
    } else if (state.pass == 2) {
      matchFunc = matchPassContains;
      hltFunc = highlightQuery;
    } else if (state.pass == 3) {
      matchFunc = matchPassRegexp;
      hltFunc = highlightRegexp;
    }

    for (; togo > 0 && i < l && state.limit > 0; i++, togo--) {
      if (info[i].n == state.n) continue;
      if (matchFunc(searchIndex[i], longSearchIndex[i], queries, regexps)) {
        info[i].n = state.n;
        result.push(hltFunc(info[i], queries, regexps, highlighters));
        state.limit--;
      }
    };
    if (searchIndex.length <= i) {
      state.pass++;
      i = state.from = 0;
    } else {
      state.from = i;
    }
  }
  return result;
}

function triggerResults(results, isLast) {
  jQuery.each(this.handlers, function(i, fn) {
    fn.call(this, results, isLast)
  })
}

}